Report 103

Desalination and Water Purification Research and Development
Report No. 103

Optimization of Various MBR
Systems for Water Reclamation
Phase III
The City of San Diego Water Department
Montgomery Watson Harza
Agreement No. 01-FC-81-0736
U.S. Department of the Interior
Bureau of Reclamation
Technical Service Center
Denver, Colorado April 2004
REPORT DOCUMENTATION PAGE
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1. AGENCY USE ONLY (Leave Blank) 2. REPORT DATE
May 2004
3. REPORT TYPE AND DATES COVERED
FinalApril 2002 to April 2004
4. TITLE AND SUBTITLE
OPTIMIZATION OF VARIOUS MBR SYSTEMS FOR WATER RECLAMATION PHASE III
FINAL TECHNICAL REPORT
5. FUNDING NUMBERS
Agreement No.
01-FC-81-0736
6. AUTHOR(S)
Samer Adham, Ph.D.
James F. DeCarolis
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
600 B Street Suite 700 MS 907
San Diego, CA 92101-4587
8. PERFORMING ORGANIZATION
REPORT NUMBER
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
Denver Federal Center
P.O. Box 25007
Denver, CO 80225-0007
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
DWPR No. 103
11. SUPPLEMENTARY NOTES
Desalination and Water Purification Research and Development (DWPR) Program
12a. DISTRIBUTION/AVAILABILITY STATEMENT
Available from the National Technical Information Service, Operations Division,
5285 Port Royal Road, Springfield, Virginia 22161
12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum 200 words)
This project evaluated the performance of MBR systems from four leading suppliers including US Filter Corporation/Jet Tech
Products Group, Zenon Environmental Inc., Ionics/Mitsubishi Rayon Corporation, and Enviroquip Inc./Kubota Corporation during
reclamation of municipal wastewater. During pilot testing, the affect of various operating conditions including feed wastewater
source (e.g. raw or advanced primary effluent) flux, HRT, and SRT on MBR performance was evaluated. In addition, latest
generation RO membranes from two leading suppliers (Saehan Industries Inc. and Hydranautics) were tested during operation on
MBR effluent as a final polishing step for salt removal. Lastly, a cost analysis was performed to determine capital and O&M costs
associated with MBR water reclamation facilities ranging in capacity from 0.2-10 MGD.
Results from this study showed that each MBR system operated successful on advanced primary effluent wastewater containing
polymer and coagulant. This finding is significant as it increases the number of suppliers and feed water sources municipalities
can choose to meet reclamation needs using the MBR process. In addition, each MBR achieved excellent removal of particulate
(effluent turbidity <0.1 NTU), organic (effluent BOD5<2 mg/L) and microbial contaminates (total and fecal coliform LRV 4-6). In
addition, valuable cost information was generated showing a significant cost savings for MBR systems designed to operate on
advanced primary effluent as opposed to raw sewage.
.
14. SUBJECT TERMSMembrane Bioreactor
15. NUMBER OF PAGES
58 in Main Report
119 in Appendices
16. PRICE CODE
17. SECURITY CLASSIFICATION
OF REPORT
UL
OF THIS PAGE
UL
OF ABSTRACT
UL
20. LIMITATION OF ABSTRACT
UL
NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)
Prescribed by ANSI Std. 239-18
298-102
Optimization of Various MBR
Systems for Water Reclamation
Phase III
Agreement No. 01-FC-81-0736
Desalination and Water Purification Research and Development
Program Final Report No. 103
600 B Street, Suite 700
San Diego, CA 92101
MWH
301 N. Lake Ave, Suite 600
Pasadena, CA 91101
Samer Adham, Ph.D. (MWH)
James F. DeCarolis (MWH)
William Pearce (City of San Diego)
U.S. Department of the Interior
Technical Service Center
Environmental Resources Team
Water Treatment Engineering and Research Group
Denver, Colorado April 2004
i
Acknowledgements
The authors would like to extend their greatest appreciation to:
City of San Diego, Water Department & Metropolitan Wastewater Department (MWWD)
William Pearce, and Larry Wassermann for oversight and project coordination.
Steve Lagos, Neil Tran, Milan Karas and Dwight Smith for support with pilot operation, data
management, and project organization.
Point Loma Satellite Laboratory
Brent Bowman, Miles Slattery, Julie Webb, Enrique Blanco, Eric Becker, Patricia Ortega,
Maricella Coronel and Greg Schlimne for performing the majority of the water quality analysis
required during the study.
City of San Diego Marine Microbiology Laboratory
Laila Othman, Roxane Davis, Sonji Romero, George Alfonso, and Joseph Toctocan for
performing all microbial analysis conducted during this study.
Point Loma Wastewater Treatment Plant
Joe Cordova, Jim Linsday, K.C. Shankles and Jim Golden for their cooperation and support
throughout the study and staff of the electrical, maintenance, operations, engineering and
warehouse sections for their services during pilot testing.
Participating Vendors
MBR: US Filter Corporation/Jet Tech Products Group, Zenon Environmental, Inc., Ionics/
Mitsubishi Rayon Corporation, Enviroquip Inc./Kubota Corporation.
Screening: Waste-Tech, Inc./Roto-Sieve.
RO: Saehan Industries Inc. and Hydranautics Corporation
UV: Aquionics, Inc.
MWH
Stephen Lacy for performing design calculations and cost estimates of full-scale MBR systems.
Jude Grounds for assisting in pilot operations, data management/analysis and report writing.
Brian Gallagher and Eric Bruce for pilot fabrication, assistance in pilot operations, and providing
technical advice.
Consultants
Rhodes Trussell, Ph.D. (Trussell Technologies, Inc.) for serving as a technical advisor
throughout the study.
Finally, the authors would like to thank the Bureau of Reclamation for their support in the
implementation of this project.
ii
Bureau of Reclamation Mission Statement
The mission of the Bureau of Reclamation is to manage, develop, and protect water and related
resources in an environmentally and economically sound manner in the interest of the American
public.
U.S. Department of the Interior Mission Statement
The mission of the Department of the Interior is to protect and provide access to our Nations
natural and cultural heritage and honor our trust responsibilities to tribes.
Disclaimer
Information contained in this report regarding commercial products or firms was supplied by
those firms. It may not be used for advertising or promotional purposes and is not to be
construed as an endorsement of any product or firm by the Bureau of Reclamation.
The information contained in this report was developed for the Bureau of Reclamation; no
warranty as to the accuracy, usefulness, or completeness is expressed or implied.
iii
Table of Contents
List of Tables .......................................................................................................................... vi
List of Figures........................................................................................................................ vii
Acronyms and Abbreviations .................................................................................................x
1. Executive Summary.............................................................................................................1
2. Introduction..........................................................................................................................3
2.1 Background.................................................................................................................3
2.2 Study Objectives ........................................................................................................5
3. Conclusions and Recommendations...................................................................................7
3.1 Operational Performance ............................................................................................7
3.1.1 MBR Systems .................................................................................................7
3.1.2 RO Membranes ...............................................................................................8
3.1.3 Screening.........................................................................................................8
3.2 Water Quality..............................................................................................................9
3.2.1 Particulate Removal ........................................................................................9
3.2.2 Organic Removal ............................................................................................9
3.2.3 Biological Nutrient Removal ..........................................................................9
3.2.4 Microbial Removal .........................................................................................9
3.3 CDHS Approval.....................................................................................................10
3.4 Costing Analysis ....................................................................................................10
3.5 Other Conclusions..................................................................................................10
3.6 Recommended Future Work..................................................................................11
4. Materials and Methods......................................................................................................13
4.1 Testing Site ...............................................................................................................13
4.2 Feed Water Quality Characteristics ..........................................................................13
4.3 Experimental Set-Up.................................................................................................13
4.3.1 Kubota MBR.................................................................................................14
4.3.2 US Filter MBR..............................................................................................14
4.3.3 Zenon MBR ..................................................................................................16
4.3.4 Mitsubishi MBR ...........................................................................................16
4.3.5 Screening Equipment ....................................................................................17
4.3.6 RO System....................................................................................................18
4.3.7 UV Pilot ........................................................................................................18
4.3.8 Determination of Calculated Parameters ......................................................19
4.3.9 Chemical Additions ......................................................................................25
4.3.10 Chemical Cleaning of Membranes..............................................................25
iv
4.4 Water Quality............................................................................................................26
4.4.1 On-site Water Quality Analyses ...................................................................26
4.4.2 Laboratory Water Quality Analyses .............................................................27
4.4.3 Sampling Protocol/Frequency.......................................................................27
4.4.4 Quality Assurance/Quality Control...............................................................27
5. Results and Discussion Phase-I: Operation of New MBR Systems..........................29
5.1 MBR Operating Conditions Phase I (Part 1) .........................................................29
5.2 MBR Operating Conditions Phase I (Part 2) .........................................................30
5.3 Membrane Performance.........................................................................................31
5.3.1 MBR Pilot Plants ..........................................................................................31
5.3.2 RO Pilot Unit ................................................................................................32
5.4 Water Quality............................................................................................................33
5.4.1 Raw Wastewater ...........................................................................................33
5.4.2 Advanced Primary Effluent ..........................................................................33
5.4.3 MBR Pilot Systems.......................................................................................33
5.4.4 RO Pilot Unit ................................................................................................35
6. Results and Discussion- Phase II: Optimization of MBR Systems................................37
6.1 MBR Operating Conditions ......................................................................................37
6.2 Membrane Performance............................................................................................38
6.2.1 MBR Pilot Plants ..........................................................................................38
6.3 Water Quality............................................................................................................40
6.3.1 Advanced Primary Effluent ..........................................................................40
6.3.2 MBR Pilot Systems.......................................................................................40
7. Title 22 Approval of MBR Systems..................................................................................43
7.1 Zenon and Mitsubishi ...............................................................................................43
7.2 Kubota and US Filter ................................................................................................43
8. MBR Performance Comparison.......................................................................................45
8.1 MBR Operating Experience......................................................................................45
8.1.1 US Filter MBR System.................................................................................45
8.1.2 Kubota MBR System....................................................................................45
8.1.3 Zenon MBR System......................................................................................45
8.1.4 Mitsubishi MBR System...............................................................................46
8.2 Operating Conditions................................................................................................46
8.2.1 Flux, HRT, SRT and MLSS..........................................................................46
8.2.2 Frequent Relaxation/Backpulsing.................................................................46
8.2.3 Air Usage (Membrane Scour and Biological Requirements) .......................46
8.2.4 Membrane Cleaning......................................................................................47
8.3 Membrane Performance............................................................................................47
8.4 MBR Effluent Water Quality (Phase I, Part 1: Kubota and US Filter).....................48
8.4.1 Particulate Removal ......................................................................................48
8.4.2 Organics Removal.........................................................................................48
8.4.3 Biological Nutrient Removal ........................................................................48
8.4.4 Total Coliform, Fecal Coliform, Total Coliphage Removal.........................49
v
8.5 MBR Effluent Water Quality (Phase II: Zenon and Mitsubishi)..............................49
8.5.1 Particulate Removal ......................................................................................49
8.5.2 Organic Removal ..........................................................................................49
8.5.3 Biological Nutrient Removal ........................................................................49
8.5.4 Total Coliform, Fecal Coliform, Total Coliphage Removal.........................49
9. Cost Analysis ......................................................................................................................51
9.1 Costing Approach .....................................................................................................51
9.2 Operation on Raw Wastewater .................................................................................52
9.2.1 Design Criteria..............................................................................................52
9.2.2 Capital Costs .................................................................................................53
9.2.3 Operation and Maintenance Costs ................................................................53
9.2.4 Total Costs ....................................................................................................54
9.3 Consideration of Advanced Primary Treatment .......................................................54
9.3.1 Design Criteria..............................................................................................54
9.3.2 Capital Costs .................................................................................................55
9.3.3 Operation and Maintenance Costs ................................................................55
9.3.4 Total Costs ....................................................................................................56
9.4 Economy of Scale Analysis ......................................................................................56
Reference List ..........................................................................................................................57
Appendix A: Tables and Figures .......................................................................................... A-1
Appendix B: Membrane Cleaning Protocols .........................................................................B-1
Appendix C: QA/QC Memorandum......................................................................................C-1
Appendix D: Photographs of Pilot Equipment ..................................................................... D-1
Appendix E: Kubota MBR Title 22 Approval Letter ............................................................E-1
Appendix F: Additional Cost Information............................................................................. F-1
vi
List of Tables
Table 4-1: Specifications for the MBR Membranes............................................................. A-2
Table 4-2: Specifications for the RO Membranes ................................................................ A-2
Table 4-3: Specifications for the Aquionics UV Pilot .......................................................... A-2
Table 4-4: Analytical Methods / Detection Limits for Measured Water Quality
Parameters........................................................................................................... A-3
Table 5-1: Raw Wastewater Quality Data During Phase I (Part 1) ...................................... A-4
Table 5-2: Advanced Primary Effluent Wastewater Quality Data During Phase I (Part 2) . A-4
Table 5-3: US Filter MBR Permeate Water Quality Data During Phase I (Part 1) .............. A-5
Table 5-4: US Filter MBR Permeate Water Quality Data During Phase I (Part 2) .............. A-5
Table 5-5: Kubota MBR Permeate Water Quality Data During Phase I (Part 1) ................. A-6
Table 5-6: Kubota MBR Permeate Water Quality Data During Phase I (Part 2) ................. A-6
Table 5-7: Saehan RO Permeate Water Quality Data During Phase I.................................. A-7
Table 5-8: Hydranautics RO Permeate Water Quality Data During Phase I........................ A-7
Table 6-1: Advanced Primary Effluent Wastewater Quality Data During Phase II ............. A-8
Table 6-2: Zenon MBR Permeate Water Quality Data During Phase II .............................. A-8
Table 6-3: Mitsubishi MBR Permeate Water Quality Data During Phase II ....................... A-9
Table 9-1: Capital Costs for Various Capacity MBR Systems Operating on
Raw Wastewater ............................................................................................... A-10
Table 9-2: O&M Costs for MBR Systems Operating on Raw Wastewater ....................... A-11
Table 9-3: Summary of Capital and O&M Costs Operating on Raw Wastewater ............. A-12
Table 9-4: Summary of Costs, $/Kgal Operating on Raw Wastewater .............................. A-12
Table 9-5: Capital Costs 1&5 Mgd MBR Operating on Advanced Primary Effluent........ A-13
Table 9-6: O&M Costs For MBRs Operating on Advanced Primary Effluent .................. A-14
Table 9-7: Summary of Capital and O&M Costs Operation on Advanced Primary
Effluent ............................................................................................................. A-14
Table 9-8: Summary of Costs, $/Kgal Operation on Advanced Primary Effluent ............. A-14
vii
List of Figures
Figure 4-1: Schematic Diagram of the Point Loma Advanced Wastewater
Treatment Plant................................................................................................ A-15.
Figure 4-2: Schematic Diagram of Pilot Treatment Train During Phase I
(Part 1 & Part 2)............................................................................................... A-16.
Figure 4-3: Schematic Diagram of Pilot Treatment Train During Phase II....................... A-17.
Figure 4-4: Kubota MBR: Side View (Top); Plan View (Bottom) ................................... A-18.
Figure 4-5: US Filter MBR: Side View (Top); Plan View (Bottom) ................................ A-19.
Figure 4-6: Zenon MBR: Side View (Top); Plan View (Bottom) ..................................... A-20.
Figure 4-7: Mitsubishi MBR: Side View (Top); Plan View (Bottom) .............................. A-21.
Figure 5-1: HRT and SRT
7-day
for the US Filter MBR..................................................... A-22.
Figure 5-2: Mixed Liquor Solids for the US Filter MBR.................................................. A-23.
Figure 5-3: DO Concentration in the US Filter MBR........................................................ A-24.
7-day
for the Kubota MBR........................................................ A-25.
Figure 5-5: DO Concentration in the Kubota MBR........................................................... A-26.
Figure 5-6: Mixed Liquor Solids for the Kubota MBR..................................................... A-27.
Figure 5-7: Membrane Performance of the US Filter MBR.............................................. A-28.
Figure 5-8: Membrane Performance of the Kubota MBR................................................. A-29.
Figure 5-9: Saehan 4040 Bl RO Membrane Performance................................................. A-30.
Figure 5-10: Hydranautics Lfc3 RO Membrane Performance .......................................... A-31.
Figure 5-11: Turbidity Removal by the US Filter MBR.................................................... A-32.
Figure 5-12: Turbidity Removal by the Kubota MBR....................................................... A-32.
Figure 5-13: Organic Removal by the US Filter MBR...................................................... A-33.
Figure 5-14: Organic Removal by the Kubota MBR......................................................... A-34.
Figure 5-15: Inorganic Nitrogen Removal by the US Filter MBR.................................... A-35.
Figure 5-16: Inorganic Nitrogen Removal by the Kubota MBR....................................... A-36.
Figure 5-17: Ortho-Phosphate Removal by the US Filter MBR........................................ A-37.
Figure 5-18: Ortho-Phosphate Removal by the Kubota MBR........................................... A-37.
Figure 5-19: Coliform and Coliphage Removal by the US Filter MBR............................ A-38.
Figure 5-20: Coliform and Coliphage Removal by the Kubota MBR............................... A-39.
Figure 5-21: Inorganic Nitrogen Removal by the Saehan 4040 Bl RO Membrane........... A-40.
Figure 5-22: Ortho-Phosphate Removal by the Saehan 4040 Bl RO Membrane.............. A-41.
Figure 5-23: Inorganic Nitrogen Removal by the Hydranautics LFC3 Ro Membrane ..... A-42.
Figure 5-24: Ortho-Phosphate Removal by the Hydranautics LFC3 Ro Membrane......... A-43.
Figure 5-25: Conductivity Profile across the Saehan 4040 Bl Ro Membrane................... A-44.
Figure 5-26: Conductivity Profile across the Hydranautics LFC3 Ro Membrane ............ A-44.
7-day
for the Zenon MBR........................................................... A-45.
Figure 6-2: Mixed Liquor Solids Concentration for the Zenon MBR............................... A-46.
Figure 6-3: Do Concentrations in the Zenon MBR ........................................................... A-47.
Figure 6-4: HRT and SRT7-day for the Mitsubishi MBR................................................. A-48.
Figure 6-5: Mixed Liquor Solids Concentration for the Mitsubishi MBR........................ A-49.
Figure 6-6: Air Flow to the Mitsubishi MBR.................................................................... A-50.
viii
Figure 6-7: Do Concentrations in the Mitsubishi MBR..................................................... A-50.
Figure 6-8: Membrane Performance of the Zenon MBR................................................... A-51.
Figure 6-9: Membrane Performance of the Mitsubishi MBR............................................ A-52.
Figure 6-10: Turbidity Removal by the Zenon MBR........................................................ A-53.
Figure 6-11: Turbidity Removal by the Mitsubishi MBR................................................. A-53.
Figure 6-12: Organics Removal by the Zenon MBR......................................................... A-54.
Figure 6-13: Organics Removal by the Mitsubishi MBR.................................................. A-55.
Figure 6-14: Inorganic Nitrogen Species in the Zenon MBR............................................ A-56.
Figure 6-15: Ortho-Phosphate Removal by the Zenon MBR............................................ A-57.
Figure 6-16: Inorganic Nitrogen Species in Mitsubishi MBR........................................... A-58.
Figure 6-17: Ortho-Phosphate Removal by the Mitsubishi MBR..................................... A-59.
Figure 6-18: Coliform and Coliphage Removal by the Zenon MBR ................................ A-60.
Figure 6-19: Coliform and Coliphage Removal by the Mitsubishi MBR ......................... A-61.
Figure 8-1: Probability Plot of Turbidity Removal by MBR Systems
During Phase I (Part 1) .................................................................................... A-62.
Figure 8-2 Probability Plot of BOD5 Removal by MBR Systems
Figure 8-3 Probability Plot of TOC Removal by MBR Systems
Figure 8-4 Probability Plot of Ammonia Removal by MBR Systems
Figure 8-5 Probability Plot of Phosphate Removal by MBR Systems
Figure 8-6 Probability Plot of Total Coliform Removal by MBRs
Figure 8-7 Probability Plot of Fecal Coliform Removal by MBRs
Figure 8-8 Probability Plot of The Total Coliphage Removal by MBRs
Figure 8-9 Probability Plot of The Turbidity Removal by MBRs
During Phase II ................................................................................................ A-70.
Figure 8-10 Probability Plot of BOD5 Removal by MBR Systems
During Phase II ................................................................................................ A-71.
Figure 8-11 Probability Plot of TOC Removal by MBR Pilot Systems
During Phase II ................................................................................................ A-72.
Figure 8-12 Probability Plot of Ammonia Removal by MBR Systems
During Phase II ................................................................................................ A-73.
Figure 8-13 Probability Plot of Ortho-Phosphate Removal by MBR Systems
During Phase II ................................................................................................ A-74.
Figure 8-14 Probability Plot of Total Coliform Removal by MBR Systems
During Phase II ................................................................................................ A-75.
Figure 8-15 Probability Plot of Fecal Coliform Removal by MBR Systems
During Phase II ................................................................................................ A-76.
Figure 8-16 Probability Plot of Total Coliphage Removal by MBR Systems
During Phase II ................................................................................................ A-77.
Figure 9-1 Outline of Costing Approach ........................................................................... A-78.
ix
Figure 9-2 MBR Reclaimed Water Schematic: Forward Flow (Top);
Recycled Flow (Bottom).................................................................................. A-79.
Figure 9-3: Total Costs of Various Capacity MBR Systems Operating on
Raw Wastewater .............................................................................................. A-80.
Figure 9-4: Total Costs of 1& 5 mgd MBR Systems (Raw Wastewater /
Primary Effluent............................................................................................... A-80.
Figure 9-5: Economy of Scale Analysis for MBR Systems Operating
on Raw Wastewater .......................................................................................... A-81
x
Acronyms and Abbreviations
BOD biochemical oxygen demand
BOD
5
five-day biochemical oxygen demand
BP back pulse
cm centimeter
CAS conventional activated sludge
CDHS California Department of Health Services
CEL Calscience Environmental Laboratory
CIL cleaned in line
CIP cleaned in place
COD chemical oxygen demand
CSTR continuously stirred tank reactor
DO dissolved oxygen
DD double deck
EBPR enhanced biological phosphorus removal
EDC endocrine disrupting compounds
ENRCCI Engineering News-Record Construction Cost Index
F/M ratio food to microorganism ratio
ft
2
square foot
gfd gallons per square foot per day
g/L grams per liter
gpd gallons per day
gpm gallons per minute
hr hour
in inch
kg kilograms
L liter
L/hr-m2 liters per hour per square meter
L/min liters per minute
L/s liters per second
mJ/cm
2
millijules per square centimeter
m
2
square meter
m
3
cubic meter
m
3
/min cubic meter per minute
m
3
/day cubic meter per day
MBR membrane bioreactor
MF microfiltration
mg milligram
MGD million gallons per day
mg/L milligrams per liter
mg/L-N milligrams per liter as nitrogen
min minute
xi
mL milliliter
MLSS mixed liquor suspended solids
MLVSS mixed liquor volatile suspended solids
mm millimeter
MPN Most Probable Number
MWH Montgomery Watson Harza
NaOCl sodium hypochlorite
NCWRP North City Water Reclamation Plant
ND non-detect
NH
3
-N ammonia as nitrogen
NH
4
Cl ammonium chloride
NO
2
-N nitrite as nitrogen
NO
3
-N nitrate as nitrogen
NTU Nephelometric Turbidity Units
NWRI National Water Research Institute
O&M operations and maintenance
OOS out of service
PFU plaque forming units
PLC Programmable Logic Controller
PLWTP Point Loma Wastewater Treatment Plant
PL Lab Point Loma Laboratories
PO
4
-P Ortho-phosphate as phosphorus
PO
4
ortho phosphate
ppm parts per million
psi pounds per square inch
QA/QC quality assurance/quality control
RAS return activated sludge
Reclamation Bureau of Reclamation
RO reverse osmosis
RR recycle ratio
s seconds
scfm standard cubic feet per minute
SBWRP South Bay Water Reclamation Plant
SDI silt density index
TDS total dissolved solids
TFC thin film composite
TKN total Kjeldahl nitrogen
TOC total organic carbon
TP total phosphorus
TSS total suspended solids
UF ultrafiltration
UV
254
ultraviolet absorbance at 254 nanometer
UVT ultraviolet transmittance
VFD variable frequency drive
VSS volatile suspended solids
WAS waste-activated sludge
xii
Symbols
Net Osmotic Pressure of the Feed and Permeate
C Degrees Celsius
$K Thousands of Dollars
g Microgram
mhos Micromhos
m Micron
f Osmotic pressure of the feedstream (psi)
Calculated Parameters
HRT Hydraulic Retention Time (hours)
IAF Integrated Averaging Factor
J Membrane Flux (gfd)
J@20C Temperature Corrected Membrane Flux (gfd)
J
SP
Specific Flux (gfd/psi)
P
NET
Net Operating Pressure (psi)
Q
NET
Net Permeate Rate (gpm)
R Salt Rejection (%)
RR Recycle Ratio
SRT Sludge Retention Time (days)
SRT
7-day
Average Sludge Retention Time over 7 days
TMP Transmembrane Pressure (psi)
1
1. Executive Summary
Wastewater reclamation is gaining popularity worldwide as a means of conserving natural
resources used for drinking water supply. The use of membrane bioreactor (MBR) technology,
which combines conventional activated sludge treatment with low pressure membrane filtration,
has been proven to be a feasible and efficient method of producing reclaimed water. The
membrane component of the MBR process eliminates the need for a clarifier and is performed
using low-pressure membranes such as microfiltration (MF) or ultrafiltration (UF). MBR
technology offers several advantages to conventional wastewater treatment including reduced
footprint, consistent and superior effluent water quality and ease of operation. For many areas, it
is necessary to further treat reclaimed wastewater to reduce its inherent salinity making it useable
for irrigation and industrial use. The superior effluent water quality of the MBR process makes
it suitable for further treatment by reverse osmosis (RO) membranes as a final polishing step in
reducing the salinity of reclaimed water.
The City of San Diego and its research consultant, Montgomery Watson Harza, MWH, have
been evaluating the MBR process through various research projects since 1997 (Adham et al.,
1998, 2000, 2001). Previous research has primarily focused on the feasibility of using MBR
technology to produce reclaimed water. In 2001, the City of San Diego was awarded a
cooperative agreement by the Bureau of Reclamation to further evaluate the MBR technology for
its potential application to water reclamation. The main purpose of the study was to evaluate
several leading manufacturers in an effort to encourage competition within the MBR industry. In
addition, the study focused on optimizing MBR operation for water reclamation. Accordingly,
the project team performed a parallel comparison of four leading MBR suppliers including US
Filter Corporation/Jet Tech Products Group, Zenon Environmental, Inc., Ionics/Mitsubishi
Rayon Corporation, and Enviroquip Inc./Kubota Corporation.
The four MBR systems were evaluated at the pilot-scale level while operating on wastewater
from the Point Loma Wastewater Treatment Plant (PLWTP) located in San Diego, CA.
Phase I testing consisted of the operation of the Kubota and US Filter MBR systems on raw
wastewater for over 3,500 hours (146 days) and operation on advanced primary effluent for over
1,200 hours (50 days). During Phase II testing, the Zenon and Mitsubishi MBR systems were
operated on advanced primary effluent for over 4,000 hours (187 days). As part of Phase I
testing, effluent from the Kubota MBR system was further treated using reverse osmosis (RO)
membranes provided by two leading RO manufacturers. The RO membranes were operated for
over 1,700 hours (70 days) and 780 hours (32 days) with Kubota MBR effluent produced from
raw wastewater and advanced primary effluent, respectively. The RO pilot unit consisted of two
single pass trains, which were configured to allow operation at 50 percent recovery. Based on
results of this testing, the project team is confident that RO membranes operating on MBR
effluent could be successfully operated with a recovery between 75 percent to 90 percent which
is the typical operating range for brackish groundwater.
The MBR systems tested were evaluated for their ability to produce high quality effluent and to
operate with minimum fouling for a reasonable time between chemical cleanings. Furthermore,
2
operation was optimized by evaluating performance on various types of wastewater (raw and
advanced primary) and at different Hydraulic Retention Time (HRT) and flux rates. Overall the
four MBR systems were capable of operating on advanced primary effluent, containing
coagulant and polymer residual, with little fouling. In addition, each system successfully
removed organic biochemical oxygen demand (BOD) consistently below 2 milligrams per liter
[mg/L]), particulate (turbidity < 0.1 Nephelometric Turbidity Units [NTU]) and microbial
contaminants (up to 6 log removal of total and fecal coliform). Also each system consistently
achieved nitrification throughout the testing period with influent wastewater ammonia as
nitrogen (NH
3
-N) averaging 30 mg/L and MBR effluent ammonia <1 mg/L. Though it was not a
goal of this study, the Kubota MBR achieved denitrification by the inclusion of an anoxic zone,
which is a required portion of their system. It was also determined that it is feasible to operate
the MBR processes at flux rates exceeding 20 gallons per square foot per day (gfd) and HRT as
low as 2 hours. Lastly, effluent from the Kubota MBR, the only MBR tested upstream of RO,
was shown to be suitable feed water for different types of RO membranes tested.
Cost estimates were developed for full-scale MBR reclamation systems ranging from
0.2-10 million gallons per day (MGD). These estimates included both capital and operational
costs related to the MBR process and subsequent disinfection. The costs associated with the
membrane portion of the MBR systems were obtained from the four participating MBR
suppliers. All other costs including headworks, biological process and disinfection costs were
estimated from preliminary design calculations performed by MWH. Results of the cost analysis
($/1000 gal) revealed that 1-MGD MBR water reclamation systems, designed to operate on raw
wastewater, ranged from $1.81-$2.23. Cost estimates ($/1000 gal) for 1-million gallon (MGD)
MBR water reclamation systems designed to operate on advanced primary effluent ranged from
$1.57-$2.00.
3
2. Introduction
2.1 Background
Due to diminishing water supplies and increasing population, wastewater reclamation is
becoming necessary throughout the world to conserve natural water resources used for drinking
water supply. The membrane bioreactor (MBR) is a leading edge technology currently being
used in countries around the world for water reclamation. Due to advances in the technology and
