Biological Filtration Monitoring
and Control Toolbox: Guidance Manual
Subject Area: Water Quality
Biological Filtration Monitoring
and Control Toolbox: Guidance Manual
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
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Biological Filtration Monitoring
and Control Toolbox: Guidance Manual
Prepared by:
Patrick J. Evans and Jennifer L. Smith
CDM Smith, 14432 Southeast Eastgate Way, Suite 100, Bellevue, WA 98007-6493
Mark W. LeChevallier, Orren D. Schneider, Lauren A. Weinrich, and Patrick K. Jjemba
American Water, 1025 Laurel Oak Road, Voorhees, NJ 08043
Jointly sponsored by:
Water Research Foundation
6666 West Quincy Avenue, Denver, CO 80235
and
U.S. Environmental Protection Agency
Washington, DC 20460
Published by:
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
DISCLAIMER
This study was jointly funded by the Water Research Foundation (WRF) and the U.S.
Environmental Protection Agency (EPA) under Cooperative Agreement No. 83406801-1. WRF and
EPA assume no responsibility for the content of the research study reported in this publication
or for the opinions or statements of fact expressed in the report. The mention of trade
names for commercial products does not represent or imply the approval or endorsement of
either the Foundation or WRF. This report is presented solely for information purposes.
Copyright © 2013
by Water Research Foundation
ALL RIGHTS RESERVED.
No part of this publication may be copied, reproduced
or otherwise utilized without permission.
ISBN 978-1-60573-194-0
Printed in the U.S.A.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
CONTENTS
LIST OF TABLES ........................................................................................................................ vii LIST OF FIGURES ....................................................................................................................... ix FOREWORD ................................................................................................................................. xi ACKNOWLEDGMENTS ........................................................................................................... xiii CHAPTER 1 INTRODUCTION ................................................................................................... 1 Overview of Biological Filtration in North America .......................................................... 1
What is Biological Filtration? ................................................................................. 1
How are Biological Filters Currently Monitored and Controlled ........................... 3 Overview of the Monitoring and Control Toolbox ............................................................. 3
Purpose and Intended Audience.............................................................................. 3
Tool Categorization and Manual Organization....................................................... 3 CHAPTER 2 MONITORING AND CONTROL TOOL EVALUATION ................................... 5 CHAPTER 3 MONITORING AND CONTROL TOOLBOX STRATEGIES ............................. 7 Monitoring and Control Toolbox Implementation ............................................................. 8
Tool Selection ......................................................................................................... 9 Develop a Baseline ............................................................................................... 10 Tool Integration .................................................................................................... 10 Monitoring and Control Tool Implementation ................................................................. 12 MONITORING AND CONTROL TOOLBOX SUMMARY TABLES .................................... 15 MONITORING AND CONTROL TOOLBOX EVALUATION SNAPSHOTS ........................ 41 Biological .......................................................................................................................... 42 Organic Carbon ................................................................................................................. 55 Water Quality .................................................................................................................... 72 Operational ........................................................................................................................ 80 Control .............................................................................................................................. 85 REFERENCES ..............................................................................................................................87 ABBREVIATIONS ...................................................................................................................... 91 v
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
TABLES
Table 3.1 Monitoring and control tool data collection frequency and importance .........................7
Table 3.2 Example use of monitoring and control toolbox ..........................................................11
Summary Table 1 Monitoring and control tool descriptions ........................................................17
Summary Table 2 Monitoring tool evaluation results ..................................................................28
Summary Table 3 Control tool evaluation results ........................................................................31
Summary Table 4 Monitoring tool evaluation criteria definitions ...............................................32
Summary Table 5 Monitoring tool evaluation criteria rating system ...........................................34
Summary Table 6 Control tool evaluation criteria definitions .....................................................37
Summary Table 7 Control tool evaluation criteria rating system .................................................38
vii
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
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FIGURES
1.1
Schematic of biological filtration elements ………………………………….…………...2
ix
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
FOREWORD
The Water Research Foundation (WRF) is a nonprofit corporation dedicated to the
development and implementation of scientifically sound research designed to help drinking
water utilities respond to regulatory requirements and address high-priority concerns. WRF’s
research agenda is developed through a process of consultation with Foundation subscribers and
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Area, Emerging Opportunities, and Tailored Collaboration programs, as well as various joint
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U.S. Bureau of Reclamation.
This publication is a result of a research project fully funded or funded in part by WRF
subscribers. WRF’s subscription program provides a cost-effective and collaborative method for
funding research in the public interest. The research investment that underpins this report will
intrinsically increase in value as the findings are applied in communities throughout the world.
WRF research projects are managed closely from their inception to the final report by the staff
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A broad spectrum of water supply issues is addressed by WRF's research agenda,
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publication as a contribution toward that end.
Denise L. Kruger
Chair, Board of Trustees
Water Research Foundation
Robert C. Renner, P.E.
Executive Director
Water Research Foundation
xi
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
ACKNOWLEDGMENTS
The authors gratefully acknowledge the input and guidance from the Project Advisory
Committee (PAC) which included Eva Nieminski (Utah Department of Environmental Quality),
Jim Smith (East Bay Municipal Utility District), Nick Dugan (EPA), Mary Jo Kirisits
(University of Texas), and Kerry Meyer (CH2M Hill, Inc.). We also appreciate very much the
support of the Foundation project manager Hsiao-wen Chen. The authors appreciate the feedback
and guidance from the following members of the technical advisory group (TAG): Ed Bouwer
(Johns Hopkins University), Anne Camper (Montana State University), Frederick Hammes
(EAWAG), Chris Schulz (CDM Smith), Joep van de Broeke, and Wilbert van de Ven (Biaqua).
This research project was made possible through funding by the Foundation and federal funds
administered through the US EPA. The authors appreciate the help of the following CDM Smith
staff: Carl Johnson, Tamzen Macbeth, Pam Salter, Janelle Amador, Steve Wyman, Benjamin
Finnegan, Mojgan Moini, and Jacqueline Wesley. We express our gratitude to the 21
participating facilities for their cooperation and participation in this project. We would like to
recognize the following utilities that provided support:
 American Water
 Central Lake County Joint Action Water Agency
 City of Ann Arbor Water Treatment Services
 City of Arlington Water Utilities
 City of Aurora, Aurora Water
 County of Henrico Department of Public Utilities
 Fort Worth Water Department
 Greater Cincinnati Water Works
 Gwinnett County Department of Water Resources
 Santa Clara Valley Water District
The authors would like to recognize the contribution of the following organizations and
individuals for their cooperation and participation on this project:
 Cornell University, Anthony Hay and Hanh Nguyen
 East Bay Municipal Utility District, Ken Gertsman and Francois Rodigari
 GE Analytical Instruments, Erin England, Jason Mangler, and Laura Stambaugh
 Hach Company, Tom Mitchell and Vadim Malkov
 Idaho State University’s Molecular Core Research Facility
 Europhins Eaton Analytical, Andrew Eaton and Polly Barrowman
 Mycometer™, Morten Miller and Lisa Rogers
 North Wind, Inc. Jennifer Wiedhass, Dana Swift and James Jackson
 LuminUltra Technologies Ltd., Dave Tracey
 Orange County Water District, Menu Leddy
 Promega Corporation, Pam Gunther
 Environmental Science Solutions, LLC, Richard Chappell
 s::can Measuring Systems, LLC., Justin Irving and David Alexander
 U.S. EPA Office of Research and Development, Christina Bennett-Stamper
xiii
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
CHAPTER 1
INTRODUCTION
OVERVIEW OF BIOLOGICAL FILTRATION IN NORTH AMERICA
Increasing demands for high quality water have necessitated the continued optimization
and implementation of cost-effective treatment processes. Biological treatment processes may be
used to treat conventional contaminants such as turbidity, tastes, and odors (Bundermann 2006,
Juhna and Melin 2006); organic and inorganic contaminants such as dissolved organic carbon
(Emelko et al. 2006; Hozalski, Bouwer, and Goel 1999); disinfection byproducts (DBPs) (Juhna
and Melin 2006, Scheideman et al. 2012, US EPA 2001); iron and manganese (Bouwer and
Crowe 1998 Tekerlekopoulou, Vasiliadou, and Vayenas 2008; Tremblay et al. 1998); ammonia
(Wert et al. 2008); nitrate (Bouwer and Crowe 1998); and assimilable organic carbon (AOC)
(Rittmann and Snoeyink 1984, Wert et al. 2008). Biological processes can also be used for
treatment of emerging contaminants such as pesticides (Bonne, Hofman, and Hoek 2002; van der
Aa et al. 2003); algal toxins (Ho et al. 2006, Hoeger et al. 2003); and endocrine disrupting
chemicals (EDC) including pharmaceuticals and personal care products (PPCPs) (Hozalski and
Bouwer 2001; Wunder, Horstman, and Hozalski 2008). In particular, biological filtration (BF) in
conjunction with physical and chemical processes is better suited for drinking water treatment of
AOC, ammonia, and nitrate than physical and/or chemical processes alone (Bouwer and Crowe
1998). BF also has the potential to decrease chlorine use, treatment residuals generation, energy
requirements, and overall treatment cost (Evans 2010, Meyer et al. 2010). While BF can be used
for a suite of treatment objectives, the most common are for removal of organic constituents,
increased biological stability, and decreased disinfection byproduct formation potential.
Therefore, the focus of this guidance is primarily on these end points.
What is Biological Filtration?
Historically, water utilities in North America rarely intentionally used BF in drinking
water treatment (Bouwer and Crowe 1998, Eighmy et al. 1997, Emelko et al. 2006), although its
efficacy has been demonstrated at full-scale systems in a number of European countries since the
1970s (Bonne, Hofman, and Hoek 2002; Bundermann 2006; Juhna and Melin 2006;
Tekerlekopoulou, Vasiliadou, and Vayenas 2008; van der Aa et al. 2003). Several water utilities
in North America have completed pilot-scale testing of biological filters (Hozalski and Bouwer
1998, US EPA 2001, Wert et al. 2008) and implemented full-scale facilities (Emelko et al. 2006,
US EPA 2001). While most filters are biologically active to some extent, purposefully designed
and operated BF is currently not a standard practice. However, it is increasingly being used to
meet demands for high quality water. Despite recent increased interest in BF, most professionals
in the drinking water industry consider BF use in North America to be nonexistent or limited
(Evans et al. 2008 and 2010).
The BF process typically involves filtration through a granular media bed comprised of
sand, anthracite, or granular activated carbon (GAC) without maintenance of a disinfectant
residual across the bed (Bouwer and Crowe 1998, Evans 2010, Rittmann and Snoeyink 1984).
As shown in Figure 1.1, bacteria grow as a biofilm (an attached culture) on the granular media
and are capable of actively degrading or transforming various contaminants such as dissolved
1
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
2 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
organic carbon (DOC) and AOC, compounds associated with tastes and odors [such as geosmin
or methyl isoborneol (MIB)], iron and manganese, etc. (Juhna and Melin 2006, Simpson 2008).
BF has been shown to be effective for removal of low molecular weight organic compounds
even at very low concentrations (Hozalski, Bouwer, and Goel 1999; Magic-Knezev and van der
Kooij 2006).
physical removal of
particulates
v
Extracellular
Polymeric
Sustances
v
bacteria in
biofilm
filter media
Figure 1.1 Schematic of biological filtration elements
BF is often preceded by pre-oxidation such as using ozone or chlorine. In this
configuration, pre-oxidation results in the formation of readily biodegradable dissolved organic
carbon (BDOC) including aldehydes, volatile fatty acids, and keto-acids but care is given to
minimize oxidant residuals in filter influent water. BF is typically used downstream of the
ozonation process to reduce AOC and BDOC, thus increasing water biological stability
(Simpson 2008, Urfer et al. 1997), and reducing the rate of biofilm accumulation in distribution
systems (LeChevallier et al. 1998). If BF is not used after ozonation, biological instability of
drinking water in distribution systems becomes more likely (Juhna and Melin 2006), resulting in
biofilm growth or an increase in such growth. This is especially true for water supplies with
higher organic carbon levels. Additionally, BF can minimize DBP formation via destruction of
organic DBP precursors (Bouwer and Crowe 1998, Simpson 2008). Use of BF has been shown
to reduce the need for residual chorine addition and the level of combined organic chlorine has
been shown to be reduced by as much as fifty percent (LeChevallier et al. 1998). Efforts are
being directed toward implementation of BF for treatment of additional contaminants including
geosmin, MIB, and algal toxins (Bouwer and Crowe 1998, Evans 2010, Ho et al. 2006, Hoeger et
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Chapter 1: Introduction | 3
al. 2003). With the increased concern of EDCs including PPCPs, BF processes offer an exciting
new avenue for cost-effective treatment of these emerging contaminants.
How are Biological Filters Currently Monitored and Controlled?
While BF is currently used in drinking water treatment and has great promise for the
future, it is typically not designed or managed as a biological process (Bouwer and Crowe 1998,
Evans et al. 2010, Lauderdale et al. 2011). Filters that are designed for physical or chemical
removal may incidentally provide biological mechanisms for removal of some of the compounds
mentioned above; however, general practice in North America discourages microbial growth in
drinking water treatment systems (Bouwer and Crowe 1998). Monitoring and control of
biological filters currently focuses on physical (e.g., head loss) and chemical (e.g., ozone dose)
aspects and not on biological aspects (Evans et al. 2011).
While research efforts over the past 15 years have established a baseline body of
knowledge on BF, many unknowns remain regarding bioprocesses in filters (Bouwer and Crowe
1998; Fonseca, Summers, and Hernandez 2001; Magic-Knezev and van der Kooij 2006; Urfer
and Huck 2001). The design criteria and framework for full-scale operation are not well defined
(Huck and Sozanski 2008b, Huck and Sozanski 2008a) and several methods for monitoring and
control have conflicting results in the literature. A more thorough understanding of how
monitoring tools impact the selection of control parameters will enhance optimization of BF
processes and their design. For example, selection of the granular media type, as a design
parameter, may or may not influence the efficacy of biodegradable organic matter (BOM)
removal, depending on the temperature ranges expected (Urfer et al. 1997). As such, biological
filters are typically not optimally operated, even in European countries where full-scale operation
is more common (Juhna and Melin 2006). Recent studies on BF in Europe have focused on
developing a suite of monitoring parameters and operational benchmarks, but even these are
focused on chemical and physical rather than biological parameters (Fiksdal and Bjorkoy 2007).
In North America, there is a lack of available and robust tools for monitoring and control of BF.
Identification, validation, and use of monitoring and control tools are necessary to establish BF
as a process that can be controlled and whose performance can be predicted.
OVERVIEW OF THE MONITORING AND CONTROL TOOLBOX
Purpose and Intended Audience
The purpose of this guidance manual is to provide utilities with a practical means to
select and implement monitoring and control tools for BF. The tools are intended to complement
current filter monitoring methods such as turbidity and pH, and control methods such as
backwashing type and duration. The intended audience includes water utility engineers,
operators, and laboratory staff, and consulting engineers and scientists.
Tool Categorization and Manual Organization
The tools are categorized with respect to whether they are associated with monitoring of
biological, organic carbon, water quality, or operational parameters or are associated with control
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
4 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
of the water treatment process. The control tools include filter operations as well as potential
upstream operations (e.g., ozone dose). This guidance manual includes the following sections:

Chapter 1 Introduction – This section provides a brief overview of BF and an
introduction to the purpose and organization of the guidance manual.

Chapter 2 Monitoring and Control Toolbox Evaluation – This section provides
descriptions, critical evaluations, and recommendations of monitoring and control
tools.

Chapter 3 Strategies for Using the Monitoring and Control Toolbox – This section
provides example scenarios of how the monitoring and control toolbox can be
implemented.

Summary Tables - This section provides summary tables of monitoring and control
tools and their evaluation results.

