Statutory directors’ duties, the civil penalty

regime and shareholder ratification: What role

does the public interest play?

INTRODUCTION
The year 2013 marked the 20th anniversary of the commencement of the civil penalty regime that is
now contained in Pt 9.4B of the Corporations Act 2001 (Cth). This reform provided the corporate
regulator, the Australian Securities and Investments Commission (ASIC), with a range of civil
measures that dramatically reduced the need for reliance upon criminal sanctions.1 These civil
penalties include remedies only available to ASIC.2 This significantly contrasts the general law
position where civil remedies are predominantly sought by the company at the behest of its
shareholders. The introduction of these statutory civil penalties, and in particular ASIC’s standing to
commence civil penalty proceedings, has raised questions as to the relevance of public interest
considerations beyond simply the interests of the company and its shareholders. The uncertainty
surrounding this topic has most recently been highlighted in ASIC v Cassimatis3 where Reeves J left
undecided the impact that the interests of the shareholders had with respect to potentially precluding
ASIC’s ability to enforce an alleged breach of s 180(1) of the Corporations Act.
This article will explore the nature and scope of the public interest dimension to the duties of a
director under the Corporations Act, and its relationship to the interests of the company and its
shareholders. At a conceptual level, the core of the debate appears to lay in the continuing trend
towards a greater emphasis on public policy and social responsibility considerations within the
corporate sector, especially in light of recent corporate collapses. This conflicts with the more
traditional understanding of the company as a private undertaking managed purely for the benefit of its
shareholders. The article will therefore commence with an analysis of the purpose and intent behind
the enactment of statutory directors’ duties and the more recent introduction of the civil penalty
*
LLB (Hons) (Qld), BCom (Qld) (Hons) (Monash). An earlier version of this article was presented in partial fulfilment of the
Honours degree of Bachelor of Commerce at Monash University. The author would like to thank Dr Phillip Lipton of the
Department of Business Law and Taxation for his invaluable comments and advice. Any remaining errors are the authors.
1
Comino V, “The Enforcement Record of ASIC Since the Introduction of the Civil Penalty Regime” (2007) 20 Australian
Journal of Corporate Law 183 at 187.
2
Corporations Act 2001 (Cth), ss 206C, 1317J(1).
3
Australian Securities and Investments Commission v Cassimatis [2013] FCA 641.

(2014) 32 C&SLJ 399 399

Piling 2020

4. Additional Design Considerations “squeezing” deformation in the lower stratum. Depending on

the geometry and reinforcement strength, the embankment
4.1 Extrusion and Edge Stability itself either undergoes very localised shearing and vertical
The aforementioned design approaches cover the design of “sinking” translation or rotational “snapping”. In both these
infinitely wide platforms. They do not provide design cases further increasing the strength of the reinforcement does
approaches to assess the platform edge stability, which can be little to improve stability of the platform.
critical particularly on restricted sites and where there is a soft
subgrade. Where extrusion is a problem, standard solutions have included
flattening the side slopes or increasing the set-back from the
In a similar way as one would consider extrusion and rotational edge of the platform. Mounded fill around the platform can
failures under a larger embankment, the platform edge stability provide counter pressure to extrusion. While sheet piling can
should be considered (Shown as Fig. 4 . These failure modes be used to cut off and retain these soft soils this solution is often
are well covered by chapter 6 of BS 8006-1 (British Standards prohibitively expensive for large temporary sites. Where the
Institute 2016), which includes design approaches for both soft soil depth is limited in depth (e.g. 2 to 3 m), it may be more
mechanisms in reinforced platforms, albeit considering them economical to simply excavate it and replace with competent
as permanent embankments. granular fill.

4.2 Extrusion - Shear Key Trenches

Rather than excavating and replacing all the underlying weak
soils, this activity can be limited to the perimeter of the site in
a trench, creating a shear key. This is a well-established
earthworks technique used to disrupt potential weak slip-
planes (Giffen 2015).

There are three possible categories of shear key (see Fig. 8):
Unreinforced Full Depth: Typically extending through the
weak soil layer(s) and embedded into stronger soils below, the
key completely isolates the weaker layer, preventing extrusion.
The granular fill to these trenches improves the drainage of the
soft underlying soils.

Reinforced Full Depth: To limit the width of the key, and

excavation, geotextiles can be used to encase the trench and
maintain the integrity of a smaller shear key trench.
Figure 6: Embankment External Failures: Top: Rotational
Failure; Bottom: Extrusion failure (Extract from BS8006- Reinforced Partial Depth: Where the depth of the soft layers,
1995)
makes a full depth trench uneconomical, a trench can be
Extrusion is particularly problematic for heavily loaded considered that extends only a limited distance into to the soft
embankments or essentially thicker working platforms over soil. This extends deep enough to limit the effective thickness
thin layers of weak soils. Here, the imposed loading can cause of the soft layer, until the destabilising extrusion pressure can
extrusion of the weak underlying soils, which have insufficient be resisted.
strength to resist the out of balance active earth pressures. Like
a toothpaste tube under pressure, this soft soil undergoes plastic
deformation out from underneath the embankment, causing the
platform to settle by displacement.