declining costs, the application of MBR technology for water reclamation has increased sharply
over the past several years. With the rapid growth of MBR technology, it is important to address
the following issues: qualification of new suppliers, evaluation of operating parameters, and
refinement of full-scale MBR cost estimates.
Worldwide market research has identified the following suppliers to be established
manufacturers of MBR systems for the treatment of municipal and industrial wastewater: Zenon,
Mitsubishi, Suez-Lyonniase-des-Eaux, Kubota and X-flow (Adham et al., 1998; van der Roest et
al., 2002; WERF 2003). Of these suppliers, only two (Zenon and Mitsubishi) were established in
the US market at the onset of this study. However, several new MBR manufacturers have
recently entered the US market, which offer systems for the treatment of municipal wastewater.
The two most prominent new comers include US Filter/Jet Tech Products Group and the Kubota
Corporation. Both manufacturers provide systems, which have unique design innovations that
are different from the MBR systems currently established in the US market. For example, the
Kubota MBR uses flat sheet membranes rather than hollow fiber membranes for solid-liquid
separation while the US Filter MBR system uses a jet aeration process to mitigate membrane
fouling. Increasing the selection pool of MBR manufacturers in the US market is important
because choosing the best supplier often comes down to specific site requirements and/or
limitations (Wallis-Lage et al., 2003).
Some of the key operating parameters, which effect the footprint and cost of full-scale MBR
systems, include SRT, HRT and membrane flux. A survey of full-scale MBR plants
(Adham et al., 1998) revealed typical values for each of these parameters: SRT >30 days; flux
(continuous) =15 gfd; and HRT = 20 hr. However, recent pilot studies have demonstrated MBRs
could operate with limited success under more optimal conditions including: HRT 2-4 hours
(Adham et al., 2000); SRT 8 days (McInnis, 2003); flux 35 gfd (van der Roest et al., 2002).
Further research is necessary to determine the limitations of the design parameters to provide
guidelines to the wastewater industry.
To date the application of MBR systems for municipal wastewater reclamation has focused on
the treatment of two sources of wastewater: raw sewage and primary effluent. Another potential
source of reclaimed water is advanced primary effluent. Advanced primary treatment differs
from primary wastewater treatment in that it typically includes the addition of coagulants and/or
polymers for solid and organic removal. Some of the potential benefits of operating MBR
4
systems on advanced primary effluent, as opposed to raw sewage, includes: reduction of process
air requirements due to reduced solid/organic loading, lower pre-screen maintenance
requirements, and reduced foot-print. A major drawback to operation on advanced primary
effluent is the potential for chemical addition (particularly organic polymers) to negatively
impact the performance of the membranes. The impacts of these chemicals on MBR performance
have not been previously studied.
In many water reclamation facilities across the world, it is necessary to reduce (total dissolved
solids) TDS to make the water usable for irrigation and industrial applications. A recent survey
sponsored by WERF (Foussereau, et al., 2002) evaluated over 100 full-scale water reclamation
facilities worldwide, which use membrane technology as tertiary treatment. Results from the
study revealed that over 97 percent of the surveyed plants, which required TDS and organic
removal, used RO membrane technology. Furthermore, greater than 40 percent of the plants
identified in the study used MBR technology for tertiary treatment with a limited number of
these plants being used as pretreatment to RO.
A recent literature review identified MBR technology as the newest method of pretreatment for
secondary effluent prior to RO treatment (Paranjape et al., 2003). The authors reported only two
full-scale facilities in North America currently implement MBR as pretreatment to RO: City of
Colony Key (0.4 MGD) and City of Laguna, Santa Maria, California (0.5 MGD). However, the
ability of MBRs to produce effluent suitable as RO feedwater has been demonstrated at the pilot
scale level. For instance, (Lozier et al., 1999), had moderate success operating RO on effluent
produced by a Zenon MBR for indirect potable reuse. Adham et al., 2000 also demonstrated
successful operation of RO on MBR effluent; however, this study was limited to one type of RO
membrane (Dow/Film Tec LF/LE thin film composite [TFC]) under conservative operating
conditions. Since that time, new generation thin film composite membranes have been
developed and the number of suppliers has dramatically increased. As a result, further testing is
necessary to increase the pool of membranes and membrane suppliers that can provide RO
membranes capable of operating on MBR effluent. Due to advances in technology, it may also
be feasible to operate these new generation RO membranes with lower pressure and higher
production and recovery rates resulting in cost reduction of full-scale facilities.
An important responsibility of the wastewater treatment industry is to develop guidelines for
estimating capital and operations and maintenance (O&M) costs associated with MBR
technology. Currently a limited amount information exists in literature regarding the cost of full-
scale MBR systems. For example, Adham et al., 2002 reported MBR costs were comparable to
oxidation ditch and conventional activated sludge processes for 1-MGD capacities. Furthermore,
when compared to various conventional treatment processes MBR was the least costly method of
producing RO feed water. Churchouse and Wildgoose 1999, evaluated trends in the cost of the
membrane component of MBR systems. The authors reported that the membrane replacement
cost for Kubota membranes dropped by 75 percent between 1992 and 2000; decreasing the
membrane portion of the overall cost from 54 percent to 9 percent. Davies et al., 1998 evaluated
the economy of scale of MBR systems. The authors compared the capital costs of MBR to
conventional activated sludge for installations of 2,350 and 37,5000 population equivalents.
Results showed the MBR costs to be approximately 60 percent lower than conventional
treatment for the smaller capacity but 46 percent higher for the larger capacity. Due to the
5
dynamic nature of the MBR industry (including membrane development, increasing number of
suppliers, increasing capacity and changing design criteria), it is imperative to periodically
update MBR cost estimates.
2.2 Study Objectives
The City of San Diego was awarded a cooperative agreement by the Bureau of Reclamation to
evaluate the application of MBR technology for water reclamation. The main objectives of the
project were to evaluate manufacturers new to the US MBR market and optimize the application
of the MBR processes for water reclamation. Accordingly, four MBR systems provided by US
Filter Corporation/Jet Tech Products Group, Zenon Environmental, Inc., Ionics/Mitsubishi
Rayon Corporation, and Enviroquip Inc./Kubota Corporation were evaluated at the pilot scale
level over a 16-month period. During this time, performance of the MBR process was evaluated
under a variety of operating conditions including feed wastewater (raw municipal wastewater
and advanced primary effluent), permeate flux and HRT. In addition, the feasibility of using
MBR effluent as feed water to newly developed RO membranes supplied by several leading
manufacturers, including Saehan and Hydranautics, was evaluated. Lastly, cost estimates were
conducted for full-scale MBR water reclamation systems ranging from 0.2-10 MGD
(800-40,000 cubic meter per day [m
3
/day]). The specific study objectives were to:
- Evaluate the feasibility of new MBR systems for water reclamation
- Assess the impact of coagulant and polymer addition to the MBR feed water
- Optimize the MBR process operation (pre-treatment/post-treatment)
- Evaluate the suitability of various newly developed RO membranes on MBR effluent
- Develop and refine cost estimates for full-scale MBR systems used to produce reclaimed
water
7
3. Conclusions and Recommendations
3.1 Operational Performance
3.1.1 MBR Systems
3.1.1.1 US Filter
- The US Filter MBR system operated on both raw wastewater and advanced primary
effluent with minimal increase in Transmembrane Pressure (TMP) with a flux of 15 gfd
and HRT of 6 hours.
- The rate of fouling observed on the US Filter membrane, as measured by the rise in TMP,
increased with flux.
- On numerous occasions during operation on raw wastewater, several components of the
US Filter MBR pilot clogged with debris and hair resulting in temporary shut down.
3.1.1.2 Kubota
- The Kubota MBR system operated on both raw wastewater and advanced primary
effluent with minimal increase in TMP with a flux of 15 gfd and HRT of 5 hours.
- Post cleaning, moderate foaming occurred in the aerobic tank of the system. However,
normal process operation, which included the transfer of mixed liquor suspended solids
(MLSS) from the aerobic zone to the anoxic zone, mitigated the foaming completely with
in 1 or 2 days after cleaning.
- On two occasions during testing, the camlock fitting on the discharge side of the
submersible transfer of the Kubota MBR pilot became detached due to oxidation
resulting in temporary shutdown.
8
3.1.1.3 Zenon
- The Zenon MBR system operated with minimal increase in TMP under extreme
operating conditions including flux of 22gfd and HRT of 2 hours; during this time
maintenance cleans were employed three times per week to mitigate membrane fouling.
- The vacuum pressure of the Zenon membrane increased sharply when a partial loss of
nitrification occurred.
- During the initial testing period, the variable frequency drive (VFD) controlling feed
water flow rate to the Zenon MBR pilot failed, which resulted in unstable operation.
3.1.1.4 Mitsubishi
- The Mitsubishi MBR system operated with moderate increase in TMP with flux of 15 gfd
and HRT of 2.8 hours.
- It was necessary to modify the blower system of the Mitsubishi MBR pilot system in
order to maintain sufficient dissolved oxygen (DO) during operation at 15 gfd.
- Post cleaning, the biological portion of the Mitsubishi MBR was unstable, which caused
a significant amount of foaming to occur in the aerobic tank.
3.1.2 RO Membranes
- The Saehan 4040 BL and Hydranautics LFC3 RO membranes operated with minimal
fouling on effluent from the Kubota MBR during operation on raw wastewater and
advanced primary effluent.
- The average net operating pressure of the Saehan 4040 BL (low-pressure) RO
membranes measured during testing was 45 pounds per square inch (psi).
- The average net operating pressure of the Hydranautics LFC3 (fouling resistant) RO
membranes measured during testing was 120 psi.
- A 1-2 mg/L dose of chloramine in the RO feed was effective at mitigating biofouling.
- The RO membranes tested achieved excellent salt rejection ranging from
96 percent-98 percent.
3.1.3 Screening
- Operational issues were experienced with the wedge-wire prescreen equipped on the US
Filter MBR Pilot during operation on raw wastewater.
- Minimal maintenance was required on the rotary brush prescreen equipped on the Kubota
pilot during operation on raw wastewater.
9
- The Roto-Sieve (RS) Model 6013-11 drum screen operated with minimal maintenance
for more than 4,000 hours of operation on primary effluent.
3.2 Water Quality
3.2.1 Particulate Removal
- All MBR systems tested achieved excellent turbidity removal. Feed turbidity ranged
from 36-210 NTU; average effluent turbidity of all systems was < 0.1 NTU.
3.2.2 Organic Removal
- All MBR systems tested achieved excellent organic removal with average effluent BOD,
total organic carbon (TOC) and chemical oxygen demand (COD) concentrations 2
mg/L, 9 mg/L and 31 mg/L, respectively.
3.2.3 Biological Nutrient Removal
- All MBR systems tested achieved complete nitrification (NH
3
<1 milligrams per liter as
nitrogen [mg/L-N]) throughout testing.
- The Kubota MBR system achieved complete denitrification during Part 1 testing and
partial denitrification during Part 2 testing.
- Partial enhanced biological phosphorus removal (EBPR) occurred in the Kubota MBR
system during Part 1 testing.
3.2.4 Microbial Removal
- Total and fecal coliforms measured in the US Filter permeate ranged from
230 to 3,000 most probable number (MPN)/100 milliliter (mL) and 22 to 230 MPN/100
mL, respectively.
- Repetitive sampling of the US Filter permeate indicated that the observed coliform
breakthrough may have resulted from the pore size distribution of the membranes and
contamination during backwashing.
- Total and fecal coliform measured in the Kubota permeate were consistently
2.2 MPN/100 mL.
- Total and fecal coliforms measured in the Zenon permeate ranged from
14 to 5,000 MPN/100 mL and <2.2 MPN/100 mL, respectively; however, after
disinfecting the permeate side of the membranes all total and fecal coliform
measurements in the Zenon permeate were 2.2 MPN/100 mL.
- Total and fecal coliform measured in the Mitsubishi permeate were consistently
2.2 MPN/100 mL.
10
3.3 CDHS Approval
- As part of the California Department Health Services (CDHS) requirements, the project
team conducted virus challenge experiments on the Kubota MBR system towards the end
of Phase I pilot testing. These results were presented in a report to CDHS (Adham and
DeCarolis, 2003).
- During this study, the Kubota and US Filter MBR systems were approved to meet the
requirements of the CDHS for Title 22 Water Recycling Criteria.
- The Zenon and Mitsubishi were approved to meet the CDHS Title 22 Water Recycling
Criteria based on previous testing conducted by the project team
(Adham et al., 2001a & 2001b).
3.4 Costing Analysis
- Cost estimates ($/1000 gal) for 1-MGD MBR water reclamation systems designed to
operate on raw wastewater ranged from $1.81-$2.24.
- Cost estimates ($/1000 gal) for 1-MGD MBR water reclamation systems designed to
operate on advanced primary effluent ranged from $1.48-$1.91.
3.5 Other Conclusions
- All MBR systems tested operated successfully on advanced primary effluent containing
polymer and coagulant residual.
- The MBR systems tested operated with reasonable cleaning intervals.
- The Kubota and US Filter MBR systems operated successfully on raw wastewater and
were capable of producing effluent water quality suitable for RO.
- Cleaning with 2 percent citric acid was found to be the most effective method for
membrane cleaning due to the presence of ferric chloride in the MBR feed water.
- O&M associated with pre-screening was significantly reduced during operation on
advanced primary effluent as opposed to raw wastewater.
- MBR operational characteristics and performance varied among the four MBR suppliers.
11
3.6 Recommended Future Work
This project has built on previous knowledge gained by the project team with regards to the
application of the MBR process for wastewater reclamation. Through pilot-scale testing, it has
been demonstrated that MBR systems from 4 major suppliers can successfully operate on
advanced primary effluent containing polymer and coagulant residual. This finding is significant
as it increases the number of suppliers and feed water sources municipalities can choose to meet
reclamation needs using the MBR process. In addition, valuable cost information was generated
showing a significant cost savings for MBR systems designed to operate on advanced primary
effluent as opposed to raw sewage.
Due to the increasing application of MBR technology for wastewater reuse in the United States,
the project team has identified the following future research needs that can be evaluated at the
pilot-scale level:
- Optimization of MBR systems to achieve high-level phosphorus removal (e.g., effluent
Total Phosphorus 0.1 mg-P/L).
- Evaluation of anaerobic MBR systems to demonstrate process advantages including
reduced energy and biomass production.
- Testing of future MBR suppliers to the US municipal wastewater treatment market
including Pall Corporation, Norit, Hydranautics, Dynatec, and Huber to meet Title 22
reclaimed water standards.
- Testing of RO membranes on MBR effluent under more aggressive operating conditions
such as higher flux (12-14 gfd) and recovery rates (75-90 percent).
- Evaluation and optimization of MBR systems to remove endocrine disrupting compounds
(EDCs) and pharmaceuticals present in municipal wastewater.
In addition, the project team strongly recommends that the City of San Diego and Reclamation
apply the knowledge gained from this and previous research studies to build and implement a
1-5 MGD MBR water reclamation demonstration facility. This demo-scale facility would
provide valuable information regarding potential scale-up and reliability issues of MBR systems
as applied to wastewater reclamation. In addition, the facility will provide valuable information
to the City of San Diego and other municipalities across the US, regarding the operation and
maintenance of full-scale MBR systems for water reclamation.
13
4. Materials and Methods
4.1 Testing Site
The pilot site used for this study was the Point Loma Wastewater Treatment Plant (PLWTP)
located in San Diego, California. Treatment at PLWTP consists of advanced primary treatment,
which includes influent screening and grit removal followed by chemical coagulation,
flocculation, sedimentation and effluent screening. PLWTP currently uses between
0.5-1.0 MGD of potable water for on-site irrigation and industrial use. The City of San Diego is
considering building a MBR system to reclaim wastewater onsite to meet these needs.
Pilot testing was conducted on a concrete slab located at PLWTP. The site had access to
sufficient wastewater supply, electrical power, and discharge channels. Proper drainage lines
were provided by the City to meet the needs of all pilot equipment. A schematic of PLWTP,
showing the location of the feed water supply used for pilot testing, is provided in Figure 4-1
(See appendix A for figures)..
4.2 Feed Water Quality Characteristics
A primary objective of this study was to determine the impacts of various treatment and
chemical addition processes on MBR performance. Thus, the MBR pilot systems were operated
using two distinct wastewater sources: municipal raw sewage and advanced primary treated
effluent. Advanced primary treatment typically includes the addition of coagulants and/or
polymers for solids and nutrients removal. The impacts of these chemicals on MBR
performance have not been previously studied.
Municipal raw sewage used for the study was passed through an influent screening and grit
removal process; a portion of this screened sewage was diverted to the MBR systems during the
early portion of the pilot study. Sewage treatment at PLWTP includes chemical
coagulation/flocculation/sedimentation. Chemical addition includes ferric chloride
(27 mg/L, average dose) and a long chain, high molecular weight anionic polymer1
(0.15 mg/L, average dose). A portion of the advanced primary effluent from PLWTP was
diverted to the MBR pilot units during the later portion of the pilot study. Both source waters
were further screened prior to MBR treatment.
4.3 Experimental Set-Up
Figures 4-2, and 4-3 are schematic diagrams of the pilot treatment trains for Phase I (Part 1 & 2)
and Phase II, respectively. During Phase I testing, Kubota and US Filter were operated on raw
wastewater (Part 1) and advanced primary effluent (Part 2). Phase II testing included operation
of Zenon and Mitsubishi on advanced primary effluent.
14
4.3.1 Kubota MBR
A general process flow schematic of the Kubota MBR pilot system is provided in Figure 4-4. As
shown, the operating volume of each zone within the process tank is as follows:
- Denitrification/anoxic zone = 1,695-gal (6.42 cubic meters [m
3
])
- Pre-nitrification zone = 638-gal (2.41 m
3
)
- Nitrification zone = 2,664-gal (10.09 m
3
)
Feed water passed through a 3.2 millimeter (mm) traveling band screen before entering the feed
holding tank. Next, the feed water was pumped from the feed holding tank to the denitrification
zone using a submerged pump with a programmable logic controller (PLC). Water was then
pumped to the pre-nitrification zone where it was aerated with fine bubble air. Mixed liquor then
flowed by gravity to the nitrification zone where filtration occurred. Constant coarse bubble
aeration was provided in the nitrification zone to minimize fouling. This aeration generated an
upward sludge crossflow over the membrane surface of approximately 0.5 m/s. Mixed liquor
overflowed back to the denitrification zone at a rate which is approximately 4 times the permeate
flow rate. Lastly, sludge was wasted daily from the pre-nitrification zone to maintain a constant
sludge age.
As shown at the top of Figure 4-4, the nitrification zone contained an upper and lower membrane
cassette. This double deck (DD) configuration offers several benefits (van der Roest et al, 2002)
including reduction of the membrane foot print, reduction of the biological volume consumed by
the membrane system and reduced air consumption used for membrane cleaning. The DD also
yields a more controllable biological process and reduces the possibility of short circuiting
Each membrane cassette contained 100 individual Type 510 flat membrane sheets to provide a
total membrane area of 1,721 square feet (ft
2
) (160 square meter [m
2
]). The use of flat sheet
membranes to separate activated sludge into solid and liquid is a unique feature of the Kubota
MBR system. Specifications of the Kubota Type 510 flat sheet membrane are provided in Table
4-1. Photos of the Kubota pilot unit and the Type 510 flat sheet membrane are provided in
Appendix D.
During Phase I (Part 1 and Part 2) pilot testing, the Kubota membrane was operated at a flux
equal to 15 gfd (25 liters per hour per square meter [L/hr-m
2
]) and a constant coarse bubble
airflow of 55 standard cubic feet minutes (scfm) (1.6 cubic meter per minute [m
3
/min]). During
Part 1, fine air bubble airflow of 10 scfm (0.3 m
3
/min) was applied, as necessary, to maintain DO
in the nitrification tank at a concentration of 2.0 mg/L. The membrane was operated using a
filtration cycle of 9 minutes followed by a 1 minute relaxation period. During relaxation
filtration stopped; coarse bubble aeration continued. Nitrified mixed liquor was circulated at
approximately 80 gpm (303 liters per minute [L/min]).
4.3.2 US Filter MBR
A general process flow schematic of the US Filter MBR system is provided in Figure 4-5. The
US Filter/Jet Tec MBR pilot was equipped with a 1,000-gallon (3.79 m
3
) anoxic tank (not
shown), 1,500-gallon (5.7 m
3
) aerobic tank, 90-gallon (0.34 m
3
) membrane tank and a 163 gallon
(0.6 m
3
) filtrate tank. Throughout testing, the system was operated with nitrification only.
15
Accordingly, before start up, the system was modified to allow feed water to bypass the anoxic
tank. During pilot operation, feed water was center fed through a 1.0 mm wedge wire slotted
rotary screen. Screened wastewater then flowed by gravity to a feed equalization tank, which
controlled flow to the aerobic tank. The equalization tank contained a submersible pump, which
transferred wastewater to the aerobic tank. Level control float switches, placed in the aerobic
tank, were used to turn the pump on/off. These level switches were adjusted shortly after start up
to lower the average operating level of the tank in order to reduce the HRT. Because of the
reduced depth in the aerobic tank, it was also necessary to modify the blower supplied on the
pilot to maintain adequate DO. The mixed liquor (MLSS) in the aerobic tank was aerated using
fine bubble diffusers located at the bottom of the tank. Next, MLSS was transferred to the
membrane tank using a self-priming pump. A portion of the mixed liquor from the membrane
tank was filtered by the membranes under a light suction while the remaining portion was
overflowed/recycled back to the aerobic tank. The filtered water was then stored in a holding
tank, which overflowed to waste. MLSS were wasted daily from the aerobic tank to maintain a
target sludge age.
Four US Filter MemJet B10 R membranes were submerged in the membrane tank for a total
membrane area of 99 ft
2
(37 m
2
). Each membrane module was made of hollow fibers with a
nominal pore size of 0.2 micron. During operation, air and mixed liquor were continuously
injected near the bottom of the membrane tank to scrub and shake the membrane fibers. Such
operation allowed for a crossflow velocity to be established on the membrane surface and
minimized membrane fouling. Specifications of the US Filter MemJet B10 R membrane are
provided in Table 4-1. Photos of the US Filter MBR pilot unit and the MemJet B10 R
membranes are provided in Appendix D.
During the initial period of Phase I (Part 1) pilot testing, the US Filter membranes were operated
at a flux of 11.5 gfd (19.2 L/hr-m2) and a constant fine bubble airflow to the aerobic tank of
25 scfm (0.7 m
3
/min). For the remainder of Part 1 testing, the flux was increased to 14.5 gfd
(24.2 L/hr-m2) and the fine bubble airflow to the aerobic tank was increased to 45 scfm
(1.3 m
3
/min).
In Part 2 testing, the US Filter membranes were operated at flux rates between 14.524 gfd
(24.2-40 L/hr-m2) to assess the affect of increased flux on membrane performance. During both
Part 1 and Part 2 testing, the coarse bubble airflow to the membrane tank was 8.5 scfm
(0.24 m
3
/min). Throughout the pilot testing a minimum DO level of 1.0 mg/L was targeted in
the aerobic. Lastly, the MLSS overflow rate was between 14-22 gpm (0.88-1.4 liters per second
[L/s]) throughout the pilot testing.
During Phase I testing, the US Filter membrane was operated using a filtration cycle of 12
minutes followed by a 1 minute backwash period. During backwashing, the membranes were
allowed to relax for 45 seconds. Next, filtrate water was pumped from the inside to the outside
of the membrane fibers for a 15 second period. Although forward filtration of wastewater was
stopped during backwashing, coarse bubble airflow to the membrane fibers was continued. Also
during backwashing, a portion of the air going to aerobic tank was diverted to the bottom (below
the jets) of the membrane tank to prevent solids from accumulating.
16
4.3.3 Zenon MBR
A schematic of the Zenon MBR pilot unit is shown in Figure 4-6. The Zenon MBR pilot unit
had a capacity of 10,000 gallons per day (gpd) (38 m
3
/day). The pilot unit came equipped with a
1,300-gallon (4.92 m
3
) aerobic tank and a 185-gallon (0.7 m
3
) ZenoGem membrane unit. A
submersible pump, placed in the primary effluent break tank, was controlled by a PLC. This
pump fed the MBR. As previously mentioned, the primary effluent passed through a 0.75-mm
perforated rotary drum screen before entering the aerobic zone. Activated sludge from the
aerobic tank was continuously recirculated to the ZenoGem unit using a submersible pump. The
overflow from the ZenoGem unit flowed back to the aerobic tank by gravity. Batch wasting was
performed from the aerobic tank to maintain a constant sludge age. Fine bubble diffusers were
installed in the aerobic tank to supply adequate DO to the bioreactor to maintain a minimum
level of
1.0 mg/L. A photo of the diffuser grid taken before the system was seeded is provided in
Appendix D.
One ZW 500d membrane cassette, containing 3 membrane elements for a total area of 720 ft
2
(69 m
2
), was submerged in the ZenoGem unit. During operation, coarse air was used to scour
the membranes and was cycled on/off at 10 s intervals. The 500d membrane is a reinforced
hollow fiber membrane with nominal pore size of 0.04 micron. Membrane specification for the
Zenon 500d membrane were obtained from the manufacturer and presented in Table 4-1. A
photograph of ZW 500d is provided in Appendix D.
During Phase II pilot testing, the Zenon MBR was tested with a target flux of 22 gfd
(37.3 L/hr-m2). The operation cycle was set for 10 minutes production and 30 seconds
relaxation for the entire testing period. Coarse air bubble flow rate to the ZenoGem tank was set
at 21 scfm (0.6 m
3
/min) and the fine air bubble flow rate to the aerobic tank was set at 56 scfm
(1.6 m
3
/min) for the entire testing period.
As part of the optimization process, the Zenon MBR system was operated under aggressive
operating conditions including high permeate flux rate (>20 gfd) and low HRT (2.0 hours).
During such operation, the manufacturer recommended that maintenance cleans be performed
three times per week to help mitigate membrane fouling. In accordance, maintenance cleans
were performed by backpulsing chlorine (250 parts per million [ppm]) or citric acid (2 percent)
to the inside of the membrane fibers to remove any build up on the membrane surface. A single
maintenance clean consisted of four such back pulses with a 30 s soak time between cycles.
4.3.4 Mitsubishi MBR
A schematic of the Mitsubishi MBR system used in this study is given in Figure 4-7. The pilot
unit was equipped with a 1,600-gallon (6.06 m
3
) aerobic tank and 250-gallon (0.95) filtrate tank.
A submersible pump, placed in the primary effluent break tank, was controlled by the
programmable logic controller (PLC) and fed the MBR. As previously mentioned, the primary
effluent passed through a 0.75-mm perforated screen before entering the aerobic zone. In the
event of tank overflow, an overflow line from the aerobic tank was drained to waste. Sludge was
batch wasted daily from the aerobic tank.
17
Two membrane banks were submerged in the aerobic tank, where coarse air diffusers
continuously agitated the membranes and aerated the biomass. To account for the increasing
oxygen demands during more aggressive conditions (i.e. low HRT), the tank was retrofitted with
fine bubble diffusers. Each membrane bank consisted of 50, 1 m
2
(10.76 ft
2
) Mitsubishi
Sterapore HF microfiltration membranes, for a total membrane area of 100 m
2
(1,076 ft
2
). The
hollow fibers were arranged horizontally and attached at both ends to permeate lines. A
complete list of membrane specifications is given in Table 4-1. (See Appendix A for tables.) A
photograph of the membrane cassette taken before installation is provided in Appendix D.
During Phase II Testing, the Mitsubishi MBR system was operated at target flux between
11.8-14.8 gfd (20 -25 L/hr-m2). The operating cycle was set at 12 minutes production and 2
minutesrelaxation for the entire testing period. Initially, the coarse bubble air flow rate was 26
scfm (0.76 m
3
/min) but was later increased to 41 scfm (1.2 m
3
/min) by modifying the blower.
Fine air flow of 10 scfm (0.29 m
3
/min) was used during operation at flux of 14.8 gfd (25 L/hr-
m2) to ensure adequate DO (e.g. 1.0 mg/L) for biological oxidation.
4.3.5 Screening Equipment
4.3.5.1 US Filter
The US Filter MBR pilot was equipped with a Contra-Shear Mini-milli Model 450M screen.
This screen is a center feed rotating drum unit with 1.0 mm wedge wire slots. During operation,
feed wastewater entered the system through an infeed tank assembly, which directs the liquid
tangentially to the rotating drum. The screen was cleaned by external/internal spray nozzles and
was enclosed by splash guards to ensure filtrate discharges below the drum. Solids removed
during the screening process fall by gravity into a collection bin. The Contra-Shear was operated
during Phase I of the US Filter MBR testing at a flow rate of 10 gallons/min. During Part 1
testing on raw wastewater the screening experienced several operational problems.
4.3.5.2 Kubota
The Kubota MBR pilot was equipped with an OR-TEC rotary brush screen type C. Main
components of the screening system included: brush assembly, scraper assembly and perforated
screen. The screen was made with #304 stainless steel and has 1/8 perforations.
4.3.5.3 Roto-Sieve
A Roto-Sieve (RS) Model 6013-11 drum screen was tested during this study. The RS 11 screen
is a rotating drum screen with 0.8 mm perforation. During operation, the wastewater is fed into
the drum through an inlet pipe, which distributes the water over the surface of the screen. The
wastewater is then filtered through the screen and discharged at the opposite end of the feed
inlet. Solids too large to pass through the screen are moved to the inlet side of the screen by the
rotating motion of the drum. These particles then exit the system via a discharge collection
hopper located below the feed inlet. The screen was also equipped with a counter rotating roller
brush which serves to continually clean the screen to prevent clogging of the perforated slots.
The brush is fixed against the outside of the drum and rotates by friction between the drum and
the brush. The system was also equipped with a sprayer head and spray nozzle to provide
cleaning of the sieve drum.
18
The Roto-Sieve screen was operated for more than 4,000 hours (167 days) during Phase II
testing of the Zenon and Mitsubishi MBR systems. The flow rate to the screen was between
20-30 gpm (1.31.9 L/s) throughout the testing period. A photograph of the RS 11 screen is
provided in Appendix D.
4.3.6 RO System
The RO pilot used in this study compared the performance of two single pass membrane trains,
one provided by Saehan, the second Hydranautics. Both trains consisted of two pressure vessels
configured in series. Each vessel contained 3 spiral wound 4 by 40 inch thin film composite
(TFC) RO elements with a membrane surface area of 85 ft
2
(7.9 m
2
) per element. In the first
train, six Saehan Model RE 4040 BL membranes were tested. The RE4040 BL represents
Saehans newest generation of RO membranes designed to treat low salinity waters using low
pressure. The second train consisted of six Hydranautics LFC3 RO membranes. LFC3
represents the newest generation RO membranes ideal for treatment of municipal wastewater.
LFC3 is characterized as a low fouling membrane capable of achieving efficient flow and salt
rejection. Specifications for the RE4040 BL and LFC3 RO membranes are provided in
Table 4-2. A photograph of the RO pilot unit is provided in Appendix D.
Both RO membrane trains were operated simultaneously on identical source waters at a constant
flux of 10 gfd (17 L/hr-m2) and feed water recovery of 50 percent. The source water for Part 1
and Part 2 testing was raw wastewater and advanced primary effluent treated by MBR,
respectively. Per the manufacturers recommendation, the RO influent was dosed with 2 mg/L
antiscalant to slow the precipitation of sparingly soluble salts. The antiscalant used was Pre-treat
Plus (King Lee Technologies, San Diego, CA). Next, feedwater passed through a 5-m cartridge
filter before being pressurized and introduced into the RO membranes. Two different methods
of pre-treatment were tested during the study to mitigate biofouling of the RO membranes.
During the first part of testing, RO feed water was dosed with low pressure UV. However, for
the remainder of testing, chloramine was dosed to the RO feed water to maintain a 1-2 mg/L total
chlorine residual concentration; no free chlorine was allowed onto the RO units.
See Section 4.3.7 for specific details of the UV pilot system.
4.3.7 UV Pilot
The Professional Line UV-system, provided by Aquionics (Erlanger, KY) was tested during this
study as a pretreatment to RO. The UV pilot consisted of a disinfection chamber, single low
pressure UV lamp, power supply and control panel. A photograph of the UV system is provided
in Appendix D. Specifications and operating conditions for the UV system are provided in Table
4-3. During operation, the UV-Output (%) was monitored from the display panel of the system.
In addition, ultraviolet transmittance (UVT) of the feed water was measured weekly and
averaged 70 percent. Flow to the UV system was 14.4 gpm (0.9 L/s) throughout testing. Based
on the feed water transmittance and feed flow the manufacturer estimates the effective dose to be
approximately 40 millijules per square centimeter (mJ/cm
2
).
19
t A
=
|
|
.
|
\
|
p
P
o
P
i
P
net
P
2
4.3.8 Determination of Calculated Parameters
4.3.8.1 Pressure Calculations
The net operating pressure (P
net
) for the RO systems was calculated according to the following
equation:
(1)
Where,
P
net
= net operating pressure (psi)
P
i
= pressure at the inlet of the pressure vessel (psi)
P
o
= pressure at the outlet of the pressure vessel (psi)
P
p
= permeate pressure
= net osmotic pressure of the feed and permeate (psi)
The integrated averaging factor (IAF) assuming 100 percent salt rejection can be used to estimate
the osmotic pressure as follows:
Where,
f
= osmotic pressure of the feed stream (psi)
IAF = 1.386 (for 50 percent recovery)
For the RO membranes, the following approximate rule of thumb can be used:
- 1,000 mg/L NaCl solution 11.5 psi of osmotic pressure,
- A correlation between NaCl and conductivity can be assumed (1mho of conductivity =
1 mg/L NaCl).
f
IAF t t = A
20
P
ON
OFF ON
Net
Q
t
t t
Q
|
|
.
|
\
|
=
The transmembrane pressure (TMP) for the Kubota MBR provided in this report is the average
driving pressure required to filter water through the upper and lower membrane banks at the
given flow rate plus piping resistance. The TMP of each membrane bank was calculated by
subtracting the dynamic pressure measured during filtration from the static head in the
membrane tank.
TMP= (P
d-upper
+ P
d lower
)/2 P
s
(2)
Where:
P
d-upper
= Dynamic Pressure measured in the upper membrane bank at given flow rate (psi)
P
d-lower
= Dynamic Pressure measured in the lower membrane bank at given flow rate (psi)
P
s
= Static Pressure Measured during Relaxation (psi)
TMP for US Filter MBR System was based on:
TMP= (P
suction
- P
permeate
) (3)
Where:
P
suction
= Pressure measured at point X in membrane tank on the suction side of the
membrane (psi)
P
permeate
= Pressure measured at point X in the membrane tank on the permeate side of
the membrane (psi)
4.3.8.2 Flow Calculations
The net permeate rate for the Mitsubishi, Zenon and Kubota MBR can be calculated using the
equation:
(4)
Where,
Q
NET
= net permeate rate (gpm)
t
ON
= the time the MBR membrane is in production (min)
t
OFF
= the time the MBR membrane is in relaxation (min)
Q
p
= Permeate flow rate (gpm)
Please note: this calculation assumes the loss of flow during cleaning in place (CIP) and
intermittent maintenance cleans is negligible.
21
BP ON
BP ON P
NET
t t
V t Q
Q
+
=
A
Q
J
p
1440
=
( ) 20 0239 . 0
20 @