Monitoring and Control Tool Evaluation Snapshots – This section provides detailed
information on applicable and acceptable tools for used in BF and justification for
ratings.
The intention of the guidance manual is to be a reference for methods of monitoring and
controlling biological filters. The guide includes what methods are available, why they are
important, how to use them, what measurement ranges are typical, what the costs are, and what
monitoring frequencies are recommended. The management practices presented in this document
will require refinement based on each utility’s treatment goals, treatment processes, and water
quality characteristics. This manual is complemented by a separate research report that provides
data collected from North American utilities using methods found in the monitoring and control
toolbox (Evans et al. 2013). These data were used to evaluate the tools and to develop the
recommendations made in this guidance manual. The reader is referenced to the research report
for the methods and data that support the recommendations presented here.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
CHAPTER 2
MONITORING AND CONTROL TOOL EVALUATION
The monitoring and control toolbox provides an evaluation of parameters that have
potential applicability for BF process management. Tools were organized into the following
categories:


Monitoring
o Biological – Indicators of bacterial concentration or activity.
o Organic carbon – Measurements of different fractions or types of organic carbon.
o Water quality – Measurements of water quality that can affect BF performance.
o Operational – Process parameters such as head loss.
Control – Parameters that affect BF performance, some of which are practical to
control (e.g., ozone dose) and others that are less so (e.g., flow rate and temperature).
A list of the evaluated tools in each of these categories is presented in Summary Table 1.
This table includes descriptions of the tools along with the overall rating. The description is
intended to provide a brief description of tools that may be appropriate for use. The overall rating
is as follows:
Green – The tool is recommended for use and is strongly recommended for use.
Yellow – The tool may be acceptable and warrants consideration and further
evaluation.
Red – The tool is not recommended for use.
The evaluation involved multiple criteria and metrics. Summary Table 1 presents
monitoring tools and control tool descriptions and evaluation results (e.g., overall rating).
Monitoring tool quantitative rankings against multiple metrics including usefulness, data quality,
implementability, and cost are presented in Summary Table 2. A quantitative calculation was not
deemed appropriate for determination of the overall rating. Rather, the overall rating was based
on multiple lines of evidence including the numeric criteria evaluations and data presented in the
accompanying research report. Control tool quantitative rankings against multiple metrics are
presented in Summary Table 3. These metrics included usefulness, implementability, and cost.
The criteria and metrics used for numeric monitoring tool evaluations are shown in Summary
Tables 4 and 5, respectively. The criteria and metrics used for numeric control tool evaluations
are shown in Summary Tables 6 and 7, respectively.
Additional detail on tools that were rated as recommended for use (green) or warrant
consideration (yellow) are included in the Monitoring and Control Tool Evaluation Snapshots
section. Each monitoring tool snapshot presents the following information:




Tool category
Tool name and method
Evaluation criteria, scores, and explanations
Overall recommendation and explanation
5
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6 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual







Method description
Treatment objectives
Typical range of results
Method Interferences
Implementation requirements
Procurement
References
Each control tool snapshot presents the following information:







Tool category
Tool name and method
Evaluation criteria, scores, and explanations
Overall recommendation and explanation
Method description
Treatment objectives
Typical range
These evaluations were intended to be used for monitoring process conditions and to
provide methods for process enhancement rather than design specifications. The purpose of this
document is not to specify particular values for parameters or absolute values that are applicable
to all systems, but instead to benchmark values observed at multiple BFs from across North
America for comparison. The tools should be further evaluated on a case-by-case basis and
trends should be evaluated over time at a particular facility. Vendors that provide services,
equipment, or test kits are listed under the procurement section. The purpose of including cited
vendors was to provide an example of what is available, and not intended to be an exhaustive list
of all providers. The vendors, manufacturers, or products listed are also not endorsed by the
Foundation but rather are provided as an initial reference only. A more detailed discussion of
each tool evaluated as applicable or acceptable are included in the section Monitoring and
Control Tool Evaluation Snapshots.
The performance metrics included in the Monitoring and Control Toolbox focus on bulk
organic parameters rather than trace contaminants. Microconstituents can also be evaluated using
standard methods but not covered in this report. BF performance monitoring will be contingent
on the utility’s particular filter treatment objectives.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
CHAPTER 3
MONITORING AND CONTROL TOOLBOX STRATEGIES
The Monitoring and Control Toolbox Summary Tables section of this guidance can be
used for developing a filter management program. Summary Tables 1, 2, and 3 provide tools
recommended for use (green) or warrant consideration on a site-specific basis (yellow). A
combination of one or more tools from each of the five categories should be selected when
developing a management strategy for biological filters including biological, organic carbon,
water quality, operational, and control. The number of tools included should fit site-specific
treatment objectives and management concerns. Biological tools can be used to directly or
indirectly assess the amount of biomass or biological activity in the filters. Organic carbon tools
can be used to quantify the loading and removal of different forms of organic carbon. Water
quality tools are used to assess filter performance (e.g. turbidity) but can also be used to assess
effects or potential effects on biological activity (e.g. temperature and nutrients). Operational
tools can be used to quantify biological filter hydraulic performance and potential impacts on
contaminant removal performance (e.g. chlorine residual). Control tools are methods that affect
biological filter operations and performance and can be used for optimization. Data for these
tools should be collected for baseline conditions and frequently enough to assess changes in filter
biology, should operation conditions unfavorable to BF occur (Table 3.1). During start-up,
optimization, and troubleshooting, parameters should be monitored more frequently. Additional
data on the usefulness, data quality, implementation, and cost for each tool are available in the
Monitoring and Control Toolbox Evaluation Forms to assist in selection of tools. While the focus
of the toolbox is on assessing biology, efficacy of organic carbon removal, and management of
operational concerns such as filter run time, other specific filter treatment objectives may warrant
sampling and analysis of additional constituents such as iron, manganese, tastes, and odors, to
name a few.
Table 3.1
Monitoring and control tool data collection frequency and importance
Tool
Frequency
Importance
Biological
Biological results will stay A baseline must be established so that if changes
fairly constant throughout in operations cause detrimental impacts to the
monitoring if no upset
filter, the impact can be assessed. Sampling must
conditions occur.
be frequent enough to assess changes and identify
potential problems early. Changes in biological
parameters may not directly correlate to changes
in removal of specific compounds of interest, but
they have more subtle impacts/correlations such
as relationships with resiliency during upset
conditions or colder temperatures.
(continued)
7
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
8 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Tool
Organic Carbon
Water quality
Operational
Control
Table 3.1 (Continued)
Frequency
Importance
Organic carbon results
Organic carbon in the filter influent and effluent
should be monitored as
can be used to assess removal. Assimilable
frequently as practicable.
organic carbon (AOC) and carboxylic acids may
also be used during start-up, optimization, and
troubleshooting to understand the type of carbon
loading the filter (e.g. more readily biodegradable
vs. complex and recalcitrant organic carbon) and
develop a control strategy for enhancing
performance.
Temperature, pH, and
Biological filters may be impacted when
turbidity should be
temperatures are below 15 degrees Celsius (oC),
monitored continuously.
particularly anthracite and sand filters. pH must
Nutrients should be
be within a range that will not hamper biological
monitored more
activity (e.g., between 6 and 8 standard units).
frequently during startup, Monitoring for nutrients such as ammonia,
optimization, and
phosphate, nitrate, and nitrite is important to
troubleshooting.
identify potential limiting factors in biology.
Continuous through the
Operational parameters such as oxidant demand
supervisory controls and
and residual may be used to develop a baseline
data acquisition (SCADA) strategy to optimize the process. Pre-oxidant dose
system.
should be tailored to provide highly degradable
carbon at the filter influent, while minimizing
residual. Head loss and filter run time can be used
to monitor impacts on general filter operations.
Continuous through the
Use tools such as pre-oxidant dose, nutrient dose,
SCADA system.
and flow rate/contact time for optimization.
MONITORING AND CONTROL TOOLBOX IMPLEMENTATION
The first step in developing a process monitoring and control strategy for biological
filtration should be the development of filter treatment objectives. Filter treatment objectives
should clearly define the target constituents for treatment and acceptable values for removal
and/or acceptable effluent concentrations. They should be developed based on regulatory
compliance, distribution system water quality, and economic considerations. Utilities should
develop a management strategy that includes a combination of tools that fit site-specific
requirements and needs. The Research Report that accompanies this guidance, A Monitoring and
Control Toolbox for Biological Filtration (Evans et al. 2013), discusses the scientific basis for
the recommendations provided herein.
In addition to developing filter treatment objectives, utilities should include at least one
tool from each monitoring category (e.g. biological, organic carbon, water quality, and
operational) as well as at least one control parameter. Process control strategies can be developed
to integrate monitoring results with specific control metrics to enhance performance. An example
could be optimizing the pre-oxidant to influent TOC ratio to enhance degradation of organic
carbon. Another example could be tying online luminescent dissolved oxygen (LDO) probe data
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Chapter 3: Strategies for Using the Monitoring and Control Toolbox | 9
with pre-oxidant dose and residual to assess the impact of oxidant residual on biological activity.
Both examples could also be integrated with monitoring attainment of specific filter treatment
objectives. Refer to Chapters 4 and 5 of the Research Report (Evans et al. 2013) for a detailed
description of the concepts that can be used for developing these strategies. A baseline of
facility-specific data on biological activity, water quality, and treatment performance should be
collected so that trend analyses may be used for comparison. Additionally, different sampling
and analysis programs will be necessary during different phases of filter operation including
normal operations, troubleshooting, and start-up/optimization.
Tool Selection
A robust process control strategy can help increase treatment efficacy. The strategy
should include monitoring of multiple types of tools, and more than one tool per type if possible.
There are several online monitoring tools available that can be integrated into a supervisory
controls and data acquisition (SCADA) system and used for process control. For example, online
LDO probes are highly recommended to be installed at the filter inlet and outlet to enable realtime monitoring of biological activity. Online TOC and UV/Vis scan analyzers can provide
meaningful information on bulk organic carbon removal and changes in organic carbon
characteristics. Oxidant dose and residual on the filter influent may also be monitored online and
monitored to optimize the formation of biodegradable organic compounds while minimizing
residual. Grab samples may be collected if online options are not available or practicable, but
should not be used for DO measurement. Biological monitoring grab samples should be collected
from the top of the filter media rather than across the filter profile or in filter influent or effluent.
Additionally, a suite of tools should be evaluated to determine which are most applicable
and whether simpler assays may be used as a proxy for more complicated or more expensive
analyses. For example, the sum of carboxylic acids expressed as carbon equivalents (acetate,
formate, and oxalate) may be used as a proxy for AOC if organic carbon is has been highly
oxidized, and if AOC concentrations are greater than 400 microgram of acetate-carbon per liter
(µg acetate-C/L). Carboxylic acid analysis is a direct measure of particular organic compounds
and is less than half the cost of the bioluminescent AOC assay using Pseudomonas fluorescens P17
and Spirillum sp. strain NOX. Alternatively, AOC may be used as a proxy for BDOC if
concentrations of AOC are above 400 µg acetate-C/L. Analysis of carboxylic acids is
significantly cheaper, easier to conduct, and can have a shorter turnaround time than AOC and
BDOC. Carboxylic acids and AOC are more sensitive than BDOC for assessing removal. The
recent development and commercial availability of a rapid bioluminescent AOC assay has
increased the practicality of analysis, although it is more expensive than carboxylic acid analysis.
If the nature of natural organic matter (NOM) is less oxidized, then UV254 may serve as a proxy
for DOC or TOC analysis. UV254 is significantly easier to conduct and requires less expensive
equipment. Online analyzers for TOC, DOC, and UV are available and provide useful data for
process monitoring and control. Adenosine triphosphate (ATP) and hydrolase enzyme activity
correlate well with each other and as such one may be used as a proxy for the other. If there are a
large number of samples being analyzed at a single time, ATP may be more cost effective than
hydrolase enzyme activity.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
10 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Develop a Baseline
A baseline should be developed over the period of at least one year to assess seasonal
impacts on water quality and treatment efficacy. This baseline should include one or more
biological parameters (e.g., ATP or hydrolase activity on media and online LDO consumption
across the filter), organic carbon parameters (e.g., TOC, DOC, AOC, and carboxylic acids),
water quality parameters (e.g., turbidity, temperature, pH, nutrients and DBP formation
potential), operational parameters (head loss accumulation rate and oxidant residual on top of the
filter), and control parameters (e.g., pre-oxidant type(s) and dose(s), nutrients, and contact time).
Monitoring over a year will be required to develop a representative baseline for comparison for
trend analysis since many of these parameters vary seasonally. Baseline data may also be
compared to benchmark data provided in the Evaluation Snapshots of this Guidance Manual.
Tool Integration
Sampling and analysis programs will vary depending on utility-specific treatment
objectives and site-specific conditions. An example sampling and analysis program is provided
below describing how the monitoring and control toolbox can be used at a utility (Table 3.2).
This is a hypothetical example to demonstrate integration of the tools and should be tailored
depending on site-specific needs. The primary modes of operation discussed below are normal
operations, troubleshooting, and start-up/optimization.
Normal Operations
Biological monitoring should be conducted by assessing DO consumption measured
continuously online. Biological monitoring using media-based samples should be conducted
monthly for ATP or hydrolase enzyme activity. If baseline values were consistently stable then
quarterly sampling may be sufficient. Media-based samples collected from the top of the filter
bed will be, in general, representative of the filter profile, unless an oxidant residual is present at
the filter influent.
Organic carbon and water quality parameters should be monitored as frequently as
possible. Monitor TOC and/or DOC in the filter influent and effluent continuously using a direct
measurement instrument. UV absorbance may be used, provided it correlates with TOC or DOC
based on historical results. DOC and UV254 may be used to calculate SUVA, which is a useful
indicator of how reactive TOC is with oxidants and the nature of organic carbon present (e.g.
more aromatic rings will have a higher absorbance). AOC should be monitored at the filter
influent and effluent weekly during normal operations and as frequently as needed during
troubleshooting/upset conditions and optimization. If pre-oxidants are used, then monitor for
carboxylic acids as well to determine the concentration of highly oxidized (and biodegradable)
NOM. If a correlation can be established between AOC and carboxylic acids, continue
monitoring carboxylic acids since this analysis is cheaper, faster, and a direct measure.
Turbidity, temperature, and pH should be monitored continuously and may be monitored
at one location (influent or effluent) as appropriate. pH and temperature are especially important
to determine whether values are within a biologically-relevant range. For example, a pH of less
than 6 or greater than 9 will impair most biological reactions. Temperature, while not practically
controllable, can affect the rate of chemical and biological reactions. Regularly monitor for
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Chapter 3: Strategies for Using the Monitoring and Control Toolbox | 11
orthophosphate and other nutrient concentrations (ammonia, nitrite and nitrate) if appropriate.
Orthophosphate should be monitored monthly at the filter influent and DBP formation potential
should be monitored monthly at the filter influent and effluent.
Head loss should be monitored continuously to evaluate hydraulic impacts. Evaluate head
loss accumulation rates for correlations with the results from other monitoring tools to identify
relationships between water quality, biological filter operations, and hydraulic performance. Prefilter oxidant dose, especially the combination of multiple pre-oxidants, results in highly
degradable organic matter and increases removal rates. However, oxidant residuals at the filter
influent can impact biological activity and should be minimized to the extent practicable.
Oxidant residual at the filter influent should be monitored as frequently as possible if preoxidants are used. Control parameters developed based on filter treatment objectives should be
tied into a SCADA system. Table 3.2 provides an example management plan to implement the
monitoring and control tools under varying operational conditions.
Table 3.2
Example use of monitoring and control toolbox
Normal
Start-up/
Monitoring Tool
Operations Troubleshooting Optimization
Biological
Adenosine Triphosphate (ATP) or
M
W
W
hydrolase activity - media
Luminescent dissolved oxygen
C
C
C
(LDO)
Extracellular polymeric substances
W
(EPS)
Organic Carbon
Total organic carbon (TOC) /
dissolved organic carbon (DOC) or
C
C
C
ultra violet (UV) spectra
W
F
F
Assimilable organic carbon (AOC)
W
F
F
Carboxylic acids
Water Quality
C
C
C
Turbidity
C
C
C
Temperature
M
W
W
Orthophosphate
C
C
C
pH
Disinfection byproduct (DBP)
M
F
F
formation potential
Operational
C
C
C
Head loss
C/F
C/F
C/F
Oxidant residual
Notes: C = Continuous, F = As frequently as practical, W = Weekly, M = Monthly, A = annually
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
12 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Troubleshooting
Analyze biological monitoring parameters such as ATP or hydrolase enzyme activity
more frequently. ATP and hydrolase enzyme activity may be sensitive to filter influent oxidant
residuals. Evaluate historical pre-oxidant dosing and filter influent oxidant residual to determine
whether an impact is likely. Free and attached extracellular polymeric substances (EPS) may be
used to identify whether biofouling is causing issues with hydraulic performance. Filter run times
and unit filter run volumes may be evaluated to assess hydraulic impacts from biological filters.
Recent research demonstrated use of hydrogen peroxide as a method for controlling excessive
biomass and does not adversely impact biological activity (Emelko et al. 2006, Evans et al. 2012,
Lauderdale et al. 2011).
Start-up/Optimization
Optimize the process using the monitoring and control toolbox in combination with other
water quality and SCADA parameters that are part of the facility’s normal monitoring program.
The pre-oxidant type, pre-oxidant dose, contact time and nutrients may be used to improve water
quality, optimize operation, and decrease cost. Increasing pre-oxidant dose can increase removal
of biodegradable carbon, but oxidant residuals can impair biological activity. Different preoxidant types have varying kinetics, react with NOM differently, and may have varying degrees
of efficacy for degradation of other contaminants of concern. Additionally, some combinations
of pre-oxidants may act synergistically to increase biodegradability of NOM. For example, the
combination of chlorine and ozone enhanced AOC production and removal at two utilities that
participated in this study. Oxidant kinetics and impacts on biodegradability and DBP-formation
should be evaluated during selection of pre-oxidants. If biological stability of treated water is of
concern, monitor treated water disinfectant demand and disinfectant dose, as well as the
distribution system chlorine residual and regrowth.
MONITORING AND CONTROL TOOL IMPLEMENTATION
This research developed and demonstrated a monitoring and control toolbox for BF.
Recommendations to utilities are as follows:

