Membrane Fouling &cleaning Ayman

RESAT EGYPT WATER
TREATMENT
3 ALKHALEEG BUILDING ALMARUTIA
PYRAMEIDS GIZA
Telefax: 202 37447164 – 0101480286
Membrane Cleaning
By Chemist
Ayman Awny Mahmoud
Poor Permeate Quality
Low Water Production
FOULING
Membrane Damage
RESAT EGYPT Frequent Cleaning

WATER TREATMEN T
Website :www.resategypt.com
Fouling Indicators
Permeate Salt Diff. Direct Indirect Corrective
Flow Passage Pressure Cause Cause Measure
   Scaling Poor Scale Cleaning;
Control Scale
Control
   Colloidal Insufficient Cleaning;
Fouling Pretreatment Improve
Pretreatment
   Biological Feed water; Cleaning;
Fouling Insufficient Biocide;
Pretreatment Improve
Pretreatment
   Organic Polymer Cleaning;
Fouling Overfeed; Improve
RESAT EGYPT Humics; Pretreatment
WATER TREATMEN T
Website :www.resategypt.com Oil
Common Fouling Risks
Survey of 150 Membrane Autopsies
AVERAGE FOULANT DIS TRIBUTION
WORLDWIDE
13.5% 4.7%
3.6% ORG
7.6% 3.7%
2.6% Fe2O3
SiO2
14.1% Al2O3
CaPO4
CaCO3
50.2% CaSO4
OTHERS
RESAT EGYPT
WATER TREATMEN T
RESAT EGYPT
WATER TREATMEN T
RESAT EGYPT
WATER TREATMEN T
Calcium Sulfate Scaling on the Vexar spacer
RESAT EGYPT
WATER TREATMEN T
Silica Fouling
RESAT EGYPT
WATER TREATMEN T
BIOFOULING RESAT EGYPT
WATER TREATMEN T
SEM: Biomass and Rod Shaped Bacteria
When do I clean?
• When any ONE of the following changes:
 Differential Pressure by 15%
 NPF by 15%
 Salt Passage by 15%
• Exceeding these limits may be irreparable
• Start planning your strategy at the 1st
indication of a minimum change!
RESAT EGYPT
WATER TREATMEN T
Maintenance Cleaning
•RO’s need to be Cleaned!
•Typically:
 SDI 3 -5 Cleaning 4 /year
 SDI 1- 3 Cleaning 2 /year
 SDI < 1 Cleaning 1 /year
Proper Cleaning Maintenance
Cleaning after a
10-15% decline
Normalized maximizes RO
Permeate performance
Flowrate
Cleaning after 10-15% decline
Time
Improper Cleaning Maintenance

Waiting too
Normalized long
Permeate to clean reduces
RO
Flowrate
performance
Cleaning after > 15% decline
Time
Telescoped membrane due to high differential pressure
Operator waited too long before cleaning
RESAT EGYPT
WATER TREATMEN T
Permanent membrane damage
User did not clean in time
RESAT EGYPT
WATER TREATMEN T
Chemical Cleaning Products
• Biocontrol-11: Non-oxidising Biocide
• RESAT-DE 22 PC-33: Chelating Agent
• Biocontrol-22: Non-oxidising Biocides
• Anti-chlorination : Cl2 Release Sanitizer

Chemical Cleaning Products
• RESAT-DE-67: Mild Alkaline Surfactant
• RESAT-DE-77: Weak Acid
• RESAT-DE-87: Strong Mineral Acid
• RESAT-DE-99: Alkaline Surfactant

Factors Influencing Cleaning
• Plant Design - Ensure CIP tank & pump
is correct size
• Plant Operation
• Membrane - Max pH/Temp limits
• Chemicals Selected
RESAT EGYPT
WATER TREATMEN T
Factors Influencing Cleaning
• Temperature
• pH
• Flow vs. Soaking
• Time
• Velocity
RESAT EGYPT
WATER TREATMEN T
Cleaning Tips
• Pressure drop < 60 PSI
• Flow 35- 40 GPM per pressure vessel (8”)
• Cleaning Solution Volume: Use 8 - 10

Gallons Per 8” element. Each pressure
vessel = 50 gallons volume
• Use Alkaline cleaners first if organic

fouling is suspected - acid can tighten
organic foulant onto the membrane
Cleaning Tips
• Max Solution Temperature advised by
Membrane Manufacturer
• Soak Membranes - reduces cleaning

solution channeling
• Clean “stage by stage”
• Replace Turbid Cleaning Solutions
• Keep good records RESAT EGYPT

WATER TREATMEN T
Keep Good Records
Cleaning Skid
Permeate
Concentrate Brine
Pressure
Vessels
Cleaning 2:1
Tank P P
LL
Heater
Feed
Cartridge
Filter
Membrane Preservation
• Preserve if out of service >24 hrs
• Sodium Bisulfite - 1%
• RESAT-DE 55 or / 56 - 0.05%
• Formaldehyde - NO - carcinogenic
• Glutraldehyde - NO - membrane damage
RESAT EGYPT
WATER TREATMEN T
Membrane Flushing
• Permeate flush if system shuts down

• Acts as a “mini clean” and removes
concentrate
• Reduces fouling and scaling
RESAT EGYPT
WATER TREATMEN T
Membrane Autopsy Service
• Destructive procedure consisting of

observations and analytical tests
on used membrane
• Determines cause of failure or poor
performance
• Results used to develop site specific
custom cleaning program
RESAT EGYPT
WATER TREATMEN T
Flat sheet test rig to determine
flow and rejection of autopsied membrane
RESAT EGYPT
WATER TREATMEN T
Flat sheet testing will ensure most effective
cleaning program is developed & used
Use RESAT-DE Autopsy as a preventative tool
See RESAT-DE Autopsy Report Example
RESAT EGYPT
WATER TREATMEN T
Thank You
Questions
RESAT EGYPT
WATER TREATMEN T

Membrane Fouling &cleaning Ayman

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RESAT EGYPT WATER

Low Water Production

RESAT EGYPT Frequent Cleaning

Improper Cleaning Maintenance

Cleaning after > 15% decline

Operator waited too long before cleaning

User did not clean in time

• Biocontrol-11: Non-oxidising Biocide

• RESAT-DE 22 PC-33: Chelating Agent

• Biocontrol-22: Non-oxidising Biocides

• Anti-chlorination : Cl2 Release Sanitizer

• RESAT-DE-67: Mild Alkaline Surfactant

• RESAT-DE-77: Weak Acid

• RESAT-DE-87: Strong Mineral Acid

• RESAT-DE-99: Alkaline Surfactant

• Flow 35- 40 GPM per pressure vessel (8”)

• Cleaning Solution Volume: Use 8 - 10

• Use Alkaline cleaners first if organic

• Soak Membranes - reduces cleaning

• Clean “stage by stage”

• Replace Turbid Cleaning Solutions

• Keep good records RESAT EGYPT

• Permeate flush if system shuts down

• Destructive procedure consisting of

Use RESAT-DE Autopsy as a preventative tool

See RESAT-DE Autopsy Report Example

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