=
T
e J C J
The US Filter/Jet Tech MBR employed backpulsing to minimize fouling. The net permeate rate
for this system was calculated with the equation:
(5)
Where,
V
BP
= volume of water backpulsed (gallons)
t
BP
= time of backpulse (min)
4.3.8.3 Flux Calculation
The flux of the RO membranes and the MBR membranes can be calculated as follows:
(6)
Where,
J = Membrane flux (gfd)
A = Total membrane surface area (ft
2
)
4.3.8.4 Temperature Correction
Low-pressure membrane fluxes are normally temperature corrected to 20C, and RO membranes
are corrected to 25C. The membrane fluxes for the MBR membranes can be temperature
corrected with the following formula:
(7)
Where,
T = feed water temperature (C)
The RO membranes were temperature corrected according to manufacturers correction factors.
22
Net
SP
P
J
J =
|
|
.
|
\
|
=
f
P
c
c
R 1 100
60
=
NET
Q
V
HRT
4.3.8.5 Specific Flux
The specific flux is the relationship between flux and the net operating pressure. The
relationship is defined by the formula:
(8)
Where,
J
SP
= specific flux (gfd/psi)
Likewise, the temperature-corrected specific flux can be calculated using the temperature
corrected flux.
4.3.8.6 Salt Rejection
The salt rejection for the RO membranes was calculated using the following equation:
(9)
Where,
R = rejection (%)
c
p
= permeate conductivity (mhos)
c
f
= feed conductivity (mhos)
4.3.8.7 Hydraulic Retention Time
The hydraulic retention time (HRT) for the MBR pilot units was calculated using the formula:
(10)
Where,
HRT = Hydraulic retention time (hours)
V = MBR volume (gallons)
23
W W W
R
Q
V
X Q
VX
SRT = =
7
...
7 2 1
7
= = =
+ + +
=
n n n
day
SRT SRT SRT
SRT
4.3.8.8 Sludge Retention Time
The sludge retention time (SRT) is defined as the total mass of activated sludge in the
MBR divided by the mass flow rate of activated sludge being removed. In order to calculate the
SRT of the MBRs, the reactors are treated as an ideal continuously stirred tank reactor (CSTR).
Under this assumption, concentration of activated sludge in the MBR will be the same as the
concentration in the waste stream and the equation will simplify as follows:
(11)
Assuming that XR is equal to X
W
.
Where,
SRT = sludge retention time (days)
X
R
= volatile suspended solids in the reactor (mg/L)
X
W
= volatile suspended solids in the waste stream (mg/L)
Q
W
= waste stream flow rate (gpd)
The seven-day SRT (SRT
7-day
) is calculated by averaging the SRT over 7 previous days as
follows:
(12)
Where,
SRT
7-day
= the 7 day average SRT
N = day
24
1 =
=
NET
R
NET
NET R
Q
Q
Q
Q Q
RR
1 =
=