Consider different monitoring and control tools to assist in attainment of treatment
objectives, optimize operations, and decrease costs. The companion document to this
research report, Monitoring and Control Toolbox Guidance Manual, should be consulted
to identify candidate tools. Biological tools can be used to directly or indirectly quantify
the amount of biomass in the filters. The amount of microbial activity is relevant to
assessing the impact that microbes can have on enhancing water quality. Organic carbon
tools can be used to quantify the loading and removal of different forms of organic
carbon. They can also be used to determine the extent of microbial activity by
documenting the amount of organic carbon that is biodegraded. Water quality tools are
often being used by utilities to assess filter performance (e.g., turbidity) but may also
assess effects or potential effects on biological activity (e.g., temperature and nutrients).
Operational tools can be used to quantify biological filter hydraulic performance such as
filter run time and potential impacts on contaminant removal performance (e.g., chlorine
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Chapter 3: Strategies for Using the Monitoring and Control Toolbox | 13







residual). Control tools are methods that affect biological filter operations and
performance and can be used to optimize performance.
Develop filter treatment objectives for the target constituents for treatment and
acceptable values for removal. Filter treatment objectives should be developed based on
regulatory compliance, distribution system water quality, and economic considerations.
Develop conceptual process control strategies for the process based on potential tools
listed in the Summary Table 1. Refer to Chapters 4 and 5 of the Research Report for
concepts that can be used for development of these strategies.
Implement one or more tools in each of the five areas: biological, organic carbon, water
quality, operational, and control. Refer to the Monitoring and Control Toolbox Guidance
Manual for specific information with regard to use, performance, implementability, and
cost of various tools. Strongly consider installation of LDO probes in the filter inlet and
outlet to enable real-time monitoring of biological activity.
Develop a baseline for your biological filters. This baseline should include one or more
biological parameters (e.g., ATP or hydrolase activity on media and DO consumption
across the filter), organic carbon parameters (e.g., TOC, DOC, AOC, and carboxylic
acids), water quality parameters (e.g., turbidity, temperature, pH, nutrients and DBP
formation potential), operational parameters (head loss accumulation rate and oxidant
residual on top of the filter), and control parameters (e.g., pre-oxidant type(s) and dose(s),
nutrients, and contact time). Monitoring over a year will be required to develop a
representative baseline since many of these parameters vary seasonally.
During normal operation monitor biomass (i.e., ATP or hydrolase activity) monthly and
monitor DO consumption continuously. If ozone is used as a pre-oxidant, be sure to
conduct a trial of the LDO probes to ensure that they can be installed in a location that
will yield representative measurements of biological DO consumption as opposed to
locations where physical gas-liquid equilibration must occur prior to obtaining a
representative result. Monitor TOC and/or DOC in the filter influent and effluent
continuously using a direct measurement instrument or UV absorbance provided it is
demonstrated to correlate. DOC and UV254 may be used to calculate SUVA, which is a
useful indicator of how reactive TOC is with oxidants and the nature of organic carbon
present (e.g. more aromatic rings will have a higher absorbance). Sample and analyze the
filter influent and effluent for AOC and, if a pre-oxidant is used, carboxylic acids.
Determine which is representative of biological filter performance and choose one
analysis for organic carbon for routine monitoring. Regularly monitor nutrients (i.e., total
phosphate, ammonia, and nitrate) and DBP formation potential in addition to online
monitoring of turbidity, pH, and temperature. Evaluate head loss accumulation rates for
correlations with the results from other monitoring tools to identify relationships between
water quality, biological filter operation, and hydraulic performance, considering the
impacts of varying flow and temperature. If chlorine or other oxidants are used as preoxidants, regularly (continuously if possible) monitor their residuals at the filter inlet.
Control the pre-oxidant dose and nutrients to improve water quality, optimize operation,
and decrease cost.
When troubleshooting analyze for biological parameters such as ATP or hydrolase
activity more frequently. Compare the results with baseline conditions.
Optimize the process using the monitoring and control toolbox in combination with
other water quality and SCADA parameters that are normally monitored.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
MONITORING AND CONTROL TOOLBOX
SUMMARY TABLES
15
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Hydrolase
enzyme activity
BactiQuant®
Test Kit
Grab
Online
Filter
Category Analyte/Method
Biological Adenosine
triphosphate
(ATP)
Luciferin/
Luciferase
Method
Water
Summary Table 1
Monitoring and control tool descriptions
 



Description
ATP is an essential energy storage biochemical present in metabolically
active cells. This method determines the quantity of ATP present as an
indicator of active biomass. Bacterial cells are lysed and the
concentration of ATP is measured after adding reagents. The reagent
contains the luciferace enzyme isolated from the firefly. The luciferase
enzyme uses energy from ATP to produce light. The light is detected
using a luminometer to quantify ATP concentration. Commercial
instruments and assays are available.
The BactiQuant®-test rapid bacteria detection technology is based on
fluorogenic detection of hydrolase enzyme activity found predominantly
in bacteria. It may be used to test water or filter media. Filter media
samples (300 mg) are added to a tube containing digestion reagents. A
synthetic enzyme substrate is added to the media and allowed to react
over a period of time based on temperature. The enzyme present in the
bacterial cells hydrolyzes the synthetic enzyme substrate. When the
synthetic substrate molecule is cleaved into two molecules by the
enzyme, one of the molecules can be made to fluoresce upon excitation
with ultraviolet (UV) light at 365 nanometers (nm); the emission
wavelength is 445 nm. The amount of fluorescence emitted is measured
using a portable fluorometer. This fluorescence correlates to a measure
of the bacterial biomass. Fluorescence measurements can be captured
electronically and may be downloaded to a computer or can be
transcribed by hand. Calculations are made to determine the
BactiQuant® Value (BQV), which is representative of the concentration
of bacteria.
(continued)
Summary Tables | 17
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Overall
Rating
Heterotrophic
plate count
(HPC)
Standard
Method (SM)
9215 C


Grab
Online
Filter
Water
Category Analyte/Method
Biological Dissolved
(cont)
oxygen (DO)
Consumption
ASTM D888-09,
Proposed EPA
Method 360.3



Description
Biological activity of the filter is measured indirectly by calculating the
consumption of DO across the filter. This provides an indicator of the
oxygen consumed by microorganisms during respiration. Online LDO
probes were used at one facility without pre-oxidation and three
facilities with ozonation. There were measurable changes in DO across
full-scale filters. The respirometric potential was sensitive to changes in
process conditions, such as temperature, oxidant residual, maintenance
activities, and source water quality. Oxygen is measured with a LDO
probe through a light-emitting diode (LED) that emits blue light to a
sensor coated with a luminescent material. The luminescent material is
excited by the LED and illuminates. As the excited chemical relaxes, a
red light is emitted. The red light is detected by a photodiode and the
time for the excited chemical to return to a relaxed state is measured.
The oxygen concentration is inversely proportional to the time it takes
for the luminescent material to return to a relaxed state. In contrast to
membrane probes, oxygen is not consumed during measurement.
Maintenance is significantly less than a membrane probe. Temperature
is recorded by the sensor and compensated for in the reading.
HPC estimates the number of live culturable heterotrophic colonies in
water. R2A agar should be used to select for slow growing organisms
typical in biological filters. The pour plate method and spread plate
methods are evaluated herein (SM 9215 A and B, respectively). The
pour plate method involves inoculation of a diluted water sample onto
warm liquid R2A agar. The agar is poured onto plates and incubated for
7 days. The spread plate method involves inoculation of a diluted water
sample onto solid R2A agar and incubation for 7 days. Both methods
rely on enumeration by visual inspection. Analysis of filter media
samples require that HPCs from the biofilm are suspended into the
aqueous phase by sonication and homogenization. Clumps of cells
released from biofilms may produce one colony and therefore
underestimate numbers. Disaggregating will reduce clumping.
Overall
Rating
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
18 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 1 (Continued)
Biological
community
structure
Terminal
Restriction
Fragment Length
Polymorphism
(TRFLP)
Grab
Online
Filter
Category Analyte/Method
Biological Extracellular
(cont)
polymeric
substances (EPS)
Phenol-sulfuric
acid assay
Water
Summary Table 1 (Continued)




Description
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
Summary Tables | 19
EPS is a compound secreted by certain kinds of bacteria that provide
the structure to hold a biofilm matrix together and aid in biochemical
communication between cells. This method determines the
concentration of EPS present in filter media, which can be used as an
indicator of biomass structure. The media sample is suspended in
solution via sonication prior to being placed into a centrifuge. The
supernatant is transferred to another test tube for extraction of free EPS
while the pellet is then suspended in a buffer for extraction of attached
EPS. The supernatant is mixed with a 50 percent phenol solution and
concentrated sulfuric acid. The presence of glucose in a sample is
indicated by development of a yellowish color. Concentration of
glucose in a sample is determined via constructing a glucose calibration
curve using a spectrophotometer. This method may be used for
suspended or attached biomass.
TRFLP is a molecular biology fingerprinting technique that evaluates
the microbial community diversity. Polymerase chain reaction (PCR)
techniques are used to amplify fluorescently labeled deoxyribonucleic
acid (DNA) strands from lysed cells; the strands are then cut at specific
sites using restriction enzymes to generate fluorescently labeled
fragments. Theoretically, each sequence derived from bacteria within
the community will generate a labeled fragment of a unique length. A
DNA sequencer separates the fragments according to length and
generates a chromatogram where each fragment is represented by a
peak of fluorescence that is proportional to the fragment's abundance.
Software analysis of the chromatogram determines the length of each
fragment relative to an internal size standard. The chromatogram
provides relative abundance data for the microbial community. A clone
library may be constructed to identify specific members of the
community. This analysis is costly, so care should be taken in
determining sampling frequency.
Overall
Rating
Grab
Online
Filter
Water
Category Analyte/Method
Biological Phospholipid
(cont)
fatty acids
(PLFA)
Modified Bligh
and Dyer Method


Electron
transport system
activity
INT reduction


Specific oxygen
uptake rate
(SOUR)
SM 2710 B


Flow cytometry


Description
Phospholipid fatty acids (PLFA) are integral components of cell
membranes. Based on presence of specific biomarkers during periods of
stress/slow growth, this method determines the concentration of total
biomass, provides information on the microbial community present, and
provides information on microbial activity. PLFA is extracted from
filter media using a chloroform-methanol-buffer and the sample is
analyzed by gas chromatography with flame ionization detector (GCFID) and mass spectroscopy (MS). This method may be used for either
suspended or attached biomass. This analysis is expensive and has
generally been limited to research-based studies.
2-para (iodo-phenyl)-3(nitrophenyl)-5(phenyl) tetrazolium chloride
(INT) is a redox-sensitive dye that turns from colorless to blue when
reduced. This dye permeates cell membranes and metabolically active
cells reduce the dye and then form a blue color. Live cells can be
discerned from dead cells microscopically. The dye can also be
extracted from the cells and measured spectrophotometrically. The
method involves treatment of filter media with the dye, subsequent
extraction, and spectrophotometric quantification. This method is
applicable to attached biomass (i.e., filter media).
Specific oxygen uptake rate (SOUR) is the rate of oxygen consumption
normalized per unit mass of filter media. Aerobic microbial metabolic
activity can be assessed by the rate at which oxygen is consumed from
filter media. A filter media sample and filter influent sample are placed
in a standard BOD bottle and an auto-stirring DO probe is inserted. The
rate of DO consumption is measured and the SOUR is calculated. The
test can be conducted at room temperature or at filter influent
temperature. This method is applicable to attached biomass (i.e., filter
media).
Flow cytometry can be used to detect numbers of small particles. While
recent research has indicated this parameter has potential, additional
research is warranted to validate applicability for biological filters.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Overall
Rating
(continued)
20 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 1 (Continued)
AOC
Bioluminescent
P17 and NOX
Method

Online
Grab
Analyte/Method

Total/dissolved
organic carbon
(TOC/DOC)
SM 5310 B or C
Filter
Category
Organic
carbon
Water
Summary Table 1 (Continued)



Description
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
Summary Tables | 21
TOC and DOC are measurements of NOM that may contribute to DBP
formation and stability problems in the distribution system. NOM
removal is a primary treatment objective of BF. TOC and DOC are
standard analytes that can be frequently monitored with grab samples or
online. DOC is measured by first filtering the sample by a 0.45micrometer (μm) filter prior to analysis.
For the high temperature combustion method for TOC (5310B), the
sample is homogenized and inorganic carbon is removed by
acidification and sparging. The sample is injected into a heated reaction
chamber packed with an oxidative catalyst. Water is vaporized and the
organic carbon is oxidized to carbon dioxide and water. Carbon dioxide
is measured using a non-dispersive infrared analyzer (NDIR) or titrated
colorimetrically.
For the persulfate-ultraviolet method (5310C), inorganic carbon is
removed by acidification and sparging or measured separately. The
sample is oxidized to carbon dioxide using ultraviolet (UV) or heat with
persulfate. The concentration of carbon dioxide is detected using either
an NDIR analyzer, colorimetrically titrated, or membrane filtration to
selectively pass carbon dioxide followed by measurement of
conductivity.
As a modification to SM 9217, this method utilizes genetically modified
strains of Pseudomonas fluorescens P17 and Spirillum sp. strain NOX
test bacteria that continuously bioluminesce. Samples are pasteurized to
kill indigenous organisms and then inoculated separately with the two
test strains. Inoculated samples are transferred to a 96-well plate and
measurements are made using a luminometer. Samples are monitored at
a predetermined frequency, until maximum luminescence is reached
indicating maximum cell yield. Maximum luminescence is converted to
AOC using a standard curve. The time to complete the assay is
significantly shorter than SM 9217, typically 1 week or less.
Overall
Rating
Grab
Online
Analyte/Method

Assimilable
organic carbon
(AOC) SM 9217
Filter
Water
Category
Organic
Carbon
(cont)

AOC
Bioluminescent
Vibrio Harveyi
Method


Carboxylic Acids
EPA Method
300.1, modified


Biodegradable
dissolved organic
carbon (BDOC)
Sand Method


Description
This method is a two-species bioassay (Pseudomonas fluorescens strain
P17 and Spirillum strain NOX) to determine biological growth
potential. Samples are pasteurized to kill indigenous organisms and
then inoculated separately with two test strains. The test organisms are
allowed to grow to maximum density and are then enumerated by the
spread plate method for heterotrophic plate counts. The inoculated test
water is spread on agar, incubated for 48 hours, and colony forming
units are enumerated by visual inspection. Plate counts are assessed at
multiple time points to determine the time when the maximum number
of cells have grown in the inoculated sample (typically daily after one
week of incubation). Turnaround time is 3 to 4 weeks.
This method utilizes a bioluminescent strain of the marine organism
Vibrio harveyi. The organisms are starved, inoculated in a pasteurized
water sample, fortified with salt, and allowed to grow. The growth is
monitored using a luminometer and the rate of luminescence is
proportional to the concentration of organic compound catabolized.
This method uses ion chromatography (IC) for carboxylic acids. There
is no need for sample preparation prior to analysis by IC, other than
filtration if samples are highly turbid. Water samples are injected into
the IC and organic anions are determined by separation on a highcapacity anion exchange column followed by conductivity detection.
BDOC is measured using biologically active sand stock with a high
biomass concentration. The stock sand is kept in an aerated flask with
dechlorinated tap water at room temperature. A few weeks are
necessary for the organisms to acclimate. A 100-gram aliquot of sand
stock is added to a sterile container and 300 mL of sample water is
added. The DOC in solution is measured at the beginning of the assay.
The liquid sample is mixed and aerated during incubation. DOC
concentrations are monitored daily throughout incubation until DOC
measurements stabilize; this period is generally 5 to 14 days. BDOC is
calculated by subtracting the initial from the minimum DOC.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Overall
Rating
(continued)
22 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 1 (Continued)
Water
Quality
Grab

Online
Analyte/Method
Ultraviolet/visible
(UV/VIS)
spectroscopy
SM 5910
Filter
Category
Organic
carbon
(cont)
Water
Summary Table 1 (Continued)



Turbidity
SM 2130



Temperature
SM 2550




Some organic compounds with complex structures containing rings and
double bonds, such as precursors of trihalomethanes and other
disinfection byproducts, organic compounds contributing to water
color, and NOM, will strongly absorb ultraviolet (UV) radiation. As
such, UV absorption may be a useful surrogate for concentrations of
aggregate organic compounds. Water samples are collected, filtered,
and then analyzed either at 254 nm or the full spectra using a
spectrophotometer. UV spectra can also be used as an indicator of
nitrate, TOC, DOC, and turbidity.
Fluorescence spectroscopy may be used as an indicator of the type and
quantity of chromophoric compounds, such as some organic carbon
(humic acids, carboxylic acids, etc.) and biomolecules (proteins,
NADH, etc.) present. Peaks in fluorescence spectra may be correlated
to specific organic compounds and may be used as an indicator of
concentration. A fluorometer may scan emission and excitation
wavelengths over a range of 200-950 nm. While some research
indicated this parameter has potential for detecting various fractions of
organic compounds, additional research is warranted to validate
applicability as a monitoring tool for biological filters.
Turbidity is measured by comparing the intensity of light scattered by
the sample due to the presence of suspended materials to light scattered
from a standard solution. The higher the intensity of scattered light, the
higher the turbidity. Turbidity removal is an important filter treatment
objective and regulatory requirement for all filters.
Temperature can affect the rate of chemical and biological reactions. A
thermocouple is used to measure temperature and a signal is
transmitted to the SCADA system.
Overall
Rating
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 23
Fluorescence
spectroscopy
Description
Disinfection
byproduct (DBP)
formation
potential
SM 5710, SM
6232B, SM
6232C, or
SM 6200
Oligochaetes1





Grab
Online
Filter
Analyte/Method
Nutrients (e.g.,
orthophosphate)
EPA Method
300, or
equivalent
pH
SM 4500-H+
Water
Category
Water
Quality
(cont)

Nutrients, especially orthophosphate, can be limiting for bacterial
growth because they are often removed during the
coagulation/sedimentation process. Addition of nutrients can promote
contaminant removal and improve hydraulic performance.

Water pH should be within a biologically relevant range, otherwise
biological activity and the rate of biological reactions will be
compromised (e.g. 6 to 9 standard units). This method includes use of a
pH electrode that measures the concentration of hydrogen ions in
solution.
Formation of disinfection byproducts such as trihalomethanes (THMs)
result from the reaction of chlorine with NOM. Total THM formation
potential (THMFP) is determined by reacting the sample with the
disinfectant used to maintain an excess of disinfectant after incubation
at room temperature for seven days. Concentrations of THMs may be
analyzed by using liquid-liquid or purge-and-trap extraction using SM
6232B or 6200, respectively.