Smith and Tatari (2016) investigated the susceptibility of

reinforced embankments over weak soils to cause extrusion.
Their analysis using the DLO software programme,
LimitState:GEO and looked at the failure mechanisms of the
platform over varying soil strengths. The stability of highly
reinforced platforms was dominated by a susceptibility to this

346
 Proceedings of the XVI ECSMGE
Geotechnical Engineering for Infrastructure and Development
ISBN 978-0-7277-6067-8

© The authors and ICE Publishing: All rights reserved, 2015

doi:10.1680/ecsmge.60678

Working platforms for tracked plant – an alternative

design approach to BR470 using hexagonal geogrid
mechanically stabilised layers
Plates-formes de travail d’usine de chenilles, une approche de
conception alternatives à une BR470 utilisant une couche stabilisé
mécaniquement avec une géogrille hexagonal
Mitul J Dalwadi*1 and John Dixon1
1
Tensar International UK
* Corresponding Author
ABSTRACT Temporary working platforms are critical for plant stability, efficiency and safe operation. The guide to good practice (BR
470), ‘Working platforms for tracked plant’ was prepared by BRE in June 2004. The prime objective of this guide is to achieve an accepta-
ble level of safety for piling and other tracked plant operations. The guide includes the option to use geosynthetic products as structural re-
inforcement. Designs based on this guideline often results in an excessively thick working platform. Extensive research has been carried
out on unbound aggregate layers mechanically stabilised with a hexagonal structure geogrid with triangular apertures. Based on this re-
search together with experience from the field, a load spread method has been developed as an alternative approach to the BR470 guide that
provides a safe but more economic design with a lower carbon footprint. This approach has been widely used on numerous projects in UK
for working platforms over weak foundation soil, sometimes including extreme loading conditions. This paper highlights the application of
mechanically stabilised working platforms on two projects with challenging geotechnical and loading conditions; Crossrail, Contract C310
at North Woolwich and a commercial development at Ipswich. The stabilised working platforms not only allowed the use of recycled mate-
rial but also reduced the thickness of working platform by up to 65% compared to a design to BR470. Thus mechanically stabilised work-
ing platforms designed with a load spread method empirically derived for hexagonal structure geogrids can reduce the cost and time of con-
struction and minimise or avoid the need to import granular fill, while still creating a sustainable, safe working platform for the tracked
plant.

RÉSUMÉ Plates-formes de travail temporaires sont essentielles pour la stabilité de l'installation, l'efficacité et la sécurité de fonctionne-
ment. Le guide de bonnes pratiques (BR 470), «les plates-formes de travail pour l'usine de camions» a été préparé par le BRE en Juin 2004
Le premier objectif de ce guide est d'atteindre un niveau de sécurité acceptable pour empilage et d'autres opérations de l'usine à chenilles.
Le guide inclut l'option d'utiliser des produits géosynthétiques comme renfort structurel. Conceptions basées sur cette directive se traduit
souvent par une plate-forme de travail trop épaisse. Des recherches approfondies ont été réalisées sur des couches d'agrégats non liés méca-
niquement stabilisé avec une structure de géogrille hexagonale avec des ouvertures triangulaires. Sur la base de cette recherche avec une
expérience sur le terrain, une méthode de charge de propagation a été conçue comme une approche alternative au guide de BR470 qui four-
nit une conception économique sûr, mais plus avec une empreinte carbone plus faible. Cette approche a été largement utilisée dans de nom-
breux projets au Royaume-Uni pour les plates-formes de travail sur des sols de fondation plus faibles, parfois inclus, conditions de charge
extrêmes. Ce document met en évidence l'application de plates-formes de travail stabilisées mécaniquement sur deux projets avec des con-
ditions géotechniques et de chargement difficiles; Crossrail, contrat C310 à North Woolwich et de développement commercial à Ipswich.
Les plates-formes de travail stabilisées non seulement permis l'utilisation de matériaux recyclés, mais aussi de réduire l'épaisseur de la
plate-forme de travail pouvant aller jusqu'à 65% par rapport à une conception avec le BR470. Ainsi les plates-formes de travail stabilisé
mécaniquement conçus avec une méthode de charge de propagation de façon empirique pour des structures de géogrille hexagonale peut
réduire le coût et le temps de construction et de réduire ou d'éviter la nécessité d'importer le remblai granulaire, tout en créant une plate-
forme de travail durable, sans danger pour le suivi du projet.