NET
R
NET
NET membrane R
Q
Q
Q
Q Q
RR
4.3.8.9 Recycle Ratio
The recycle ratio (RR) for MBR systems operating with anoxic and aerobic tanks is defined as
the ratio of the flow of MLSS from the aerobic tank to the anoxic tank, divided by the net
permeate rate. The Kubota MBR was the only MBR system operated with an anoxic and aerobic
tank. During operation of the Kubota MBR, MLSS was pumped from the anoxic tank to the
aerobic tank and returned to the anoxic tank by gravity. Accordingly, only the flow rate from the
anoxic to aerobic tank was recorded. As a result, the RR for Kubota MBR was calculated as
follows:
(13)
Where,
RR = Recycle Ratio
Q
R
= Flow Rate from the anoxic tank (gpm)
Because the US Filter and Zenon MBR systems were equipped with an aerobic tank and separate
membrane tank, the RR was determined as the ratio of the flow rate of MLSS from the
membrane tank to the aerobic tank divided by the net permeate rate. The RR for these two MBR
systems were calculated as follows:
(14)
Where,
RR = Recycle Ratio
Q
R-membrane
= Flow Rate from the membrane tank to the aerobic tank (gpm)
25
4.3.9 Chemical Additions
4.3.9.1 Antiscalant Addition for RO Membranes
In order to control inorganic scaling on the RO membranes an antiscalant product was used
1
.
The antiscalant was added in-line; upstream of the RO membranes at the manufacturers
recommended dosage of 2.0 ppm using a chemical-metering pump
2
.
4.3.9.2 Chloramine Addition for RO Membranes
In order to control biological fouling on the RO membranes, a 1.0 mg/L chloramine residual was
maintained in the MBR effluent during portions of the study. Chloramines were formed in-situ
by dosing free chlorine, followed by ammonia (3.9/1 Cl
2
/NH
4
ratio). The chemicals were added
using chemical metering pumps
3
.
4.3.10 Chemical Cleaning of Membranes
All chemical cleanings were performed in accordance to the manufacturers recommended
protocol. These protocols are provided in Appendix B.
Mitsubishi and Kubota MBR systems were cleaned in-line (CIL) the presence of MLSS by
introducing chemicals to the inside of the membranes through the permeate lines. Chemicals
passed from the inside to the outside of the membranes by gravity.
Zenon and US Filter membranes were cleaned in place (CIP) by first transferring MLSS present
in the membrane tank to the aerobic tank. This allowed for the membranes to be soaked in the
direct presence of chemicals. Maintenance cleans were performed on the Zenon membranes
twice per week using a 250 ppm NaOCl and once per week using 2 percent citric acid solution.
The RO membranes were cleaned using 0.1 percent sodium hydroxide. The chemical solution
was mixed using RO permeate in an external cleaning skid which consisted of a 100 gallon
chemical tank, a heating element and a centrifugal pump. The solution was recycled through the
RO concentrate line back to the membrane cleaning tank at a rate of 4-6 gpm for 1 hour. Next,
the membranes were allowed to soak for 1 hour. Finally, the cleaning solution was completely
drained from the membranes and the system was brought back on-line.
1
King Lee Technologies, Pretreatment Plus 0100, San Diego, CA
2
LMI Milton Roy, Model P121, Acton, MA
3
LMI Milton Roy, Model P121, Acton, MA
26
4.4 Water Quality
4.4.1 On-site water quality analyses
4.4.1.1 Temperature
The temperatures of the aerobic tank of the MBR systems were monitored using in-line
temperature gages and a DO probe
4
, these values were periodically field verified using an
alcohol thermometer. The temperature of the RO influent was determined using an in-line
temperature gauge
5
.
4.4.1.2 pH
A desktop pH meter
6
, was used throughout the study to determine pH of the raw wastewater,
primary effluent, MBR effluent and MLSS. The meter was calibrated daily using a 3 point
calibration with buffers 4, 7, and 10. The calibration was confirmed daily using a laboratory
check standard.
4.4.1.3 Turbidity
The turbidity of the MBR effluents was determined using an on-line turbidimeter
7
. On-line
measurements were periodically verified using a bench top turbidimeter
8
.
4.4.1.4 Silt Density Index (SDI)
Silt density index (SDI) analyses were performed on the MBR effluents using a SDI machine
9
.
The SDI machine filtered water through a disposable 0.45-m filter. The SDI value was
determined by periodic monitoring of the flow rate through the filter, at a constant pressure, over
a 15-minute period.
4
YSI Model 55, Yellow Springs, OH
5
ReoTemp, San Diego, CA
6
Fisher Scientific International Inc. Accumet Research AR15, Hampton NH
7
Hach Co., Model 1720D, Loveland, CO
8
Hach Co, Model 2100N, Loveland, CO
9
Chemetek, FPA-2000, Portland, OR
27
4.4.1.5 UV-254 Absorbency
Samples collected for TOC analysis were also analyzed for UV-254 absorbency using a
spectrophotometer
10
.
4.4.1.6 Conductivity
On-line conductivity of the RO influent and effluent was also monitored using on-line
conductivity meters
11
. Measured values were compared with daily conductivity results from the
laboratory to ensure continued accuracy.
4.4.1.7 Free and Total Chlorine Residual
The total chlorine residual of RO influent was monitored using grab samples and a colorimetric
test kit
12
.
4.4.2 Laboratory Water Quality Analyses
All laboratory water quality analysis were performed at one of the following locations: Point
Loma Laboratory (PL Lab), the City of San Diego Water Quality Laboratory at Alvarado,
Calscience Environmental Laboratories (CEL Lab) or the City of San Diego Marine Micro Lab.
Table 4-4 summarizes the detection limits and methods used for all of the laboratory analyses
that were performed.
4.4.3 Sampling Protocol/Frequency
All water quality samples were collected as grab samples using sample containers provided from
the corresponding laboratory. All samples were transported to the lab in a cooler and were
processed within the allowable holding period. During sampling, sample ports were allowed to
flush before samples were collected. All microbial samples were collected using aseptic
techniques. The sample ports were flamed and flushed before a sample was collected.
4.4.4 Quality Assurance/Quality Control
Appropriate measures were taken at the pilot site in order to attain the highest amount of quality
control and quality assurance. Appendix C contains a technical memorandum documenting the
quality assurance/quality control (QA/QC) that was performed throughout the study.
10
Hach Co., DR/4000U spectrophotometer, Loveland, CO
11
Myron L Company, Series 750
12
Hach Co., Test Kit Model CN-80, Loveland, CO
29
5. Results and Discussion Phase-I: Operation
of New MBR Systems
5.1 MBR Operating Conditions Phase I (Part 1)
During Phase I (Part 1) pilot testing, the US Filter and Kubota MBR systems were operated on
raw wastewater from the PLWTP. The US Filter system was initially operated with an aerobic
tank and membrane tank having a combined HRT of 7.6 hours at a flux of 11.5 gfd (19.8 L/hr-
m2). Later, the operating level of the aerobic tank was lowered and the flux was increased to
14.5 (24.9 L/hr-m2). These changes reduced the combined HRT to 6.0 hours. Throughout Part
1 investigations, US Filter MBR was operated with an average internal recycle ratio (RR) of 6.
A mixed liquor wasting routine was implemented to allow an SRT
7-day
of 9 days and MLSS
concentrations of 912 grams per liter (g/L). The HRT and SRT
7-day
data are presented in Figure
5-1; mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids
(MLVSS) concentrations are presented in Figure 5-2. As shown, on several occasions during
Part 1 testing the MLSS measured in aerobic tank dropped below 4,000 mg/L. This was due to a
glitch in the pilot system, which allowed feed water to fill the aerobic tank above the high level
set point. After each occurrence, it was necessary to drain the aerobic tank back to the normal
operating level before bringing the system back on line, effectively wasting the accumulated
solids.
The DO measured in the aerobic tank and system air flow rates are presented in Figure 5-3. The
upper graph shows the DO was consistently between 24 mg/L during the first 1,349 hours (56
days) of operation. Following this period, the membrane flux was increased. This resulted in a
steady decrease in the DO to values < 0.5 mg/L. To avoid anoxic conditions, the flux was
reduced back to 11.5 gfd (19.8 L/hr-m2). Accordingly, the DO in the aerobic tank resumed to
values between 3-5 mg/L. After 2,620 hours (109 days) of operation, the blower on the system
was modified to increase the fine air flow rate to the aerobic tank from 25 to 45 scfm (0.7 to 1.3
m
3
/min). Following this modification, the flux was increased back to 14.5 (24.9 L/hr-m2) and
the DO was maintained between 2-4 mg/L. The increase of fine air flow to the membrane tank is
illustrated in the lower graph of Figure 5-3. Also shown, the coarse air flow to the membrane
tank was steady at 9 scfm for the entire testing period. The DO was reduced again after 4,302
hours
(179 days) of operation when the flux was increased to values ranging from 19-24 gfd
(32.2-40.7 L/hr-m2).
The Kubota MBR was operated with aerobic and anoxic tanks using Type 510 flat sheet
membranes under following conditions: flux= 14.5 gfd (24.9 L/hr-m2); HRT=5.1 hours; RR= 4.
The mixed liquor wasting rate was set to achieve an SRT of 11days and a MLSS concentration
between 12-14 g/L. The HRT and SRT
7-d
values are presented in Figure 5-4. The DO
30
concentrations measured in the aerobic tank are presented in Figure 5-5. As shown, DO in the
aerobic tank was consistently between 1.2 and 2.4 mg/L. The MLSS and MLVSS concentrations
measured in the aerobic tank and the MLVSS wasting rate are presented in Figure 5-6. The
upper graph shows that after 1,670 hours (70 days) of operation, the system was drained
resulting in a significant decrease in the MLSS concentration. As a result, the DO measured in
the aerobic tank increased to 5.4 mg/L. However, as shown in Figure 5-5, the DO gradually
decreased to target of 2 mg/L due to growth of MLSS. After this occurrence, the system was
restarted and the MLSS were allowed to increase to 17.8 g/L. At that time, the daily wasting
schedule was resumed to meet the target MLSS concentration of 12-14 g/L. As shown in the
lower graph, the normal wasting rate required to meet the solids target was between 16-20
kilograms (kg) VSS / day.
5.2 MBR Operating Conditions Phase I (Part 2)
At the end of Part 1 testing, the feed piping to the US Filter and Kubota MBR systems were
modified to supply advanced primary effluent. Next the membranes from each MBR system
were cleaned in accordance to the manufacturers protocol. The RO membranes on the Kubota
MBR RO skid were also cleaned prior to beginning Part 2 testing. Due to the lower organic
content of the advanced primary effluent it was necessary to establish new sludge wasting rates
for each MBR system to maintain the target MLSS during Part 2 testing.
The US Filter MBR system was operated under similar operating conditions as Part 1 testing,
including combined HRT = 6.0 hours; Flux = 14.5 gfd, RR = 6; fine air flow rate = 45 scfm;
coarse air flow rate = 9 scfm and MLSS= 9-12 g/L. However, the mixed liquor wasting rate
required to maintain the target MLSS gave an SRT
7-day
between 30-40 days. The MLSS and
normal sludge wasting rate for Part 1 and Part 2 testing are presented in Figure 5-2. As shown in
the lower graph, the normal sludge wasting necessary to maintain the MLSS between 9-12 g/L
was much less during Part 2 (0.7-2.0 kg VSS/day) than Part 1 (4.0-6.0 kg VSS/day). Also, the
DO during Part 2 was consistently measured to be between 5-7 mg/L. The decreased wasting
rate necessary to maintain target MLSS and the increase in DO are both associated with the
lower organic content of advanced primary effluent as compared to raw wastewater.
The Kubota MBR system was also operated under similar operating conditions as Part 1,
including combined HRT = 5.1 hours; Flux = 14.5 gfd, and RR = 4. However, the target MLSS
was reduced to 9-12 g/L and the mixed liquor wasting rate required to meet this goal resulted in a
SRT of 18 days (9 days Part 1). As shown in Figure 5-5, the DO in the aerobic tank during Part
2 was much higher than Part 1 and ranged from 3.5 5.5 mg/L.
31
5.3 Membrane Performance
5.3.1 MBR Pilot Plants
The membrane performance of the US Filter MBR during Phase I testing is presented in Figure
5-7. As indicated, after 1,182 hours (49 days) of operation, several chlorinated backwashes were
employed to disinfect the permeate piping. This reduced the TMP, measured at 11.5 gfd
(19.8 L/hr-m2), from 1.3 to 0.93 psi (0.09 to 0.06 bar). Over the next 1,438 hours (60 days) of
operation, the TMP increased to 1.62 psi (0.11 bar). As indicated, after 2,620 hours (109 days)
of operation, the permeate flux was increased from 11.5 to 14.5 gfd (19.8 to 24.9 L/hr-m2). This
caused the TMP to increase from 1.62 to 2.14 psi (0.11 to 0.15 bar). After 2,954 hours
(123 days) of operation the system was cleaned using chlorine, which reduced the TMP,
measured at 14.5 gfd, from 3.17 to 2.04 psi (0.22 to 0.14 bar). Post cleaning, the system was
operated for approximately 11 days during which time no fouling was observed. At this time,
the system was cleaned again using both acid and chlorine. This cleaning reduced the TMP from
2.12 to 1.34 psi. Such results indicate that acid was more effective than chlorine in cleaning the
membranes. This is expected due to the presence of ferric chloride in the raw wastewater. In the
presence of alkalinity, ferric chloride undergoes a hydrolysis reaction, which forms ferric
hydroxide causing a red precipitate. When discharging the spent acid solution, it was observed
to have a reddish color indicating ferric chloride. Following the cleaning, the MBR was operated
at 14.5 gfd (24.9 L/hr-m2) for nearly 1,000 hours (42 days), during which time the TMP
increased from 1.34 to 2.7 psi. The system was then cleaned again using acid and chlorine which
reduced the TMP to 0.9 psi. After the cleaning, the system was brought back on line and the flux
was increased to 19-24 gfd. During operation at high flux rates the TMP increased dramatically.
Such results indicate the rate of fouling observed on the US Filter membranes, as measured by
rate of TMP increase, increased with increased flux. This data also suggests the critical flux of
the membrane is 15 gfd. Lastly, during Part 2 testing on advanced primary, the US Filter MBR
system was operated for 1,000 hours (42 days) at 14.5 gfd during which time minimal fouling
was observed. Such results indicate the US Filter system can operate successfully on advanced
primary effluent containing polymer and coagulant residual.
Membrane performance data of the Kubota MBR system measured during Phase I testing is
presented in Figure 5-8. As shown in the upper graph, a sharp increase in TMP was observed
during the initial 788 hour (33 days) of operation following the start up period. During this time
the TMP increased from 1.38 psi (.095 bar) to 5.76 psi (0.4 bar). The manufacturer was notified
and recommended the bottom membrane bank be immediately taken offline to avoid damaging
the membranes. As indicated, this reduced the TMP to 2.52 psi (0.17 bar). Shortly thereafter,
the manufacturer sent field technicians to the pilot site to assess the cause of the fouling.
Accordingly, both membrane banks were removed from the system for observation. Visual
inspection revealed that the flat sheet membranes were covered with reddish-orange precipitate,
indicating the presence of ferric hydroxide. A photograph taken during the inspection is
provided in Appendix D. In addition, the inch permeate line originally used on the pilot unit
was replaced with 2 inch line which is used in standard design of full scale Kubota MBR
systems. It is believed the inch piping may have resulted in flow restriction which increased
the pressure loss on the permeate side of the membranes. The membrane cassettes were replaced
and the membranes were cleaned using chlorine and acid before bringing the system back in
32
service. As shown, following the cleaning, the Kubota MBR operated for over 2,000 hours
(83 days) at a flux of 15 gfd (25.41 L/hr-m2) with a TMP between 1-3 psi (.07-0.21 bar) with
little or no membrane fouling. During Part 2 testing on advanced primary, the Kubota system
was operated for 1,800 hours (75 days) at 15 gfd (25.41 L/hr-m2) during which time TMP was
between 1-2 psi (.07-0.14 bar) with no fouling observed. Such results indicate the Kubota MBR
system can operate successfully on advanced primary effluent containing polymer and coagulant
residual.
5.3.2 RO Pilot Unit
The performance of the Saehan RE 4040 BL RO membranes operating at 10 gfd (16.7 L/hr-m2)
and 50 percent recovery on Kubota MBR effluent is shown in Figure 5-9. As shown, during the
first 252 hours (10.5 days) the system was operated at 12.4 gfd (21 L/hr-m2). However, in order
to simultaneously operate two membrane trains, it was necessary to reduce the flux to 10 gfd
(16.7 L/hr-m2) due to limitations on the quantity of available feed water. During the next
500 hours of operation the net operating pressure increased from 44.6 to 57.5 psi (3.1 to 4.0 bar)
indicating the membranes had fouled. At that time, the membranes were cleaned according to
the manufacturers recommendation using 0.1 percent sodium hydroxide (pH 13). The cleaning
was very effective; reducing the net operating pressure to 34.8 psi at 10 gfd. A similar fouling
trend was observed over the next 300 hours (12.5 days) as the net operating pressure increased to
49.0 psi (3.4 bar). The membranes were cleaned again which reduced the net operating pressure
to 37.7 psi. Prior to this cleaning, the pre-filters on the RO skid were removed from the system
for inspection. It was observed that the pre-filters had undergone a severe discoloration due to
an excessive amount of algae growth, which occurred in the Kubota MBR permeate. A photo
showing the used pre-filters and a new pre-filter is provided in Appendix D. As a result, two
steps were taken to prevent the algae growth in the RO feed water: First, the clear storage tank
and permeate piping of the Kubota MBR system were replaced with opaque material to block
sunlight. Secondly, a dosing pump was installed to allow for the addition of 1-2 mg/L
chloramine to the feed water prior to reaching the RO membranes; prior to this a low pressure
UV system was used as pretreatment. After the changes, the system was cleaned and put in
service at run hour 1,150. As shown, the system operated for over 818 hours (34 days) during
which time the net operating pressure increased from 37.7 to 50 psi indicating chloramine
addition was successful in mitigating RO membrane fouling. The membranes were then cleaned
one last time prior to Part 2 testing. The net operating pressure increased from 37.2 to 46.7 psi
over 700 hours (29.1 days) of operation on Kubota MBR effluent produced from advanced
primary effluent.
The performance data of the Hydranautics LFC3 RO membrane operating on Kubota MBR
permeate at 50 percent recovery during Phase I testing is shown in Figure 5-10. As shown
during Part 1 testing, the flux was reduced to 10 gfd after 24 hours (1 day) of operation, which
lowered the net operating pressure to 112.5 psi (7.8 bar). The net operating pressure remained
constant for the next 539 hours (22.5 days) of operation. However, over the next 217 hours
(9 days) of operation the pressure increased sharply resulting in a final net operating pressure of
188 psi (13 bar). Following the changes described above to reduce algae growth, the LFC3
operated for over 800 hours (33 days) during which time the net operating pressure only
increased slightly (113 psi to 131 psi). Lastly, during Part 2 testing the LFC3 operated for over
700 hours with minimal fouling.
33
5.4 Water Quality
5.4.1 Raw Wastewater
The results of raw wastewater grab sample analyses conducted by the Point Loma Satellite and
Alvarado Water Treatment Facility Laboratories are presented in Table 5-1. The values shown
are typical of municipal wastewater.
5.4.2 Advanced Primary Effluent
The results of the advanced primary effluent wastewater grab sample analyses conducted by the
Point Loma Satellite and Alvarado Water Treatment Facility Laboratories are presented in Table
5-2.
5.4.3 MBR Pilot Systems
5.4.3.1 Turbidity and Silt Density Index (SDI)
The US Filter MBR effluent on-line turbidity data is provided in Figure 5-11. During Part 1 the
raw wastewater turbidity was between 58-210 NTU. The MBR effluent ranged from
0.01 to 0.12 NTU with average value of 0.03 NTU. During Part 2, the advanced primary effluent
turbidity ranged from 36-130 NTU. MBR effluent ranged from 0.02 to 0.06 NTU with average
value of 0.05 NTU.
The Kubota MBR effluent on-line turbidity data is provided in Figure 5-12. During Part 1, the
raw wastewater turbidity was between 58-210 NTU. The Kubota MBR effluent ranged from
0.05 to 0.13 NTU with average value of 0.08 NTU. During Part 2, the advanced primary effluent
turbidity raged from 36-130 NTU. MBR effluent ranged from 0.06 to 0.13 NTU with average
value of 0.08 NTU. Kubota MBR SDI values measured during Phase I ranged from 0.9-1.1.
5.4.3.2 BOD
5
, COD and TOC
The five-day biochemical oxygen demand (BOD
5
), COD and TOC values for raw wastewater,
advanced primary effluent and the US Filter MBR effluent are shown in Figure 5-13. The
median value of BOD
5
, COD and TOC measured in the raw wastewater was 213 mg/L, 463
mg/L and 40 mg/L, respectively. The organic content of the advanced primary effluent was
significantly lower with median values of BOD
5
and COD measuring 97 mg/L and 216 mg/L,
respectively. The BOD
5
of the US filter effluent was < 2 mg/L for all samples; except at 768
hours of operation when BOD
5
was measured to be 6.7 mg/L. All US Filter MBR effluent TOC
samples were < 10 mg/L and the majority of COD samples measured by the Point Loma Satellite
Lab were < 50 mg/L. Previous studies indicate MBR effluent COD < 20 mg/L. As a result, on
several occasions COD samples were sent to a commercial lab for analysis. The results showed
the average COD in US Filter MBR effluent was 21 mg/L. The discrepancy in COD results
maybe due to the presence of chloride which can elevate results.
34
The BOD
5
, COD and TOC values for raw wastewater, advanced primary effluent and the Kubota
MBR permeate are shown in Figure 5-14. The BOD
5
of the Kubota MBR effluent was 2 mg/L
for all samples. All Kubota MBR effluent TOC samples were < 10 mg/L and the majority of
COD samples measured by the Point Loma Satellite Lab were < 55 mg/L. The average value of
COD measured by Calscience Laboratories was 15 mg/L.
5.4.3.3 Biological Nutrient Removal
The inorganic nitrogen results including ammonia, nitrate/nitrite and nitrite from the raw
wastewater, advanced primary effluent and US Filter MBR effluent are shown in
Figure 5-15. As shown, the NH
3
-N content of the raw wastewater and advanced primary effluent
were essentially the same with an average value of 27 mg/L. All of the US Filter MBR effluent
samples measured for NH
3
-N during the study were < 2 mg/L with many values below the
detection limit of 0.2 mg/L. Also, the (NO
3
/NO
2
)-N of MBR effluent was consistently above
20 mg/L. Such results indicate the system was completely nitrifying throughout the testing.
Figure 5-17 shows Ortho-phosphate as phosphorus (PO
4
-P) results for analyses conducted on the
raw wastewater, advanced primary effluent and US Filter MBR effluent. As shown, the Ortho-
phosphate (PO
4
) content of the raw wastewater and advanced primary effluent was very low with
values measuring between 0.054- 2.24 mg/L. The US Filter permeate PO
4
ranged from 0.12-
0.65 mg/L. Because the US Filter system was only operating with an aerobic zone it was not
possible for BPR (biological phosphorus removal) to occur.
The inorganic nitrogen results for the Kubota MBR system are shown in Figure 5-16. As shown,
during Part 1, the Kubota MBR successfully removed ammonia, nitrate and nitrite to values
< 1 mg/L N. Such results indicate the system was fully nitrifying and denitrifying during this
time period. However, during Part 2 testing the amount of NO
3
/NO
2
in the Kubota effluent
increased. For example, during Part 1 all values were < 1 mg/L but during Part 2 values ranged
from 3.4 6.8 mg/L. Such results indicate that denitrification was decreased during operation on
advanced primary effluent. This observation is believed to have resulted from excess DO in the
MBR system due to the lower organic content of the advanced primary effluent. During Part 2
testing, the minimum air required for membrane scouring resulted in DO measured in the aerobic
to be between 3-5 mg/L. Introduction of DO into the anoxic zone would slow down the
denitrification process. Figure 5-18 shows PO-P results for analyses conducted on the Kubota
MBR system. During Part 1, the majority of the feed wastewater samples ranged from
0.2 1.5 mg/L, while the Kubota effluent was consistently below 0.1 mg/L. These results
indicate BPR was occurring in the anoxic zone of the Kubota MBR system. However, during
Part 2 the PO
4
in the Kubota effluent increased to values ranging from 0.2-0.4 indicating a
decline in BPR. The decrease in BPR is directly related to the partial loss of denitrification also
observed during Part 2 testing. The presence of NO
3
in the anoxic tank created an anoxic
environment that was not conducive to BPR.
35
5.4.3.4 Total Coliform, Fecal Coliform, Total Coliphage
The results of total coliform, fecal coliform and total coliphage analyses conducted on the feed
wastewater and US Filter MBR effluent are presented in Figure 5-19. Initial results from Part 1
testing showed total and fecal coliform rejections (3-5 log) were obtained with total coliform
permeate levels (MPN/100 ml) ranging from 230 to 3,000 and fecal coliform permeate levels
(MPN/100 ml) ranging from 22 to 230. However, after 1700 hours of operation, higher total and
fecal coliform rejections (4-7 log) were achieved, with total coliform permeate levels ranging
from 2 to 240 MPN/100 ml and fecal coliform permeate levels below 10 MPN/100 ml. The
enhanced removal may be due to pore plugging of a portion of the larger pores within the
membrane pore size distribution. Lastly, the US Filter MBR obtained 3-4 log rejection of natural
coliphage throughout the testing period.
Several measures were taken during the study to determine the cause of high total and fecal
coliform counts measured in the US filter MBR effluent. These included: disinfecting the
permeate side of the membrane, replacing the permeate sample location; taking samples at
different times in the filtration cycle and taking samples just after cleaning the membranes.
Overall, results showed that total and fecal counts were higher in samples taken just after a
backwash and just following a membrane cleaning. A possible explanation of the results
follows. First, the permeate piping became contaminated during backwashing due to the
presence of algae and bacterial growth which occurred in the permeate storage tank. Second,
cleaning the membranes removed the dynamic layer formed on the membrane surface, reducing
the sieving ability of the membranes.
The results of total coliform, fecal coliform and total coliphage analyses conducted on the
Kubota MBR system are presented in Figure 5-20. As indicated, samples were analyzed from
both the upper and lower membrane cassettes. Total and fecal coliform rejections (5-7 log) were
obtained with most permeate levels at or below the detection limit (2.2 MPN/100 ml). In
addition, significant rejections (3-5) of total coliphage virus were also obtained by the Kubota
MBR system.
5.4.3.5 Other Water Quality Parameters
The results of the US Filter MBR system analyzed by the Point Loma Satellite and Alvarado
Water Treatment Facility Laboratories during Part 1 and Part 2 testing are presented in
Tables 5-3 and 5-4, respectively. Laboratory results for the Kubota MBR system are presented
in Tables 5-5 and 5-6, respectively.
5.4.4 RO Pilot Unit
5.4.4.1 Inorganic Nitrogen and Ortho-Phosphate Removal
The Saehan 4040 BL RO feed and permeate inorganic nitrogen species are shown in Figure 5-21.
The RO permeate NH
3
-N values were all below 0.3 mg/L with many values below detection; the
NO
3
-N values were between 0.1 and 1.9 mg/L; and the NO
2
-N values ranged from 0.006 to
0.021 mg/L with many values below detection. Ortho-phosphate measured in the Saehan RO
36
feed and permeate is shown in Figure 5-22. All PO
4
measurements in the RO permeate were
below 0.03 mg-P/L with majority below the detection limit of 0.02 mg-P/L.
The Hydranautics LFC3 RO feed and permeate inorganic nitrogen species are shown in
Figure 5-23. The RO permeate NH
3
-N values were all below 0.3 mg/L with many values
below detection; the NO
3
-N values were between 0.1 and 0.8 mg/L; and the NO
2
-N values
ranged from 0.005-0.019 mg/L with many values below detection. Ortho-phosphate
measurements in the LFC3 RO permeate are shown in Figure 5-24. All PO
4
measurements in
the RO permeate were below 0.04 mg-P/L with majority below the detection limit of 0.02 mg-
P/L.
5.4.4.2 TOC Removal
All TOC measurements in the effluent of the Saehan 4040 BL and Hydranautics LFC3 RO
membranes were below detection of 0.5 mg/L.
5.4.4.3 Salt Rejection
The conductivity measured in the feed and Saehan RO permeate is provided in Figure 5-25. The
Saehan RO membranes achieved greater than 96 percent reduction in conductivity throughout
the testing.
The conductivity measured in the feed and Hydranautics LFC-3 RO permeate is provided in
Figure 5-26. The LFC-3 RO membranes achieved greater than 98 percent reduction in
conductivity throughout the testing.
The results of the Kubota Saehan RO samples analyzed by the Point Loma Satellite and
Alvarado Water Treatment Facility Laboratories are presented in Table 5-7. Laboratory results
for the Kubota Hydranautics RO pilot unit can be found in Table 5-8.
37
6. Results and Discussion- Phase II:
Optimization of MBR Systems
6.1 MBR Operating Conditions
Upon completion of Phase I testing, the Kubota and US Filter MBR systems were
decommissioned and removed from the pilot site. Next, the site was completely cleared and
prepared to accommodate the Zenon and Mitsubishi MBR pilot systems. Representatives from
each manufacturer came to the site to commission their MBR systems and assist the project team
in preparing hydraulic and electrical connections. Past research by the project team
demonstrated that the Zenon and Mitsubishi MBR systems could operate successfully on raw
municipal wastewater (Adham et al., 2000). Therefore, during Phase II testing, both systems
were connected to receive advanced primary effluent to assess the affect of polymer and
coagulant addition on their performance. Furthermore, the project team worked closely with
Zenon, the current market leader in MBR technology, to test their system under extreme
operating conditions. Both systems were seeded using activated sludge from the nearby South
Bay Water Reclamation Plant (SBWRP). During start up, the systems were operated without
wasting to allow the MLSS to increase to target values of 10-12 g/L, the operation goal. At this
time, a daily wasting routine was implemented to maintain the MLSS concentration in the
aeration tanks.
Zenon. The Zenon MBR system was operated with an aerobic tank and ZenoGem tank having a
combined HRT of 2 hours at a flux of 22 gfd (37.3 L/hr-m2). The ZW 500 d membrane was
operated with a 10 minutesfiltration cycle, followed by a 30 s relaxation period. Maintenance
cleans were performed three times per week (2/week, 250 mg/L-NaOCl, 1/week, citric acid-2
percent). A mixed liquor wasting routine was implemented to give an SRT 7-d of 18-21 days
and MLSS concentration of 1012 g/L.
HRT and SRT 7-d data are presented in Figure 6-1. The Zenon MBR concentrations of MLSS
and MLVSS are presented in Figure 6-2. As indicated, after 2,300 hours of operation the MLSS
concentration decreased from 10.7 to 3.3 g/L. This occurred due to failure of the wasting valve
on the pilot system. The valve was repaired and the system was re-seeded with a fresh batch of
MLSS of approximately 5.0 g/L from the SBWRP. As shown, the MLSS reached the target
10-12 g/L shortly thereafter. As presented in Figure 6-2, the normal sludge-wasting rate required
to maintain the target solids concentration was 2-3 kg VSS/day. The course bubble aeration in
the ZenoGem tank was operated at 21 scfm (0.6 m3/min) intermittently (10 s on, 10 s off). The
aerobic tank air flow rate was constant at 56 scfm (1.6 m3/min). The DO measured in the
aerobic tank is presented in Figure 6-3. As shown during stable operation the DO was between
0.5 to 1.5 mg/L.
38
Mitsubishi. The Mitsubishi MBR system was initially operated with an aerobic tank having a
HRT of 3.5 hours at a flux of 11.8 gfd (20 L/hr-m2). Later, the flux was increased to 14.7 gfd
(24.9), which reduced the HRT to 2.8 h. The Mitsubishi Sterapore HF membrane was operated
with a 12 minutes filtration cycle, followed by a 2-minute relaxation period; air stayed on during
relax. Mixed liquor was wasted daily to give an SRT 7-d of 25-37 days and MLSS concentration
of 1115 g/L. HRT and SRT 7-d data are presented in Figure 6-4. The Mitsubishi MBR
concentrations of MLSS and MLVSS are presented in Figure 6-5.
As shown, the MLSS was allowed to increase from 3.6 to 12.9 g/L during start up. After
2,352 hours of operation, the MLSS were severely diluted resulting in a decrease in
concentration from 10.3 to 2.2 g/L. The MLSS dilution occurred during an attempt to control
foam using a spray nozzle attached near the overflow of the aeration tank. Lastly at 2,568 hours
of operation the blower on the system failed and the system was shut off. During the down time,
the solids in the aeration tank received no air and therefore went anoxic. A new blower was
installed and the system was re-seeded and brought back online at 3,000 hours of operation.
The total and fine air flow rate provided to the aerobic tank is provided in Figure 6-6. Initially,
the system was only operated with coarse air bubble aeration at a rate of 45 scfm (1.3 m
3
/min).
However, as the flux was increased, the DO in the aerobic tank dropped below values conducive
for nitrification. Several modifications were made to the aeration system to combat the low DO
levels. First, at 489 hours of operation an in-line check valve was removed from the blower
which increased the air flow to 52 scfm (1.5 m
3
/min). Second, after 650 hours of operation, the
blower was modified which further increased the air flow to 67 scfm (1.9 m
3
/min). Lastly, after
1,447 hours of operation fine bubble diffusers were added to the aeration tank. The fine bubble
air flow rate was set between 10-16 scfm (0.28-0.45 m
3
/min) for the remainder of the testing.
The DO measured in the aerobic tank is provided in Figure 6-7. During steady periods of
operation the DO was maintained around 0.5 mg/L (with coarse air only) and 1-2 mg/L (with
coarse and fine air).
6.2.1 MBR Pilot Plants
Zenon. The membrane performance data from the Zenon MBR system is presented in
Figure 6-8. As indicated at 674 hours of operation, the variable frequency drive (VFD)
controlling the influent feed pump failed. Over the next 150 hours of operation the overall
vacuum pressure increased from 1.0 (0.069 bar) to 3.3 psi (0.23 bar). This sharp increase in
vacuum pressure resulted from the system being operated with no input of feed water. As
filtration continued, the operating HRT decreased with the level in the aerobic tank. Eventually,
the DO in the aerobic tank became insufficient for biological oxidation of organic material to
occur which caused membrane fouling. At 800 hours (33 days) of operation, the membranes
were cleaned using acid and chlorine. The cleaning reduced the overall vacuum pressure from
3.3 to 1.9 psi
(0.23 to 0.13 bar). During the next operational period the VFD continued to fail; resulting in
unstable operation and continued membrane fouling. It should be noted that during this time
period the on-site engineer worked with a representative from Zenon to change the settings on