Description

Oligochaetes may cause maintenance problems or water quality issues
downstream of the biological filter. This method is a direct enumeration
technique based on visual inspection. Water samples are passed through
a naidid column trap (pvc pipe with a 121-μm steel screen). Naidids
trapped in the water column are enumerated by pouring the water into a
beaker placed over a light source.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Overall
Rating
(continued)
24 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 1 (Continued)
Oxidation
reduction
potential (ORP)
SM 2580
Operational Head loss/filter
run time
Online pressure
transducer or
level sensor,
SCADA
Oxidant demand
SM 2350






Grab
Online
Analyte/Method
Estrogenic
substances
Enzyme-linked
immune-sorbant
assay (ELISA)
test kit
Filter
Category
Water
Quality
(cont)
Water
Summary Table 1 (Continued)

Description
Estrogenic substances in a water sample are mixed with a coloring
enzyme and placed into the well of a micro-plate. Antibodies that
have been immobilized to the well surface bind to estrogenic
substances in solution. Unbound molecules are removed by washing
and a substrate is added that produces a colored product when reacted
with the bound antibody/estrogenic substance. Concentrations are
determined colorimetrically at 450 nm.
Oxidation reduction potential can be a useful parameter for
monitoring oxidation state for anaerobic systems. ORP can also be an
indicator of oxidant residual present.
Overall
Rating
Head loss can be an important indicator of filter fouling or clogging.
This may be associated with physical removal of particulates but may
also be an indicator of excessive biofilm formation. Filter run time is
generally associated with head loss as backwashing can be triggered
by head loss exceeding a set point. Both may be used to monitor the
impact of biological growth on hydraulic performance.


©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
Summary Tables | 25
Oxidant demand is the oxidant dose needed to oxidize organic
compounds in solution. To conduct the test, subsamples are dosed
with varying concentrations of a standard oxidant solution (e.g.
chlorine, ozone, permanganate). Oxidant residual, pH, and
temperature are measured after a specified reaction time. Typical
reaction times are 5 minutes, 1 hour, and 24 hours. The demand at
these contact times can provide information on the characteristics of
organic carbon present and oxidant kinetics. At the end of the test, if
all the demand has been satisfied, then an oxidant residual will not be
present.
Control
Oxidant dose
SCADA system


Grab
Online
Filter
Water
Category Analyte/Method
Operational Oxidant residual
(cont)
Multiple are
possible:
chlorine (SM
4500-Cl G),
Permanganate
(SM 4500KMnO4)
Ozone (SM 4500O3)
Chlorine dioxide
(SM 4500-ClO2),
or equivalent


Description
Oxidant residual may be measured using a variety of standard
methods; a few common oxidants are presented as follows. Chlorine
residual may be measured colorimetrically, where N,N-diethyl-pphenylenediamine (DPD) reacts with with the sample. Free chlorine
reacts with the DPD indicator, producing a red color. Total chlorine
can be measured using iodide with the DPD indicator. For total
chlorine, combined chlorine oxidizes the iodine to iodide, which then
reacts with the DPD indicator and turns pink; at the same time, free
chlorine reacts with the DPD indicator and turns the solution pink.
The degree of pink coloration is proportional to the concentration of
chlorine present in the sample. A spectrophotometer can quantify
concentrations at wavelengths ranging from 515 to 530 nm.
Permanganate may be measured using a spectrophotometric method at
525 nm.
Ozone is measured colorometrically using an indigo reagent. Indigo is
rapidly oxidized by ozone in an acidic solution and the absorbance at
600 nm is linear with concentration of ozone.
Chlorine dioxide is measured using the DPD method at 530 nm to
one-fifth of the extent of its chlorine content. It may also be measured
using an iodometric titration.
Pre-oxidants are primarily used for disinfection and oxidation of iron
and manganese, taste and odor compounds, and color. Use of preoxidants also increases the biodegradability of NOM and in turn
reduces DBP formation and stability issues in the distribution system.
The ratio of oxidant to TOC directly affects BF monitoring
parameters including AOC, carboxylic acids, and BDOC. Dose can be
optimized to maximize water quality and minimize cost.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Overall
Rating
(continued)
26 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 1 (Continued)
Notes:
Grab
Online
Analyte/Method

Nutrient dose
(e.g.,
orthophosphate)
SCADA system
Flow rate/contact 
time
Control
valve/flow meter
Filter
Category
Control
(cont)
Water
Summary Table 1 (Continued)
Description

Nutrients, especially orthophosphate, can be limiting for bacterial
growth because they are often removed during the
coagulation/sedimentation process. Addition of nutrients can promote
contaminant removal and improve hydraulic performance.