1395
Geotechnical Engineering Discussion
Volume 167 Issue GE1 Vardanega, Kolody, Pennington et al.

the geotechnical reduction factors (similar to partial factors), and Platforms. American Petroleum Institute, Washington, DC,
a risk analysis matrix is used to search for a value of the USA.
reduction factor applicable to the specific design project being Burland JB, Butler FG and Dunican P (1966) The behaviour and
undertaken. This gives the design engineer the flexibility to design of large diameter bored piles in stiff clay. Proceedings
reduce the partial factors if good ground investigation data and of the ICE Symposium on Large Bored Piles, London, UK,
load testing are carried out, or increase them if designing in an pp. 51–71.
unfamiliar soil deposit. The code itself gives advice on the Caltrans (2011) California Amendments to Aashto LRFD Bridge
elements of geotechnical risk that the designer must consider; in Design Specifications, 4th edn. California Department of
other words, they recognise that a ‘one size fits all’ approach is Transportation, Sacramento, CA.
perhaps limited. Eurocode 7 aims to achieve a similar result by FHWA (Federal Highway Administration) (2010) Drilled Shafts:
encouraging the designer to vary the characteristic values of soil Construction Procedures and LRFD Design Methods, Report
properties in relation to the quality of the supporting data, while No FHWA NHI-10-016. National Highway Institute,
keeping the values of partial factors constant. Washington, DC, USA.
Guha S (1995) Dynamic Characteristics of Old Bay Clay
The discussion of the adhesion factor Æ for bored pile design is Deposits in the East San Francisco Bay Area. PhD thesis,
interesting. The parameter Æ relates to the soil deposit being Purdue University, Ann Arbor, MI, USA.
studied; the value Æ ¼ 0.5 is commonly used in London Clay. Paikowsky S (2004) Load and Resistance Factors for Deep
Increasing Æ to account for rate effects in clay might be Foundations, NCHRP Report 507. Transportation Research
warranted, but only if load-test data were also available (e.g. Board, Washington, DC, USA.
Burland et al., 1966). For example, previous use of ‘constant rate Patel D (1992) Interpretation of results of pile tests in London
of penetration’ tests generally showed slightly higher values of Æ Clay. In Piling: European Practice and Worldwide Trends
for London Clay (Patel, 1992). For static loading, Æ ¼ 0.7 used in (Sands MJ (ed.)). Thomas Telford, London, UK, pp. 100–
the Caltrans amendment, as noted by the discussers, does seem 110.
surprisingly high for a stiff clay (API, 1984); the overall Poulos HG (2004) An approach for assessing geotechnical
reliability of the design will depend not only on this and the reduction factors for pile design. Proceedings of the 9th
applied strength reduction factor, but also on the factors applied Australia New Zealand Conference on Geomechanics,
to loads. We understand that, in practice, the use of this value is Auckland, New Zealand, vol. 1, pp. 109–115.
often replaced by results from load testing. Standards Australia (2009) AS2159-2009: Piling: design
and installation. Standards Australia, Sydney, NSW,
REFERENCES Australia.
Aashto (2007) LRFD bridge design specifications. Customary US Vardanega PJ, Kolody E, Pennington SH, Morrison PRJ and
Units, 4th edn. American Association of State Highway and Simpson B (2012) Bored pile design in stiff clay I: codes of
Transportation Officials, Washington, DC, USA. practice. Proceedings of the Institution of Civil Engineers –
API (1984) Planning, Designing and Constructing Fixed Offshore Geotechnical Engineering 165(4): 213–232.

88
Drink. Water Eng. Sci., 10, 61–68, 2017
https://doi.org/10.5194/dwes-10-61-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.

Online total organic carbon (TOC) monitoring for water

and wastewater treatment plants processes and
operations optimization
Céline Assmann, Amanda Scott, and Dondra Biller
Analytical Instruments, a Division of GE Power, Boulder, Colorado, USA
Correspondence to: Céline Assmann (celine.assmann@ge.com) and Amanda Scott (amanda.scott@ge.com)
Received: 21 February 2017 – Discussion started: 2 March 2017
Revised: 18 May 2017 – Accepted: 25 May 2017 – Published: 7 August 2017

Abstract. Organic measurements, such as biological oxygen demand (BOD) and chemical oxygen de-
mand (COD) were developed decades ago in order to measure organics in water. Today, these time-consuming
measurements are still used as parameters to check the water treatment quality; however, the time required to
generate a result, ranging from hours to days, does not allow COD or BOD to be useful process control parame-
ters – see (1) Standard Method 5210 B; 5-day BOD Test, 1997, and (2) ASTM D1252; COD Test, 2012. Online
organic carbon monitoring allows for effective process control because results are generated every few minutes.
Though it does not replace BOD or COD measurements still required for compliance reporting, it allows for
smart, data-driven and rapid decision-making to improve process control and optimization or meet compliances.
Thanks to the smart interpretation of generated data and the capability to now take real-time actions, munici-
pal drinking water and wastewater treatment facility operators can positively impact their OPEX (operational
expenditure) efficiencies and their capabilities to meet regulatory requirements. This paper describes how three
municipal wastewater and drinking water plants gained process insights, and determined optimization opportu-
nities thanks to the implementation of online total organic carbon (TOC) monitoring.