the VFD in hopes of correcting the problem. It was finally decided to remove the VFD from the
39
system and operate using a constant feed pump, controlled by level sensors placed in the aerobic
tank. At this time, a representative from Zenon came to the site to make appropriate changes to
the system to allow such operation.
A membrane cleaning was performed again at 1,350 hours (56 days) of operation which reduced
the overall vacuum pressure from 7.5 to 2.3 psi (0.52 to 0.16 bar). The system was then placed
in operation at a flux of 22 gfd (37.3 L/hr-m2) and HRT of 2 hours. As shown, the overall
vacuum pressure remained near 2.5 psi (0.17 bar) for nearly 550 hours (23 days) of operation.
However, at 1,850 hours of operation nitrification was partially lost; which caused the overall
vacuum pressure to quickly increase from 2.5 to 9.5 psi (0.17 to 0.66 bar). Based on discussions
with Zenon, it was determined that the decrease in nitrification and subsequent membrane
fouling may have resulted from a low, operating food to microorganism ratio (F/M ratio). The
manufacturer recommended increasing the MLSS in the aeration to approximately 11 g/L to
maintain F/M ratio < 0.4 day -1. The system was cleaned again at time of operation 1,950 hours
and placed back into operation. As previously explained the mixed liquor was diluted at 2,350
hours of operation. The system was cleaned again after 2,450 hours of operation which reduced
the overall vacuum pressure to 1.8 psi (0.12 bar). Post cleaning, the system was brought back on
line at flux of 17 gfd
(28.8 L/hr-m2). At 2,639 hours of operation the flux was increased to 22 gfd (37.3 L/hr-m2) and
HRT of 2 h. The 500 d membrane was operated for over 1,800 hours (75 days) at these
conditions during which time the overall vacuum pressure only increased from 1.3 (0.09 bar) to
3.0 psi (0.21 bar).
Mitsubishi. The membrane performance of the Mitsubishi MBR system is shown in Figure 6-9.
As indicated the flux was increased to 11.8 gfd (20 L/hr-m2) after 128 hours (5.3 days) of
operation. The system was operated for over 1,500 hours (62 days) during which time the
overall vacuum pressure increased from 0.71 (0.05 bar) psi to 2.0 psi (0.14 bar). As part of
optimizing the Mitsubishi MBR system, the flux was increased to 14.8 gfd (25.1 L/hr-m2) after
1,700 hours (70.8 days) of operation. Over the next 150 hours (6.3 days) of operation the overall
vacuum pressure was stable at 2.5 psi and the DO in the system remained above 0.5 mg/L. As
indicated, the membranes were cleaned after 1,850 hours (77 days) of operation. The cleaning
reduced the vacuum pressure from 2.6 (0.18 bar) to 1.3 psi (0.09 bar). Post cleaning, the system
was brought back on-line at the target flux of 14.8 gfd (25.1 L/hr-m2). However, as shown in the
upper graph, after 1,990 hours of operation it was necessary to decrease the operating flux
because of excessive foaming in the aerobic tank. The foaming is believed to have resulted from
the membrane cleaning because chlorine was brought into direct contact with the MLSS. As
shown during the next 724 hours (30 days) of operation foaming continued and resulted in
unstable operation of the MBR system. During this time period, several tactics were employed
to mitigate foaming and resume stable operation. For example, a sprayer system was constructed
and installed on the pilot system. The sprayer system consisted of inch tubing which
surrounds the perimeter and passes across the center of the aeration tank. Spray nozzles which
produce a fine mist were placed every 6 inches along the tubing. The sprayer system was
operated using a timer which can be set to turn on/off up to 6 times per day.
The Mitsubishi MBR system was shut down after 2,568 hours (107 days) operation when the
blower failed. A new blower was immediately ordered and installed within 2 weeks of the
40
occurrence. The aerobic tank was drained, flushed with potable water and reseeded prior to start
up because the MLSS was without aeration for several weeks. The system was brought back on
line after 3,000 hours of operation at a flux of 11.8 gfd (20 L/hr-m2) and the MLSS was allowed
to reach
14 g/L. At this time the flux was increased to 14.8 gfd (25.1 L/hr-m2) and the Mitsubishi
Sterapore HF membrane was operated for over 800 hours (30 days) during which time vacuum
pressure increased from 2.13 to 3.27 psi.
6.3 Water Quality
6.3.1 Advanced Primary Effluent
The results of advanced primary effluent wastewater grab sample analyses conducted by the
Point Loma Satellite and Alvarado Water Treatment Facility Laboratories are presented in Table
6-1.
6.3.2 MBR Pilot Systems
6.3.2.1 Turbidity
The Zenon MBR effluent on-line turbidity data is provided in Figure 6-10. As shown, the
advanced primary effluent turbidity measured during Phase II testing ranged from 23-63 NTU.
During the entire testing period, the Zenon MBR effluent turbidity ranged from 0.03 to 0.1 NTU
with average value of 0.06 NTU. As shown, at 2700 hours of operation the MBR effluent
turbidity decreased from 0.06 to 0.04 NTU after the turbidimeter was cleaned.
The Mitsubishi MBR effluent on-line turbidity data is provided in Figure 6-11. During the entire
testing period, the Mitsubishi MBR effluent turbidity ranged from 0.04 to 0.10 NTU with
average value of 0.07 NTU. As shown, the turbidimeter cleaning performed at 3,772 hours of
operation reduced the turbidity from 0.08 NTU to 0.05 NTU.
6.3.2.2 BOD
5
, COD and TOC
The BOD
5
, COD and TOC values for advanced primary effluent and the Zenon MBR effluent
are shown in Figure 6-12. The median value of BOD
5
, COD and TOC measured in the advanced
primary effluent during Phase II testing was 112 mg/L, 237 mg/L and 44 mg/L, respectively.
The BOD
5
in the Zenon MBR effluent was below the detection limit of 2 mg/L in all samples.
Zenon MBR effluent TOC samples were all < 9 mg/L and all COD samples < 28 mg/L.
The BOD
5
, COD and TOC values for the advanced primary effluent and the Mitsubishi MBR
effluent are shown in Figure 6-13. The BOD
5
in the Mitsubishi MBR effluent samples were all
< 2 mg/L. All Mitsubishi MBR effluent TOC samples were < 10 mg/L and the COD ranged
from 18-31 mg/L with median value of 21 mg/L.
6.3.2.3 Biological Nutrient Removal
The inorganic nitrogen results including ammonia, nitrate/nitrite and nitrite from the Zenon
MBR effluent are shown in Figure 6-14. All of the Zenon MBR samples measured for NH
3
-N
were < 2 mg/L except the sample taken at 1,872 hours of operation which measured 5.0 mg/L.
At this time, the MBR system was being operated with F/M > 0.4 day-1 which is above the
41
manufacturers recommendation. Following this event, the F/M was decreased by increasing the
MLSS concentration and nitrification was resumed. As shown in the middle graph, the
(NO
3
/NO
2
)-N of MBR effluent was consistently above 18 mg/L indicating complete nitrification.
Figure 6-15 shows PO
4
-P results for analyses conducted on the advanced primary effluent and
Zenon MBR effluent. As shown, the PO
4
content of the advanced primary effluent was between
0.035- 1.23 mg/L and Zenon MBR effluent ranged from 0.3 to 1.24 mg/L. BPR will not occur in
MBR systems operating with only an aerobic tank.
The inorganic nitrogen results for the Mitsubishi MBR system are shown in Figure 6-16. The
high levels of ammonia (>5 mg/L) present in the Mitsubishi permeate during the initial
600 hours of operation indicate the system was not achieving complete nitrification. Such data is
expected as the seed sludge was growing during this time period and the nitrifying bacteria are
relatively slow growers. However, after 850 hours of operation all ammonia samples from the
Mitsubishi permeate were below 1.0 mg/L as N. The achievement of nitrification can also be
seen in the plot of nitrite/nitrate which shows a trend of increasing NO
2
/NO
3
concentration in the
Mitsubishi permeate with an increase in time of operation. Figure 6-17 shows PO
4
-P results for
analyses conducted on the advanced primary effluent and Mitsubishi effluent.
6.3.2.4 Total Coliform, Fecal Coliform, Total Coliphage
The results of total coliform, fecal coliform and total coliphage analyses conducted on the feed
wastewater and Zenon MBR effluent are presented in Figure 6-18. As shown, the Zenon system
achieved total and fecal coliform rejections ranging from 3-7 log. The total coliform measured
in the Zenon permeate were quite high ranging from 14 to 5,000 MPN/100 mL while the fecal
coliform were consistently below the detection limit of 2.2 MPN/100 mL. Also shown, the
Zenon MBR system achieved total coliphage rejections (4.0-5.5 log) with all values in the
permeate at or below the detection limit of 1.0 plaque forming units (PFU)/100 mL.
The fact that the Zenon permeate showed high total coliform counts, despite low counts of fecal
coliform and total coliphage suggested the presence of contamination on the permeate side of the
membrane. Accordingly, the entire permeate piping system was disinfected after 2,900 hours of
operation. As shown, all post disinfection total and fecal coliform measurements in the Zenon
MBR permeate were 2.2 MPN/100 ml.
Figure 6-19 presents the total and fecal coliform and total coliphage in the influent and effluent
of the Mitsubishi measured during Phase II testing. As shown, the Mitsubishi system achieved
excellent rejections (5.5-7.0 log) of total and fecal coliform with permeate levels consistently
below the detection limit of 2.2 MPN/100 mL. Such data indicates the Mitsubishi MBR is an
excellent barrier to bacteria present in the feed wastewater.
Also shown, the Mitsubishi system achieved between 3-5 log rejection of total coliphage with
many measurements in the permeate below the detection level of 1.0 PFU/100 mL. The data
collected during the first 1,100 hours of operation, clearly shows a trend of decreased permeate
coliphage with increasing time of operation. This would be expected for two reasons. First, the
amount of total coliphage absorbed to the MLSS increases with increased solids concentration.
Secondly, as the membranes become clogged the pore size is decreased which results in removal
of virus and other particles which could normally pass through the membrane. It should be noted
new membranes were installed on the pilot system before beginning the study.
42
The results of water quality analysis conducted on Zenon MBR effluent by the Point Loma
Satellite and Alvarado Water Treatment Facility Laboratories is presented in Tables 6-2.
Likewise, laboratory results for the Mitsubishi MBR system from Phase II testing are presented
in Table 6-3.
43
7. Title 22 Approval of MBR Systems
7.1 Zenon and Mitsubishi
In March 2000, the project team met with the CDHS to develop a specific testing protocol for the
approving MBR systems as an acceptable filtration technology for compliance with the State of
Californias Water Recycling Criteria (Title 22). It was decided approval would be based on the
systems ability to meet the following criteria:
- Turbidity performance (not to exceed 0.2 NTU more than 5 percent of the time within
24-hour period; and 0.5 NTU anytime)
- Long Term Operational Data (approval to be based on flux and vacuum pressure range)
- Approval to be membrane specific
- Demonstrate ability of the system to achieve 1-log virus reduction at the 50th percentile
Shortly after these criteria were established, the project team performed long term testing on the
Zenon and Mitsubishi MBR systems under grant funding from the Reclamation (Adham et al.,
2000). Following this testing, the project team conducted virus challenge studies on these
systems through funding provided by the National Water Research Institute. Based on the
results from these two research projects, both the Zenon and Mitsubishi MBR systems received
Title 22 approval in April 2001 (Adham et al., 2001 a and b).
7.2 Kubota and US Filter
At the end of Phase I pilot testing of the current study, representatives from Enviroquip
Inc./Kubota Corporation expressed interest in obtaining regulatory approval for the use of the
Kubota MBR to meet California's Title 22 Water Recycling Criteria. Accordingly, the project
team conducted additional testing on the Kubota MBR system at PLWTP to meet the
requirements established by the CDHS. The project team prepared a report summarizing the
results of the virus challenge experiments and operational performance data collected from the
evaluation of the Kubota MBR system pilot system at PLWTP. This report was submitted to the
CDHS in February 2003 (Adham and DeCarolis, 2003). In March 2003, the CDHS sent an
approval letter to Kubota stating their acceptance of the Kubota Type 510 flat sheet membrane to
meet Title 22 water recycling criteria. A copy of the approval letter is presented in Appendix E.
Also during the current study, representatives from the US Filter Corporation/Jet Tech Products
Group contacted the project team and the CDHS regarding Title 22 approval requirements for
MBR systems. After reviewing MBR operational data collected from Point Loma, the CDHS
44
accepted the MemJet B10 R membrane to meet the Title 22 water recycling criteria. The virus
rejection data of the MemJet B10 R membrane was collected during CDHS approval testing of
the membrane for drinking water applications conducted at the Aqua 2000 research center.
(Adham and Gramith, 2001).
45
8. MBR Performance Comparison
8.1 MBR Operating Experience
The four MBR pilot systems were all completely automated, however; a varying degree of
operator attention was required for each pilot system. The following summarizes operational
experiences with each system.
8.1.1 US Filter MBR System
On numerous occasions during operation on raw wastewater several components of the US filter
MBR pilot were clogged with debris and hair which ultimately caused the system to enter into
alarm mode and shut down. In particular, clogging occurred in the following areas: pre-
screen, piping from the aerobic tank to the membrane tank and the rotameter located before the
membrane tank. Another operational problem experienced with the US Filter MBR system was
the level control system equipped in the aerobic tank. On several occasions during testing the
tank overflowed causing the MLSS to be severely diluted. This made it difficult to maintain a
steady SRT. It was later discovered that the wiring for the high/low level switched was reversed.
As a result, when the aerobic tank level reached a high level the feed pump would continue as if
the level was low. These reoccurring incidences throughout the testing made it necessary to
provide a significant amount of operator attention to keep the US Filter MBR operating at steady
state.
8.1.2 Kubota MBR System
On two occasions during testing, the stainless steal camlock fitting on the discharge side of the
submersible transfer pump located in anoxic zone deteriorated and became detached. The
transfer pump is used to transfer wastewater from the anoxic tank to the aerobic tank where
membrane filtration occurs. Once the camlock became detached, the membrane tank received no
further input of feed wastewater and therefore the level dropped as filtration continued. Because
the transfer pump was submerged, it was necessary to use a fork lift to remove the pump from
the system in order to replace the camlock fitting. Also, as mentioned in Section 5.3, the pilot
system was originally equipped with permeate piping lines. This appears to have caused an
increase in pressure loss associated with piping loss. As a result, the system was taken offline.
During this time it was necessary to remove the membrane cassettes using a crane and replace
perm piping with 2 line. Once these modifications were made, the Kubota MBR pilot operated
smoothly with little operator attention.
8.1.3 Zenon MBR System
During the initial period of Phase II testing, the VFD controlling the feed water flow rate to the
aerobic tank failed. The VFD was removed from the system and replaced with level control
switches. From this point forward the Zenon MBR required minimal operator attention.
46
8.1.4 Mitsubishi MBR System
Upon increasing the flux rate it was necessary to modify the blower system equipped on the
Mitsubishi pilot to provide adequate DO for biological oxidation. Also, after the first membrane
cleaning event the biological system was unstable causing a significant amount of foam to form
in the aerobic tank. During periods of foaming the Mitsubishi MBR system required a lot of
operator attention to prevent MLSS from spilling over the top of the aeration tank. This included
building and installing a sprayer system to help control foaming.
8.2 Operating Conditions
8.2.1 Flux, HRT, SRT and MLSS
The US Filter and Kubota MBR systems were operated with flux and HRT values typical of full
scale MBR processes. These include flux of 15 gfd and HRT ranging from 4-8 h. However, the
Zenon and Mitsubishi systems were operated under more extreme operating conditions in effort
to optimize the MBR process for water reclamation. For example, the flux of the Zenon and
Mitsubishi MBRs systems was increased and sustained at 22 gfd and 15 gfd, respectively. Such
flux values exceed the manufacturers recommended membrane flux. The HRT of the Zenon and
Mitsubishi systems were ultimately reduced to 2 hours and 2.8 h, respectfully. All four systems
were operated with typical SRT (11-20 days) and MLSS concentrations (9-14 g/L) used in full
scale MBR processes.
8.2.2 Frequent Relaxation/Backpulsing
The Kubota, Mitsubishi and Zenon MBR systems relaxed during operation to prevent membrane
fouling while the US Filter system used backwashing. The frequency and duration of relaxations
ranged from 9-12 minutes and 0.5 2 minutes, respectively. The backwash frequency and
duration of the US Filter MBR was 12 minutes and 1 minute, respectively. The use of
relaxation, as opposed to backpulsing, eliminates the need for additional permeate storage tanks
and/or valves and piping. In addition, total coliform results collected from the US filter MBR
system also suggest that backpulsing can introduce contamination into the permeate piping due
to algae growth in the permeate tank. Lastly, as reported by Adham et al., 1998, membrane
integrity is another factor to consider in systems that use backpulsing. The authors explained
that during filtration the applied vacuum pressure typically causes the solids to clog broken
fibers. However, on systems that backpulse these seals can become broken over time which
makes it necessary to replace the compromised fiber(s).
8.2.3 Air Usage (Membrane Scour and Biological Requirements)
Each MBR system used coarse bubble aeration to reduce membrane fouling. Membrane airflow
rates per membrane area (scfm/ft
2
) for the US Filter, Kubota, Zenon and Mitsubishi MBR
systems were 0.023, 0.033, 0.030, and 0.028, respectively. The Zenon MBR system was the
only system operated with intermittent coarse air, which reduced the total air usage by
50 percent. Each system also used fine bubble aeration to provide sufficient DO to the activated
sludge. The fine air to the Kubota MBR was applied intermittently as necessary to maintain 2
mg/L DO in the aerobic tank. All other MBR systems tested were operated with constant fine
bubble aeration.
47
8.2.4 Membrane Cleaning
The cleaning procedures for all four MBR systems used chlorine (2-3 g/L) followed by citric or
oxalic acid (2 percent). However, the Zenon and US Filter membranes were cleaned in place
(CIP) while the Mitsubishi and Kubota membranes were cleaned in-line (CIL). During a CIP,
the membranes were isolated from the MLSS and chemicals were recirculated through the
membranes prior to soaking. During a CIL, the membranes were not isolated from the MLSS
and chemical was allowed to slowly flow by gravity from the inside to the outside of the
membranes. This procedure introduces chemicals into direct contact with activated sludge.
Such contact caused a significant amount of foaming to occur in the Kubota and Mitsubishi
MBR systems during post cleaning operation. For the Kubota MBR system, which transferred
MLSS from anoxic to aerobic zone foaming was mitigated within 1 or 2 days following a
cleaning event with no added foam control. However in the case of Mitsubishi, which was only
operated with an aerobic tank, foaming persisted for several weeks after cleaning. As a result, it
was necessary to install a sprayer system for foam control. Other than foaming issues, both
methods of cleaning were effective at reducing vacuum pressure. Furthermore, acid was the
most effective cleaning chemical for all four systems.
All four MBR systems demonstrated good membrane performance throughout the testing.
The Kubota and US filter membranes required minimal cleaning during operation on both raw
wastewater (Part 1) and advanced primary effluent (Part 2). In Part 1 testing, the Kubota MBR
was only cleaned once after 788 hours (33 days). Post cleaning the membrane was operated for
over 2,000 hours (83 days) at 15 gfd without cleaning. During Part 2, no cleanings were
performed and the membrane operated for over 1,800 hours (75 days) at 15 gfd on advanced
primary effluent with no fouling. During Part 1 testing, the US Filter was cleaned with chlorine
after
2,954 hours (123 days) at 11.5 gfd. Shortly after, the system was cleaned using acid which
further reduced the TMP. Following this cleaning the membrane operated for nearly 1,000 hours
(42 days) at 14.5 gfd during which time little fouling occurred. The system was cleaned again
after 4,201 hours of operation to begin testing at increased flux rates ranging from 19-24 gfd. In
Part 2 testing no cleanings were performed and the US Filter membrane was operated for 1,000
hours (42 days) at 14.5 gfd during which time little membrane fouling was observed.
The Zenon membrane was cleaned after 800 hours (33 days) and 1,350 (56 days) of operation
due to problems associated with the feed pump which caused membrane fouling. After this
problem was fixed the membrane was operated for 600 hours (25 days) at 22 gfd before another
cleaning was performed. A final cleaning was necessary at time of 2,500 hours (104 days) due
to dilution of the solids. The system was then operated for 1,800 hours (75 days) at 22 gfd
without cleaning and with minimal fouling. Throughout testing, maintenance cleans were
performed three times per week on the Zenon membrane to mitigate fouling. The Mitsubishi
MBR system was cleaned after 1,850 hours (77 days) while operating at 11.8 gfd. Following
this cleaning the system was operated at low flux due to excessive problems with foaming. The
system was brought back online at 3,000 hours of operation and operated for 800 hours (30 days)
at a flux of 15 gfd without cleaning. During this time minimal membrane fouling occurred.
48
Each MBR system demonstrated the ability to operate for a run time of 1800 hours (75 days)
between membrane cleanings with minimal to moderate increases in vacuum pressure. The
increased amount of cleaning necessary on the Zenon system was largely due to the reduced
HRT and increased flux under which the system was operated.
8.4 MBR Effluent Water Quality (Phase I, Part 1: Kubota and US
Filter)
The US Filter and Kubota MF membranes produced turbidity values 0.06 NTU and
0.10 NTU, respectively, in 90 percent of the samples as shown in Figure 8-1. The slightly
lower turbidity values measured in the US Filter MBR effluent as compared to Kubota MBR
effluent may be due to differences in the on-line turbidity instrumentation equipped on each
MBR system. As presented in Appendix C, the US Filter was equipped with a GLI Accu4
turbidimeter while the Kubota MBR system was equipped with Hach 1720D turbidimeter. This
was confirmed by analyzing a series of grab samples from each membrane using a desktop
turbidimeter. Results showed the average turbidity of the US filter and Kubota membranes to be
0.06 NTU and 0.07 NTU, respectively.
8.4.2 Organics Removal
Both MBR systems produced excellent removal of organic constituents while operating on raw
wastewater. For instance, as shown in Figure 8-2, the BOD
5
measured in the MBR effluent was
below the detection limit of 2 mg/L in 92 percent of the US filter samples and 100 percent of the
Kubota samples. Figure 8-3 shows a probability plot of TOC measured in the raw wastewater
and effluent from both MBR systems. As shown, both the US filter and Kubota MBR systems
produced TOC 9 mg/L in 90 percent of all sample measurements.
During Part 1 testing the US Filter and Kubota MBR systems produced effluent with
NH
3
< 2 mg-N/L in 90 percent of all samples measured as shown in Figure 8-4. Such results
indicate that the both MBR systems successfully achieved nitrification during operation on raw
wastewater. Also, shown the total inorganic nitrogen in the US filter system was < 27 mg-N/L in
80 percent of samples while the Kubota MBR effluent was <2 mg/L in 100 percent of the
samples. Such results indicate that Kubota system successfully achieved complete denitrification
throughout Part 1 testing. As expected denitrification was not observed in he US filter MBR
because the anoxic tank was bypassed and the system was only operated with an aerobic zone.
Both MBR systems showed removal of Ortho-phosphate during Part 1 testing as shown in
Figure 8-5. The MBR PO
4
measured < 0.5 mg-P/L and < 0.1 mg/L in 90 percent samples of the
US filter and Kubota MBR systems respectively. The higher removal of Ortho-phosphate
removal by the Kubota system was attributed to the presence of the anoxic zone which provides
a conducive environment for BPR occur once.
49
8.4.4 Total Coliform, Fecal Coliform, Total Coliphage Removal
Both MBR systems removed total and fecal coliform throughout Part 1 Testing as shown in
Figures 8-6 and 8-7, respectively. Total coliform analysis showed the US Filter MBR effluent
contained 1,000 MPN/100 mL in 90 percent of all samples and Kubota MBR effluent was
2 MPN/100 mL in 100 percent of the samples measured.
Fecal coliforms in the US filter MBR effluent were 100 MPN/100 mL in 90 percent of samples
and Kubota MBR effluent 2 MPN/100 mL in 100 percent of the samples measured.
Figure 8-8 shows the US Filter MBR total coliphage was 30 PFU/100 mL in 80 percent of
samples and Kubota MBR total coliphage effluent was <10 PFU/100 mL in 80 percent of the
samples.
8.5 MBR Effluent Water Quality (Phase II: Zenon and Mitsubishi)
The Zenon UF and Mitsubishi MF membranes produced turbidity values < 0.10 NTU,
respectively, in 90 percent of the samples as shown in Figure 8-9.
8.5.2 Organic Removal
Both MBR systems produced excellent removal of organic constituents during Phase II testing.
As shown in Figure 8-10, the BOD
5
measured in the MBR effluent was below the detection limit
of 2 mg/L in 100 percent of the samples measured in the Zenon and Mitsubishi MBR effluent
samples. Figure 8-11 shows a probability plot of TOC measured in the primary effluent and
effluent from both MBR systems. As shown both the Zenon and Mitsubishi MBR systems
produced TOC 9 mg/L in 90 percent of all sample measurements.
During Phase II testing the Zenon and Mitsubishi MBR systems produced effluent with
NH
3
< 1 mg-N/L in 90 percent and 70 percent, respectively, as shown in Figure 8-12. The
samples of Mitsubishi effluent that were >1 mg/L-N were measured during the start up period,
prior to the establishment of the nitrifying bacteria in the MLSS. Such results indicate that both
MBR systems successfully achieved nitrification during operation on primary effluent. As
shown in Figure 8-13 PO
4
was measured to be 0.65 mg-P/L and 0.75 mg/L in 70 percent of
the samples from Zenon and Mitsubishi MBR systems, respectively. Accordingly, the primary
effluent contained 0.9 mg-P/L in 70 percent of the samples. Such data indicates that Ortho-
phosphate removal was not significant during Phase II testing.
8.5.4 Total Coliform, Fecal Coliform, Total Coliphage Removal
Both MBR systems removed total and fecal coliforms throughout Phase II testing as shown in
Figures 8-14 and 8-15 respectively. The Zenon MBR produced 1,100 MPN/100 mL in
80 percent of all effluent samples and Mitsubishi MBR effluent was 10 MPN/100 mL in
80 percent of the samples measured. Higher counts of total coliform measured in the Zenon
permeate was shown to be a result of contamination on the permeate side of the membrane.
50
Fecal coliforms in the Zenon MBR effluent were 2 MPN/100 mL in 80 percent of samples and
2 MPN/100 mL in 100 percent of the samples measured from the Mitsubishi MBR.
Figure 8-16 shows the Zenon UF membrane total coliphage were 1 PFU/100 mL in
100 percent of samples and Mitsubishi MF membrane produced total coliphage effluent
20 PFU/100 mL in 80 percent of the samples.
51
9. Cost Analysis
9.1 Costing Approach
A cost analysis was performed to determine capital and operational costs of full-scale MBR
water reclamation systems for treatment capacities ranging from 0.2-10 MGD
(800-40,000 m
3
/day). The specific approach used to perform the costs analysis is outlined in
Figure 9-1. As shown, the project team began by first organizing a workshop with all
participating MBR manufacturers including: US Filter Corporation/Jet Tech Products Group,
Zenon Environmental, Inc., Ionics/ Mitsubishi Rayon Corporation, Enviroquip Inc./Kubota
Corporation. During this workshop members of the project team met with representatives from
each manufacturer to discuss the major factors affecting the cost and operation of full-scale MBR
systems. Based on information gathered during this workshop, the project team developed a
specific list of operational and design criteria to be used in preparing the cost estimates. Key
parameters included flux, HRT, SRT, and MLSS. In addition, items such as cleaning interval,
membrane replacement period and warranty information was established based on discussions
with the manufacturers.
Following the workshop, the project team developed and sent a memo to each manufacturer
requesting budgetary cost estimates of capital and O&M costs for the membrane portion of MBR
systems for the capacities being considered. A modified version of this memo which contains
information specific to the current study is provided in Appendix F. As described, the
manufacturers were requested to provide membrane costs based on specific operating parameters
such as flux, TMP, loss of active membrane area and redundancy. At the same time, the MWH
design team completed cost estimates for complete MBR water reclamation systems (excluding
membrane costs) including headworks, process basins, mechanical equipment, blower and pump
building, chlorination system and effluent storage. Initial cost estimates were based on the
operation of raw wastewater. These costs were further refined for 1 and 5 MGD installations to
determine the cost savings associated with operation on advanced primary effluent.
52
9.2 Operation on Raw Wastewater
9.2.1 Design Criteria
Cost analyses were performed for 0.2, 0.5, 1.0, 5 and 10 MGD (800, 2,000, 4,000, 20,000, and
40,000 m
3
/day) installations. All systems were assumed to be sewer mining or scalping facilities
built on a clean plot of land and designed to operate on raw municipal wastewater. Such
facilities differ from end-of-pipe systems as raw wastewater is acquired directly from a sewer
pipe and all residuals (screenings, grit and waste-activated sludge [WAS]) are returned to the
same pipe which eliminates the need for sludge handling and disposal. The following wastewater
characteristics, typical of raw municipal wastewater, were used to model the MBR systems:
BOD
5
290 mg/L
COD 700 mg/L
TSS (total suspended solids) 320 mg/L
VSS 260 mg/L
NH
3
-N 30 mg/L
TKN (total Kjeldahl nitrogen) 60 mg/L
TP (total phosphorus) 2 mg/L
TDS 1,200 mg/L
Alkalinity 245 mg/L
Temperature 20 C
The MBR systems were designed using the following criteria:
Flux 15 gfd @ 15 C
MLSS 8,000 mg/L
F/M 0.13 day-1
HRT 6 h
SRT 10 days
Furthermore, all installations were designed to meet the following effluent water conditions:
Complete nitrification (i.e. NH
4
+-N<1.0 mg/L)
Denitrification (i.e. NO
3
-N<10 mg/L)
Biochemical Oxygen Demand (BOD
5
) < 2.0 mg/L
Biological Phosphorus Removal (i.e. Total Phosphorus-P <0.2 mg/L)
A schematic of the MBR reclaimed water system is provided in Figure 9-2. As shown, the
system included a biological reactor with three distinct zones (anoxic, anaerobic and oxic),
membrane bays and a chlorine contact chamber. The system was designed to allow screened and
degritted wastewater to enter the anoxic zone. Next, the wastewater would pass through the
anaerobic and oxic zone before entering the membrane bays. As shown, solids would then be re-
circulated from the membrane bay to the oxic zone. This would provide a crossflow velocity on
the membrane surface, which would help mitigate fouling and allow excess DO to be consumed.
As shown, MLSS was also re-circulated from the oxic zone to the anoxic zone. This allows
nitrates produced from the nitrification process to be brought into the anoxic environment, which
53
is conducive for denitrification. Lastly, re-circulation from the anoxic zone to the aerobic zone
promotes enhanced biological phosphorous removal (EBPR).
9.2.2 Capital Costs
Table 9-1 provides the capital costs for each capacity designed to operate on raw wastewater.
The table includes total capital costs ($K) and amortized capital costs ($K/year) assuming a
5 percent interest rate over a 30 year period. As shown, the total capital cost estimate for the
1.0-MGD installation ranged from $7,710 $9,280, while the amortized cost ($/yr) ranged from
$502-$604. The range in capital costs directly reflects the range of membrane costs acquired
from the four participating MBR manufacturers.
The headworks for all installations consisted of bar screening (6 mm), vortex grit removal, lift
pumps and odor control. All capital costs associated with headworks were taken from standard
budgetary costs used by the MWH.
Basin costs include concrete and ancillary costs associated with the aerobic/membrane, anoxic
and anaerobic components of the MBR system. In addition, the costs include basin excavation,
structural fill, back fill and waste dirt to haul off site. Lastly, for the 1, 5 and 10 MGD
installations the basin costs includes a 5-ton bridge crane; for smaller capacities it was assumed
the bridge crane would be rented as needed and therefore was included in the O&M costs
(See Section 9.2.3).
Mechanical costs shown include fine screening, mixers, aeration equipment, and recirculation
pumps and piping. Fine screening costs were provided by Waste Tech Inc (Libertyville, IL).
The costs were based on Roto-Sieve (RS) perforated drum screens and includes costs of both
duty and stand screens as recommended by the manufacturer. A factor of 25 percent was
included in the mechanical cost to account for equipment installation.
Membrane system costs including membranes, pumps, blowers and miscellaneous equipment
were developed from budgetary cost proposals provided by the participating manufactures. Each
manufacturer was requested to provide membrane costs to include a 5-year non-prorated
warranty.
Blower and pump building costs shown are based on two-story building and include all capital
costs associated with process blowers, blower piping and valving and blower instrumentation. A
factor of 25 percent was added the cost to account for equipment installation.
9.2.3 Operation and Maintenance Costs
Table 9-2 provides the annual O&M costs and the total estimated O&M costs (5 percent interest
rate over a 30-year period) for all MBR installations considered. Membrane replacement costs
were provided by the participating manufacturers and are based on an 8-yr membrane life. The
MWH design team provided all other annual costs. Unit cost assumptions for these annual costs
are provided in Appendix F. The table shows the annually O&M cost ($K/yr) for the
1-MGD installation ranges from $158-$212.
54
9.2.4 Total Costs
Table 9-3 provides a summary of the capital and O&M costs for all capacities operating on raw
wastewater. The total capital costs and estimated O&M costs were summed to provide present
worth values of each installation. The present worth values shown are based on a 5 percent