Contact time affects NOM removal and is controlled by the total flow
rate and the number of filters in operation at any given time. The
ability to control this parameter is limited however due to water
demand constraints.
Overall
Rating
1. Beaudet et al. 2000
Summary Tables | 27
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Method
Luciferin/
Luciferase(1,2)
BactiQuant®
SM 9215 C(3,14)
ASTM D888-09,
or equivalent(4)
Phenol-sulfuric
acid assay(5)
Transcription
restriction
fragment length
polymorphism
(TRFLP) (6)
Data Quality
Implementability
Operating and
maintenance
Capital
Applicability to small
utilities
Data acquisition
requirements
Ease of use
Training requirements
Technology maturity
Selectivity/specificity
Representativeness
Span
Accuracy
Precision
Response/turnaround time
Ability to control
Usefulness
Cost
3
2
2
4
4
5
5
5
5
3
3
3
3
3
4
4
3
2
2
4
5
5
3
4
5
3
3
4
3
3
4
5
3
2
1
2
5
5
5
2
4
5
2
2
2
5
4
5
2
2
3
5
5
5
5
3
5
2
5
5
5
4
5
5
2
2
5
3
4
5
5
5
4
3
3
3
3
3
4
4
2
2
1
1
4
3
5
3
5
3
1
1
1
1
1
1
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Overall Rating
Analyte
Adenosine
triphosphate
(ATP)
Hydrolase
enzyme activity
Heterotrophic
plate count
(HPC)
Dissolved
oxygen (DO)
consumption
Extracellular
polymeric
substances
(EPS)
Biological
community
structure
Correlations to treatment
objectives
Metrics for evaluation
Category
Biological
(continued)
28 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 2
Monitoring tool evaluation results
Analyte
Total/Dissolved
Organic carbon
(TOC/DOC)
Assimilable
organic carbon
(AOC)
Method
SM 5310 B or
C(14)
SM 9217(14)
Bioluminescent
P17 and NOX
method(7,8)
Carboxylic acids EPA Method
300.1,
modified(9,10)
Biodegradable
Sand
dissolved
method(11,12,13)
organic carbon
(BDOC)
Ultraviolet/visib UV-VIS spectra,
le (UV/VIS)
UV254, SM
spectroscopy
9510(14)
Online UV-VIS
spectra
Data Quality
Implementability
Operating and
maintenance
Capital
Applicability to small
utilities
Data acquisition
requirements
Ease of use
Training
requirements
Technology maturity
Selectivity/specificity
Representativeness
Span
Accuracy
Precision
Response/turnaround
time
Ability to control
Usefulness
Cost
3
3
5
3
5
5
5
4
3
5
4
4
3
2
2
3
3
5
5
1
4
4
4
4
5
5
2
2
1
1
1
2
2
5
5
3
5
4
4
4
5
3
2
2
1
2
1
2
3
4
5
1
5
5
5
3
5
4
2
3
3
3
1
4
4
4
5
1
2
5
2
4
4
2
2
2
1
1
1
4
3
4
3
4
5
5
3
3
3
5
3
3
3
3
4
5
3
4
2
5
3
4
4
2
2
3
3
3
3
3
3
4
(continued)
Summary Tables | 29
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Overall Rating
Category
Organic
carbon
Correlations to
treatment objectives
Metrics for evaluation
Summary Table 2 (Continued)
Oxidant residual
Oxidant demand
Method
SM 2130(14)
SM 2550(14)
EPA Method 300,
or equivalent
SM 4500-H+(14)
SM 5710, SM
6232B,
SM 6232C, or
SM 6200(14)
Online pressure
transducer or
level sensor,
SCADA
Multiple, see
Summary Table 1
SM 2350(14)
Data Quality
Implementability
Operating and
maintenance
Capital
Applicability to small
utilities
Data acquisition
requirements
Ease of use
Training requirements
Technology maturity
Selectivity/specificity
Representativeness
Span
Accuracy
Precision
Response/turnaround time
Ability to control
Usefulness
Cost
5
3
5
5
4
1
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
4
4
4
5
5
4
5
3
5
5
5
5
5
5
3
3
3
3
2
3
5
2
5
4
5
5
5
5
5
5
5
5
5
5
4
4
2
5
3
3
5
5
5
4
3
5
2
2
1
1
1
3
4
4
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
4
5
4
5
5
5
5
5
5
5
5
3
5
4
4
2
2
2
2
5
5
5
5
5
5
3
3
3
3
4
4
Notes: Refer to Summary Tables 4 to 7 for the evaluation methodology. The maximum score is 5 and minimum is 1.
1. Velten et al. 2007
6. Liu et al. 1997
11. Allgeier et al. 1996
2. Magic-Knezev and van der Kooij 2004 7. Weinrich, Giraldo, and Lechevallier 2009
12. Volk et al. 1994
3. Camper et al. 1985
8. Haddix, Shaw, and LeChevallier 2004
13. Joret, Levi, and Volk 1991
4. Urfer and Huck 2001
9. Peldszus, Huck, and Andrews 1996
14. APHA, AWWA, and WEF 1999
5. Dubois et al. 1956
10. Randke 2001
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Overall Rating
Analyte
Turbidity
Temperature
Nutrients (e.g.,
ortho-phosphate)
pH
Disinfection
byproduct (DBP)
formation
potential
Operational Head loss/filter
run time
Correlations to treatment
objectives
Metrics for evaluation
Category
Water
quality
30 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 2 (Continued)
3
4
3
2
3
5
4
3
3
3
3
4
3
4
4
5
2
3
Control valve/flow
meter/number of filters
in service
3
5
5
4
2
2
4
4
1
4
2
1
4
Implementability
Capital
Operating and
maintenance
5
Applicability to small
utilities
5
SCADA requirements
3
Requirement for major
modifications
5
Usefulness
Regulatory acceptance
5
Technology maturity
4
General applicability to
all processes
Applicability to existing
biofilters
5
Established metrics for
design
5
Sensitivity of process to
parameter
Method
SCADA system
SCADA system
Cost
Overall Rating
Analyte
Oxidant dose
Nutrient dose
(e.g., orthophosphate)
Flow rate/
contact time
Correlation to treatment
objectives
Category
Control
Ability to control
Summary Table 3
Control tool evaluation results
Notes:
Refer to Summary Tables 4 to 7 for the evaluation methodology. The maximum score is 5 and minimum is 1.
Summary Tables | 31
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
32 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 4
Monitoring tool evaluation criteria definitions
Definition
Criteria
Usefulness
Metrics for evaluation
The degree to which accepted benchmarks exist for
comparison and interpretation of results.
Correlations to treatment
objectives
The degree to which the parameter either directly measures the
treatment objective or affects performance of BF to meet the
treatment objective.
Ability to control
The ability to use operational controls to alter the parameter
with the goal of enhancing performance.
Response/ turnaround
time
The ability for the method to produce a result within the
timeframe required to capture system variability. This includes
the time lapse between when the parameter is collected and
when analytical results are available.
Data Quality
Precision
An expression of mutual agreement among individual
measurements of the same property taken under prescribed
similar conditions.
The degree of agreement of a measurement within an accepted
reference or true value and is a measure of the bias in a
system.
The smallest signal that can be detected (i.e. lower detection
limit) and the smallest amount of input signal change can be
detected reliably (i.e. resolution).
Accuracy
Sensitivity
Representativeness
Selectivity/specificity
The degree to which data directly represents the characteristic
being measured, parameter variations at a sampling point,
and/or an environmental condition (i.e. direct measure vs.
surrogate).
The degree to which data represents only the property or
component of interest (i.e. background interference).
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 33
Criteria
Implementability
Technology maturity
Summary Table 4 (Continued)
Definition
The degree to which accepted, standardized procedures are
available and historical data exists.
Training requirements
The level of effort required to train personnel to operate and
maintain equipment or conduct sampling and analysis
associated with the monitoring parameter.
Ease of use
The ability for personnel to easily collect data and analyze inhouse (i.e. data acquired online or onsite vs. need to sample
and ship to outside specialty analytical laboratory).
Data acquisition
requirements
The level of effort required to collect data (i.e. online vs.
sampling and analysis with intrusive work that interferes with
operations).
The ability for small utilities to utilize the technology. This
includes a preference for methods that can meet time and
budget constraints and require minimal training to implement
and interpret.
Applicability to small
utilities
Cost
Capital
Operations and
maintenance
Cost incurred to bring the instrument/method to operable
status, including initial purchase and installation.
Cost to operate and maintain an instrument/method incurred
over the lifetime of the instrument/method.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
34 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 5
Monitoring tool evaluation criteria rating system
Rating
Criterion
Usefulness
Metrics for
evaluation
Correlations to
treatment
objectives
Response/
turnaround time
Data Quality
Accuracy
Sensitivity
2
not practical to
control
Ability to
control
Precision
1
benchmarks are
not well
understood for
drinking water,
data are limited
to research
studies
unrelated to
treatment
objective
>1 week
>1 day
3
some
benchmark data
available from
full scale
utilities
4
5
well
established
benchmarks
for drinking
water utilities
some correlation
to treatment
objective or
indirect measure
of treatment
objective
direct
measure of
treatment
objective
somewhat
practical to
control
highly
practical to
control
hours
minutes
online
precision of
method is low
with respect to
precision
requirements for
parameter
precision of
method is
moderate with
respect to
precision
requirements for
parameter
precision of
method is
high with
respect to
precision
requirements
for parameter
accuracy of
method is low
with respect to
accuracy
requirements for
parameter
accuracy of
method is
moderate with
respect to
accuracy
requirements for
parameter
accuracy of
method is
high with
respect to
accuracy
requirements
for parameter
method
sensitivity does
not cover typical
parameter range
method
sensitivity
covers typical
parameter range
method
sensitivity
covers more
than typical
parameter
range
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 35
Summary Table 5 (Continued)
Rating
Selectivity/
specificity
1
indirect
measure of
analyte with
weak
correlation
high degree of
interference
Technology
maturity
method is not
well developed
Training
requirements
requires
specialized
training and
expertise that
utility
personnel
typically do not
have
complicated
method that is
not appropriate
for utilities and
requires
contracting
with an outside
laboratory or
university
Implementability
Data Quality
Criterion
Representativeness
Ease of use
2
3
indirect
measure of
analyte with
strong
correlation
some
interference,
but negligible
at typical
concentrations
method is well
developed, but
not used for
drinking water
assessment
requires
moderate
training and
expertise
applicable to
some but not
all utility
personnel
somewhat
complicated
method that is
appropriate for
some utilities
or online
instrument
that requires
significant
maintenance
4
5
direct
measure of
analyte
no
interference
in typical
sample
matrix
standard
method
training
requirements
are minimal
and broadly
applicable to
all utility
personnel
very simple
analysis that
can be
conducted at
the utility or
online
instrument
that requires
minimal
maintenance
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
36 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Summary Table 5 (Continued)
Criterion
Data acquisition
requirements
1
complicated
manual
sampling and
data
analysis/entry
are required
limiting data
frequency
Applicability to
small utilities
not applicable to
small utilities
because of need
for complicated
equipment and
highly
specialized staff
Capital
instrument cost
>$20,000
Operations and
maintenance
high
Cost
Implementability
Ratings
2
3
manual
sampling and
data entry are
simple, or
online
instrument
provides
discrete data
(rather than
continuous data
transmission)
allowing more
frequent, but
discontinuous
data collection
somewhat
applicable to
small utilities
but requires
more training
and/or
specialized
equipment than
is typically
available
instrument cost
<$10,000, or use
of outside lab
4
moderate
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
5
online
equipment
that
continuously
transmits data
to SCADA
system
very
applicable to
small utilities
because of
method
simplicity
and
availability
instrument
cost <$5000
or generally
present at
utilities
low
Summary Tables | 37
Summary Table 6
Control tool evaluation criteria definitions
Criteria
Definition
Usefulness
Ability to control
Degree to which it is practical to change the control parameter
Correlation to treatment
objectives
The existence of a quantitative relationship between changes in the
control parameter and attainment of treatment objectives
Sensitivity of process to
parameter
The degree to which practical changes in the control parameters can
lead to significant changes in attainment of the treatment objective
Established metrics for
design
General applicability to
all processes
The existence of established design criteria
Applicability to existing
biological filters
Applicability to existing biofiltration processes
Implementability
Technology maturity
Broad applicability to all types of biofiltration designs (i.e. media types,
pre-oxidants, etc.)
The extent to which the control strategy has been implemented in the
drinking water industry
Regulatory acceptance
The potential for regulatory acceptance of the control strategy
Requirement for major
modifications
The need for major design and construction work to implement the
control strategy
SCADA requirements
The need for major SCADA upgrades and/or programming
Applicability to small
utilities
The ability for small utilities to utilize the technology. This includes a
preference for methods that can meet time and budget constraints.
Cost
Capital
Operations and
maintenance
Cost incurred to bring the control strategy to operable status, including
initial design and construction
Cost to operate and maintain the control system
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
38 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Usefulness
Summary Table 7
Control tool evaluation criteria rating system
Criterion
Ability to control
1
not practical
to control
Correlations to
treatment
objectives
unrelated to
treatment
objective
some effect on
attainment of
treatment objective
strong effect
on attainment
of treatment
objective
Sensitivity of
process to
parameter
large changes
in the control
variable result
in small
changes in
water quality
moderate changes
in the control
variable result in
moderate changes
in water quality
small changes
in the control
variable result
in large
changes in
water quality
Established
metrics for
design
benchmarks
are not well
understood for
drinking
water, data are
limited to
research
studies
applicability
limited to one
type of filter
design
some benchmark
data available from
full scale utilities
well
established
benchmarks
for drinking
water utilities
applicable to some
but not all types of
filter designs
applicable to
all types of
fitler designs
cannot be used
in existing
biological
filters
method is not
well
developed, is
experimental,
or is
theoretical
moderate potential
for use in existing
biological filters
easily used in
existing
biological
filters
standard
control
strategy
currently in
use
General
applicability to
all processes
Implementability
Applicability to
existing
biological filters
Technology
maturity
2
Rating
3
somewhat practical
to control within
limits
4
control strategy has
a sound scientific
and engineering
basis but has not
been implemented
in the drinking
water industry
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
5
highly
practical to
control
(continued)
Summary Tables | 39
Table 7 (Continued)
Rating
Implementability
Criterion
Regulatory
acceptance
1
regulatory
agencies are
unlikely to
accept control
strategy
3
moderate potential
for acceptance
4
5
control
strategy is
widely
accepted by
regulatory
agencies
no design or
construction
changes
required
Requirement for
major
modifications
major process
modifications
required
moderate design
changes required
SCADA
requirements
requires
expansion of
SCADA
system and
significant
programming
not applicable
due to
complicated
equipment or
specialized
staff
requires SCADA
programming but
no system
expansions
required
already
implemented
in typical
SCADA
systems
somewhat
applicable and
requires more
training and/or
specialized
equipment than is
typically available
very
applicable to
small utilities
because of
method
simplicity and
availability
high
high
moderate
moderate
low
low
Applicability to
small utilities
Cost
2
Capital
Operations and
maintenance
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
MONITORING AND CONTROL TOOLBOX EVALUATION SNAPSHOTS
41
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
42 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Biological
Adenosine triphosphate (ATP)
Luciferin/luciferase test kits
Criterion
Usefulness
Data Quality
Implementability
Metrics for evaluation
Rating
3
Correlations to treatment
objectives
Ability to control
2
Response/turnaround time
4
Precision
4
Accuracy
5
Span
Representativeness
5
5
Selectivity/specificity
Technology maturity
5
3
Training requirements
3
Ease of use
3
Data acquisition
requirements
Applicability to small
utilities
Capital
Operating and maintenance
3
2
Explanation
Ranges in values at 14 full-scale utilities
were between 8.3x102 and 1.1x108
picograms (pg) of ATP per gram (g) filter
media. Order of magnitude changes over
time are considered significant4.
Biological activity can impact performance
but is typically not a limiting factor.
Concentrations are reduced when an
oxidant residual is present at the filter
influent4.
Analysis time requires five minutes for the
luminescence reading, and 3 hours are
needed for kits requiring a media-based
calibration curve.
Relative percent difference for field
duplicates was on average 43 percent
(n=4) 4. Other assays have shown
variability of 8 percent with 6 percent
standard deviation between duplicates
(n=19)5.
Coefficient of variation was on average 15
percent (n=74)4.
101 to 109 pg ATP/g filter media
Measures ATP concentrations of all living
organisms present including algae.
Directly measures ATP concentrations.
Assay is well developed but is not standard
practice in drinking water.
Requires in-house analysis with
approximately 4 hours of training.
Requires sampling of media and 3 hours
for in-house analysis. Requires sterile
equipment.
Requires manual sampling of filter media.
3
Requires sampling and low cost
equipment.
Cost
4
Luminometer is $6,000 to $7,000.
4
Reagents/disposables cost between $1 and
80 per sample depending on the number
analyzed and test kit used. This cost
decreases with the number of samples
performed.
Recommendations
ATP concentrations provide a useful indicator of microbial activity. Concentrations
on biological filters tend to be consistent over time so periodic monitoring is
sufficient. This parameter may also be useful for optimization testing and
troubleshooting.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 43
Biological
Adenosine triphosphate (ATP)
Luciferin/luciferase test kits (Continued)
Method Description:
Treatment
Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
ATP is an essential energy storage biochemical present in metabolically active
cells. This method determines the quantity of ATP present which can be used as
an indicator of active biomass present. Bacterial cells are lysed and the
concentration of ATP present is measured after incubating at 30˚C by
luminescence from the luciferase enzyme. The luciferase enzyme was isolated
from fireflies and requires energy from ATP to produce light. Commercial
instruments are available.
ATP concentrations are not an indicator of performance or attainment of
treatment objectives, but do provide an indication of active biomass.
102-108 pg ATP/g filter media4
Some test kits quantify ATP using a standard curve of spikes with known
concentrations of ATP. For filter media-based samples using these kits, there
can be interference from sorption of ATP on GAC. The effect of sorption can be
compensated for by reviewing the slope and intercept of the standard curve.
Sample turbidity can interfere with readings by physical obstruction of light
produced. Salts and nonionic chemicals may impact the reagents used in the
assay.
The sample volume needed for media-based samples is less than 100 grams. The
samples may be collected from the top of the filter media. However, if an
oxidant residual is present in filter influent water, profiling of the filter may be
warranted. Monitoring should be conducted monthly or quarterly during normal
operations and more frequently (weekly) during start-up, process optimization,
and troubleshooting. Normal fluctuations in ATP concentrations over time are
typically less than an order of magnitude, but may vary depending on sitespecific conditions. The time for analysis is approximately 3 hours. Holding
times are not well documented and should be evaluated on a site-specific basis.
Some assays require reagents to be stored at -20˚C prior to use. Other assays are
stable at 4˚C for up to six months. Once the reagents are activated they should
be used as soon as possible.
Promega BacTiter-Glo™ ATP Test Kit, www.promega.com
LuminUltra Deposit and Surface AnalysisTM ATP Test Kit,
www.luminultra.com
1. Velten, S., F. Hammes, M. Boller, and T. Egli. 2007. Rapid and Direct
Estimation of Active Biomass on Granular Activated Carbon Through
Adenosine Tri-phosphate (ATP) Determination. Water Research. 41(9):
1973-1983
2. Magic-Knezev, A. and D. van der Kooij. 2004. Optimization and
Significance of ATP Analysis for Measuring Active Biomass in Granular
Activated Carbon Filters Used in Water Treatment. Water Research.
38(18): 3971-3979.
3. Velten, S., M. Boller, O. Koster, J. Helbing, H. Weilenmann, and F.
Hammes. 2011. Development of Biomass in a Drinking Water Granular
Activated Carbon (GAC) Filter, Water Research, 45(19): 6347-6354.
4. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
5. Tracey, David. 2011. LuminUltra internal research. Personal
Communication.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
44 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Biological
Hydrolase enzyme activity
BactiQuant®
Criterion
Usefulness
Data Quality
Implementability
Cost
Recommendations
Metrics for
evaluation
Rating
3
Explanation
Ranges in values at 4 full-scale utilities were
between 56 and 7x104 BQV/g of filter media.
Order of magnitude changes over time are
considered significant.
Biological activity can impact performance but is
typically not a limiting factor.
Concentrations are reduced when an oxidant
residual is present at the filter influent.
Analysis time requires approximately 1 hour.
Correlations to
treatment objectives
Ability to control
2
Response/turnaround
time
Precision
4
Accuracy
5
Span
3
Representativeness
4
Selectivity/specificity
Technology maturity
5
3
Training
requirements
Ease of use
3
Data acquisition
requirements
Applicability to
small utilities
Capital
3
Relative percent difference for field duplicates
was on average 19 percent (n=3)2.
Evaluation of water samples under the ETV
program1 demonstrated R2 values ranging from
0.9138 to 0.9923. Coefficient of variation was on
average 15 percent (n=41)4.
Minimum detection of 10 fluorescence units.
Fluorescence units greater than 20,000 may
extend into the non-linear range.
Measures hydrolase enzyme activity of all
bacteria present. BQV correlated well with ATP
for media samples at four full-scale water utilities
(R2=0.78)2.
Directly measures hydrolase activity.
Assay is well developed but is not standard
practice in drinking water.
Requires in-house analysis with minimal training
(approximately 4 hours).
Requires sampling of media and 1 hour for inhouse analysis.
Requires manual sampling of filter media.
3
Requires sampling and low cost equipment
2
5
4
4
Purchase of fluorometer and basic laboratory
equipment ($5,000 - $10,000).
Operating and
5
Reagents/disposables are approximately $13 to
maintenance
$25 per sample depending on quantity.
Hydrolase activity provides a useful indicator of biomass. Concentrations on
biological filters tend to be consistent over time so periodic monitoring is sufficient.
This parameter may also be useful for optimization testing and troubleshooting.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
4 = favorable/low cost
5 = very favorable/very low cost
3 = average
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
Summary Tables | 45
Method Description:
Treatment
Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
Biological
Hydrolase enzyme activity
BactiQuant® (Continued)
The BactiQuant®-test rapid bacteria detection technology is based on fluorogenic
detection of hydrolase enzyme activity found predominantly in bacteria. It is
applicable to testing of water or filter media. Filter media samples [300 milligrams