1 Introduction taminants including petroleum products, organic acids like

humic and fulvic acids, pesticides, pathogens, etc. It is a
Growing populations and expanding industries are pulling non-specific, but inclusive parameter for monitoring organ-
on water resources while adding nutrients and pollutants to ics. Knowing and understanding TOC levels coming into,
water sources. These facts coupled with heightened public throughout, and leaving a plant can be used as a measure of
demand for quality water at affordable prices has the wa- treatment efficacy and as an indicator of contamination. As
ter industry under scrutiny. Whether complying with wa- opposed to methods like biological oxygen demand (BOD)
ter regulations, optimizing treatment processes for saving and chemical oxygen demand (COD), TOC includes all or-
time and money, or looking to better manage a plant during ganic compounds and can be achieved in a matter of min-
times of emergency (flood, fire, security threat, drought or utes with instrumentation as opposed to hours or days with
industrial spill), knowing and understanding organics and or- reagents in a laboratory.
ganic removal can be extremely valuable. Total organic car- This paper discusses the three organics measurement
bon (TOC) monitoring is one of the most important param- methodologies mostly used today (BOD, COD, TOC) and
eters that drinking water and wastewater facilities can use to provides examples of three municipal drinking water and
make decisions about treatment. wastewater treatment plants that have implemented online
Measuring TOC can be critical to a water treatment facil- TOC monitoring as a tool to make informative and rapid
ity’s water quality in helping to optimize treatment processes. treatment decisions, allowing them to optimize their plants
TOC is useful in detecting the presence of many organic con- processes and operations: City of Boulder (75th Street) Pub-

Published by Copernicus Publications on behalf of the Delft University of Technology.

62 C. Assmann et al.: Online TOC monitoring for water and wastewater treatment plants processes

lic Works Wastewater Treatment Facility, Colorado (USA), COD analysis uses toxic chemicals and generates haz-
Twin Oaks Valley Water Treatment Plant in San Marcos, Cal- ardous waste, that require proper handling and disposal. In-
ifornia (USA) and City of Englewood Water Treatment Plant, deed, along with the potassium dichromate in 50 % sulfuric
Colorado (USA). acid solution, pre-prepared COD vials also contain silver sul-
fate as a catalyst and mercuric sulfate to mitigate chloride
2 Discussion of the methods for organics interferences.
measurements and regulatory frameworks
2.1.3 TOC measurements
2.1 The methods for organics measurements in water
and wastewater The TOC test is gaining popularity because it only takes
5–10 min to complete. At the heart of the TOC test is a
Since the 1970s, laboratory analytical methods for organics carbon-analyzing instrument that measures the total organic
measurements have been developed with the aim to estab- carbon in a water or wastewater sample. There are different
lish the concentration (typically in mg L−1 or ppm) of or- types of analyzers, but all oxidize organic carbon into car-
ganics (i.e., carbon-containing) matter to determine the rel- bon dioxide (CO2 ) and measure that CO2 generated using
ative “strength” of a water and a wastewater sample. Today a detection method. Oxidation methods include combustion,
there are three common laboratory tests used to determine the UV persulfate, and super-critical water oxidation while de-
gross amount of organic matter: BOD, COD and TOC (total tection methods include NDIR (non-dispersive infrared) and
organic carbon). Though these tests measure different things membrane conductivity (see Potter and Wimsatt, 2005, and
in water, there is overlap in the results, and some correlations ASTM D5173-15, 2015).
could be established (see Kiepper, 2016). COD and BOD are laboratory techniques, whereas TOC
can be done in the laboratory (offline measurements) or on-
2.1.1 BOD measurements line (at-line measurements). The value of online analysis
is obviously getting real-time data to see process changes
BOD measures the amount of dissolved oxygen needed
and make quick process decisions based on the observed
by aerobic biological organisms to oxidize organic mate-
fluctuations. Online TOC analyzers typically require main-
rial in a water sample. BOD is commonly expressed as
tenance throughout the year and have consumable parts that
BOD5, miligrams of O2 consumed per liter of sample dur-
need to be changed out. Newer TOC analyzers, however, are
ing 5 days of incubation at 20 ◦ C. It is an indirect measure-
designed for ease of use and have minimized maintenance
ment of organic quality or pollution in water (see Standard
down to once per quarter with calibration every 6–12 months.
Method 5210 B, 1997).
The cost of ownership and complexity is more important
cBOD (carbonaceous BOD) is a BOD measurement where
with TOC than with COD or BOD: TOC test procedures are
a nitrification inhibitor is added to the BOD sample, to stop
relatively simple and straight forward, but are specific to the
the oxidation of ammonia to nitrate, and measure specifically
type of carbon-analyzing instrument utilized. Thus, no “typ-
the organic carbon contribution to oxygen demand.
ical” TOC procedure exists. The instrument manufacturer’s
To ensure proper biological activity during the BOD test,
procedures should be followed accurately to achieve the best
a water sample must be free of chlorine and copper, in pH
results.
range 6.5 to 7.5, and needs to have adequate microbiological
TOC is a highly sensitive, non-specific measurement of
population. Besides this, the BOD test is well known to have
the organics present in a sample. Suspended particulate, col-
a challenging reproducibility from person to person, and gen-
loidal and dissolved organic matter are part of the TOC mea-
erates a result after the 5 days of incubation.
surement.