interest rate over a 30-year period. As shown, the present worth ($K) for the 1-MGD was
estimated between $10,139-$12,539. Table 9-4 provides total costs ($/1000 gallon) for each
capacity. These costs were derived from the amortized capital cost and the annual O&M cost
associated with each capacity. The table shows the total cost ($/1000 gallon) for the 1-MGD
capacity ranged from $1.81-$2.24.
Figure 9-3 illustrates the range of total costs ($/1000 gallon) based on the various membrane
suppliers for 0.2-10 MGD installations operating on raw wastewater. The shaded area on the
graph shows the difference between the high and low end of the range. As shown, the range is
greatest for 0.2-MGD facilities and decreases with capacity.
9.3 Consideration of Advanced Primary Treatment
The above cost estimates were tailored for municipalities which, like the City of San Diego, are
considering using the MBR process to reclaim wastewater at an existing advanced primary
wastewater treatment facility. The major factors considered when performing the cost estimates
for such facilities were:
- Access to advanced primary effluent
- Ability to use the existing headworks
Reclaimed water generated at an existing facility, such as PLWTP, can be used to meet industrial
and irrigation demands on-site reducing the use of imported potable water.
9.3.1 Design Criteria
To accommodate for on-site demand and the potential for increased demand from adjacent areas,
costing was performed for 1 and 5-MGD (4,000 and 20,000 m
3
/day) MBR facilities. All
facilities were assumed to be scalping facilities built on a clean plot of land and designed to
operate on advanced primary effluent. The following wastewater characteristics, typical of
advanced primary treated municipal wastewater, were used to perform the process design of the
MBR systems:
BOD
5
130 mg/L
COD 280 mg/L
TSS 65 mg/L
VSS 50 mg/L
NH
3
-N 30 mg/L
TKN 40 mg/L
55
TP 2 mg/L
TDS 1,200 mg/L
Alkalinity 230 mg/L
Temperature 20 C
Comparing the above water quality to the raw wastewater quality (Section 9.2.1) it is evident
there is a significant reduction of organic (BOD/COD) and particulate (TSS/VSS) contaminates
by the advanced primary treatment process.
All installations on advanced primary effluent were based on following criteria:
Flux 15 gfd @ 15 C
MLSS 8,000 mg/L
F/M 0.13 day-1
HRT 3 h
SRT 10 days
It should be noted the HRT was reduced by 50 percent (i.e. 6 hours to 3 h) as compared to MBR
installations designed to operate on raw wastewater. This reduction is attributed to the lower
organic and solid loading rate to the MBR system during operation on advanced primary
effluent.
9.3.2 Capital Costs
Table 9-5 provides capital costs for MBR installations designed to operate on advanced primary
effluent. The table shows the total capital cost ($K) and the amortized cost ($K/yr) assuming
5 percent interest rate over a 30-yr period for each capacity. As shown, the total capital cost for
the 1.0-MGD installations range from $6,150 $7,730, while the amortized costs ($K/yr) range
from $400-$503. A comparison of these costs to the capital cost estimates for the 1.0 MGD
installations operating on raw wastewater, indicates a savings between 17 percent-20 percent is
realized by designing MBRs to operate on advanced primary effluent when no headworks costs
are considered.
The specific capital cost items reduced for MBR plants operating on advanced primary effluent
include basin costs, mechanical equipment costs and blower and pump building costs. All of the
costs listed above are related to the solid and organic loading rate to the MBR system, which is
reduced during operation on advanced primary effluent. In addition, the capital cost is reduced
due to the exclusion of a headworks system, which would be necessary if the facility was not
being built at an existing plant.
9.3.3 Operation and Maintenance Costs
Table 9-6 provides the annual O&M costs for MBR facilities designed to operate on advanced
primary effluent. As shown, the O&M costs are provided for both the first year and total
estimated costs, assuming a 5 percent interest rate over 30-yr period. Membrane replacement
costs were provided by the participating manufacturers and are based on 8-yr membrane life. All
other annual costs were provided by MWH. Specific unit costs and assumptions regarding
annual costs are provided in Appendix F. As shown in Table 9-6, the annual O&M costs ($K/yr)
56
for the 1-MGD installations range from $139-$194. A comparison of these costs to the annual
O&M cost estimates for the 1.0 MGD installations operating on raw wastewater, indicates
savings of 8 percent-12 percent is realized by designing MBRs to operate on advanced primary
effluent when no headworks costs are included.
O&M cost reduction for systems operating on primary effluent is attributed to lower electrical
requirements for the biological process, reduced equipment repair and reduced diffuser
replacement.
9.3.4 Total Costs
Table 9-7 provides a summary of the capital and O&M costs for 1.0 and 5.0 MGD capacities
designed to operating on primary effluent. The total capital costs and estimated O&M costs
were summed to provide present worth values of each installation. The present worth values
shown are based on a 5 percent interest rate over a 30-year period. As shown, the present worth
($K) for the 1-MGD was estimated between $8,287-$10,712. Table 9-8 provides total costs
($/1000 gallon) for each capacity. These costs were derived from the amortized capital cost and
the annual O&M cost associated with each capacity. The table shows the total cost ($/1000
gallon) for the 1-MGD capacity ranged from $1.48-$1.91.
Figure 9-4 shows the total costs ($/1000 gallon) for 1.0 and 5.0 MGD installations operating on
raw wastewater and advanced primary effluent. The costs in this graph are based on median
total cost values presented in Section 9.2.4 and 9.3.4. As shown, the total cost is reduced for
both capacities based on design using advanced primary effluent (excluding headwork costs) and
the reduction increases with capacity.
9.4 Economy of Scale Analysis
Figure 9-5 presents total costs ($K/MGD) for 1.) complete MBR systems and 2.) membranes
only. Costs shown are for systems designed to operate on raw wastewater and are based on
median values determined in Sections 9.2.4. The plot shows both costs decrease with increasing
capacity indicating an economy of scale; however, the scale is more profound for the complete
MBR system costs.
57
Reference List
Adham, S., Gagliardo, P., Membrane Bioreactors for Water Repurification- Phase I, Desalination
Research and Development Program Report No. 34, Project No. 1425-97-FC-81-30006J, Bureau
of Reclamation, November, 1998.
Adham, S., Mirlo R. and Gagliardo, P., Membrane Bioreactors for Water Reclamation - Phase II,
Desalination Research and Development Program Report No. 60; Project No. 98-FC-81-0031,
Bureau of Reclamation, November, 2000.
Adham, S., Trussell, S., Membrane Bioreactors: Feasibility and Use in Water Reclamation, Final
Report Project #98-CTS-5, Water Environment Research Foundation, 2001.
Adham, S., Askenaizer, D., Trussell, R., and Gagliardo, P., Assessing the Ability of the Zenon
Zenogem Membrane Bioreactor to Meet Existing Water Reuse Criteria, Final Report, National
Water Research Institute, 2001 a.
Adham, S., Askenaizer, D., Trussell, R., and Gagliardo, P., Assessing the Ability of the Zenon
Mitsubishi Sterapore Membrane Bioreactor to Meet Existing Water Reuse Criteria, Final Report,
National Water Research Institute, 2001 b.
Adham, S., San Diego trials show MBR competes on cost and quality, Desalination & Water
Reuse Vol. 1213, 2002.
Adham, S., DeCarolis, J, Assessing the Ability of the Kubota Membrane Bioreactor to Meet
Existing Water Reuse Criteria, Final Report, 2003.
Adham, S., Gramith, K, California Department of Health Services Certification Testing for the
US Filter PVdF Membrane, Final Report, January 2001.
Churchhouse, S.J., Wildgoose, D., Membrane Bioreactors hit the big time from lab to full-scale
installation. MBR2-Proc. @ Inlt Meeting on Membrane Bioreactors for Wastewater Treatment,
University, Crainfield, UK. Pg. 14, 1999
Davies, W.J., Le, M.S., and Heath, C.R., Intensified activated sludge process with submereged
microfiltration. Wat. Sci. Technology. 38 (4-5), 421-429, 1998
Foussereau, X., Paranjape, S., and Reardon R., The Current Status of the Use of Membranes for
Wastewater Treatment. WEFTEC 2003 Proceedings.
Henze, M., Harremoes P., Jansen, J. and Arvin E., Wastewater Treatment Biological and
Chemical Processes Third Edition Springer-Verlag Berlin Heideberg New York 2002
58
Lozier, J., Fernandez, A., Hines, B., and Carns, K., Using a Membrane Bioreactor/Reverse
Osmosis System for Indirect Potable Reuse. Amer. Water Works Assoc. Membrane Conference.,
1999.
McInnis Amanda, Membrane Bioreactor Testing at Reduced SRT for King County, WA.
Proceedings from the 2002 AWWA Membrane Technology Conference
McInnis Amanda, Membrane Bioreactor Testing at Reduced SRT for King County, WA.
Proceedings from the 2002 AWWA Membrane Technology Conference.
Paranjape, S., Reardon R., and Foussereau, X., Pretreatment Technology for Reverse Osmosis
Membrane used in Wastewater Reclamation Application- Past, Present and Future Literature
Review. WEFTEC 2003 Proceedings
Point Loma Ocean Outfall Annual Monitoring Report, Program No. R-2002-0025 NPDES No.
CA 0107409, City of San Diego January December 2002
Stephenson, T., Judd S., Jefferson B., and Brindle K., Membrane Bioreactors for Wastewater
Treatment, IWA Publishing, London 2000.
van der Roest, H.F., Lawrence, D.P., van Bentem, A.G.N Membrane Bioreactors for Municipal
Wastewater Treatment, IWA Publishing. STOWA 2002.
Wallis-Lage, MBR Systems: Similarities and Differences between Manufactures
WEFTEC 2003 Proceedings
WERF and CH2Mhill, Membrane Bioreactors for Wastewater Treatment;
www.werf.org/products/membranetool/home, 2003.
APPENDIX A
Tables and Figures
This Appendix contains the tables and figures referred to in the main report.
A-i
LIST OF TABLES
TABLE 4-1: SPECIFICATIONS FOR THE MBR MEMBRANES .........................................................................................A-2
TABLE 4-2: SPECIFICATIONS FOR THE ROMEMBRANES.............................................................................................A-2
TABLE 4-3: SPECIFICATIONS FOR THE AQUIONICS UVPILOT.....................................................................................A-2
TABLE 4-4: ANALYTICAL METHODS / DETECTION LIMITS FOR MEASURED WATER QUALITY PARAMETERS..............A-3
TABLE 5-1: RAWWASTEWATER QUALITY DATA DURING PHASE I (PART 1)..............................................................A-4
TABLE 5-2: ADVANCED PRIMARY EFFLUENT WASTEWATER QUALITY DATA DURING PHASE I (PART 2) ..................A-4
TABLE 5-3: US FILTER MBR PERMEATE WATER QUALITY DATA DURING PHASE I (PART 1)....................................A-5
TABLE 5-4: US FILTER MBR PERMEATE WATER QUALITY DATA DURING PHASE I (PART 2)....................................A-5
TABLE 5-5: KUBOTA MBRPERMEATE WATER QUALITY DATA DURING PHASE I (PART 1) .......................................A-6
TABLE 5-6: KUBOTA MBRPERMEATE WATER QUALITY DATA DURING PHASE I (PART 2) .......................................A-6
TABLE 5-7: SAEHAN ROPERMEATE WATER QUALITY DATA DURING PHASE I..........................................................A-7
TABLE 5-8: HYDRANAUTICS ROPERMEATE WATER QUALITY DATA DURING PHASE I .............................................A-7
TABLE 6-1: ADVANCED PRIMARY EFFLUENT WASTEWATER QUALITY DATA DURING PHASE II................................A-8
TABLE 6-2: ZENON MBRPERMEATE WATER QUALITY DATA DURING PHASE II .......................................................A-8
TABLE 6-3: MITSUBISHI MBR PERMEATE WATER QUALITY DATA DURING PHASE II ...............................................A-9
TABLE 9-1: CAPITAL COSTS FOR VARIOUS CAPACITY MBR SYSTEMS OPERATING ON RAWWASTEWATER...........A-10
TABLE 9-2: O&MCOSTS FOR MBRSYSTEMS OPERATING ON RAW WASTEWATER ................................................A-11
TABLE 9-3: SUMMARY OF CAPITAL AND O&MCOSTS OPERATING ON RAWWASTEWATER ...................................A-12
TABLE 9-4: SUMMARY OF COSTS, $/KGAL OPERATING ON RAWWASTEWATER ......................................................A-12
TABLE 9-5: CAPITAL COSTS 1&5 MGDMBROPERATING ON ADVANCED PRIMARY EFFLUENT.............................A-13
TABLE 9-6: O&MCOSTS FOR MBRS OPERATING ON ADVANCED PRIMARY EFFLUENT ..........................................A-14
TABLE 9-7: SUMMARY OF CAPITAL AND O&MCOSTS OPERATION ON ADVANCED PRIMARY EFFLUENT................A-14
TABLE 9-8: SUMMARY OF COSTS, $/KGAL OPERATION ON ADVANCED PRIMARY EFFLUENT...................................A-14
A-ii
LIST OF FIGURES
FIGURE 4-1: SCHEMATIC DIAGRAM OF THE POINT LOMA ADVANCED WASTEWATER TREATMENT PLANT..............A-15
FIGURE 4-2: SCHEMATIC DIAGRAM OF PILOT TREATMENT TRAIN DURING PHASE I (PART 1 &PART 2)..................A-16
FIGURE 4-3: SCHEMATIC DIAGRAM OF PILOT TREATMENT TRAIN DURING PHASE II ...............................................A-17
FIGURE 4-4: KUBOTA MBR: SIDE VIEW (TOP); PLAN VIEW (BOTTOM) ...................................................................A-18
FIGURE 4-5: US FILTER MBR: SIDE VIEW (TOP); PLAN VIEW (BOTTOM)................................................................A-19
FIGURE 4-6: ZENON MBR: SIDE VIEW (TOP); PLAN VIEW (BOTTOM)......................................................................A-20
FIGURE 4-7: MITSUBISHI MBR: SIDE VIEW (TOP); PLAN VIEW (BOTTOM) ..............................................................A-21
FIGURE 5-1: HRT AND SRT
7-D
FOR THE US FILTER MBR........................................................................................A-22
FIGURE 5-2: MIXED LIQUOR SOLIDS FOR THE US FILTER MBR...............................................................................A-23
FIGURE 5-3: DOCONCENTRATION IN THE US FILTER MBR ....................................................................................A-24
FIGURE 5-4: HRT AND SRT
7-D
FOR THE KUBOTA MBR...........................................................................................A-25
FIGURE 5-5: DOCONCENTRATION IN THE KUBOTA MBR........................................................................................A-26
FIGURE 5-6: MIXED LIQUOR SOLIDS FOR THE KUBOTA MBR..................................................................................A-27
FIGURE 5-7: MEMBRANE PERFORMANCE OF THE US FILTER MBR..........................................................................A-28
FIGURE 5-8: MEMBRANE PERFORMANCE OF THE KUBOTA MBR .............................................................................A-29
FIGURE 5-9: SAEHAN 4040 BL ROMEMBRANE PERFORMANCE ..............................................................................A-30
FIGURE 5-10: HYDRANAUTICS LFC3 ROMEMBRANE PERFORMANCE.....................................................................A-31
FIGURE 5-11: TURBIDITY REMOVAL BY THE US FILTER MBR.................................................................................A-32
FIGURE 5-12: TURBIDITY REMOVAL BY THE KUBOTA MBR....................................................................................A-32
FIGURE 5-13: ORGANIC REMOVAL BY THE US FILTER MBR ...................................................................................A-33
FIGURE 5-14: ORGANIC REMOVAL BY THE KUBOTA MBR.......................................................................................A-34
FIGURE 5-15: INORGANIC NITROGEN REMOVAL BY THE US FILTER MBR...............................................................A-35
FIGURE 5-16: INORGANIC NITROGEN REMOVAL BY THE KUBOTA MBR..................................................................A-36
FIGURE 5-17: ORTHO-PHOSPHATE REMOVAL BY THE US FILTER MBR...................................................................A-37
FIGURE 5-18: ORTHO-PHOSPHATE REMOVAL BY THE KUBOTA MBR......................................................................A-37
FIGURE 5-19: COLIFORM AND COLIPHAGE REMOVAL BY THE US FILTER MBR ......................................................A-38
FIGURE 5-20: COLIFORM AND COLIPHAGE REMOVAL BY THE KUBOTA MBR..........................................................A-39
FIGURE 5-21: INORGANIC NITROGEN REMOVAL BY THE SAEHAN 4040 BL ROMEMBRANE ...................................A-40
FIGURE 5-22: ORTHO-PHOSPHATE REMOVAL BY THE SAEHAN 4040 BL ROMEMBRANE .......................................A-41
FIGURE 5-23: INORGANIC NITROGEN REMOVAL BY THE HYDRANAUTICS LFC3 ROMEMBRANE............................A-42
FIGURE 5-24: ORTHO-PHOSPHATE REMOVAL BY THE HYDRANAUTICS LFC3 ROMEMBRANE................................A-43
FIGURE 5-25: CONDUCTIVITY PROFILE ACROSS THE SAEHAN 4040 BL ROMEMBRANE..........................................A-44
FIGURE 5-26: CONDUCTIVITY PROFILE ACROSS THE HYDRANAUTICS LFC3 ROMEMBRANE .................................A-44
FIGURE 6-1: HRT AND SRT7-D FOR THE ZENON MBR............................................................................................A-45
FIGURE 6-2: MIXED LIQUOR SOLIDS CONCENTRATION FOR THE ZENON MBR ........................................................A-46
FIGURE 6-3: DOCONCENTRATIONS IN THE ZENON MBR ........................................................................................A-47
A-iii
FIGURE 6-4: HRT AND SRT7-D FOR THE MITSUBISHI MBR.....................................................................................A-48
FIGURE 6-5: MIXED LIQUOR SOLIDS CONCENTRATION FOR THE MITSUBISHI MBR.................................................A-49
FIGURE 6-6: AIR FLOW TO THE MITSUBISHI MBR....................................................................................................A-50
FIGURE 6-7: DOCONCENTRATIONS IN THE MITSUBISHI MBR.................................................................................A-50
FIGURE 6-8: MEMBRANE PERFORMANCE OF THE ZENON MBR................................................................................A-51
FIGURE 6-9: MEMBRANE PERFORMANCE OF THE MITSUBISHI MBR........................................................................A-52
FIGURE 6-10: TURBIDITY REMOVAL BY THE ZENON MBR.......................................................................................A-53
FIGURE 6-11: TURBIDITY REMOVAL BY THE MITSUBISHI MBR...............................................................................A-53
FIGURE 6-12: ORGANICS REMOVAL BY THE ZENON MBR .......................................................................................A-54
FIGURE 6-13: ORGANICS REMOVAL BY THE MITSUBISHI MBR................................................................................A-55
FIGURE 6-14: INORGANIC NITROGEN SPECIES IN THE ZENON MBR.........................................................................A-56
FIGURE 6-15: ORTHO-PHOSPHATE REMOVAL BY THE ZENON MBR.........................................................................A-57
FIGURE 6-16: INORGANIC NITROGEN SPECIES IN MITSUBISHI MBR ........................................................................A-58
FIGURE 6-17: ORTHO-PHOSPHATE REMOVAL BY THE MITSUBISHI MBR.................................................................A-59
FIGURE 6-18: COLIFORM AND COLIPHAGE REMOVAL BY THE ZENON MBR ............................................................A-60
FIGURE 6-19: COLIFORM AND COLIPHAGE REMOVAL BY THE MITSUBISHI MBR.....................................................A-61
FIGURE 8-1: PROBABILITY PLOT OF TURBIDITY REMOVAL BY MBRSYSTEMS DURING PHASE I (PART 1)...............A-62
FIGURE 8-2 PROBABILITY PLOT OF BOD
5
REMOVAL BY MBRSYSTEMS DURING PHASE I (PART 1)........................A-63
FIGURE 8-3 PROBABILITY PLOT OF TOCREMOVAL BY MBR SYSTEMS DURING PHASE I (PART 1) .........................A-64
FIGURE 8-4 PROBABILITY PLOT OF AMMONIA REMOVAL BY MBRSYSTEMS DURING PHASE I (PART 1).................A-65
FIGURE 8-5 PROBABILITY PLOT OF PHOSPHATE REMOVAL BY MBRSYSTEMS DURING PHASE I (PART 1) ..............A-66
FIGURE 8-6 PROBABILITY PLOT OF TOTAL COLIFORM REMOVAL BY MBRS DURING PHASE I (PART 1) ..................A-67
FIGURE 8-7 PROBABILITY PLOT OF FECAL COLIFORM REMOVAL BY MBRS DURING PHASE I (PART 1)...................A-68
FIGURE 8-8 PROBABILITY PLOT OF THE TOTAL COLIPHAGE REMOVAL BY MBRS DURING PHASE I (PART 1)..........A-69
FIGURE 8-9 PROBABILITY PLOT OF THE TURBIDITY REMOVAL BY MBRS DURING PHASE II ....................................A-70
FIGURE 8-10 PROBABILITY PLOT OF BOD
5
REMOVAL BY MBRSYSTEMS DURING PHASE II ...................................A-71
FIGURE 8-11 PROBABILITY PLOT OF TOCREMOVAL BY MBRPILOT SYSTEMS DURING PHASE II...........................A-72
FIGURE 8-12 PROBABILITY PLOT OF AMMONIA REMOVAL BY MBRSYSTEMS DURING PHASE II ............................A-73
FIGURE 8-13 PROBABILITY PLOT OF ORTHO-PHOSPHATE REMOVAL BY MBRSYSTEMS DURING PHASE II .............A-74
FIGURE 8-14 PROBABILITY PLOT OF TOTAL COLIFORM REMOVAL BY MBR SYSTEMS DURING PHASE II ................A-75
FIGURE 8-15 PROBABILITY PLOT OF FECAL COLIFORM REMOVAL BY MBR SYSTEMS DURING PHASE II ................A-76
FIGURE 8-16 PROBABILITY PLOT OF TOTAL COLIPHAGE REMOVAL BY MBR SYSTEMS DURING PHASE II ..............A-77
FIGURE 9-1 OUTLINE OF COSTING APPROACH..........................................................................................................A-78
FIGURE 9-2 MBRRECLAIMED WATER SCHEMATIC: FORWARD FLOW (TOP); RECYCLED FLOW (BOTTOM) ............A-79
FIGURE 9-3: TOTAL COSTS OF VARIOUS CAPACITY MBR SYSTEMS OPERATING ON RAW WASTEWATER................A-80
FIGURE 9-4: TOTAL COSTS OF 1&5 MGDMBRSYSTEMS (RAWWASTEWATER / PRIMARY EFFLUENT) ................A-80
FIGURE 9-5: ECONOMY OF SCALE ANALYSIS FOR MBR SYSTEMS OPERATING ON RAW WASTEWATER..................A-81
A-2
Table 4-1: Specifications for the MBR Membranes
1
Flow capacity based on recommend design flux and active membrane area supplied with the pilot unit.
Table 4-2: Specifications for the RO Membranes
Table 4-3: Specifications for the Aquionics UV Pilot
Units Value
Characteristics
Lamp Type NA Low pressure
Lamp Power watts 150
Design Flow Rate gpm 30
Operating Conditions
Flow Rate gpm 14.4
Feed Water UV Transmittance % 70
Estimated UV Dose mJ/cm
2
~42
Units Saehan Hydranautics
Commercial Designation --- RE 4040-BL LFC3-4040
Active Membrane Area ft
2
(m
2
) 85 (7.9) 85 (7.9)
Membrane Material --- Polyamide (thin film composite) Polyamide (thin film composite)
Operating pH Range --- 3-10 3-10
Maximum Feedwater Turbidity NTU <1 <1
Maximum Feedwater SDI (15 minute) --- <5 <5
Maximum Operating Temperature
o
F (
o
C) 113 (45) 113 (45)
Free Chlorine Resistance mg/L <0.1 <0.1
Specific Flux @ 25 deg C gfd/psi 0.20 0.10
Maximum Operating Pressure psi (bar) 600 (40) 600 (40)
Units Kubota US Filter Zenon Mitsubishi
Commercial Designation ---- Type 510 MemJet B10 R ZW 500 D Sterapore HF
Membrane Classification ---- MF MF UF MF
Membrane Configuration Vertical Vertical Vertical Horizontal
Approx. Size of Element (LxWxH) mm 490X6X1000 1850x100 1930X711X229 886X606X1483
Number of Sheets per membrane cassette --- 100 ------ ------ ------
Number of Fibers per membrane cassette ----- ----- ~2000 ~2700 ~1820
Inside Diameter of Fiber mm ----- 0.65 0.75 0.35
Outside Diameter of Fiber mm ----- 1 1.9 0.54
Length of Fiber m ----- 1.5 1.7 3.24
Active Membrane Area (MBR Pilot) ft
2
(m
2
) 1721 (160) 398 (37) 720 (67) 1076 (100)
1
Flow Capacity (MBR Pilot) gpm 17.6 4.0 7.5 9.2
Flow Direction --- outside - in outside - in outside - in outside - in
Nominal Membrane Pore Size micron 0.4 0.08 0.04 0.4
Absolute Membrane Pore Size micron ----- 0.2 0.1 0.5
Membrane Material/Construction ---
chlorinated
polyethylene;
flat sheet
PVDF/
hollow fiber
proprietary/
hollow fiber
polyethylene/
hollow fiber
Recommended Design Flux gfd (L/h-m
2
) 14.7 (24.9) 14.4 (24.4) 15 (25.4) 12.3 (20.8)
Standard Testing pH range --- 5.8 - 8.6 2-11 5-9.5 2-12
Vacuum Pressure for System psi (bar) <3 (<0.2) <7.3 (<0.5) <11.9 (<0.8) <5.8(<0.4)
A-3
Table 4-4: Analytical Methods / Detection Limits for measured Water Quality Parameters
Parameter Units Method Number and
Type
Detection Limit
Total/Volatile
Suspended Solids
mg/L SM 2540D&E 1.6
Ammonia-N mg/L SM 4500 B&E 0.2
BOD5 mg/L SM 5210B 2
COD mg/L SM5220D/EPA 410.4 22/5
Nitrate/Nitrite-N mg/L HACH 8171 0.1
Nitrite-N mg/L HACH 8507 0.005
Ortho-Phosphate-P mg/L HACH 8048 0.02
Total Hardness mg/L as CaCO3 EPA 130.1/130.2 0.3
Alkalinity mg/L as CaCO3 SM 2320 B 1.5
TKN mg/L EPA 351.3 0.5
TOC mg/L EPA 415.1 0.5
Total Coliform MPN/100 mL SM 9221E <2 MPN/100 mL
Fecal Coliform MPN/100 mL SM 9221B <2 MPN/100 mL
Coliphage pfu/100 mL
1
SM 9224F <1PFU /100mL
HPC CFU/mL SM 9215B 1 CFU/mL
1
20th Edition Addendum.
A-4
Table 5-1: Raw Wastewater Quality Data during Phase I (Part 1)
No. of
Analyses Units Median Maximum Minimum
Ammonia-N 22 mg/L 27.3 30.2 22.4
Nitrate/Nitrite -N 24 mg/L 0.56 2.4 0.36
Nitrite -N 24 mg/L 0.005 0.05 0.001
TKN 14 mg/L 42.9 69.0 33.9
Ortho-Phosphate-P 24 mg/L 0.61 1.53 0.054
BOD
5
20 mg/L 213 274 88.3
COD 23 mg/L 463 783 211
TOC 16 mg/L 40 56 15
Total Hardness 9 mg/L 533 578 15
Calcium Hardness 9 mg/L 245 270 160
Magnesium Hardness 9 mg/L 285 315 192
Alkalinity 20 mg/L 264 286 233
Table 5-2: Advanced Primary Effluent Wastewater Quality Data during Phase I (Part 2)
No. of
Ammonia-N 7 mg/L 26.6 29.4 24.1
Nitrite -N 5 mg/L 0.026 0.16 0
TKN 1 mg/L 44.8 44.8 44.8
BOD
5
8 mg/L 97 110 57.8
COD 6 mg/L 216 245 147
TOC 1 mg/L 44 44 44
A-5
Table 5-3: US Filter MBR Permeate Water Quality Data during Phase I (Part 1)
No. of
Ammonia-N 14 mg/L 0.3 0.2 0
Nitrate/Nitrite -N 25 mg/L 22 39.9 5.34
Nitrite -N 23 mg/L 0.02 9 0
TKN 8 mg/L 8.45 13.2 2.62
TKN (CEL) 2 mg/L 0.7 0.7 0.7
BOD
5
21 mg/L ND 6.27 ND
COD 23 mg/L 43 66 ND
TOC 16 mg/L 6.1 7.6 3.3
Alkalinity 21 mg/L 64.3 108 30.1
Table 5-4: US Filter MBR Permeate Water Quality Data during Phase I (Part 2)
No. of
Ammonia-N 3 mg/L ND ND ND
Nitrite -N 3 mg/L 0.045 0.077 0.042
TKN 2 mg/L 1.2 1.3 1.1
BOD
5
3 mg/L ND ND ND
COD 3 mg/L 31 47 26
COD (CEL) 2 mg/L 10.05 15 5.1
TOC 2 mg/L 6.35 6.6 6.1
Alkalinity 3 mg/L 65.1 83.4 48.4
A-6
Table 5-5: Kubota MBR Permeate Water Quality Data during Phase I (Part 1)
No. of
Ammonia-N 22 mg/L 0.3 7.6 ND
Nitrite -N 18 mg/L 0.012 0.19 0.005
TKN 8 mg/L 7.06 14.80 2.53
BOD
5
16 mg/L ND ND ND
COD 18 mg/L 52 80 29
TOC 13 mg/L 7 8 3.5
Table 5-6: Kubota MBR Permeate Water Quality Data during Phase I (Part 2)
No. of
Ammonia-N 8 mg/L 0.2 1.4 ND
Nitrite -N 24 mg/L 0.165 2.71 0.006
TKN (CEL) 3 mg/L 0.2 0.8 0.12
BOD
5
21 mg/L ND 2 ND
COD 5 mg/L 52 59 29
COD (CEL) 4 mg/L 16.5 23 5.1
TOC 5 mg/L 7 9 6.2
Total Hardness 8 mg/L 6 15 2.53
Magnesium Hardness 9 mg/L 0 0 0.009
Alkalinity 20 mg/L 280 495 14.2
A-7
Table 5-7: Saehan RO Permeate Water Quality Data during Phase I
No. of
Ammonia-N 18 mg/L 0.2 0.3 0.2
Nitrate/Nitrite N 18 mg/L 0.45 1.9 0.10
Nitrite N 19 mg/L ND 0.05 ND
TKN (PL LAB) 7 mg/L 2.6 15.1 ND
TKN (CEL) 4 mg/L ND 0.7 ND
COD 18 mg/L ND 29 ND
COD (CEL) 4 mg/L 6.35 8 ND
TOC 12 mg/L ND ND ND
Calcium Hardness 5 mg/L 10 11 6.8
Alkalinity 17 mg/L 7 8.8 4.5
Table 5-8: Hydranautics RO Permeate Water Quality Data during Phase I
No. of
Ammonia-N 17 mg/L 0.2 0.3 0.2
Nitrite -N 18 mg/L ND 1.90 ND
TKN (PL LAB) 7 mg/L ND 8.0 ND
TKN (CEL) 3 mg/L ND ND ND
Ortho-Phosphate-P 18 mg/L ND 0.04 ND
COD 18 mg/L 41.2 66.3 ND
COD (CEL) 3 mg/L 5.1 21 ND
TOC 0 mg/L ND ND ND
Alkalinity 17 mg/L 5 17.9 0.049
A-8
Table 6-1: Advanced Primary Effluent Wastewater Quality Data during Phase II
No. of
Ammonia-N 16 mg/L 25.5 28 23
Nitrite -N 16 mg/L 0.01 0.02 0.005
TKN 8 mg/L 29 35.0 1.4
BOD
5
14 mg/L 112 165 83.8
COD 26 mg/L 237 285 149
COD (CEL) 7 mg/L 200 230 150
TOC 7 mg/L 44 50 37
1
1
Total hardness is presented as CaCO
3.
Table 6-2: Zenon MBR Permeate Water Quality Data during Phase II
No. of
Ammonia-N 12 mg/L 0.6 5 ND
Nitrate/Nitrite -N 15 mg/L 23.1 5 ND
Nitrite -N 15 mg/L 0.013 0.103 0.006
TKN 8 mg/L 0.98 1.7 0.7
BOD
5
14 mg/L ND ND ND
COD (CEL) 6 mg/L 18 28 8
TOC 7 mg/L 6.4 8.6 6.1
1
Alkalinity 16 mg/L 66 111 7.35
1
3.
A-9
Table 6-3: Mitsubishi MBR Permeate Water Quality Data during Phase II
No. of
Ammonia-N 12 mg/L 0.3 16 0.3
Nitrite N 13 mg/L 0.057 5.19 0.006
TKN 6 mg/L 4.2 33.0 ND
BOD
5
12 mg/L ND ND ND
COD (CEL) 6 mg/L 21 31 18
TOC 7 mg/L 6.6 8.7 5.6
Conductivity 66 micromho 2,475 3,270 1,300
1
1
3.
A-10
Table 9-1: Capital Costs for Various Capacity MBR Systems Operating on Raw Wastewater
Headworks $250 $300 $450 $1,800 $3,100
Basins $101 $222 $484 $2,101 $4,154
MBR System $512-$1,375 $991-$1,688 $1,579-$2,347 $5,975-$6,614 $9,600-$12,200
Mechanical $96 $176 $420 $2,438 $5,779
Blower and Pump building $78 $152 $247 $861 $1,661
Chlorine Dosing System $62 $123 $217 $1,083 $2,167
Subtotal $1,099-$1,962 $1,964-$2,660 $3,397-$4,165 $14,258-$14,897 $26,461-$29,061
Electrical, 15% $165-$294 $295-$399 $510-$625 $2,139-$2,235 $3,969-$4,359
Mechanical/ Plumbing/HVAC, 13% $143-$255 $255-$346 $442-$541 $1,854-$1,937 $3,440-$3,778
Sitework, 9% $99-$177 $177-$239 $306-$375 $1,283-$1,341 $2,381-$2,615
Subtotal $1,506-$2,688 $2,691-$3,644 $4,654-$5,706 $19,533-$20,409 $36,252-$39,814
Contractor Overhead and Profit, 15% $226-$403 $404-$547 $698-$856 $3,061-$2,930 $5,438-$5,972
Subtotal-Construction Cost $1,731-$3,091 $3,094-$4,191 $5,352-$6,562 $22,463-$23,470 $41,689-$45,786
Land $250 $500 $750 $1,750 $2,500
Contingency, 15% $260-$464 $464-$629 $803-$984 $3,370-$3,521 $6,253-$6,868
Engineering/Legal/Administration, 15% $260-$464 $464-$629 $803-$984 $3,370-$3,521 $6,253-$6,868
$2,500-$4,270 $4,520-$5,950 $7,710-$9,280 $30,950-$32,260 $56,700-$62,020
Interest Rate 5% 5% 5% 5% 5%
Number of Years 30 30 30 30 30
P/A Factor
15.37 15.37 15.37 15.37 15.37
$294-$387 $502-$604 $2,013-$2,099 $3,688-$4,034 Amortized Capital Cost, $/yr
Total Capital Cost, $
$163-$278
Item
Capital Costs, $K
0.2 MGD 0.5 MGD 1.0 MGD 5.0 MGD 10.0 MGD
A-11
Table 9-2: O&M Costs for MBR Systems Operating on Raw Wastewater
1
Crane cost for 1, 5, and 10 MGD included in capital costs.
2
Membrane replacement costs based on 8-yr life; annual cost shown would be used to fund account
annually.
Electrical Power for Process/Miscellaneous $14 $35 $70 $350 $701
Equipment Repairs/Lubricants/Replacement $6-$11 $10-$14 $16-$21 $70-$70 $144-$149
1
Crane $2.0 $3.0 -------- -------- ---------
Chemical Cleaning $1.6 $4.0 $8.0 $40.0 $80.0
Chemical Cost for Disinfection $0.9 $2.3 $4.6 $22.8 $45.7
Diffuser Replacement $0.5 $1.2 $2.4 $11.8 $23.5
2
Membrane Replacement $5-$15 $10-$40 $20-$80 $87-$400 $171-$800
Labor $18 $25 $31 $88 $229
$54-$58 $94-$120 $158-$212 $671-$983 $1,394-$2,028
Interest Rate 5% 5% 5% 5% 5%
Number of Years 30 30 30 30 30
P/A Factor
15.37 15.37 15.37 15.37 15.37
Total Estimated O&M Costs, $K
Total O&M Costs in First Year, $K
$830-$892 $1,445-$1,845
Item
$2,429-$3,259 $10,315-$15,111 $21,429-$31,175
O & M Costs, $K/yr
0.2 MGD 0.5 MGD 1.0 MGD 5.0 MGD 10.0 MGD
A-12
Table 9-3: Summary of Capital and O&M Costs MBR Operating on Raw Wastewater
Table 9-4: Summary of Costs, $/kgal MBR Operating on Raw Wastewater
$2,500-$4,270 $830-$892 $3,330-$5,162
$4,520-$5,950 $1,445-$1,845 $5,965-$7,795
$7,710-$9,280 $2,429-$3,259 $10,139-$12,539
$30,950-$32,260 $10,315-$15,111 $41,265-$47,371
$56,700-$62,020 $21,429-$31,175 $78,129-$93,195
1
5
10
0.2
0.5
Capacity (MGD)
Raw Wastewater
Capital Costs, $K Total O&M Costs, $K Present Worth Value, $K
$163-$278 $54-$58 $217-$336 $2.97-$4.60
$294-$387 $94-$120 $388-$507 $2.13-$2.78
$502-$604 $158-$212 $660-$816 $1.81-$2.24
$2,013-$2,099 $671-$983 $2,684-$3,082 $1.47-$1.69
$3,688-$4,034 $1,394-$2,028 $5,082-$6,062 $1.39-$1.66
Capacity (MGD)
10
O&M Costs, $K/yr Total Cost $/1000 gal
0.2
1
0.5
5
Raw Wastewater
Amortized Capital Costs,
$K/yr
Total Cost $K/yr
A-13
Table 9-5: Capital Costs 1&5 MGD MBR Operating on Advanced Primary Effluent
1
Excluded headworks cost assume facilities are built at existing advanced primary treatment plant.
1
Headworks
$0 $0
Basins $281 $1,099
MBR System $1,579-$2,347 $5,975-$6,614
Mechanical $395 $2,518
Blower and Pump Building $166 $497
Chlorine Dosing System $217 $1,083
Subtotal $2,638-$3,406 $11,812-$11,173
Electrical, 15% $396-$511 $1,676-$1,772
Mechanical/Plumbing/HVAC, 13% $343-$443 $1,452-$1,536
Sitework, 9% $237-$307 $1,006-$1,063
Subtotal $3,614-$4,667 $15,307-$16,183
Contractor Overhead and Profit, 15% $542-$700 $2,296-$2,427
Subtotal-Construction Cost $4,156-$5,367 $17,603-$18,610
Land $750 $1,750
Contingency, 15% $623-$805 $2,640-$2,792
Engineering/Legal/Administration, 15% $623-$805 $2,640-$2,792
$6,150-$7,730 $24,630-$25,940
Interest rate
5% 5%
Number of Years
30 30
P/A Factor
15.37 15.37
$400-$503 $1,602-$1,687
Item
Capital Costs, $K
1.0 MGD 5.0 MGD
Amortized Capital Cost, $/yr
Total Capital Cost, $
A-14
Table 9-6: O&M Costs for MBR Operating on Advanced Primary Effluent
1
Membrane replacement costs based on 8-yr life; annual cost shown would be used to fund account annually.
Table 9-7: Summary of Capital and O&M Costs Operation on Advanced Primary Effluent
Table 9-8: Summary of Costs, $/kgal Operation on Advanced Primary Effluent
Electrical Power for Process/Miscellaneous $56 $280
Equipment Repairs/Lubricants/Replacement $13-$18 $65-$65
Chemical Cleaning $8 $40
Chemical Cost for Disinfection $4.6 $22.8
Diffuser Replacement $1.3 $6.4
1
Membrane Replacement $20-$80 $87-$400
Labor $31 $88
$139-$194 $590-$903
Interest rate 5% 5%
Number of Years 30 30
P/A Factor 15.37 15.37
Total Estimated O&M Costs, $
Yearly O&M Costs, $/yr
Item
$2,137-$2,982 $9,070-$13,881
O&M Costs, $/yr
1.0 MGD 5.0 MGD
$6,150-$7,730 $2,137-$2,982 $8,287-$10,712
$24,630-$25,940 $9,070-$13,881 $33,700-$39,821
1
5
Advanced Primary Effluent
Capacity (MGD)
Capital Costs, $K Total O&M Costs, $K Present Worth Value, $K
$400-$503 $139-$194 $572-$729 $1.48-$1.91
$1,602-$1,687 $590-$903 $2,241-$2,614 $1.20-$1.42
Amortized Capital
Costs, $K/yr
Total Cost $K/yr
1
5
Capacity (MGD)
O&M Costs,
$K/yr
Total Cost
$/1000 gal
A-15
Figure 4-1: Schematic Diagram of the Point Loma Advanced Wastewater Treatment Plant
Grit
Chamber
Sedimentation
Basin
Primary
Sludge
Grit Screenings
Ferric
Chloride
Flow Baffling
(Solids flocculation)
Effluent Screening
Ocean Discharge
Coagulation
Process
Anionic
Polymer
Raw Wastewater
(MBR Feed)
Primary Effluent
(MBR Feed)
A-16
Feed
Holding
Tank
Kubota MBR
RO
Effluent
Permeate
Tank
Kubota MBR RO Skid
Brine
WAS
Process Tank
US Filter
Permeate
Aerobic Tank
US Filter MBR
Permeate
Tank
WAS
Equalization
Tank
Raw Wastewater
(Part 1)
Drum
Screen
Advanced
Primary Effluent
(Part 2)
Rotary
Brush
Screen
.
Figure 4-2: Schematic Diagram of Pilot Treatment Train during Phase I (Part 1 & Part 2)
A-17
Primary Effluent
Break Tank
Aerobic Tank
Mitsubishi MBR
Permeate
Tank
WAS
Aerobic Tank
ZenoGem Tank
Zenon MBR
Permeate
Tank
WAS
Drum Screen
(0.75 mm screen)
Advanced
Primary Effluent
from PLWTP
Over Flow to
Grit Chamber
MBR Effluent
MBR Effluent
Figure 4-3: Schematic Diagram of Pilot Treatment Train during Phase II
A-18
Figure 4-4: Kubota MBR: Side View (Top); Plan View (Bottom)
Permeate
Raw
Wastewater
Pre-
nitrification
Zone
Denitrification
Zone
Feed
Holding
Tank
Screen
638 gal 1,695 gal
Nitrification Zone
Upper membrane bank
WAS
7
2,664 gal
8
500 gal
Process Tank
15
7
Upper / Lower Membrane Cassettes
Coarse
Bubble
Diffuser
Submerged
Transfer
Pump
Platform with
Guard rail
Nitrification Zone Denitrification Zone
Mixer
A-19
Figure 4-5: US Filter MBR: Side View (Top); Plan View (Bottom)
B
WAS
Wastewater
7.8
7.5
Air
Fine Air Diffusers
1.0 mm wedge
wire screen
Mixed Liquor
3.5
Equalization
Tank
Aerobic Tank
Membrane Tank
Permeate
Storage Tank
7.5
1.6
1.2
1500 gal
90 gal
Wastewater
1 mm Screen
Equalization
Tank
A-20
Figure 4-6: Zenon MBR: Side View (Top); Plan View (Bottom)
B
WAS
MBR
Permeate
Advanced
Primary
Effluent
3.5
7.8
7.8
Coarse Air
Diffusers
Fine Air Diffusers
Aerobic Tank
ZenoGem Tank
Permeate
7.5
2.8
1.6
1300 gal
185 gal
Advanced
Primary
Effluent
0.75 mm
Screen
A-21
Permeate
Advanced
Primary
Effluent
WAS
7.2
1.1
5.3
Coarse air
0.75 mm screen
WAS
Permeate
Advanced
Primary
Effluent
8.7
4.6
1601 gal
Figure 4-7: Mitsubishi MBR: Side View (Top); Plan View (Bottom)
A-22
0
4
8
12
16
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
Time of Operation, h
H
R
T
,