(mg)] are added to a tube containing digestion reagents. A synthetic enzyme
substrate is added to the media and left to react over a period of time based on
temperature. The enzyme present in the bacterial cells hydrolyzes the synthetic
enzyme substrate. When the synthetic substrate molecule is cleaved into two
molecules by the enzyme, one of the molecules can be made to fluoresce upon
excitation with ultraviolet (UV) light at 365 nanometers (nm); the emission
wavelength is 445 nm. The amount of fluorescence emitted is measured using a
portable fluorometer. This fluorescence correlates to a measure of the bacterial
biomass. Fluorescence measurements can be captured electronically and may be
downloaded to a computer or can be transcribed by hand. Calculations are made to
determine the BactiQuant® Value (BQV), which is representative of the
concentration of bacteria in the sample.
BQV is not an indicator of performance or attainment of treatment objectives, but
does provide an indication of the active biomass present on the filter.
5 to 80,000 BQV/g for media filter samples2.
Phosphate buffers interfere with the assay.
The sample volume needed for media-based samples is less than 100 g. The
samples may be collected from the top of the filter media. However, if an oxidant
residual is present in filter influent water, profiling of the filter may be warranted.
Monitoring should be conducted periodically, during start-up, or during process
optimization. Normal fluctuations in BQV concentrations over time are typically
less than an order of magnitude, but may vary depending on site-specific
conditions. The time for analysis is approximately 1 hour. Holding times are not
well documented and should be evaluated on a site-specific basis. Reagents have a
shelf life of approximately 1 year.
Mycometer™ BactiQuant®. www.mycometer.com
1. Battelle and the Environmental Technology Verification Program: Advanced
Monitoring Systems Center. 2011. Quality Assurance Project Plan for
Verification of Mycometer™ - test Rapid Fungi Detection and BactiQuant® test Rapid Bacteria Detection Technologies. Version 1.0.
2. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
46 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Biological
Heterotrophic plate count (HPC)
Standard Method 9215 – R2A agar
Criterion
Usefulness
Data Quality
Implementability
Cost
Recommendations
Metrics for
evaluation
Rating
3
Correlations to
treatment objectives
Ability to control
2
Response/turnaround
time
Precision
2
1
Explanation
Ranges in values at 14 full-scale utilities were
between 1x106 and 1x1011 Colony Forming Unit
(CFU)/g of filter media3. Oder-of-magnitude
changes over time are considered significant.
Biological activity can impact performance but is
typically not a limiting factor.
HPC concentrations were relatively constant and
independent of operating conditions3.
Analysis time requires 5-7 days.
5
Relative percent difference for field duplicates
was on average 24 percent (n=4)3.
Accuracy
5
Coefficient of variation was on average 28
percent (n=75)3.
Span
5
Minimum detection of 10 CFU/g
Representativeness
2
Measures number of active heterotrophic bacteria
that are culturable on R2A agar in the lab. This is
typically less than 10 percent of the bacteria
density measured using direct count microscopy.
Selectivity/specificity
4
Media is selective for slow growing microbes.
Colony forming units may arise from pairs,
chains, clusters, or single cells of bacteria.
Technology maturity
5
Standard method accepted in the industry.
Training
2
Requires training in microbiology laboratory
requirements
methods.
Ease of use
2
Difficult for personnel who have not been trained
in microbiology.
Data acquisition
2
Requires manual sampling of filter media and
requirements
laboratory analysis or use of an outside lab.
Applicability to
5
Analysis is commonly conducted in the drinking
small utilities
water industry.
Capital
4
Purchase of sonicator, homogenizer, incubator,
and basic laboratory equipment ($5,000 $10,000).
Operating and
5
Low cost for reagents/disposables.
maintenance
Samples may be sent to an outside lab after
biomass is suspended for analysis at a cost of
$15-25/sample.
This parameter is well established in the drinking water industry and has been used
in several research projects on biological filtration. HPC may be an indicator of
active biomass, but may not correlate with ATP and BQV.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
4 = favorable/low cost
5 = very favorable/very low cost
3 = average
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 47
Biological
Heterotrophic plate count (HPC)
SM 9215 – R2A agar (Continued)
Method description:
Treatment objectives:
Typical range:
Interferences:
Implementation
Requirements:
Procurement:
References:
HPC estimates the number of active culturable heterotrophic colonies in water. R2A
agar should be used to select for slow growing organisms typical in drinking water
biological filters. The pour plate method and spread plate methods are evaluated
herein (Standard Method 9215 A and B, respectively). The pour plate method
involves inoculation of a diluted water sample onto warm liquid R2A agar. The agar
is poured onto plates and incubated for 7 days. The spread plate method involves
inoculation of a diluted water sample onto solid R2A agar and incubation for 7 days.
Both methods rely on enumeration by visual inspection. Analysis of filter media
samples require that HPCs from the biofilm are suspended into the aqueous phase
by sonication and homogenization. Clumps of cells released from biofilms may
produce one colony and therefore underestimate the number of bacteria present.
Disaggregating prior to plating will reduce clumping.
HPC are not an indicator of performance or attainment of treatment objectives, but
do provide an indication of the biomass present on filter media.
106-1011 CFU/g for filter media3
Possible contamination during the handling and preparation of a sample poses a
significant interference. Good microbiological laboratory techniques such as proper
sterilization (aseptic techniques) and inoculation practices are essential in
minimizing interferences.
Colony forming units may arise from pairs, chains, clusters, or single cells of
bacteria. Dilution of samples aids in discriminating between multiple cells that grow
in the same colony but may reduce precision of the assay.
The sample should be collected in a sterile 120 mL bottle. The sample holding time
is 24 hours at 4˚C. Sodium thiosulfate quenching agent is recommended as a
preservative.
Bacteria are extracted from the media using a homogenizer, blender, or a lowenergy sonicator. An autoclave is required for sterilization of laboratory equipment.
Samples are incubated for 5 to 7 days at 20 to 28˚C.
If analyzed by an outside laboratory the following equipment is required: sonicator
or homogenizer2, reagents1.
Several outside laboratories can perform standard heterotrophic plate counts using
R2A agar.
If analyzed by the utility the following equipment is additionally required:
autoclave, incubator, plates and reagents1.
1. APHA, AWWA, and WEF (American Public Health Association, the American
Water Works Association, and the Water Pollution Control Federation). 1999.
Standard Methods for the Examination of Water and Wastewater, 20th Edition.
Washington, D.C.: APHA.
2. Camper, A. K., M. W. LeChevallier, S. C. Broadaway, and G. A. McFeters.
1985. Evaluation of Procedures to Desorb Bacteria from Granular Activated
Carbon. J. Microbiological Methods. 3: 187-198.
3. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
48 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Biological
Dissolved oxygen consumption
Online luminescent dissolved oxygen (LDO) - ASTM D888-9C, proposed EPA Method 360.3
Criterion
Usefulness
Explanation
Ranges in values for DO consumption at 4 full-scale
utilities were between 0 and 4 milligrams per liter
(mg/L)3.
Correlations to treatment
2
Biological activity can impact performance but is
objectives
typically not a limiting factor.
Ability to control
3
Potential to control with residual ozone.
Response/turnaround time
5
Online
Data Quality
Precision
5
Mean percent recovery was 99.5 percent from 11
laboratories who tested the method2; repeatability of
0.5 percent of span (0.1 mg/L).
Accuracy
5
Below 1 part per million (ppm): ±0.1 ppm, above 1
ppm: ±0.2 ppm
Span
5
0 to 20 mg/L; limit of detection for calculating
consumption was approximately 0.1 mg/L at two
filters tested over a duration of one year.3
Representativeness
3
Indirect measure of microbial activity by measuring
consumption of DO from the influent to the effluent
of the filter.
Selectivity/specificity
5
Luminescence measured by the probe is proportional
to the DO concentration.
Implementability
Technology maturity
2
Method for measuring DO is well developed but the
application for estimation of biological respiration
online is new.
Training requirements
5
Instrumentation set up is simple. Calibration to site
elevation is recommended at set-up.
Ease of use
5
Online instrument can be tied into SCADA system
or connected to a data storage device.
Data acquisition
5
Instrument can be tied into SCADA systems or
requirements
downloaded from a memory storage device. No
warm-up time necessary, <1 minute to 95 percent
response.
Applicability to small
4
Data can be monitored online and equipment is
utilities
relatively inexpensive.
Cost
Capital
5
Approximately $1,600 for each LDO probe, $1,100
for a controller and $450 for a flow through cell;
total cost of approximately $6,000.
Operating and
5
Cleaning and calibration required monthly to
maintenance
annually depending on water quality characteristics.
Sensor cap may require replacement (approximately
$160). The first calibration should be immediately
upon installation.
Recommendations Typical membrane-based DO sensors require frequent maintenance, making online
instrumentation less desirable. The LDO probe alleviates many of these problems as
maintenance requirements are low. The reduction of DO across the filter can be used as an
indicator of the respiration of active biomass. Additional controlled testing to validate uses
of the data for design and optimization in full-scale filters are warranted, such as the utility
of respiration rate constants and activation energies.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Metrics for evaluation
Rating
2
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 49
Biological
Dissolved oxygen consumption
Online luminescent dissolved oxygen (LDO) - ASTM D888-9C, proposed EPA Method 360.3
(Continued)
Method
Description:
Treatment
Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Biological activity of the filter is indirectly measured by calculating the consumption of
DO across the filter. This provides an indicator of the oxygen consumed by
microorganisms during respiration. Data from one facility without pre-oxidation and
three facilities with ozonation indicated that differences in DO across full-scale filters
could be measured online. The respirometric potential was sensitive to changes in process
conditions, such as temperature, oxidant residual, maintenance activities and source water
quality changes. DO is measured by the LDO probe through a light-emitting diode (LED)
that emits blue light to a sensor coated with a luminescent material. The luminescent
material illuminates and gets excited by the LED. As the excited chemical relaxes, a red
light is emitted. The red light is detected by a photodiode and the time for the excited
chemical to return to a relaxed state is measured. The oxygen concentration is inversely
proportional to the time it takes for the luminescent material to return to a relaxed state.
DO is not consumed during measurement. Temperature is compensated for in the DO
reading and temperature readings are recorded by the temperature sensor.
Changes in DO concentrations are not an indicator of performance or attainment of
treatment objectives, but provide an indicator of active biomass respiration.
Net reduction across the filter of 0 to 4 mg/L3. This may be higher for GAC filters with
new media, an equilibration period of approximately one week may be required.
Plants with ozone may have supersaturated oxygen concentrations. While atmospheric
equilibration is possible (off-gassing), DO does not readily come out of solution. If the
probes are installed at a location representative of DO concentrations entering the filter,
then no data manipulation is required. However, if the influent probe is taken from a
monitoring point in a pipeline upstream of the filter influent, DO off-gassing may occur.
The facility can monitor DO concentrations at various points in the plant to determine
whether off-gassing is significant. If DO off-gassing is suspected, DO consumption may
be broken up into maximum and minimum values. The maximum DO consumption that
can be attributable to biological respiration should be calculated as the difference between
the influent and effluent concentrations. The minimum value should be calculated as the
difference between the influent saturated DO and the effluent concentrations.
Iron deposits have been shown to interfere with the DO reading. For dissolved iron
concentrations greater than 0.1 mg/L, cleaning with sodium bisulfite will remove buildup.
DO sorption during media reactivation was observed to subside after newly reactivated
GAC media was placed online for approximately one week. The effect of sorption onto
GAC media should be censored from data analysis.
The data logging interval, time stamp, and elevation or barometric pressure should be
entered into the sensor when set-up. While the probes are calibrated at the factory using
air as the calibration point, the concentration of oxygen in air varies at different
elevations; calibration should be performed on-site as soon as possible.
Placement of the instruments is important for representative data collection. If the
influent probe can be measured from the actual filter influent, those data would be
preferable over a sample tap from the influent pipeline. The probe measuring from the
filter influent should be installed at a location that is in equilibrium with the atmosphere
and downstream of a weir or another other process that could alter DO concentrations. If
this is not possible, both probes can be placed in flow-through cells that receive water
from a tap in the pipeline. The flow-through cells can have water flow from the top to the
bottom of the cell, or from the bottom to the top. The former may help reduce build-up of
solids, particularly for the influent probe.
The sensor will function better with consistent flow and pressure (+/- 5 percent) with flow
between 2 and 200 liters per minute.
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
50 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Biological
Dissolved oxygen consumption
Online luminescent dissolved oxygen (LDO) - ASTM D888-9C, proposed EPA Method 360.3
(Continued)
Implementation
Requirements:
Procurement:
References:
Data can be collected by tying the instrument into SCADA or by connecting a data storage
device to the controller.
Maintenance of the probes requires cleaning and calibration monthly to annually.
Calibration is a 1-point calibration in air. The sensor should be calibrated at the facility
even though it is factory-calibrated. The first calibration has the largest change in reading,
and the sensor is highly reliable after this calibration. The probes are highly robust in
handling solids accumulation on the sensor surface. The sensor can be cleaned using a soft
toothbrush and a light detergent such as liquinox. If iron deposits are likely to accumulate,
sodium bisulfate can be used for removal.
Two LDO probes, two controllers, and two flow-through cells are required.
1. American Society for Testing and Materials (ASTM) Method D888-9C. Standard test
methods for dissolved oxygen in water, instrumental probe procedure - luminescencebased sensor. December 2009.
2. Hach Company. 2004. Report on the validation of proposed EPA Method 360.3
(luminescence) for the measurement of dissolved oxygen in water and wastewater.
August 2004.
3. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich, and P. K.
Jjemba. 2013. A Monitoring and Control Toolbox for Biological Filtration. Denver,
Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 51
Biological
Extracellular polymeric substances (EPS)
Phenol-sulfuric acid assay
Criterion
Usefulness
Data Quality
Implementability
Cost
Correlations to
treatment objectives
2
Ability to control
5
Response/turnaround
time
Precision
3
Accuracy
5
Span
Representativeness
5
5
Selectivity/specificity
Technology maturity
4
3
Training requirements
3
Ease of use
3
Data acquisition
requirements
Applicability to small
utilities
Capital
3
Explanation
Limited data are available from research studies.
Best used for evaluating trends over time.
Excess production of EPS can decrease filter run
time and can signify a stressed biological
community 2.
EPS concentrations are reduced when an oxidant
residual is present at the filter influent.
Analysis time requires approximately 1 to 2
days3.
Highly reproducible - experiments repeated on
different days by different operators produced
variations of < 0.01 to 0.02 absorbance units3.
The method can be expected to be accurate to
within ± 2 percent3.
0.04 to 2.64 mg/g filter media3
Measures EPS concentrations in both attached
and non-attached biofilm.
Directly measures EPS concentrations.
Assay is simple and easy but is not standard
practice in drinking water.
Requires in-house analysis with approximately 4
hours of training.
Requires sampling of media and 12 hours of
laboratory work for in-house analysis.
Requires manual sampling of filter media.
3
Requires sampling and standard equipment.
Metrics for evaluation
Rating
2
4
4
Purchase of spectrophotometer ($4,000 to
$7,000).
Operating and
4
Reagents/disposables cost approximately $50 per
maintenance
sample.
Recommendations
EPS concentrations provide a useful indicator of biomass. Concentrations on
biological filters tend to be consistent over time so periodic monitoring is sufficient.
This parameter may also be useful for optimization testing and troubleshooting.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
52 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Method Description:
Treatment
Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
Biological
Extracellular polymeric substances (EPS)
Phenol-sulfuric acid assay (Continued)
EPS is a compound secreted by certain kinds of bacteria that provides a structure
that holds the biofilm matrix together and aids in biochemical communication
between cells. This method determines the concentration of EPS present on filter
media, which can be used as an indicator of biomass structure. The media sample
is suspended in solution prior to being placed into a centrifuge. The supernatant is
transferred to another test tube for extraction of free EPS while the pellet is
resuspended in a buffer and incubated for extraction of attached EPS. The
supernatant is mixed with a 50 percent phenol solution and concentrated sulfuric
acid. The presence of glucose in a sample is indicated by development of a
yellowish color. The concentration of glucose in a sample is determined via
constructing a glucose calibration curve on a spectrophotometer. This method may
be used for suspended or attached biomass.
The presence of EPS may not correlate directly to filter performance but it does
provide an indication of the biomass and could impact treatment objectives
including filter run time. If excessive EPS is present.
0.04-2.64 mg total glucose (free + bound) per gram of media 2,3.
The PBS and tris buffer solutions used for extraction of free and bound EPS,
respectively, have absorbance values that need to be subtracted for correcting
background absorbance in actual samples. Thus, in addition to an instrument
calibration blank (deionized water), two other batch blanks need to be analyzed:
free EPS blank (phosphate buffer) and bound EPS blank (tris buffer)-.
The sample preparation (e.g. homogenization) can introduce significant variability
in free EPS if it is not conducted consistently. For example, particulates or other
solids on the filter media can be highly variable between samples.
The sample size needed for media-based samples is 2 grams. Samples may be
collected from the top of the filter media. However, if an oxidant residual is
present, profiling of the filter may be warranted. Monitoring should be conducted
periodically, during start-up, or during process optimization. The turnaround time
for analysis is approximately 1 to 2 days (minimum of 12 hours). Holding times
are not well documented and should be evaluated on a site-specific basis. Once the
reagents are activated they should be used as soon as possible.
Equipment necessary for performing EPS analysis include high-speed centrifuge,
temperature-controlled water bath, vortexer, sonicator, analytical balance,
spectrophotometer and reagents1.
1. Dubois, M., K. Gilles, J. Hamilton, P. Rebers, and F. Smith. 1956.
Colorimetric Method for Determination of Sugars and Related Substances.
Analytical chemistry, 28(3): 350-365.
2. Lauderdale, C. V., J. C. Brown, P. A. Chadik, and M. J. Kirisits. 2011.
Engineered Biofiltration for Enhanced Hydraulic and Water Treatment
Performance. Denver, Colo.: Water Research Foundation.
3. Unpublished CDM Smith internal research, 2011.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 53
Biological
Biological community structure
Transcription restriction fragment length polymorphism (TRFLP)
Criterion
Usefulness
Data Quality
Implementability
Cost
Metrics for evaluation
Rating
2
Correlations to treatment
objectives
2
Ability to control
1
Response/turnaround time
Precision
1
4
Accuracy
3
Span
5
Representativeness
3
Selectivity/specificity
Technology maturity
5
3
Training requirements
Ease of use
1
1
Data acquisition
requirements
Applicability to small
utilities
Capital
Operating and
maintenance
1
1
Explanation
Benchmarks for drinking water are not
well understood but a few research reports
are available for reference1,2.
Biological activity can impact
performance but is typically not a limiting
factor. Specific organisms may be needed
for removal of particular contaminants.
May be practical to control, but targets and
control methods are not well established
Requires 4-6 weeks.
Precision of the method is high when
conditions are consistent, but method is
sensitive to small changes in procedures3.
Accuracy of community representation is
not well established.
Method is sensitive even at low biomass
concentrations.
Direct measurements of community
structure and trends over time are useful.
Highly specific analysis.
Developed but not standard for drinking
water.
Requires highly specialized training.
Requires complex sample preparation and
analyses.
Requires sampling and shipment to an
outside laboratory.
May not be feasible due to cost.
1
1
Requires specialized outside lab.
Commercial lab cost of $700 per sample
for microbial community diversity,
identification and relative quantity of
microorganisms present by phylogenetic
class and genus. Cost does not include a
clone library used to identify species
present.
Recommendations
This method provides information on microbial community structure and
diversity, and a clone library can be created to identify particular species present.
This method may be useful for special studies such as process optimization,
troubleshooting, or tracking of particular microbes such as those degrading
PPCPs. Microbial community diversity correlated strongly with water quality
parameters such as carboxylic acids, nitrogen, and phosphorous concentrations at
five different biological filters4. Additional testing to verify correlations between
particular communities and filter performance is warranted.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
54 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Biological
Biological community structure,
Transcription restriction fragment length polymorphism (TRFLP) (Continued)
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
TRFLP is a molecular biology fingerprinting technique that evaluates the microbial
community diversity. PCR techniques are used to amplify fluorescently labeled DNA
strands from lysed cells; the strands are then cut at specific sites using restriction enzymes
to generate fluorescently labeled fragments. Theoretically, each unique sequence derived