2.1.2 COD measurements

2.2 Regulatory frameworks
COD is a popular alternative and complementary test to
BOD, with the major advantage that it only takes few hours The COD usual method (DIN 38409-H41) is using chro-
to complete, compared to the 5 days for BOD. COD analy- mate and mercury, which are toxic chemicals. For this rea-
sis is based on the principle to measure the change in color son, there is a tendency to look for alternatives to the param-
caused by the chemical oxidation of the sample. The oxida- eter COD and to promote the use of the parameter TOC or
tion is achieved by closed reflux of a potassium dichromate chrome-free COD.
in sulfuric acid solution. Similarly to BOD Analysis, it is an In Europe, the development of TOC as a parameter is be-
indirect measurement of organic quality or pollution in water ing reflected in a number of documents, within the Indus-
and is commonly expressed as milligrams of O2 consumed trial Emissions Directive 2010/75/EU (Integrated Pollution
per liter of sample (see ASTM D1252, 2012). Prevention and Control), such as ROM (Report On Moni-
toring of Emissions from IED-Installations), final draft doc-
ument: “total organic carbon (TOC)/chemical oxygen de-

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C. Assmann et al.: Online TOC monitoring for water and wastewater treatment plants processes 63

mand (COD): in some member states, there is a trend to re- The City of Boulder’s (WWTF) 2008 upgrades marked an
place COD by TOC for economic and environmental rea- important transition from a trickling filter/solids contact pro-
sons. The use of chromate and mercury, necessary for the cess to a modified Ludzack–Ettinger (MLE) biological nutri-
COD determination, can be avoided by determining TOC, ent removal process. The new activated sludge process has
which can be measured continuously by online analyzers.” successfully reduced effluent ammonia and nitrate concen-
(see Joint Research Centre, 2017). Some countries, like Swe- trations to levels comfortably below current Colorado Dis-
den, are looking for alternative technologies (see SWWA, charge Permit System (CDPS) discharge permit limits. How-
2017). ever, effective 1 December 2017, the same permit proposes
In the USA, National Pollutant Discharge Elimination lower daily maximum ammonia limits and new daily max-
System (NPDES) was established under the administration imum nitrate limits. If the Boulder WWTF’s future nitrate
of the Environmental Protection Agency (EPA). With mini- limit (17.9 mg N L−1 for flows ≥ 20 MGD) were imposed on
mal exceptions, NPDES is the primary program that manages effluent nitrate quality from 2011 to 2014, 111 violations
discharge limits or effluent limitations guidelines (ELG) for would appear, illustrating the future vulnerability of the cur-
the release of process effluent or wastewater to public wa- rent WWTF configuration.
terways (see NPDES Permit Program Basics, 2016 and State On-site testing and process modeling pointed to the same
NPDES Program Authority, 2016). The NPDES system al- cause of incomplete denitrification: a carbon limitation in the
lows for “authorized alternatives” to oxygen demand, such anoxic zones of the WWTF’s MLE process (see Sigmon et
as TOC measurement, correlating to oxygen demand, as a al., 2014). The use of data from an online TOC Analyzer
means for operators to have faster and more accurate mon- allowed the City of Boulder WWTF to demonstrate that the
itoring and process control (see NPDES Permit Program, diurnal patterns of carbon and nitrogen were offset enough to
2015). contribute to the WWTF’s carbon limitation. This presents a
host of optimization opportunities that were previously over-
2.3 Discussion about the determination of the looked as carbon / nitrogen ratios were considered on a daily
correlation factor basis. The city’s Nitrogen Upgrades Project, currently in the
construction phase, will address the WWTF’s carbon limita-
There are a number of ways to properly determine the cor- tion by implementing external carbon addition via the sugary
relation factor between TOC and the oxygen demand param- by-product of the beer brewing process from a nearby brew-
eter of choice, BOD5 or COD. The method detailed in the ery and acetic acid (see Sigmon et al., 2016).
Instrumentation Testing Association (ITA) test report is spe- A TOC Analyzer (GE’s InnovOx∗ ) is being used in this
cific with corresponding statistical analyses; refer to the Im- study to provide online monitoring of aeration basin influ-
plementation Protocol (see Nutt and Tran, 2013). ent (ABI) TOC concentrations. The analyzer collects a sam-
A treatment facility should work with its state NPDES ple from a continuously pumped stream and uses heated per-
(or other local authority in other countries, like DREAL in sulfate oxidation chemistry assisted by supercritical water to
France) administrator to execute a long-term, correlation test oxidize organic carbon. During this supercritical water oxi-
and replace BOD or COD with TOC as the primary discharge dation (SCWO), the Analyzer’s reactor is heated to 375 ◦ C
parameter. National regulatory agencies (e.g., USEPA, state and pressurized to 220 bar, which conditions are beyond wa-
DEPs – Departments of Environmental Protection – in the ter’s critical point.
USA) may have specific requirements on the number of sam-
ples and test period (see Nutt and Tran, 2013).
3.2 Results and further investigations