h
Part 1 Part 2
0
50
100
150
200
250
300
350
400
450
500
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
W
a
s
t
i
n
g

R
a
t
e
,

g
a
l
/
d
0
5
10
15
20
25
30
35
40
45
S
R
T

7
-
d
,

d
Wasting Rate, gal/d SRT-7d
7-d
for the US Filter MBR
A-23
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
TSS VSS
Solids
Dilluted
Part 1 Part 2
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
V
S
S

W
a
s
t
i
n
g

R
a
t
e
,

k
g

V
S
S
/
d
Figure 5-2: Mixed Liquor Solids for the US Filter MBR
A-24
0
2
4
6
8
10
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
D
O
,

m
g
/
L
Aerobic Tank
Increased Flux
Part 1 Part 2
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
A
i
r

F
l
o
w
,

s
c
f
m
Total Air Flow Aerobic Tank Membrane Tank
Modif ied
Blower
Figure 5-3: DO Concentration in the US Filter MBR
A-25
0
2
4
6
8
10
12
14
16
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
H
R
T
,

h
Part 1 Part 2
0
200
400
600
800
1000
1200
1400
1600
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500

W
a
s
t
i
n
g

R
a
t
e
,

g
a
l
/
d
0
5
10
15
20
25
30
35
40
45
50
S
R
T
7
-
d
,

d
Wasting Rate SRT 7-d
7-d
for the Kubota MBR
A-26
0
1
2
3
4
5
6
7
8
9
10
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
D
O
,

m
g
/
L
Aerobic Tank
Part 1 Part 2
Figure 5-5: DO Concentration in the Kubota MBR
A-27
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
22,000
24,000
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Aerobic Tank TSS Aerobic Tank VSS
Pilot Modif ications
Part 1 Part 2
0
10
20
30
40
50
60
70
80
90
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
V
S
S

W
a
s
t
i
n
g

R
a
t
e
,

k
g

V
S
S
/
d
Figure 5-6: Mixed Liquor Solids for the Kubota MBR
A-28
0
2
4
6
8
10
12
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
T
M
P
,

p
s
i
0
5
10
15
20
25
30
35
40
T
e
m
p
e
r
a
t
u
r
e
,

d
e
g

C
TMP Membrane Tank Temperature
cl
2
Backwash
Chemical Clean (cl
2
+acid)
Chemical Clean (cl
2
)
cl
2
Backwash
Part 1 Part 2
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
Time of Operation, hr
F
l
u
x

@

2
0
C
,

g
f
d
0
5
10
15
20
25
30
35
S
p
e
c
i
f
i
c

F
l
u
x

@

2
0
C
,

g
f
d
/
p
s
i
Flux @ 20C Specif ic Flux @ 20C
14.5 gf d
Target Flux =
11.5 gf d 11.5 gf d 14.5 gf d 19-24 gf d 14.5 gf d
Figure 5-7: Membrane Performance of the US Filter MBR
A-29
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
Time of Operation, hr
A
v
e
r
a
g
e

T
M
P
,

p
s
i
0
5
10
15
20
25
30
35
A
e
r
o
b
i
c

T
a
n
k

T
e
m
p
e
r
a
t
u
r
e
,

d
e
g

C
Average TMP Aerobic Tank Temperature
Start up
Chemical Cleaning
Bottom membrane
cassette of f line
Part 1 Part 2
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
F
l
u
x

@

2
0
C
,

g
f
d
0
5
10
15
20
25
30
35
40
S
p
e
c
i
f
i
c

F
l
u
x

@

2
0

d
e
g

C
,

g
f
d
/
p
s
i
Target Flux=15 gf d
Figure 5-8: Membrane Performance of the Kubota MBR
A-30
0
25
50
75
100
125
150
175
200
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
N
e
t

O
p
e
r
a
t
i
n
g

P
r
e
s
s
u
r
e
,

p
s
i
0
5
10
15
20
25
30
35
40
T
e
m
p
e
r
a
t
u
r
e
,

C
Net Operating Pressure Temperature
Began chloramine
addition
Membrane Cleaning
Part 1 Part 2
0
5
10
15
20
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
F
l
u
x

@
2
5
C
,

g
f
d
0.0
0.2
0.4
0.6
0.8
S
p
e
c
i
f
i
c

F
l
u
x

@

2
5
C
,

g
f
d
/
p
s
i
Target Flux = 10 gf d
Figure 5-9: Saehan 4040 BL RO Membrane Performance
A-31
0
25
50
75
100
125
150
175
200
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
N
e
t

O
p
e
r
a
t
i
n
g

P
r
e
s
s
u
r
e
,

p
s
i
0
5
10
15
20
25
30
35
40
T
e
m
p
e
r
a
t
u
r
e
,

d
e
g

C
Net Operating Pressure Temperature
Began chloramine
addition
Membrane Cleaning
Part 1 Part 2
0
5
10
15
20
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
F
l
u
x

@

2
5

d
e
g

C
,

g
f
d
0.0
0.1
0.2
0.3
0.4
S
p
e
c
i
f
i
c

F
l
u
x

@

2
5

d
e
g

C
,

g
f
d
/
p
s
i
Target Flux = 10 gf d
Figure 5-10: Hydranautics LFC3 RO Membrane Performance
0.01
0.10
1.00
10.00
100.00
1000.00
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
T
u
r
b
i
d
i
t
y
,

N
T
U
Feed Wastewater Turbidity MBR Permeate Turbidity
Part 1 Part 2
Figure 5-11: Turbidity Removal by the US Filter MBR
0.01
0.10
1.00
10.00
100.00
1000.00
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
T
u
r
b
i
d
i
t
y
,

N
T
U
Feed Wastewater Turbidity MBR Permeate Turbidity
Part 1 Part 2
Figure 5-12: Turbidity Removal by the Kubota MBR
A-33
1
10
100
1000
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater BOD5 MBR Permeate BOD5
open symbols denote below detection limit
Part 1 Part 2
1
10
100
1000
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater COD MBR Permeate COD (City Lab) MBR Permeate COD (Commercial Lab)
Part 1 Part 2
1
10
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater TOC MBR Permeate TOC
Part 1 Part 2
Figure 5-13: Organic Removal by the US Filter MBR
A-34
1
10
100
1000
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater BOD5 MBR Permeate BOD5
Part 1 Part 2
1
10
100
1000
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater COD MBR Permeate COD (City Lab) MBR Permeate COD (Commercial Lab)
Part 1 Part 2
1
10
100
1000
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater TOC MBR Permeate TOC
Part 1 Part 2
Figure 5-14: Organic Removal by the Kubota MBR
A-35
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Watsewater NH3-N MBR Permeate NH3-N
Part 1 Part 2
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater NO3-N MBR Permeate NO3-N
Part 1 Part 2
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Part 1 Part 2
Figure 5-15: Inorganic Nitrogen Removal by the US Filter MBR
A-36
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater NH3-N MBR Permeate NH3-N
Part 1 Part 2
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Feed Wastewater NO3/NO2-N MBR Permeate NO3/NO2-N
Part 1 Part 2
0
10
20
30
40
50
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Part 1 Part 2
Figure 5-16: Inorganic Nitrogen Removal by the Kubota MBR
A-37
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
P
/
L
Feed Wastewater PO4-P MBR Permeate PO4-P
Part 1 Part 2
Figure 5-17: Ortho-Phosphate Removal by the US Filter MBR
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
P
/
L
Feed Wastewater PO4-P MBR Permeate PO4-P
Part 1 Part 2
Figure 5-18: Ortho-Phosphate Removal by the Kubota MBR
A-38
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
s
,

M
P
N
/
1
0
0
m
L
Feed Wastewater Total Coliforms MBR Permeate Total Colif orms
Permeate Line Disinf ected
Part 1 Part 2
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0

m
L
Feed Wastewater Fecal Coliforms MBR Permeate Fecal Coliforms
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0

m
L
Feed Wastewater Total Coliphage MBR Permeate Total Coliphage
Figure 5-19: Coliform and Coliphage Removal by the US Filter MBR
A-39
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0
m
L
Feed Wastewater Total Coliforms Lower Permeate Total Coliforms Upper Permeate Total Colif orms
open symbols denote below detection
Part 1 Part 2
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0

m
L
Feed Wastewater Fecal Coliforms Lower Permeate Fecal Colif orms Upper Permeate Fecal Colif orms
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

p
f
u
/
1
0
0
m
L
Feed Wastewater Total Coliphage Lower Permeate Total Coliphage Upper Permeate Total Coliphage
Figure 5-20: Coliform and Coliphage Removal by the Kubota MBR
A-40
0.001
0.010
0.100
1.000
10.000
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
Feed NH3-N RO Permeate NH3-N
0.001
0.010
0.100
1.000
10.000
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
Feed NO3/N02 RO Permeate NO3/NO2-N
0.001
0.010
0.100
1.000
10.000
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
Feed NO2-N RO Permeate NO2-N
Figure 5-21: Inorganic Nitrogen Removal by the Saehan 4040 BL RO Membrane
A-41
0.01
0.10
1.00
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
P
/
L
Feed PO4-P RO Permeate PO4-P
Figure 5-22: Ortho-Phosphate Removal by the Saehan 4040 BL RO Membrane
A-42
0.001
0.010
0.100
1.000
10.000
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
Feed NH3-N RO Permeate NH3-N
0.001
0.010
0.100
1.000
10.000
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
Feed NO3/NO2-N RO Permeate NO3/NO2-N
0.001
0.010
0.100
1.000
10.000
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
Feed NO2-N RO Permeate NO2-N
Figure 5-23: Inorganic Nitrogen Removal by the Hydranautics LFC3 RO Membrane
A-43
0.01
0.10
1.00
0 300 600 900 1200 1500 1800 2100 2400 2700 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
P
/
L
Feed PO4-P RO Permeate PO4-P
Figure 5-24: Ortho-Phosphate Removal by the Hydranautics LFC3 RO Membrane
A-44
1
10
100
1000
10000
0 500 1000 1500 2000 2500 3000
C
o
n
d
u
c
t
i
v
i
t
y
,

m
i
c
r
o
m
h
o
s
Permeate Conductivity Feed Conductivity
Figure 5-25: Conductivity Profile across the Saehan 4040 BL RO Membrane
1
10
100
1000
10000
0 500 1000 1500 2000 2500 3000
C
o
n
d
u
c
t
i
v
i
t
y
,

m
i
c
r
o
m
h
o
Feed Conductivity Permeate Conductivity
Figure 5-26: Conductivity Profile Across the Hydranautics LFC3 RO Membrane
A-45
0
2
4
6
8
0 500 1000 1500 2000 2500 3000 3500 4000 4500
H
R
T
,

h
0
50
100
150
200
250
300
350
0 500 1000 1500 2000 2500 3000 3500 4000 4500
S
o
l
i
d
s

W
a
s
t
i
n
g

R
a
t
e
,

g
a
l
/
d
0
5
10
15
20
25
30
35
40
S
R
T

7
-
d
,

d
Figure 6-1: HRT and SRT7-d for the Zenon MBR
A-46
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
0 500 1000 1500 2000 2500 3000 3500 4000 4500
S
o
l
i
d
s

C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
TSS VSS
Mixed Liquor Diluted
Start Up
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500
V
S
S

W
a
s
t
i
n
g

R
a
t
e

(
k
g

V
S
S
/
d
a
y
)
Figure 6-2: Mixed Liquor Solids Concentration for the Zenon MBR
A-47
0
1
2
3
4
5
6
7
8
9
10
0 500 1000 1500 2000 2500 3000 3500 4000 4500
D
O
,

m
g
/
L
Aerobic Tank
Figure 6-3: DO Concentrations in the Zenon MBR
A-48
0
2
4
6
8
10
0 500 1000 1500 2000 2500 3000 3500 4000 4500
H
R
T
,

h
0
50
100
150
200
250
300
350
0 500 1000 1500 2000 2500 3000 3500 4000 4500
S
o
l
i
d
s

W
a
s
t
i
n
g

R
a
t
e
,

g
a
l
/
d
0
5
10
15
20
25
30
35
40
45
50
S
R
T

7
-
d
,
d
System shut down
Figure 6-4: HRT and SRT7-d for the Mitsubishi MBR
A-49
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
18,000
20,000
0 500 1000 1500 2000 2500 3000 3500 4000 4500
S
o
l
i
d
s

C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
TSS VSS
Solids Diluted/ re-seeded
Start Up
System re-seeded/on line
Shut down to replace blower
0
2
4
6
8
10
12
14
16
18
20
0 500 1000 1500 2000 2500 3000 3500 4000 4500
V
S
S

W
a
s
t
i
n
g

R
a
t
e
,

k
g

V
S
S
/
d
a
y
Figure 6-5: Mixed Liquor Solids Concentration for the Mitsubishi MBR
A-50
0
10
20
30
40
50
60
70
80
90
100
0 500 1000 1500 2000 2500 3000 3500 4000 4500
A
i
r

F
l
o
w
,

s
c
f
m
Total Air Flow Fine Air Flow
Replaced Blower Shives
Removed Check Valve
Added Fine Bubble Dif f users
Figure 6-6: Air Flow to the Mitsubishi MBR
0
1
2
3
4
5
6
7
8
9
10
0 500 1000 1500 2000 2500 3000 3500 4000 4500
D
O
,

m
g
/
L
Aerobic Tank
Figure 6-7: DO Concentrations in the Mitsubishi MBR
A-51
0
1
2
3
4
5
6
7
8
9
10
0 500 1000 1500 2000 2500 3000 3500 4000 4500
V
a
c
u
u
m

P
r
e
s
s
u
r
e
,

p
s
i
0
4
8
12
16
20
24
28
32
36
40
T
e
m
p
e
r
a
t
u
r
e
,

C
Vacuum Pressure Maintenance Clean Zenogem Tank Temperature
VFD
Failure
VFD
Failure
Chemical
Clean
nitrif cation
lost
Flux
Increased
MLSS
Diluted
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000 3500 4000 4500
F
l
u
x

@

2
0
C
,

g
f
d
0
5
10
15
20
25
30
35
S
p
e
c
i
f
i
c

F
l
u
x

@

2
0
C
,

g
f
d
/
p
s
i
Target Flux = 22 gfd
Figure 6-8: Membrane Performance of the Zenon MBR
A-52
0
1
2
3
4
5
6
7
8
9
10
0 500 1000 1500 2000 2500 3000 3500 4000 4500
V
a
c
u
u
m

P
r
e
s
s
u
r
e
,

p
s
i
0
4
8
12
16
20
24
28
32
36
40
T
e
m
p
e
r
a
t
u
r
e
,

C
Overall Vacuum Pressure Aerobic Tank Temperature
Foaming
Blower Failed
Chemical Cleaning
System on line
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000 3500 4000 4500
Time of Operation (hours)
F
l
u
x

@

2
0
C
,

g
f
d
0
5
10
15
20
25
30
35
S
p
e
c
i
f
i
c

F
l
u
x

@

2
0
C
,

g
f
d
/
p
s
i
Target Flux = 11.8 gf d 14.8 gf d
Figure 6-9: Membrane Performance of the Mitsubishi MBR
A-53
0.01
0.10
1.00
10.00
100.00
1000.00
0 500 1000 1500 2000 2500 3000 3500 4000 4500
T
u
r
b
i
d
i
t
y

(
N
T
U
)
Primary Ef f luent Turbidity MBR Permeate Turbidity
Turbidimeter cleaned time of operation = 2,742 h
Figure 6-10: Turbidity Removal by the Zenon MBR
0.01
0.10
1.00
10.00
100.00
1000.00
0 500 1000 1500 2000 2500 3000 3500 4000 4500
T
u
r
b
i
d
i
t
y

(
N
T
U
)
Primary Ef f luent Turbidity MBR Permeate Turbidity
Figure 6-11: Turbidity Removal by the Mitsubishi MBR
A-54
1
10
100
1000
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n

(
m
g
/
L
)
Primary Ef fluent BOD5 MBR Permeate BOD5
open symbols denote below
1
10
100
1000
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n

(
m
g
/
L
)
Primary Ef f luent COD MBR Permeate COD
0.10
1.00
10.00
100.00
1000.00
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n

(
m
g
/
L
)
MBR Permeate TOC
Figure 6-12: Organics Removal by the Zenon MBR
A-55
1
10
100
1000
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n

(
m
g
/
L
)
Primary Eff luent BOD5 MBR Permeate BOD5
1
10
100
1000
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n

(
m
g
/
L
)
Primary Ef f luent COD MBR Permeate COD
0.10
1.00
10.00
100.00
1000.00
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
MBR Permeate TOC
Figure 6-13: Organics Removal by the Mitsubishi MBR
A-56
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n

m
g
-
N
/
L
MBR Permeate NH3-N
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
MBR Permeate NO2/NO3-N
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
MBR Permeate NO2-N
Figure 6-14: Inorganic Nitrogen Species in the Zenon MBR
A-57
0
0.5
1
1.5
2
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
P
/
L
Primary Ef fluent PO4-P MBR Permeate P04-P
Figure 6-15: Ortho-Phosphate Removal by the Zenon MBR
A-58
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
MBR Permeate NH3-N
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
MBR Permeate NO2/NO3-N
0
5
10
15
20
25
30
35
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
MBR Permeate NO2-N
Figure 6-16: Inorganic Nitrogen Species in Mitsubishi MBR
A-59
0
0.5
1
1.5
2
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
P
/
L
Primary Eff luent PO4-P MBR Permeate P04-P
Figure 6-17: Ortho-Phosphate Removal by the Mitsubishi MBR
A-60
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0
m
L
Primary Ef fluent Total Coliforms MBR Permeate Total Coliforms
After Disinfection
li i
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n

(
M
P
N
/
1
0
0
m
L
)
Primary Eff luent Fecal Colif orms MBR Permeate Fecal Colif orms
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000 3500
C
o
n
c
e
n
t
r
a
t
i
o
n
,

P
F
U
/
1
0
0
m
L
Primary Ef fluent Total Coliphage MBR Permeate Total Coliphage
Figure 6-18: Coliform and Coliphage Removal by the Zenon MBR
A-61
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0
m
L
Primary Ef fluent Total Colif orms MBR Permeate Total Colif orms
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0
m
L
Primary Eff luent Fecal Coliforms MBR Permeate Fecal Colif orms
1.E+00
1.E+01
1.E+02
1.E+03
1.E+04
1.E+05
1.E+06
1.E+07
1.E+08
1.E+09
0 500 1000 1500 2000 2500 3000
C
o
n
c
e
n
t
r
a
t
i
o
n
,

P
F
U
/
1
0
0

m
L
Primary Eff luent Total Coliphage MBR Permeate Total Coliphage
Figure 6-19: Coliform and Coliphage Removal by the Mitsubishi MBR
A-62
0.01
0.1
1
10
100
1000
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Raw Wastewater Turbidity
Kubota MBR Permeate Turbidity
US Filter MBR Permeate Turbidity
T
u
r
b
i
d
i
t
y
,

N
T
U
Percent
Figure 8-1: Probability Plot of Turbidity Removal by MBR Systems during Phase I (Part 1)
A-63
1
10
100
1000
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Raw Wastewater BOD5
Kubota MBR Permeate BOD5
US Filter MBR Permeate BOD5
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Percent
Figure 8-2 Probability Plot of BOD
5
Removal by MBR Systems during Phase I (Part 1)
A-64
.01 .1 1 5 10 20 30 50 70 80 90 95 99 99.9 99.99
Raw Wastewater TOC
Kubota MBR TOC
US Filter MBR Permeate TOC
0
6
12
18
24
30
36
42
48
54
60
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Percent
Figure 8-3 Probability Plot of TOC Removal by MBR Systems during Phase I (Part 1)
A-65
0
10
20
30
40
50
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Raw Wastewater Ammonia-N
Kubota MBR Permeate Total Inorganic Nitrogen
US Filter MBR Permeate Total Inorganic Nitrogen
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
N
/
L
Percent
Figure 8-4 Probability Plot of Ammonia Removal by MBR Systems during Phase I (Part 1)
A-66
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Raw Wastewater PO4-P
Kubota MBR Permeate PO4-P
US Filter MBR Permeate PO4-P
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
P
/
L
Percent
Figure 8-5 Probability Plot of Phosphate Removal by MBR Systems during Phase I (Part 1)
A-67
Figure 8-6 Probability Plot of Total Coliform Removal by MBRs during Phase I (Part 1)
10
0
10
1
10
2
10
3
10
4
10
5
10
6
10
7
10
8
.01 .1 1 5 10 20 30 50 70 80 90 95 99 99.9 99.99
Raw Wastewater Total Coliforms
Kubota MBR Permeate Total Coliforms
US Filter MBR Permeate Total Coliforms
Percent
A-68
10
0
10
1
10
2
10
3
10
4
10
5
10
6
10
7
10
8
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Raw Wastewater Fecal Coliforms
Kubota MBR Permeate Fecal Coliforms
US Filter MBR Permeate Fecal Coliforms
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0

m
L
Percent
Figure 8-7 Probability Plot of Fecal Coliform Removal by MBRs during Phase I (Part 1)
A-69
10
0
10
1
10
2
10
3
10
4
10
5
10
6
.01 .1 1 5 10 20 30 50 70 80 90 95 99 99.9 99.99
Raw Wastewater Total Coliphage
Kubota MBR Permeate Total Coliphage
US Filter MBR Permeate Total Coliphage
C
o
n
c
e
n
t
r
a
t
i
o
n
,

P
F
U
/
1
0
0

m
L
Percent
Figure 8-8 Probability Plot of the Total Coliphage Removal by MBRs during Phase I (Part 1)
A-70
0.01
0.1
1
10
100
1000
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Primary Effluent Turbidity
Zenon MBR Permeate Turbidity
Mitsubishi MBR Permeate Turbidity
T
u
r
b
i
d
i
t
y
,

N
T
U
Percent
Figure 8-9 Probability Plot of the Turbidity Removal by MBRs during Phase II
A-71
1
10
100
1000
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Primary Effluent BOD5
Zenon MBR Permeate BOD5
Mitsubishi Permeate BOD5
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Percent
Figure 8-10 Probability Plot of BOD
5
Removal by MBR Systems during Phase II
A-72
0
12
24
36
48
60
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Primary Effleunt TOC
Zenon MBR TOC
Mitsubishi MBR Permeate TOC
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
/
L
Percent
Figure 8-11 Probability Plot of TOC Removal by MBR Pilot Systems during Phase II
A-73
0
5
10
15
20
25
30
35
40
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Primary Effluent Ammonia-N
Zenon MBR Permeate Ammonia-N
Mitsubishi Permeate Ammonia-N
C
o
n
c
e
n
t
r
a
t
i
o
n

m
g
-
N
/
L
Percent
Figure 8-12 Probability Plot of Ammonia Removal by MBR Systems during Phase II
A-74
0
0.5
1
1.5
2
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Primary Effluent PO4-P
Zenon MBR Permeate PO4-P
Mitsubishi Permeate PO4-P
C
o
n
c
e
n
t
r
a
t
i
o
n
,

m
g
-
P
/
L
Percent
Figure 8-13 Probability Plot of Ortho-Phosphate Removal by MBR Systems during Phase II
A-75
Figure 8-14 Probability Plot of Total Coliform Removal by MBR Systems during Phase II
10
0
10
2
10
4
10
6
10
8
10
10
.01 .1 1 5 10 2030 50 7080 90 95 99 99.9 99.99
Primary Effluent Total Coliforms
Zenon MBR Permeate Total Coliforms
Mitsubishi Permeate Total Coliforms
Percent
A-76
10
0
10
1
10
2
10
3
10
4
10
5
10
6
10
7
10
8
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Primary Effluent Fecal Coliforms
Zenon MBR Permeate Fecal Coliforms
Mitsubishi Permeate Fecal Coliforms
C
o
n
c
e
n
t
r
a
t
i
o
n
,