from bacteria within the community will generate a labeled fragment of a unique length. A
DNA sequencer separates the fragments according to length and generates a
chromatogram where each fragment is represented by a peak in fluorescent intensity that
is proportional to the fragment's abundance. Software analysis of the chromatogram
determines the length of each fragment relative to an internal size standard. The
chromatogram provides relative abundance data for the microbial community. In order to
identify specific members of the community, a clone library of the community is also
required. Clone library development is available through specialized labs.
TRFLP chromatograms are not an indicator of performance or attainment of treatment
objectives, but do provide an indication of the microbial community present on the filter
and may be used to identify class and genus level information.
TRFLP results may be used to calculate species richness, diversity, and evenness. Further
research is necessary before typical ranges can be defined, and before it will be possible to
identify common species.
Many compounds, such as humic and fulvic acids, can co-extract with DNA and inhibit
the PCR. The relative abundance of different fragments can be influenced by changes in
DNA extraction methods and PCR conditions. Data analysis requires chromatographic
interpretation, and different laboratories use different standards in that interpretation.
The media sample size needed is 0.5-1g. The sample must be chilled on ice and shipped
immediately or stored for up to a few weeks at -20˚C. Samples should be analyzed in
triplicate. Outside lab services will typically be used, as the analysis requires specialized
equipment including a PCR thermocycler, high-speed centrifuge, and a genetic analyzer,
with capital costs of $50,000 to $200,000.
Laboratories: Microbial Insights, Inc., several university labs can also perform this
analysis.
1. Lauderdale, C. V., J. C. Brown, P. A. Chadik, and M. J. Kirisits. 2011. Engineered
Biofiltration for Enhanced Hydraulic and Water Treatment Performance. Denver,
Colo.: Water Research Foundation.
2. Chowdhury, Z., A. Travilia, J. Carter, T. Brown, R. S. Summers, C. Corwin, T.
Zearley, M. Thurman, I. Ferrara, J. Olson, R. Thacker, and P. Barron. 2010. Cost
Effective Regulatory Compliance With GAC Biofilters. Denver, Colo.: Water
Research Foundation.
3. Liu, W., T. Marsh, H. Cheng, and L. Forney. (1997) Characterization of microbial
diversity by determining terminal restriction fragment length polymorphisms of genes
encoding 16S rRNA. Applied Environmental Microbiology. 63: 4516-4522.
4. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich, and P. K.
Jjemba. 2013. A Monitoring and Control Toolbox for Biological Filtration. Denver,
Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 55
Organic Carbon
Total/dissolved organic carbon (TOC/DOC)
SM 5310 B or C
Criterion
Usefulness
Data Quality
Implementability
Cost
Recommendations
Metrics for evaluation
Rating
3
Correlations to treatment
objectives
3
Ability to control
5
Response/turnaround time
3
Precision
5
Accuracy
5
Span
5
Representativeness
Selectivity/specificity
4
3
Technology maturity
Training requirements
5
4
Ease of use
4
Explanation
Ranges in values at 14 full-scale utilities
were between 0.37 and 3.83 mg/L for
TOC and 0.49 and 3.76 for DOC using
method 5310 B. Removals across the filter
were between 0 and 1.6 mg/L for TOC
and 0 and 1.4 for DOC2.
Partially related to biological stability;
may be directly related to filter treatment
objectives.
Highly controllable - pre-oxidants can be
used to change the nature of TOC and
DOC to be more readily biodegradable.
A few hours conducted in-house, or 1
week if conducted by an outside lab.
Standard method with precision between 5
and 10 percent1 for grab samples. Relative
percent difference between online
measurement of TOC and grab samples
was 13 percent2 at one facility (n=20).
Standard method; coefficient of variation
was on average 1.2 percent for TOC
(n=63) and 1.3 percent for DOC (n=61)2.
Detection limit typically less than
0.2 mg/L; varies depending on instrument
Partially related to biological stability.
AOC is more selective for organic carbon
related to biological stability.
Standard method.
Automated analysis that is easily learned.
Automated analysis that requires little
effort.
Data acquisition requirements
3
Requires sampling and analysis or can be
monitored online.
Applicability to small utilities
2
Small utilities typically do not have this
type of instrumentation but could send
samples to an outside laboratory.
Capital
2
Laboratory TOC analyzer is $10,000 $15,000; online TOC analyzer is $20,000.
Operating and maintenance
3
$1,250 per year for consumables. $25-$50
per sample for outside laboratory analysis.
Well established parameter that provides information directly relating to
performance/treatment objectives for TOC which are related to biological stability.
Benchmarks are available for comparability and instrumentation for grab samples are
relatively low cost.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
4 = favorable/low cost
5 = very favorable/very low cost
3 = average
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
56 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Organic Carbon
Total/dissolved organic carbon (TOC/DOC)
SM 5310B or C (Continued)
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
TOC and DOC are measurements of NOM which can contribute to DBP formation
and stability problems in the distribution system. NOM removal is a primary treatment
objective of many biological filters. TOC and DOC are standard analytes that are
either collected as grab samples and analyzed by laboratory or collected using an
online instrument. For the high temperature combustion method for TOC (5310B), the
sample is homogenized and inorganic carbon is removed by acidification and
sparging. The sample is then injected into a heated reaction chamber packed with an
oxidative catalyst. Water is vaporized and the organic carbon is oxidized to carbon
dioxide and water. The carbon dioxide is measured using a non-dispersive infrared
analyzer or titrated colorimetrically.
For the persulfate-ultraviolet method for TOC (5310C), inorganic carbon is removed
by acidification and sparging or measured separately. The sample is oxidized to
carbon dioxide using ultraviolet (UV) or heat with persulfate. The concentration of
carbon dioxide is detected using either an NDIR analyzer, colorimetrically titrated, or
membrane filtration to selectively pass carbon dioxide followed by measurement of
conductivity.
DOC is typically measured by filtering the sample with a 0.45-μm filter.
DOC concentrations may be related to attainment of treatment objectives.
0.1-5 mg/L influent, net reduction across filter of 0 to 2 mg/L2
Another important loss can occur if turbid water, with large carbon-containing
particles, fails to enter the needle used for injection. Filtration, although necessary to
eliminate particulate organic matter when only DOC is to be determined, can result in
loss or gain of DOC, depending on the physical properties of the carbon-containing
compounds and the adsorption or desorption of carbonaceous material on the filter.
Check filters for their contribution to DOC by analyzing a filtered blank.
Note that any contact with organic material may contaminate a sample. Avoid
contaminated glassware, plastic containers, and rubber tubing. Analyze sample
treatment, system, and reagent blanks. Lower temperature used for combustion
(680˚C) has reduced interference due to dissolved salts, resulting in lower blank
values. Gases evolved from combustion, such as water, halide compounds, and
nitrogen oxides, may interfere with the detection system. Consult manufacturers’
recommendations regarding proper selection of scrubber materials and check for any
matrix interferences. The major limitation to high-temperature techniques is the
magnitude and variability of the blank.
For online instruments using SM 5310 C, the in-line filter may need to be removed for
water samples from the filter influent. It is critical to perform regular
operational/maintenance activities as recommended by the manufacturer. Instrument
maintenance includes replacing the UV lamp every 6 months, sample pump tubing
annually, replacing the acid and oxidizer reagents approximately every 3 months,
replacing the ion exchange resin bed annually, and maintenance on the syringe pumps.
Significant down-time may be required if the instrument requires maintenance by the
manufacture (e.g. > 1month).
Samples collected for analysis by an outside laboratory should be collected in a
carbon-free amber glass bottle and stored at 4˚C prior to analysis. Samples can be
preserved by acidification to pH less than 2 standard units and then may be stored up
to 28 days.
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 57
Procurement:
References:
Organic Carbon
Total/dissolved organic carbon (TOC/DOC)
SM 5310B or C (Continued)
TOC analyzers: www.hach.com, www. Shimadzu.com, www.geinstruments.com
Several laboratories perform this analysis.
1. APHA, AWWA, and WEF (American Public Health Association, the American
Water Works Association, and the Water Pollution Control Federation). 1999.
Standard Methods for the Examination of Water and Wastewater, 20th Edition.
Washington, D.C.: APHA.
2. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich, and
P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological Filtration.
Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
58 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Organic Carbon
Assimilable organic carbon (AOC)
SM 9217 (van der Kooij assay)
Criterion
Usefulness
Data Quality
Implementability
Cost
Recommendations
Metrics for evaluation
Rating
3
Correlations to treatment
objectives
Ability to control
5
Response/turnaround
time
Precision
1
5
Explanation
Ranges in values at 14 full-scale utilities were
between 10 and 370 μg acetate-C/L. Removals
across the filter were between 0 and
220 μg acetate-C/L2.
May be directly related to treatment objectives.
Degree of up-stream oxidation can influence
influent concentrations of AOC and reduction
of AOC across the filter2.
Approximately 3 to 4 weeks.
4
A single laboratory test had a precision of ±
17.5 percent for P17 (n=58)1. Relative percent
deviation for field duplicates was 5 percent for
one set of samples2.
Accuracy
4
Coefficient of variation was on average 11
percent for (n=34)2.
Span
4
A minimum of 10 µg acetate-C/L.
Representativeness
4
Accepted measure of biological stability and
regrowth potential, but is a bioassay and an
indirect measure of carbon. Growth of biomass
is converted to concentrations of acetate carbon
equivalents.
Selectivity/specificity
5
Highly specific analysis.
Technology maturity
5
Standard method.
Training requirements
2
Requires specialized training in microbiology
laboratory methods (may take several days to
train).
Ease of use
2
Difficult for personnel who are not trained in
microbiology.
Data acquisition
1
Requires manual sampling and analysis and
requirements
likely use of an outside lab.
Applicability to small
1
Unlikely to be used by most small utilities due
utilities
to cost.
Capital
1
Performing the test in house requires autoclave
and incubator ($5,000 - $10,000).
Operating and
2
Low cost for reagents/disposables. $400 to
maintenance
$500 per sample for outside laboratory
analysis.
Although AOC is considered to be an important indicator of biological stability, the
SM 9217 is cumbersome, expensive, and has a long turnaround time. The assay can
underestimate the total quantity of AOC due to limitations on monitoring frequency.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
4 = favorable/low cost
5 = very favorable/very low cost
3 = average
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
Summary Tables | 59
Organic Carbon
Assimilable organic carbon (AOC)
SM 9217 (van der Kooij assay) (Continued)
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
This method is a two-species bioassay (Pseudomonas fluorescens strain P17 and
Spirillum strain NOX) used to determine biological growth potential. Samples are
pasteurized to kill indigenous organisms and then inoculated separately with the two
test strains. The test organisms are allowed to grow to maximum density and are then
enumerated by the spread plate method for plate counts. The inoculated test water is
spread on agar, incubated for 48 hours, and colony forming units are enumerated by
visual inspection. Plate counts need to be assessed at multiple time points to
determine when the maximum number of cells have grown in the inoculated sample
(typically daily after one week of incubation).
AOC concentrations are an indicator of biological stability.
5-400 µg-acetate-C/L2
Untreated surface waters, especially those with high concentrations of suspended
solids or high turbidity, can contain large numbers of spore-forming bacteria that
may survive pasteurization, grow, and interfere with the enumeration of P17 and
NOX on spread plates. Such waters generally have high AOC concentrations and can
be diluted with organic-free water amended with mineral salts or prefiltered through
carbon-free filters. Potable waters that have been disinfected and carry a disinfectant
residual will inhibit growth of the test organism unless the disinfectant is quenched;
a sodium thiosulfate or sodium thiosulfite quenching agent is typically included as a
preservative to mitigate this. Surface waters from reservoirs treated with copper
sulfate also may be inhibitory unless a chelating agent is added to the sample, and
lime softened waters with elevated pH values may require pH adjustment. Any
amendment to a sample requires a control for AOC contamination.
The sample should be collected in a 250 mL borosilicate glass bottle that is free of
organic carbon (acid washed, muffled at 550˚C) with Teflon-lined caps. Preservation
with sodium thiosulfate is recommended; the sample holding time is 72 hours once
pasteurized.
If analyzed by the utility the following equipment is required: incubator, plates,
reagents1.
Several laboratories perform this analysis.
1. APHA, AWWA, and WEF (American Public Health Association, the American
Water Works Association, and the Water Pollution Control Federation). 1999.
Standard Methods for the Examination of Water and Wastewater, 20th Edition.
Washington, D.C.: APHA.
2. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich, and
P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
60 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Organic Carbon
Assimilable organic carbon (AOC)
Bioluminescent P17 and NOX method
Criterion
Usefulness
Metrics for evaluation
Correlations to treatment
objectives
Ability to control
Data Quality
Implementability
Cost
Recommendations
Rating
2
5
Explanation
Ranges in values at 14 full-scale utilities were
between 14 and 1440 µg-acetate-C/L.
Removals across the filters were between 0 and
190 μg acetate-C/L3.
May be directly related to treatment objectives.
5
Degree of up-stream oxidation can influence
influent concentrations of AOC and removal of
AOC across the filter3.
Response/turnaround time
3
3 days to approximately 1 week.
Precision
5
Relative percent deviation for field duplicates
was 23 percent (n=5)3.
Accuracy
4
The correlation between SM 9217 and the
bioluminescent method was strong (R2=0.92,
n=13)2. Coefficient of variation was on average
14 percent (n=123)3.
Span
4
A minimum of 10 µg acetate-C/L.
Representativeness
4
Accepted measure of biological stability and
regrowth potential. It is a bioassay and an
indirect measure of carbon. Growth of biomass
is converted to concentrations of acetate carbon
equivalents.
Selectivity/specificity
5
Highly specific analysis.
Technology maturity
3
Developed from standard method, but still
novel to the industry.
Training requirements
2
Requires specialized training in microbiology
laboratory methods (may take several days).
Ease of use
2
Difficult for personnel who are not trained in
microbiology.
Data acquisition
1
Requires manual sampling and analysis and
requirements
likely use of outside lab.
Applicability to small
2
More likely to be used by small utilities than
utilities
SM 9217 due to decreased cost and turnaround
time and commercial availability of the assay.
Capital
1
Purchase of luminometer ($20,000).
Operating and
2
Low costs for consumables. Approximately
maintenance
$250/sample for outside laboratory analysis.
This method has a significantly shorter turnaround time and is less cumbersome than
SM 9217. This assay is commercially available. Trend analysis at a single utility will
be the most reliable use of data.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
4 = favorable/low cost
5 = very favorable/very low cost
3 = average
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
Summary Tables | 61
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
Organic Carbon
Assimilable organic carbon (AOC)
Bioluminescent P17 and NOX method (Continued)
As a modification to SM 9217, this method utilizes genetically modified strains of
Pseudomonas fluorescens P17 and Spirillum sp. strain NOX bacteria that
continuously bioluminesce. Samples are pasteurized to kill indigenous organisms
and then inoculated separately with the two test strains. Inoculated samples are
transferred to a 96-well plate and measurements are made using a luminometer.
Samples are monitored at a predetermined frequency, until maximum luminescence
is reached indicating maximum cell yield. Maximum luminescence is converted to
AOC using a standard curve. The time to complete the assay is significantly shorter
than SM 9217, typically 1 week or less.
The maximum growth rate (μmax) can be also be assessed using Monod kinetics.
This can provide information on cell growth and NOM quality by comparing the
kinetics of P17 and NOX.
AOC concentrations are an indicator of biological stability.
5-1,500 µg-acetate-C/L3
Untreated surface waters, especially those with high concentrations of suspended
solids or high turbidity, can contain large numbers of spore-forming bacteria that
may survive pasteurization, grow, and interfere with the enumeration of P17 and
NOX on spread plates. Such waters generally have high AOC concentrations and
can be diluted with organic-free water amended with mineral salts or prefiltered
through carbon-free filters. Potable waters that have been disinfected and carry a
disinfectant residual will inhibit growth of the test organism unless the disinfectant
is neutralized; a sodium thiosulfate quenching agent is typically included as a
preservative to mitigate this. Surface waters from reservoirs treated with copper
sulfate also may be inhibitory unless a chelating agent is added to the sample, and
lime softened waters with elevated pH values may require pH adjustment. Any
amendment to a sample requires a control for AOC contamination.
The sample should be collected in a 250 mL borosilicate glass bottle that is free of
organic carbon (acid washed, muffled at 550˚C) with Teflon-lined caps and stored
at 4˚C. Preservation with sodium thiosulfate is recommended; the sample holding
time is 72 hours once pasteurized.
If analyzed by the utility the following equipment is required: luminometer,
incubator, plates, reagents1,2.
Laboratories: Eurofins Eaton Analytical, Inc.
1. Haddix, P. L., N. J. Shaw, and M. W. LeChevallier. 2004. Characterization of
Bioluminescent Derivatives of Assimilable Organic Carbon Test Bacteria.
Applied and Environmental Microbiology. 70(2): 850-854.2.
2. Weinrich, L. A., E. Giraldo, and M. W. LeChevallier. 2009. Development and
Application of a Bioluminescence AOC Test in Reclaimed Waters. Applied
Environmental Microbiology. 75(23): 7385-7390.
3. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
62 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Organic Carbon
Carboxylic acids
EPA Method 300.1 - modified
Criterion
Usefulness
Data Quality
Implementability
Metrics for evaluation
Rating
3
Correlations to treatment
objectives
4
Ability to control
5
Response/turnaround time
1
Precision
5
Accuracy
5
Span
5
Representativeness
3
Selectivity/specificity
Technology maturity
5
4
Training requirements
Ease of use
2
3
Data acquisition
requirements
Applicability to small
utilities
3
Explanation
Ranges in values at 14 full-scale utilities for the
sum of carboxylic acids expressed as carbon
equivalents were between 2 and 183 µg-C/L and
removal across the filter was as high as 171 μgC/L3.
May be directly related to treatment objectives
since this may correlate well with AOC at
facilities with pre-oxidation3.
Demonstrated effect of pre-oxidation and
biological filter operations on carboxylic acid
formation/degradation3.
Holding time is approximately 2 days at 4˚C and
several months if frozen at -20˚C.
Highly precise and reproducible method
utilizing Ion Chromatography (IC).
Highly accurate with typical recovery of ± 5
percent.
0.003 to 10 mg/L depending on the analyte of
interest.
Measures some but not all organic compounds
related to biological stability; particularly those
generated during pre-oxidation.
Highly specific analysis.
Method well developed, but not typically used
by utilities.
Requires highly specialized training in IC.
IC is automated but requires maintenance if
analyzed in-house.
Requires sampling and analysis.
3
Likely to be too expensive for small utilities to
perform in-house; cost for outside laboratory
analysis is low.
Cost
Capital
1
Purchase of an IC system (approximately
$50,000) along with support laboratory
accessories such as a MilliQ-deionized water.
Operating and maintenance
4
Annual preventive maintenance of the IC system
is approximately $1,500.
$50 per sample for outside laboratory analysis.
Recommendations
The sum of carboxylic acids including acetate, formate, and oxalate expressed as carbon
equivalents can be used as an indicator of AOC or BDOC if the facility uses preoxidation, particularly ozone. This method may be used to monitor attainment of
treatment objectives for Biostability. The sum of carboxylic acids correlated well with
AOC when the concentration was greater than 400 μg-acetate-C/L. If no pre-oxidation is
used, carboxylic acids are likely low.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 63
Organic Carbon
Carboxylic acids
EPA Method 300.1 – modified (Continued)
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
This method uses IC to analyze for carboxylic acids. There is no need for sample
preparation prior to analysis by IC, other than filtration if samples are highly turbid.
Water samples are injected into the IC and organic anions are determined by
separation on a high-capacity anion exchange column followed by conductivity
detection.
Carboxylic acid concentrations are directly related to biological activity and can act
as an indicator to filter performance.
1-1,000 micrograms/liter (µg/L)3
Method interferences may be caused by contaminants in the reagent water, reagents,
glassware, and other sample processing apparatus that lead to discrete artifacts or
elevated baselines in an IC. These interferences can lead to false positive results for
target analytes as well as reduced detection limits.
All samples must be filtered through 0.45 μm filters prior to introduction to the IC to
prevent damage to the instrument column and flow systems. ACS grade reagents and
deionized water free of analytes of interest are to be used to perform an analysis.
IC system and deionized water dispenser.
Laboratories: East Bay Municipal Utility District and Europhins Eaton Analytical.
1. Peldszus, S., P. M. Huck, et al. 1996. Determination of Short Chain Aliphatic,
Oxo- and Hydroxy-Acids in Drinking Water at Low Microgram per Liter
Concentrations. Journal of Chromatography. 723: 27-34
2. Peldszus, S., P. M. Huck, et al. 1996. Determination of Carboxylic Acids in
Drinking Water at Low µg/L Concentrations: Method Development and
Application. In Proc. of the Twenty-Fourth Annual AWWA Water Quality
Technology Conference. Denver, Colo.: AWWA
3. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich, and
P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological Filtration.
Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
64 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Organic Carbon
Biodegradable dissolved organic carbon (BDOC)
BDOC sand method
Criterion
Usefulness
Data Quality
Implementability
Cost
Recommendations
Explanation