3 City of Boulder Public Works Wastewater After implementing online TOC analysis, The City of Boul-
Treatment Facility, Colorado (USA) der WWTF demonstrated that the diurnal patterns of carbon
and nitrogen are offset enough to contribute to the WWTF’s
3.1 Method and objective carbon limitation. Data showed that the peak nitrogen load-
ing of the plant occurs approximately 8 h before the peak car-
The City of Boulder 75th Street Wastewater Treatment Facil-
bon loading. Therefore, the biological denitrification process
ity (WWTF), USA, gained insight and determined optimiza-
has its highest carbon requirement (due to the highest nitro-
tion opportunities through the use of online TOC monitoring
gen input) hours before it actually receives its highest carbon
implemented since March 2015. In addition, the city is look-
input. This disconnect between nutrient loading and nutri-
ing to gain approval for long-term BOD : TOC correlations
ent requirement presents a host of optimization opportunities
(see Babatola and Xu, 2009) from the State of Colorado in
that were previously overlooked since as carbon : nitrogen ra-
order to replace BOD analysis with TOC analysis, which is
tios were originally determined via a daily composite which
a faster, easier, and more accurate method of measuring the
masked the actual offset in the timing of the peak load.
organic strength of wastewater (see APHA, AWWA, WEF,
Figure 1a and b show the diurnal patterns of ammonia and
2013).
TOC at the ABI and of nitrate at the secondary clarifier in-

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64 C. Assmann et al.: Online TOC monitoring for water and wastewater treatment plants processes

– determine how to most efficiently use and control the

primary clarifier bypass option;

– adjust the side stream ammonia load to improve the sec-

ondary influent C / N ratio.

In addition to providing insight into diurnal variability of the

WWTF’s carbon limitation, TOC is a faster, easier, and more
accurate alternative to BOD. Indeed, TOC is a direct mea-
surement of gross amount of organic matter in waters, in-
cluding suspended particulates, colloidal and dissolved or-
ganic matter, while BOD measures the biologically active
organic matter indicating amount of oxygen needed for the
biological degradation. Every organic compound has a dif-
ferent BOD. Therefore, BOD is poor in precision, and takes
5 days to generates a result, which is not useful for process
monitoring. TOC, however, generates a result every few min-
utes (typically less than 10) and has a more stable baseline.
While BOD and cBOD limits have appeared in NPDES
permits since their inception, The Code of Federal Reg-
ulations (40CFR133.104(b)), standard methods (APHA,
AWWA, WEF, 2013) and the EPA’s NPDES Permit Writ-
ers’ Manual (US EPA, 2010) all allow for the replacement
of BOD methods with TOC methods following the devel-
opment of long-term site-specific correlations (see standard
method 5210 B, 1997 and Nutt and Tran, 2013). The City of
Boulder’s WWTF engaged in a long-term correlation study
starting September 2013, measuring TOC in influent, aer-
Figure 1. (a) Weekly diurnal patterns of ammonia and TOC at
the aeration basin influent (ABI) and of nitrate at the secondary ation basin influent, and final effluent using several TOC
clarifier influent (SCT Eff). (b) Daily diurnal patterns of ammonia methodologies on 24 h flow-based composite samples, which
and TOC at the ABI and of nitrate at the secondary clarifier influ- were also analyzed for BOD/cBOD. Regression equations
ent (SCT Eff). were developed from long-term correlations at each process
area according to APHA, AWWA, WEF (2013) to estimate
BOD and cBOD from TOC and are illustrated in Table 1.
fluent (SCT Eff) on weekly and daily cycles. Ammonia and These data were submitted to the Colorado Water Quality
nitrate account for the majority of the inorganic nitrogen in Control Division for approval and inclusion into the city’s
the ABI and the SCT Eff, respectively; therefore, these trends CDPS discharge permit, which expired 30 April 2016 and,
can be approximated to be total nitrogen trends on both the as of the time of publication, is on administrative extension.
influent and effluent of the activated sludge system. As de- With the number of data pairs used for each correlation,
scribed previously with an 8 h delay between the daily nitro- the table shows the linear regression best-fit line equation and
gen peak, which occurs in the morning (around 11:30 LT) R 2 value associated with each correlation.
and daily carbon peak, which occurs in the early evening
(19:00–20:00 LT), it is apparent that nitrogen moves through
the activated sludge system before peak influent carbon oc- 4 Twin Oaks valley Water Treatment Plant in
curs at the aeration basin influent. This offset in diurnal ni- San Marcos, California (USA)
trogen and carbon patterns is a significant contributing factor
to the WWTF’s carbon limitation. 4.1 Method and objective
To further investigate how the offset of diurnal nitrogen The Twin Oaks Valley Water Treatment Plant in San Mar-
and carbon peaks affects denitrification, a calibrated diurnal cos, CA, commissioned in 2008, is a zero discharge plant
model will be developed by the plant’s engineers using Dy- and one of the world’s largest submerged membrane ultra-
namita’s Sumo process simulation software. Key objectives filtration water treatment plants (100 MGD). The plant uses
of the modeling effort will be to GE Water & Process Technologies ZeeWeed ∗ 1000 ultrafil-
– determine the optimum set points for the carbon feed tration (UF) membranes in its treatment process. The source
system control philosophy; water is 95 % surface water that is mixed with reclaim water
on-site from an equalization (EQ) basin. The reclaim water is