M
P
N
/
1
0
0

m
L
Percent
Figure 8-15 Probability Plot of Fecal Coliform Removal by MBR Systems during Phase II
A-77
10
0
10
1
10
2
10
3
10
4
10
5
10
6
.01 .1 1 5 10 20 30 50 7080 90 95 99 99.9 99.99
Primary Effluent Total Coliphage
Zenon MBR Permeate Total Coliphage
Mitsubishi Permeate Total Coliphage
C
o
n
c
e
n
t
r
a
t
i
o
n
,

P
F
U
/
1
0
0

m
L
Percent
Figure 8-16 Probability Plot of Total Coliphage Removal by MBR Systems during Phase II
A-78
Conducted MBR Costing Workshop
Developed Specific MBR Design Criteria
Requested Membrane Costs
from 4 MBR Suppliers
Performed Preliminary Process Design of
Complete MBR Reclamation Facilities
Compiled Costs MBR and Process Costs to
develop Total Cost Estimates for 0.2-10 mgd
MBR Reclamation facilities
Tailored Costs to Consider Operation on
+
Figure 9-1 Outline of Costing Approach
A-79
Figure 9-2 MBR Reclaimed Water Schematic: Forward Flow (Top); Recycled Flow (Bottom)
Perm. Pumps Perm. Pumps
Chlorine Contact Chlorine Contact
Finished Water Finished Water Forebay Forebay
Selectors Selectors Nitrification Nitrification Membranes Membranes
Anoxic Anoxic
Zones Zones
Anaerobic Anaerobic
Zones Zones
Oxic Oxic Zones Zones
Screened Screened
&& Degritted Degritted
Wastewater Wastewater
Membrane Membrane
Bays Bays
Reclaimed Reclaimed
Water Water
Finished Water Pumps Finished Water Pumps
Selectors Selectors Nitrification Nitrification Membranes Membranes
Anoxic Anoxic
Zones Zones
Anaerobic Anaerobic
Zones Zones
Oxic Oxic Zones Zones
Screened Screened
&& Degritted Degritted
Wastewater Wastewater
Membrane Membrane
Bays Bays
Solids Recirculation System Solids Recirculation System
MLSS Recycle System MLSS Recycle System
A-80
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
5.00
0.2 0.5 1 5 10
Capacity, mgd
T
o
t
a
l

C
o
s
t

(
$
/
1
0
0
0

g
a
l
)
Figure 9-3: Total Costs of Various Capacity MBR Systems Operating on Raw wastewater
1
5
Primary Effluent
Raw Wastewater
0.00
0.50
1.00
1.50
2.00
2.50
Total Cost
($/1000 gal)
Capacity, mgd
Figure 9-4: Total Costs of 1& 5 MGD MBR Systems (Raw Wastewater / Primary Effluent)
A-81
0
4,000
8,000
12,000
16,000
20,000
24,000
0.2 0.5 1 5 10
Capacity, mgd
T
o
t
a
l

C
o
s
t

(
$
K
/
m
g
d
)
MBR System Costs Membrane Costs
Figure 9-5: Economy of Scale Analysis for MBR Systems Operating on Raw Wastewater
APPENDIX B
Membrane Cleaning Protocols
B-1
MEMBRANE CHEMICAL CLEANING PROTOCOLS
Mitsubishi MBR In-Line Chemical Cleaning Protocol
In-Line Chlorine/Acid Cleaning
NaOCl: effective concentration of 3,000 mg/L (0.3%)
Citric Acid: effective concentration of 2,000 mg/L (0.2%)
1. Mix together water with cleaning compound to achieve desired solution in the chemical
cleaning tank (40 gallons).
2. Close ball valve that is before the suction pump.
3. Open the two swagelok ball valves so the center chemical injection point is open to each side
of the membrane fibers.
4. Connect the ball valve on the chemical tank to the union on the injection port.
5. Allow the chemical tank to rest on the edge of the MBR tank.
6. Open the ball valve on the chemical tank and allow the chemical solution to back flow
through the membrane for 2 hours.
7. After 2 hours, close the valve on the chemical tank and allow the chemical solution to soak in
the membrane fibers for an additional 2 hours.
8. Repeat for the other membrane side.
9. Once complete, close the swage valves and open the ball valve near the suction side of the
pump.
10. Resume normal operation.
B-2
Zenon Clean-in-Place (CIP) Protocol
Chemical Reagent: Sodium Hypochlorite (effective chlorine concentration: 2,000 mg/L) or Citric
Acid (effective pH = 2.0-3.0, approximately 2,000-3,000 mg/L)
1. Isolate the ZenoGem tank.
2. Drain the ZenoGem tank by pumping mixed liquor into the aeration basin.
3. Hose down ZenoGem until water appears clear.
4. Prepare chemical reagent in CIP tank.
5. Backpulse the cleaning solution through the membrane until tank is empty.
6. Recirculate the dilute solution through membranes; measure flux, then allow to soak.
7. Repeat Step 6 until flux is equal in two consecutive readings. Allow to soak overnight, if
necessary.
8. Drain tank and hose down until there is no chlorine present.
9. Put back into service.
Zenon Maintenance Cleaning Protocol
Chemical Reagent: Sodium Hypochlorite (concentration = 250 mg/L in BW Tank) or Citric Acid
(concentration = 2,000 mg/L in BW Tank)
1. Shut down pilot unit.
2. Let the system relax for 5 minutes.
3. Fill the CIP (clean in place) tank with the cleaning solution.
4. Put the system in Backpulse mode.
5. Backpulse the system for 15 seconds at a flow rate of 16.7 gpm.
6. Relax for 30 seconds.
7. Backpulse the system for 10 seconds.
8. Relax for 30 seconds.
9. Repeat steps 7 and 8, two times.
10. Put system back into service.
B-3
Kubota Chlorine Cleaning Protocol
1. Prepare 160 gallons of 0.5 % (w/w) of sodium hypochlorite.
2. Stop the feed to system.
3. Stop filtration.
4. Stop MBR blower.
5. Stop recycle pump
6. Open caps on the 2 permeate lines (upper and lower membrane banks) at the top of the
nitrification tank.
7. Insert the chemical feed pump discharge into the upper permeate line.
8. Pump 80 gallons of the sodium hypochlorite solution prepared in Step 1.
9. Insert the chemical feed pump discharge into the lower permeate line.
11. Close caps on the permeate lines.
12. Soak membranes for 2 hours.
13. Turn all equipment back on and put the system in auto.
Kubota Oxalic Acid Cleaning Protocol
1. Prepare 160 gallons of 1% (w/w) Oxalic Acid.
2. Stop the feed to system.
3. Stop filtration.
4. Stop MBR blower.
5. Stop recycle pump
6. Open caps on the 2 permeate lines (upper and lower membrane banks) at the top of the
nitrification tank.
7. Insert the chemical feed pump discharge into the upper permeate line.
9. Insert the chemical feed pump discharge into the lower permeate line.
11. Close caps on the permeate lines.
12. Soak membranes for 1 hour.
13. Turn all equipment back on and put the system in auto.
B-4
US Filter Chemical Cleaning Protocol
Chemical Reagent: Sodium Hypochlorite (chlorine concentration = 100 mg/L) or Citric Acid
(acid concentration = 2,000 mg/L)
1. Isolate the aeration tank.
2. Pump the mixed liquor from the aeration tank.
3. Fill the aeration tank with rinse water (from the filtrate tank).
4. Aerate membranes and reticulate rinse water through mixed liquor manifold for 10 minutes.
5. Drain the rinse water.
6. Fill the aeration tank with chlorinated CIP water.
7. Recirculate chemical through lumens.
8. Recirculate chemical though mixed liquor manifolds.
9. Recirculate chemical through in-tank air manifold.
10. Soak for up to 4 minutes.
11. Drain tank and hose down until there is no chlorine present.
12. Return to normal operation.
B-5
Cleaning Protocol for Saehan RE4040 BL and Hydranautics LFC Reverse
Osmosis Membranes
Chemical Reagent: 0.1 gallons for sodium hydroxide, 0.025 gallons of sodium lauryl dodecyl
sulfate, pH 11 12, Temperature 30C, Volume of Chemical Reagent: 0.81 L/ft
2
of membrane
area.
1. Flush pressure vessels at 5 gpm with RO permeate for several minutes.
2. Circulate the cleaning solution at 5 gpm for 30 minutes. If the cleaning solution colors
becomes turbid, restart with freshly prepared cleaning solution.
3. Check pH of cleaning solution while in circulation. If pH increase by more than 0.5 pH
units, add acid (HCL).
4. Turn recirculation pump off and allow the membranes to soak for 1 hour.
5. Circulate the cleaning solution again at 10 gpm for 30 - 60 minutes.
6. Drain and flush cleaning tank.
7. Rinse pressure vessels with RO permeate whose pH has been adjusted to 4.5 - 5.5 using
hydrochloric acid (HCL) for several minutes. The minimum temperature of the rinse
water should be 68 F (20 C). Have both permeate and concentrate valves open during
flushing. Flushing should be once-through step.
8. Operate the system as normal.
APPENDIX C
QA/QC Memorandum
C-1
M E M O R A N D U M
To: Samer Adham, Ph.D. Date: 10-09-03
From: James DeCarolis / Jude Grounds
Reference:
Subject: Optimization of Various MBR
Systems for Water Reclamation:
QA/QC Protocol
Pilot testing for the Bureau of Reclamation project entitled Optimization of Various MBR
Systems for Water Reclamation, was begun in April of 2002 at the Point Loma Waste Water
Treatment Plant (PLWWTP) in San Diego, California. To ensure the accuracy and integrity of
the data collected, a number of quality assurance and quality control procedures were followed
throughout the experiment. This Technical Memorandum (TM) summarizes these procedures
for the on-site instrument verification and water quality analysis performed by the project team,
including:
On-line Turbidimeters
On-line Conductivity Meter
On-line Dissolved Oxygen (DO) Meters
Membrane System Thermometers
Membrane System Pressure Gauges
Membrane System Rotameters
Membrane System Level Sensors
Membrane/UV System Run Hour Clock
Chemical Feed Pumping Rate
Portable DO/Temperature Meter
Desktop pH Meter
Desktop Turbidimeter
Desktop Ultraviolet (UV) Spectrophotometer
Desktop Silt Density Index (SDI) Analyzer
The sampling protocol for off-site water quality analysis is also described herein. All off-site
water quality analysis were analyzed at one of the following locations: onsite, Point Loma
laboratory (PL Lab) the City of San Diego Water Quality Laboratory @ Alvarado and
Calscience Environmental Laboratories (CEL Lab). All labs have the State of California
Department of Health Services (DHS) Environmental Laboratory Accredited Programs (ELAP),
and follow the associated QA/QC requirements.
C-2
Lastly, this TM provides the QA/QC procedures followed to ensure accurate data management
and data analyses of all water quality and operational data collected during this study.
ON-LINE TURBIDIMETERS
Two types of on line turbidimeters systems were used during testing to acquire MBR permeate
turbidities. Permeate turbidities of the Kubota, Zenon and Mitsubishi MBR systems were
measured using Hach 1720D turbidimeters while the US Filter permeate turbidity was measured
using a GLI Accu4 turbidimeter system. The GLI system contained a Model T53 analyzer an
8320 sensor. Both the 1720 D and Accu4 systems are designed to accurately measure low range
turbidity. Turbidity values were manually collected from each MBR on a daily basis. The
following procedures were followed to ensure the integrity and accuracy of this data:
- A primary calibration of the on-line turbidimeters was performed at the beginning of the
test period and as needed during testing.
- On-line turbidities were compared to desktop turbidities to verify accurate calibration.
- The manufacturers specified acceptable discharge flow range for the Hach 1720 D is 250
to 750 mL/min and the GLI Accu4 is 190 to 1500 mL/min. On-line turbidimeter flows
were verified daily with a graduated cylinder and stopwatch, and adjusted as necessary.
- The turbidmeters were periodically cleaned using a 50 ppm free chlorine solution to
remove build of ferric hydroxide precipitate and/or algae.
ON-LINE CONDUCTIVITY METER
Three dedicated Fisher Scientific digital conductivity meters were used to check the conductivity
of the RO feedwater (i.e. Kubota MBR permeate) and each of the RO permeates. These meters
were calibrated at the beginning, and end of the test period using standard solutions; daily
comparisons are performed between the on-line conductivity readings and on-site lab results.
The first meter was used to measure the feed water to the RO system and was calibrated using a
conductivity standard of 2764 mhos @ 25 C. The remaining conductivity meters were used
for RO permeate and were calibrated using a 23 mhos @ 25 C standard.
ON-LINE DISSOLVED OXYGEN (DO) METER
DO meters equipped on the Kubota and US Filter MBR systems were calibrated using the
manufacturers protocol at the beginning of the study. To ensure accuracy, values were compared
throughout the study to those measured by the hand held DO meter.
MEMBRANE SYSTEM THERMOMETERS
At the beginning of the study, all thermometers that were verified at a normal operating
temperature (25-30C) using an NIST thermometer. Monthly verification of system
thermometers was performed. The thermometers used to monitor the temperature of the MBRs
were all within 5% error. The thermometers used to measure the RO influent water were also
verified and within 5% error.
C-3
MEMBRANE SYSTEM PRESSURE GAUGES
Pressure and vacuum gauges supplied with the membrane systems tested were verified against
recently purchased grade 3A certified pressure and vacuum gauges. The certified pressure and
vacuum gauges were manufactured by Ashcroft and have an accuracy of 0.25% over their range
(0-30 psi pressure, 0-30 in Hg vacuum). Where possible, system gauges were removed and tested
over the expected range of operating pressures against the verification gauge, using a portable
hand pump. The vacuum gauge for the Mitsubishi MBR is a pressure transmitter that has been
factory calibrated to an accuracy of 1%. The calibration report from the manufacturer is on file
at the PLWTP pilot site. The vacuum gauge for the Zenon system had an average error less than
5 % over the range of normal operating pressures. The pressure gauges for the RO skids were
also within 5% error.
MEMBRANE SYSTEM ROTAMETERS
Membrane system liquid flow rates were verified volumetrically by bucket tests using calibrated
containers or graduated cylinders and a stopwatch. The measured flow rate was compared with
flows indicated on the rotameters. Measured and indicated flow rates agreed to within 5% for
both the Zenon MBR permeate and the Mitsubishi MBR permeate. The combined flow rates,
concentrate and permeate, of the RO skid were checked volumetrically and were both within 5%
error.
Membrane system air flow rotameters were factory calibrated prior to the study. [Please note:
there exists no practical method of volumetrically verifying the air flow rates during the pilot
study.]
C-4
MEMBRANE SYSTEM LEVEL SENSORS
Three Endress+Hauser level sensors were included as part of the Zenon MBR skid. All sensors
were factory calibrated prior to installation; the accuracy of the sensors were verified over the
range of values using a standard measuring tape.
MEMBRANE/UV SYSTEM RUN HOUR CLOCK
All system run hour clocks used during this study are periodically checked for accuracy using a
stop watch.
CHEMICAL FEED PUMPING RATE
The LMI pumps used for chemical injection were continually checked for accuracy. Upon start-
up, the pumps were checked on a daily basis; this frequency was decreased to once per week
after pumping consistency was demonstrated. The accuracy is verified using a graduated
cylinder and stopwatch.
PORTABLE DISSOLVED OXYGEN/TEMPERATURE METER
A hand-held YSI Model 55 dissolved oxygen meter was used to measure DO in the aerobic tank
of the MBR systems. The DO meter was factory calibrated prior to the study, and was re-
calibrated before every use according to manufacturers directions. Periodic comparisons
between the hand-held meter, and the PL Lab DO sensor were also performed to ensure
continued accuracy. The meter membrane and electrolyte solution are replaced as needed.
DESKTOP pH METER
A Fisher Scientific Accumet Model AR 15 desktop pH meter1 was used throughout the study to
determine pH of the raw wastewater, primary effluent, MBR Effluent and MLSS. The meter was
calibrated daily using a 3 point calibration with buffers 4, 7, and 10. The calibration was
confirmed daily using a Laboratory check standard.
DESKTOP TURBIDIMETER
A Hach 2100N desktop turbidimeter was used to perform onsite turbidity analyses of feed and
permeate samples. Readings were recorded in non-ratio operating mode. The following quality
assurance and quality control procedures were followed to ensure the integrity and accuracy of
onsite laboratory turbidity data:
Weekly primary calibration of turbidimeter according to manufacturers specification.
Daily secondary standard calibration verification. Two secondary standards (approx.
0.05 NTU, and 19.1 NTU) were recorded after primary calibration and on the remaining
working days until the next primary calibration.
1
Fisher Scientific International Inc. Accumet Research AR15, Hampton NH
C-5
DESKTOP UV SPECTROPHOTOMETER
Samples collected for TOC analysis were analyzed for UV-254 absorbency using a Hach
DR/4000 UV spectrophoteter. This instrument was returned to the factory for calibration prior to
the study; the instrument was zeroed prior to each measurement.
DESKTOP SDI ANALYZER
A Chemetek, model FPA-2000 was used to measure SDI values on Kubota and US filter
permeate. This equipment was calibrated by the manufacturer prior to the pilot study.
Electronic results from the SDI tests were periodically forwarded to the manufacturer to ensure
continued accuracy.
The filters used for the SDI analysis were GelmanSciences 0.45 um, Sterile Acrodisc, HT
Tuffryn membrane (low protein binding, non-pyrogenic, product number 4184). MWH has used
these filters for SDI analysis in previous reclamation studies. Samples of these filters were also
forwarded to Chemetek for independent analysis.
WATER QUALITY SAMPLING PROTOCOL
All sample lines are properly sterilized (for microbial samples) and flushed for a minimum of
one minute prior to sampling. Sample containers are obtained from the labs performing the
analyses and all preservation chemicals are added to the bottles by the lab prior to sampling,
when required. Filtering or any other required preparatory steps are also be performed by the
respective lab performing the analysis. A courier from the MWWD or CEL Labs transports all
samples that will be analyzed off site. Standard shipping and packing procedures are followed,
including isolating samples and storage of samples in a cooler packed with plastic bubble wrap
to prevent breaking of glass sample bottles. Ice packs are added to the coolers containing
samples requiring storage at 4 degrees C. The samples will be delivered and analyzed within the
allotted holding time for each measured parameter.
A chain of custody is filled out on-site by the person performing the sampling and given to the
courier when the samples are picked up for delivery. Upon receipt, a representative from the lab
will sign the Chain of Custody and the samples will be released to their custody. A copy of the
signed Chain of Custody will then be sent back to the sampler and will be kept on file at the pilot
site.
DATA MANAGEMENT/ANALYSES
All water quality data collected on-site was merged with data obtained from offsite laboratories
throughout the study. Operational data was recorded on raw data sheets and routinely inputted
into a database. The water quality and operational databases were combined to create a
comprehensive database which was used for data analysis, retrieval, reporting and graphics. All
data inputted to the database was checked and verified by the onsite engineer. Lastly, data files
were periodically sent to TAC members during the study for analysis.
APPENDIX D
Photographs of Pilot Equipment
D-1
Kubota MBR Pilot Unit
D-2
Kubota: Upper Membrane Cassette (top); Lower Membrane Cassette (bottom)
D-3
Kubota Type 510 Membrane (single sheet)
D-4
Kubota Type 510 Membrane (after 2 months operation)
D-5
US Filter MBR Pilot Unit
D-6
US Filter MBR Pilot Membrane Tank
D-7
US Filter MemJet B10 R Membranes
D-8
US Filter MemJetB10 R Membranes
D-9
Zenon MBR Pilot Unit
D-10
Zenon 500d Membrane Cassette
D-11
Zenon MBR Aeration Tank with Fine Bubble Diffusers (Plan View)
D-12
Mitsubishi MBR Pilot Unit (Plan view)
Mitsubishi MBR Pilot Unit (front view)
D-13
Mitsubishi Sterapore HF Microfiltration Membranes
D-14
RO Pilot Skid
RO Pre Filters: New (bottom); After 1 month Operation (top)
D-15
Aquionics UV Pilot System Control Panel (Top); UV Reactor (Bottom)
D-16
Pre-Screen (Roto-Sieve Model 6013-11)
APPENDIX E
Kubota Title 22 Approval Letter
APPENDIX F
Additional Costing Information
F-1
M E M O R A N D U M
To: Membrane Manufacturer
From: Samer Adham, Ph.D./Steve Lacy, P.E.
Prepared by: James DeCarolis/Jude Grounds
Subject: MWH/MBR Vendor Workshop
MWH would like to thank you for your recent participation in the MBR Costing
Workshop. The workshop generated a lot of discussion and information regarding full-
scale design and costing issues related to the Bureau of Reclamations (USBR) project
entitled Optimization of Various MBR Systems for Water Reclamation. To meet the
costing requirements of the project, we would like to request additional capital and
operation/maintenance information associated with the membrane and ancillary systems.
The following memo outlines these additional requirements.
MWH will perform the biological portion of the design based on decisions made during
the workshop. The following design criteria will be used for preliminary design and
costing of the biological system:
1. Feed Water Costs will be generated for operation on both raw wastewater and
advanced primary effluent, assuming the following influent wastewater
characteristics:.
Parameter Raw Wastewater Primary Effluent

BOD
5
(mg/L) 290 130
COD (mg/L) 700 280
TSS (mg/L) 320 65
VSS (mg/L) 260 50
NH
3
-N (mg/L) 30 30
TKN (mg/L) 60 40
TDS (mg/L) 1,200 1,200
Alkalinity (mg/L) 245 230
Temperature (
o
C) 20 20
F-2
2. SRT The design SRT will between 10-15 days.
3. MLSS MLSS will range from 8,000 10,000 mg/L.
4. MBR Effluent The biological portion of the MBR system will be designed to
meet the following effluent water conditions:
- Complete nitrification (i.e. NH
4
+
-N<1.0 mg/L),
- Denitrification (i.e. NO
3
-N<10 mg/L)
- Biological Oxygen Demand (BOD) < 2.0 mg/L
Below are the key membrane system design criteria developed from discussions during
the workshop. Please use these as guidelines when developing costs for the membrane
system:
Capacity Costs will be generated for 0.2, 0.5, 1.0, 5.0 and 10 MGD MBR systems.
System will be for a sewer mining (scalping) plant. Residuals controlled through wasting
to a downstream treatment facility.
Peaking MBR systems will be designed with 1.0 Q.
Operating Flux Membrane costs will be based on net operating flux of 15 gfd @ 15
deg C.
Operating TMP - Costs will be based on operating TMP of 2 psi, with a range of 1 4
psi.
Screening Costs will include 0.8 mm perforated center feed rotary drum screens
required for both feed water sources. Screen capacity will be based on peak flow; during
periods of low flow, mixed liquor will be recycled/re-screened.
Cleaning Interval A minimum of 2 CIPs will be required per year; the frequency of
maintenance cleaning will be per the manufacturers recommendation.
Redundancy The MBR systems will be designed at average conditions to operate with
one filter unit out of service (OOS) for a routine relaxing and an additional membrane
filter unit OOS for chemical cleaning. System must be designed to accommodate
increased flow to remaining filter units due to OOS unit.
Warranty Costing will include a 5-year, non-prorated warranty. Warranty to cover
manufacturing defects, normal wear and include the cost for providing replacement
membranes to the plant site.
Please provide the following capital and operation/maintenance cost information as
described below. For your convenience, we have attached a spreadsheet to be used for
reporting cost estimates.
CAPITAL COSTS
Please provide the following capital costs for 0.2, 0.5, 1.0, 5.0 and 10 MGD capacities
(for both feed waters, if different):
1. Membrane Costs - Please provide membrane costs for the capacities listed above.
Include the membrane model number and values for total surface area and total
F-3
number of membrane filter units. The membrane cost shall be based on the following
conditions:
- Net operating flux of 15 GFD @ 15C
- Average operating TMP of 2.0 psi (This constitutes a average operating specific
flux of 7.5 gfd/psi @ 15 C)
- Net operating flux does not include loss of MBR permeate due to downtime and
the use of MBR permeate for membrane cleaning (including relaxation or
backwashing, CIPs and maintenance cleans, if applicable)
- Assume that 15% of the active membrane area will be lost over a 5 year period
due to irreversible fouling
- The number of membrane units used for costing must meet the redundancy
criteria listed above
2. Chemical Cleaning Equipment Please provide itemized list of cost for any
equipment necessary to perform CIPs and maintenance cleans including: pumps,
tanks, valves and ancillary equipment/instrumentation.
3. Membrane Chamber Please provide the sizing requirements for the membrane
chamber(s) to accommodate the various MBR system capacities. Include in the costs
for the membranes any internal components to the membrane chamber such as
membrane support systems, internal beams and ancillary equipment. The membrane
chamber must be sized with four feet of free-board for foam control.
4. Valves, piping and system controls Please provide itemized list of costs for all
valves piping and system controls necessary in the membrane chamber. Include any
costs for standard PLC associated with the membrane tank.
5. Membrane Aeration System Please provide the membrane aeration system design
and costs for the various components of the membrane aeration system. The design
should include items such as: air flow control valves, isolation valves, flow meters
and rotameters. The design should be based on the necessary airflow requirement for
membrane scouring. Please include membrane aeration system design and costs for
0.2, 0.5, 1.0, 5.0 and 10 MGD facilities. Equipment to provide air for the biological
treatment will be provided by others.
6. Permeate Collection System - Please provide costs for pumps, flow control valves,
and isolation valves related to the permeate collection system. In addition, please
provide cost of turbidimeters, flow meters, and TMP measuring equipment and
associated transmitters.
7. Warranty- Please provide a description and cost for a 5-year non-prorated warranty
for the various plant capacities.
F-4
OPERATION AND MAINTENANCE COSTS (O&M)
Please provide the following O&M costs for 0.2, 0.5, 1.0, 5.0 and 10 MGD capacities (for
both feed waters, if different):
1. Personnel Please estimate the number of hours per day for operation and
maintenance.
2. Chemical Requirements Please provide the amount of chemical required (lbs/year)
to perform CIPs and maintenance cleans. This quantity should be adequate to
perform a minimum of 2 CIPs per year and the manufacturers recommended number
of maintenance cleans per year. It should be noted the system should be operated to
meet the TMP requirement listed above.
3. Membrane replacement Please provide estimated membrane replacement cost over
a twenty year period. Assume membrane replacement every 8 years.
4. Electrical Permeate and backwash pump and blower demands (kWh) based on a
normal operating TMP of 2 psi. Additionally, electrical demands for all ancillary
systems should also be included in the estimate.
5. Spare parts Please identify and estimate the cost of spare parts typically incurred on
yearly basis.
To meet the project schedules, we would appreciate if you could provide these costs no
later than July 25th, 2003. If you would like to discuss any of the information requested
above, please contact James DeCarolis (619 221-8325).
F-5
Unit Cost Assumptions used to estimate MBR O&M Costs
Annual Cost Units Unit Cost Assumptions
Electrical power for process/miscellaneous kwh $0.08 Power usage = 100 kwh/day-mgd.
Equipment repairs/lubricants/replacement Is/yr 2%
Percentage of Capital Equipment inc. Headworks, MBR system,
Mechanical and Blower and pump building.
Crane per rental $1,000.00
Crane rental needed 2/yr for 0.2 mgd; 3/yr for 0.5 mgd. Crane to
be purchased for 1, 5 and 10 mgd systems included in capital
costs.
Sodium Hypochlorite gallons $0.50
Citric Acid kg $2.40
Sodium Hydroxide (neutralization) kg $0.31
Sodium Bisulfite (neutralization) kg $0.77
Sodium Hypochlorite gallons $0.50 Annual cost based on 3 mg/L dose @12% sol.
Diffuser Replacement per diffuser $25 8-year replacement life; 9" fine bubble diffusers.
Membrane Replacement Is/yr NA 8-year replacement life;provided by mfgs.
Labor per hour $50
(0.2 mgd) = 1 hr/day, 5 days/week + 1 hr /day, 2 days /week (0.5
mgd) = 1.5 hr/day, 5 days/week + 1 hr /day, 2 days /week (1
mgd) = 2 hr/day, 5 days/week + 1 hr /day, 2 days /week (5 mgd)
= 6 hr/day, 5 days/week + 2 hr /day, 2 days /week (10 mgd) = 16
hr/day, 5 days/week + 4 hr /day, 2 days /week.
Total Costs based on 2 cleanings per year. Quantity of each
chemical required derived from estimates provided by Zenon
Environmental.
Chemical Cleaning (Membranes)
Chemical Cost for Disinfection

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Desalination and Water Purification Research and Development

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