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C. Assmann et al.: Online TOC monitoring for water and wastewater treatment plants processes 65

Table 1. Summary of the City of Boulder’s long-term correlation between BOD and TOC and between cBOD and TOC for both plant
influent and final effluent wastewater matrices.

wastewater Correlation Number of Linear regression best-fit equation R2

matrix data pairs
BOD : TOC 27 BOD = 1.7607 (TOC) + 13.716 0.7123
Influent
cBOD : TOC 27 cBOD = 1.2842 (TOC) + 11.184 0.6714
BOD : TOC 80 BOD = 1.8464 (TOC) − 8.241 0.5137
Effluent
cBOD : TOC 80 cBOD = 0.7561 (TOC) + 2.5513 0.3698

Figure 3. TOC for both streams showing removal from influent to

effluent.
Figure 2. Schematic flow diagram of Twin Oaks Water Treatment
Plant’s implementation of TOC Analyzer.
4.2 Results and further investigations

Near-real-time online analysis of the organic carbon removal

for different chemical treatments allowed for rapid under-
primarily backwash from the UF membrane trains. The pro- standing of the best treatment options and optimization of
cess of recycling water on-site starts with equalization fol- treatment as shown in Fig. 2. For example, in this case, on-
lowed by addition of coagulant/flocculant and then settling line analysis of the organic carbon contributed to understand-
in Lamella plate settlers. The settled water is combined with ing source water better and in real-time so smarter decisions
the raw water and fed to the UF membranes. Schematic of could be made to chemical dosages adjustments, protecting
the treatment is illustrated in Fig. 2. membranes from fouling (increasing their life time), and fi-
In order to optimize membrane performance, treatment nally contributing to saving money on operational expendi-
processes and organic loading of the membranes must be tures, while making effluent quality better (see Biller and
monitored closely to minimize organic and inorganic fouling Mullet, 2016).
potential. Online analysis of plate settler influent and effluent TOC
The purpose of this study was to use online TOC monitor- showed an initial TOC removal efficiency of about 40–50 %.
ing of the influent and effluent to the plate settlers to try to While trying different chemical treatment options, online
understand why membrane fouling was occurring and then to TOC analysis provided near-real-time insight into the effi-
adjust treatment to prevent fouling from continuing. TOC is ciency of the treatment. Controlling the pH provided better
used as an analytical tool help understand what is being recy- TOC removal efficiency than adding a different coagulant.
cled on-site and how well organics are removed before going This is illustrated in Fig. 4.
back to the membranes. Organics monitoring is important for Future analysis of online TOC for these two streams will
membrane treatment because organics are the main source of continue to provide information on the organic carbon re-
membrane fouling (see Liu, 2017). moval efficiency of reclaim water treatment so that mem-
Organic carbon levels for the two streams (influent and ef- brane performance can be optimized at this plant. Membrane
fluent to the plate settlers) were measured using a Sievers pre-treatment with pH control or coagulant changes can help
InnovOx Online TOC Analyzer as shown in Fig. 3. The In- improve membrane lifetimes, increase backwash cycles, and
novOx Analyzer uses SCWO to oxidize organics and NDIR maintain removal efficiency. If pre-treatment is inadequate it
detection to determine organic carbon concentrations. can lead to inorganic fouling (too much coagulant) or organic
For this study, the analyzer was run in non-purgeable or- fouling (too much organic material). Thus, proper monitor-
ganic carbon (NPOC) mode. NPOC mode involves acidifica- ing of organic removal and chemical usage is key to mem-
tion of the sample followed by sparging with CO2 -free air in brane optimization.
order to remove any inorganic carbon in the sample prior to As reclaiming and recycling of water becomes increas-
oxidation. ingly common at industrial and municipal plants, online

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66 C. Assmann et al.: Online TOC monitoring for water and wastewater treatment plants processes

More recent testing has shown that TOC may be a far bet-
ter indicator of a fully optimized treatment process. This is
particularly true if TOC measurements can be made imme-
diately as various process changes are made to a jar testing
plan. Real-world advantages of fully optimized jar tests may
include reduced chemical usage or cost, improved removal
of organics, minimization of membrane fouling, minimiza-
tion of sludge production, and a reduction in regulated DBPs.
Jar testing is beneficial for plants so they can optimize their
treatment processes to pick the right coagulant type and co-
agulant dosage.
City of Englewood, CO, is a drinking water treatment
Figure 4. TOC removal efficiencies for pH control and coagulant plant that treats surface water from South Platte River with
changes. a 28 MGD conventional treatment. They were using 60 ppm
of coagulant (alum sulfate) and expressed desire to reduce
chemical costs.
monitoring of TOC should be used so that water treatment In order to conduct their process improvement and find
can be optimized for maximum TOC removal. cost savings opportunities, the City of Englewood expanded
their process data for jar testing from just turbidity to in-
5 City of Englewood Water Treatment Plant, clude TOC. Before conducting any trials, they were dosing
Colorado (USA) chemicals blindly to ensure compliance with the new DBP
regulations, which require both TOC removal and minimiz-
5.1 Objective and method ing formation of DBPs at the furthest point in their distribu-
tion system. By dosing excess chemicals, they were able to
One of the most valuable ways that TOC analysis can be meet regulations but this also led to high chemical costs, high
used in municipal drinking water plants is to understand the sludge production and costly sludge removal.
amount of disinfection by-product (DBP) precursors. DBPs
form when residual chlorine from disinfection and bromide
in water streams react with organic content over time. Known 5.2 Results and further investigation
as carcinogens, they are strictly regulated throughout the dis- They managed to reduce operational cost expenditures within
tribution system. The ultimate dilemma of disinfection is the several steps of plant optimization, including the ability to
need to balance disinfectant dosing to control microbial risk change pH, coagulant type or coagulant dosage to obtain
with TOC removal to control DBP formation. optimum results and ensure removal of organics and know
Enhanced coagulation is one of the means to decrease when to regenerate granular activated carbon (GAC).
TOC content of water. It can be optimized using jar testing By having TOC analysis on-site and jar testing data with
as a tool for proactive process control in order to simulate TOC and turbidity, plant operators did not have to wait for
the performance of various chemical coagulants and process third party test results and could make immediate process
conditions without having to test the full-scale treatment pro- decisions.
cess. For many plants, the rule requires optimization of the The plant was able to save over USD 100 k in chemicals
treatment process to increase the removal of TOC, which can and disposal costs and shown in Table 2. They also realized
often be improved by selecting the optimum dose of alu- that effective TOC removal does not always correlate to ef-
minium or ferric-based coagulant. Other treatment parame- fective turbidity removal or vice versa; therefore, TOC and
ters including the addition of permanganate, powdered acti- turbidity levels must both be monitored. Typical coagulants
vated carbon, or pH adjustment can also be easily modeled can remove TOC to a certain degree, beyond that amount ex-
(see Sytsma et al., 2015). cess chemical is a waste of money and requires excess sludge
Traditionally, turbidity and UV254 have been used as pri- removal. Characteristics of a plant’s source water can change
mary indicators of good floc formation and removal of or- rapidly, including pH, alkalinity and the organic composition
ganics in jar tests. Turbidity is an indicator of water clarity of the water. Online TOC monitoring is the most effective
but does not distinguish between inorganic, organic, or par- means for frequent process observation.
ticulate contaminant. UV254 measures the aromatic content Further investigation consists in using TOC data and TOC
of organic matter in water, but not all organic molecules ab- characterization to try and better understand what types of
sorb in that wavelength and there are multiple interferences organics are impacting treatment such as coagulant dose,
at 254 nm, such as ferric compounds, which can lead to ei- DBP formation and membrane fouling. Also, a better under-
ther over or under reporting of the estimated organic carbon standing of source water characteristics and organic loading
content of the water. can help size system processes. As water reuse systems be-

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C. Assmann et al.: Online TOC monitoring for water and wastewater treatment plants processes 67

Table 2. Chemical and disposal cost savings achieved by adding in TOC analysis.

Dosage Coagulant Coagulant Coagulant Coagulant Disposal Total

(mg L−1 ) usage/year costs/year savings/ waste/year costs/year savings/
year year
Stage 1: D/DBPR implemented 60 1 410 588 lbs USD 136 827 NA 1 830 yards3 USD 100 650 NA
Coagulant reduction 45 959 049 lbs USD 106 454 USD 30 373 1250 yards3 USD 68 750 USD 62 723
1st optimization study with TOC 36 728 028 lbs USD 86 003 USD 50 824 920 yards3 USD 50 600 USD 100 874
2nd optimization study with TOC 20 426 174∗ USD 53 698∗ USD 83 129∗ 700 yards3,∗ USD 38 500∗ USD 145 279∗
∗ Usage, costs and savings are calculated for 1 year based on current dosage rate recently implemented. NA = not available.

come more viable, TOC analysis gains interest as an indica- a result of the 14th International CCWI Conference, Amsterdam,
tor for the health of each train in a multiple barrier treatment the Netherlands, 7–9 November 2016.
process, helping both to protect human and environmental
Edited by: Edo Abraham
health.
Reviewed by: two anonymous referees

6 Conclusions
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