Ranges in values at 14 full-scale utilities were
between 0.05 and 1.14 mg/L and removals
across the filter were between 0 and 0.484.
Correlations to treatment
4
Directly related to treatment objectives,
objectives
possibly less so than AOC.
Ability to control
5
Highly controllable - especially with a preoxidant4.
Response/turnaround time
1
Approximately 2 weeks, but depends on
nature of organic carbon present in sample.
Precision
2
Can be highly dependent on maintenance of
sand culture and frequency of monitoring.
Relative percent difference for field duplicates
was on average 26 percent (n=5)4.
Accuracy
5
Limited due to lack of comparable standards.
The percent recovery on a spiked sample was
95 percent4.
Span
2
Lower detection limit of the assay is 0.2 mg/L,
even if the TOC instrument detection limit is
lower5.
Representativeness
4
Direct measurement of BDOC. Interferences
from endogenous respiration after the
minimum concentration is reached reduces the
sensitivity of this assay.
Selectivity/specificity
4
Direct measurement of BDOC.
Technology maturity
2
Typically used in research studies, non
standard.
Training requirements
2
Requires sampling and specialized laboratory
training.
Ease of use
2
Requires preparation and maintenance of sand
culture and daily monitoring of DOC
concentrations. The greatest error in
measurement is associated with ability to
detect minimum concentrations.
Data acquisition requirements
1
Requires sampling, nonstandard method.
Applicability to small utilities
1
Likely to be too expensive for small utilities.
Capital
1
Purchase of TOC analyzer ($15,000 $25,000).
Operating and maintenance
4
Low costs for consumables. Approximately
$200 to $250 per sample for outside
laboratory analysis.
BDOC concentrations can provide useful information on filter removals, which can be
associated with treatment performance as well as biological activity. However,
concentrations must be above 0.2 mg/L to produce a meaningful result. The assay is not
sensitive to changes across the filter of less than 0.2 mg/L.
Metrics for evaluation
Rating
4
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
4 = favorable/low cost
5 = very favorable/very low cost
3 = average
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
Summary Tables | 65
Method
Description:
Treatment
Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
Organic Carbon
Biodegradable dissolved organic carbon (BDOC)
BDOC sand method (Continued)
BDOC is measured using biologically active sand stock with a high biomass
concentration. The stock sand is kept in an aerated flask with dechlorinated tap water at
room temperature. A few weeks are necessary for the stock organisms to acclimate. A
100 gram aliquot of sand stock is added to a sterile container and 300 mL of sample is
added. The DOC in solution is measured at the beginning of the assay. The liquid sample
is mixed and aerated during incubation. DOC concentrations are monitored as they
decrease daily until DOC measurements stabilize; this period is generally 5 to 14 days.
BDOC is calculated by subtracting the initial DOC concentration from the minimum
DOC concentration.
BDOC can provide insight to treatment performance. BDOC can also be related to
biological activity by looking at the changes in BDOC from the filter influent and
effluent.
0-3 mg/L4
After the minimum concentration is reached endogenous respiration can occur. As cells
die and lyse, the organic carbon concentration can increase. If the DOC measurement
was not collected at the true minimum, an erroneous value can be reported. This reduces
the sensitivity of this assay. More frequent monitoring will increase the quality of the
result.
The sample should be collected in a 500 mL amber glass bottle and stored at 4 ˚C until
analysis. Preservation with sodium thiosulfate is recommended; the sample holding time
is not well documented but should be analyzed within 24 hours. Turbid samples should
be filtered.
If analyzed by the utility the following equipment is required: pump for aeration unit,
sand, oven, TOC measurement method, basic laboratory equipment. TOC Analyzers can
be purchased from a variety of vendors such as: www.hach.com, www.Shimadzu.com,
www.geinstruments.com
Laboratories: Europhins Eaton Analytical, Colorado School of Mines
1. Joret, J.C. and Y. Levi, 1986. Méthode Rapide D’évaluation du Carbone éliminable
Des Eaux Par Voie Biologique. Trib. Cebedeau. 39: 3-9.2.
2. Volk, C., C. Renner, C. Robert, J. C. Joret. 1994. Comparison of Two Techniques
for Measuring Biodegradable Dissolved Organic Carbon in Water. Environmental
Science and Technology. 15, 545-556.3.
3. Allgeier, S. C., R. S. Summers, J. G. Jacangelo, Vanessa A. Hatcher, D. M. Moll, S.
M. Hooper, J. W. Swertferger, and R. B. Green. 1996. A Simplified and Rapid
Method for Biodegradable Dissolved Organic Carbon Measurement. In Proc. of the
Twenty-Fourth Annual AWWA Water Quality Technology Conference. Denver,
Colo.: AWWA.
4. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich, and P.
K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological Filtration.
Denver, Colo.: Water Research Foundation.
5. Escobar, I. C. and A. A. Randall. 2001. Assimilable Organic Carbon (AOC) and
Biodegradable Organic Carbon (BDOC): Complementary Measurements. Water
Research. 35(18): 3971-3979.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
66 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Organic Carbon
Ultraviolet/visible (UV/VIS) spectroscopy
UV/VIS scan, UV254, SM 5910
Criterion
Usefulness
Data Quality
Implementability
Metrics for evaluation
Rating
3
Correlations to treatment
objectives
4
Ability to control
Response/turnaround
time
Precision
3
4
Accuracy
5
Span
Representativeness
3
3
Selectivity/specificity
3
Technology maturity
Training requirements
5
3
Ease of use
3
Data acquisition
requirements
Applicability to small
utilities
Capital
3
5
Explanation
Ranges in values at 14 full-scale utilities for
UV254 were between 0.01 and 0.08 abs/cm2.
Demonstrated correlation to AOC at one
utility2; may correlate to TOC, DOC, color,
and DBP precursers1.
Potentially high if use pre-oxidation.
Analysis time is short – a few minutes.
Relative percent difference for duplicate
analyses was 4.9 percent for the 90th
percentile (n=33,306)1.
Coefficient of variation for UV254 was on
average 10.5 percent from 8 labroaries1.
There are no standards for comparison to
assess accuracy with a standard value.
Minimum of 0.001 cm-1
Indirect measure of NOM, strong correlations
with TOC, DOC, color, and DBP precursors
(e.g. R2>0.9) in some cases1,2.
Demonstrated correlations may not be
broadly applicable, site-specific correlations
should be tested and verified.
Standard method that is well developed.
Analysis requires minimal training. Spectral
data analysis can be complicated.
Analysis is easy to conduct, but spectral
analysis interpretation is more complicated.
Requires sampling.
3
SUVA is applicable, spectral analysis is less
so.
Cost
4
Purchase of spectrophotometer ($7,000 $8,000).
Operating and
5
Minimal maintenance and consumables.
maintenance
Lamp replacement frequency can vary and
range between $200 and $1,000; filters are
approximately $1,000.
Approximately $20 to $25 per sample for
outside laboratory analysis.
Recommendations
Ultraviolet (UV) absorbing organic compounds, such as humic and fulvic acids with
many aromatic rings, absorb UV light proportional to concentration. UV254 data
may be used to estimate aggregate concentrations of organic matter, which may be
used to assess performance. Spectral analysis may provide additional information on
organic matter compositional changes. SUVA is well established and some
benchmark data from full-scale utilities are available; nitrate can also be estimated
by UV spectra.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 67
Organic Carbon
UV/VIS spectroscopy
UV/VIS scan, UV254, SM 5910 (Continued)
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
Some organic compounds, such as precursors of trihalomethanes and other
disinfection byproducts, organic compounds contributing to water color, and NOM,
will strongly absorb ultraviolet (UV) radiation. As such, UV absorption may be a
useful surrogate for concentrations of aggregate organic compounds. Water samples
are collected, filtered, and then analyzed at 254 nanometers (nm) using a
spectrophotometer. Other wavelengths, such as 220 and 275 nm can be used to
determine nitrate using SM 4500-NO3 B. UV spectra may be used to asses how the
NOM character changes.
UV/VIS is an indicator to filter performance for removal of organic compounds.
0.01-2 abs/cm2
The primary interferences in UV-absorption measurements are from colloidal
particles, and UV-absorbing inorganic carbon, notably ferrous iron, and bromide.
Ozone, chlorate, chlorite, and chloramines, and reducing agents such as thiosulfate
will absorb ultraviolet light at 253.7 nm. Evaluate and correct for UV absorption
contributed by specific interfering substances. If cumulative corrections exceed 10
percent of the total absorption, select an alternate wavelength and/or use another
method. Because UV absorption by organic matter may vary at pH values below 4
or above 10 standard units, avoid being in this range by using a buffer 1. Typical
absorption scans of NOM are smooth curves of increasing absorption with
decreasing wavelength, with the highest values near 254 nm. As wavelengths
decrease near 190 nm, water molecules begin absorbing UV. Sharp peaks or
irregularities in the absorption scan may be indicative of inorganic interferences or
unexpected organic contaminants. Because many organic compounds in water and
wastewater (e.g., carboxylic acids and carbohydrates) do not absorb significantly in
the UV wavelengths, UV absorption may be correlated with DOC or soluble
chemical oxygen demand (COD). However, use such correlations with care because
they may vary between facilities and seasonally on the same water, as well as
between raw and treated waters. In addition, chemical oxidation (e.g., ozonation,
chlorination) of the organic material may reduce UV absorption without removing
the organic carbon and thus may change correlations. Because UV absorption and
correlations with UV absorption are site-specific, they may not be comparable from
one water source to another.
It is important to perform regular maintenance of the lamps following the
manufacturer's recommendation.
Spectrophotometer and basic laboratory equipment, www.hach.com
Several labs perform this analysis
1. APHA, AWWA, and WEF (American Public Health Association, the American
Water Works Association, and the Water Pollution Control Federation). 1999.
Standard Methods for the Examination of Water and Wastewater, 20th Edition.
Washington, D.C.: APHA.
2. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich, and
P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
68 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Organic Carbon
UV/VIS spectroscopy
Online UV/VIS spectroscopy
Criterion
Usefulness
Data Quality
Implementability
Cost
Metrics for evaluation
Rating
3
Correlations to treatment
objectives
4
Ability to control
2
Response/turnaround time
Precision
5
3
Accuracy
4
Span
Representativeness
Selectivity/specificity
4
2
2
Technology maturity
3
Training requirements
3
Ease of use
Data acquisition
requirements
3
3
Applicability to small
utilities
Capital
3
3
Explanation
UV spectra were used to identify turbidity,
TOC, DOC and nitrate concentrations at
one facility. DOC correlated strongly with
grab samples (R2 = 0.75, n=10)2. Other
analytes were inconclusive.
Can be used for measuring turbidity, TOC,
DOC, and nitrate. Demonstrated
correlation to AOC in one study 3.
Potentially high for AOC, especially with
pre-oxidation.
Online instrument.
Variable depending on analyte and
facility. Relative percent difference
between laboratory and grab samples for
DOC was on average 10.5 percent
(n=10) 2.
Variable depending on analyte and
facility.
Variable depending on analyte.
Indirect measure with strong correlations.
Demonstrated correlation to AOC in one
study but may not be broadly applicable.
Method well developed and used by some
utilities.
Online equipment with some operations
and maintenance (O&M) requirements.
Online equipment with reliable data.
Online equipment, data analysis can be
cumbersome depending on water quality
and data acquisition frequency.
Applicable but may be too costly.
Online spectrophotometer ($20,000 $25,000).
Low O&M.
Operating and
4
maintenance
Recommendations
Data may be assembled to estimate a variety of constituents (TOC, DOC, nitrite,
nitrate, ammonia, turbidity, etc.).This instrument is not well established, though
some benchmark data at two full-scale utilities are available for comparison2.
Additional data are required to validate findings.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 69
Organic Carbon
UV/VIS spectroscopy
Online UV/VIS spectroscopy (Continued)
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
Online UV spectra may be used as a surrogate to estimate concentrations of
turbidity, TOC, DOC, nitrite, nitrate, ammonia, and turbidity. Preliminary
findings indicate that UV spectra may also correlate with AOC, carboxylic acids,
aromatics, phenolics, hydrocarbons, most chromophores, and disinfection
byproducts3,4. UV/VIS spectra are measured over a wavelength range of 200-800
nanometers (nm). These online probes are optical devices that measure light
adsorption in the UV/Visible range using a lamp that passes through a path
length of up to 10 centimeters and photodiode array. The absorbance at each
wavelength is used to create a fingerprint and linear combinations of absorbance
at are used to determine concentrations of various constituents.
UV/VIS spectra can be directly related to TOC, DOC, turbidity, nitrate, nitrite,
and ammonia.
0.0-2 abs/cm2
The primary interferences in UV-absorption measurements are from colloidal
particles, UV-absorbing organic carbon other than those of interest, and UVabsorbing inorganic carbon, notably ferrous iron, and bromide. Certain oxidants
such as ozone, chlorate, chlorite, and chloramines, as well as reducing agents
such as thiosulfate, will absorb ultraviolet light. Many natural waters and waters
processed in drinking water treatment plants have been shown to be free of these
interferences.
UV absorption by organic matter may vary at pH values below 4 or above 101.
Analysis of the UV spectra from 200 to 400 nm can indicate the presence of
interferences. Typical absorption scans of NOM are smooth curves of increasing
absorption with decreasing wavelength, with the highest values near 254 nm.
Sharp peaks or irregularities in the absorption scan may be indicative of
inorganic interferences or unexpected organic contaminants.
Preliminary research has shown several organic compounds in water and
wastewater (e.g., carboxylic acids and carbohydrates) may correlate with UV
spectra, but additional studies are warranted to validate findings. UV absorption
should be correlated to DOC or soluble COD. However, use such correlations
with care because they may vary between facilities and seasonally on the same
water, as well as between raw and treated waters. In addition, chemical oxidation
(e.g., ozonation, chlorination) of NOM may reduce UV absorption without
removing the organic carbon and thus may change correlations.
Use of standard correlations to water quality parameters can lead to erroneous
results due to the high variability in water quality between facilities. Therefore, a
site-specific calibration to establish the correlation between UV absorption and
the analytes of interest is recommended.
Online spectrophotometer requires routine automatic calibration at wavelengths
of interest as well as operational/maintenance activities, as recommended by the
manufacturer. Primary maintenance activities include cleaning the sensor
window with 3 percent hydrochloric acid. The instrument needs to be aligned
property when installed and physical obstruction of the sensor window will
interfere with readings. Monthly maintenance is typically required. Data analysis
can be complex depending on data acquisition frequency and water quality.
s::can spectro::lyser™, s::can Measuring Systems, LLC, www.s-can.us
ChemScan® UV process analyzers, Applied Spectrometry Associates, Inc.,
www.chemscan.com
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
70 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Organic Carbon
UV/VIS spectroscopy
Online UV/VIS spectroscopy (Continued)
References:
1.
2.
3.
4.
APHA, AWWA, and WEF (American Public Health Association, the
American Water Works Association, and the Water Pollution Control
Federation). 1999. Standard Methods for the Examination of Water and
Wastewater, 20th Edition. Washington, D.C.: APHA.
Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
van den Broeke, J., P. S. Ross, A. W. C. van der Helm, E. T. Baars, and L.
C. Rietveld. 2008. Use of Online UV/Vis-spectrometry in the Measurement
of Dissolved Ozone and AOC concentrations in Drinking Water Treatment.
Water Science and Technology. 57(8): 1169 - 1175.
Cochram, J. and P. Barron. 2011. Evaluating an In-Process Multiple
Wavelength UV Spectrolyzer’s Capability to Monitor TTHM’s and HAAs.
In Proc. of the Thirty-Ninth Annual AWWA Water Quality Technology
Conference. Denver, Colo.: AWWA.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
71 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Water Quality
Turbidity
Online turbidimeter, SM 2130
Criterion
Usefulness
Data Quality
Implementability
Cost
Recommendations
Metrics for evaluation
Rating
5
Correlations to treatment
objectives
Ability to control
5
Response/turnaround time
Precision
5
5
Accuracy
Span
Representativeness
Selectivity/specificity
Technology maturity
Training requirements
Ease of use
Data acquisition
requirements
Applicability to small
utilities
Capital
Operating and maintenance
5
5
5
5
5
5
5
5
4
Explanation
Ranges in values at 14 full-scale utilities
were between 0.01 and 1.50
nephelometric turbidity units (NTU)2.
Filter effluent turbidity is a regulatory
requirement.
May be controllable through upstream
treatment process modifications.
Online.
Well established method with
reproducible results; varies depending on
instrument.
Typically 2 percent of reading.
Typically 0.001 to 100 NTU.
Direct measure.
Direct measure.
Standard method.
Minimal training.
Easy analysis.
Online.
5
Equipment already required. Easy to
apply to biofiltration monitoring.
4
Turbidimeter with controller ($2,500)
4
Low cost for maintenance and
calibration.
This is a standard analyte that facilities are required to monitor and could easily be
incorporated into a monitoring plan for biological filtration.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Method Description:
The intensity of light scattered by the sample due to the presence of suspended
materials is compared to light scattered from a standard solution. The higher the
intensity of scattered light, the higher the turbidity2.
Treatment Objectives:
Changes in turbidity can be an indicator of causes for low filter run times and
volumes. Keeping influent turbidity at low constant values lowers the risk of poor
filter performance due to expedited clogging.
Typical Range:
0-2 NTU2
Interferences:
Highly colored samples
Implementation
Online turbidimeters are generally calibrated prior to shipment. The instrument
Requirements:
must be recalibrated before use to meet published accuracy specifications. In
addition, recalibration is recommended after any significant maintenance or repair
and at least once every three months during normal operation. The turbidimeter
body and bubble trap must be thoroughly cleaned and rinsed before initial use and
prior to each calibration.
Procurement:
Multiple vendors are available for online low-level turbidimeters.
(continued)
71
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
72 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
References:
1.
2.
Water Quality
Turbidity
Online turbidimeter, SM 2130
APHA, AWWA, and WEF (American Public Health Association, the
American Water Works Association, and the Water Pollution Control
Federation). 1999. Standard Methods for the Examination of Water and
Wastewater, 20th Edition. Washington, D.C.: APHA.
Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 73
Water Quality
Temperature
Online temperature probe, SM 2250
Criterion
Usefulness
Metrics for evaluation
Data Quality
Rating
3
Correlations to treatment
objectives
5
Ability to control
Response/turnaround time
Precision
1
5
5
Explanation
Ranges in values at 14 full-scale utilities
were between 8 and 32 ˚C2.
Full-scale data demonstrate effect of
temperature on performance, particularly
at low temperatures below 50 ˚C2,3.
Not a practical parameter to control.
Online.
Well established method with
reproducible results.
Assessment method well developed.
Covers full range of temperatures.
Direct measure.
No interference.
Standard method/well established.
Minimal training.
Online equipment.
Online data.
Accuracy
5
Span
5
Representativeness
5
Selectivity/specificity
5
Technology maturity
5
Training requirements
5
Ease of use
5
Data acquisition
5
requirements
Applicability to small
5
Most utilities already have equipment in
utilities
place.
Capital
4
Temperature probe ($1,500)
Operating and maintenance
5
Minimal maintenance.
This is a standard analyte that most facilities monitor and could easily be
incorporated into a monitoring plan for BF.
Implementability
Cost
Recommendations
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
4 = favorable/low cost
5 = very favorable/very low cost
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
3 = average
Temperature can affect the rate of chemical and biological reactions. A
thermocouple is used to measure temperature and a signal is transmitted to the
SCADA system.
Temperature is directly linked to biological activity and performance and can be
used to dictate when biological filter performance may change.
5-20 ˚C2
None
Online temperature transmitter contains automatic internal calibration.
Temperature transmitter, multiple vendors are available.
1. APHA, AWWA, and WEF (American Public Health Association, the
American Water Works Association, and the Water Pollution Control
Federation). 1999. Standard Methods for the Examination of Water and
Wastewater, 20th Edition. Washington, D.C.: APHA.
2. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
3. Moll, D., R. Summers, A. Fonesca, and W. Matheis. 1999. Impact of
Temperature on Drinking Water Biofilter Performance and Microbial
Community Structure. Environmental Science & Technology. 33(14): 23772382.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
74 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Water Quality
Nutrients (e.g., orthophosphate)
EPA Method 300, or equivalent
Criterion
Usefulness
Explanation
Ranges in influent total phosphate
values at 14 full-scale utilities were
between 0 and 5.8 mg/L2.
Correlations to treatment
4
Can impact biological activity if
objectives
concentrations are below sustainable
growth requirements.
Ability to control
5
Chemical addition to meet nutrient
requirements is possible.
Response/turnaround time
3
Analysis time requires several hours for
EPA Method 300 and minutes for field
test kits.
Data Quality
Precision
5
Well established methods with
reproducible results, varies depending
on method.
Accuracy
5
Assessment methods well developed,
varies depending on method.
Span
5
Low detection limits are possible; range
of 0.05 to 20 mg/L depending on
method.
Representativeness
5
Direct measure.
Selectivity/specificity
5
Low probability of interference, but
varies depending on method.
Implementability
Technology maturity
5
Standard method in drinking water
industry. Recent development for BF
application3.
Training requirements
3
May require specialized training for lab
staff if EPA Method 300 is used.
Ease of use
3
If field test kits are not used, an outside
laboratory may be more attainable than
purchasing an IC.
Data acquisition requirements
3
Requires sampling.
Applicability to small utilities
3
Field test kits are more applicable than
EPA Method 300.
Cost
Capital
2
EPA Method 300 requires purchase of
IC ($15,000 - $20,000) other equivalent
methods may require purchase of
spectrophotometer ($8,000).
Operating and maintenance
3
Low cost disposables. $15-$25 for
outside laboratory analysis or
approximately $1 to $2 per sample for
field test kits.
Recommendations
Nutrients, especially orthophosphate, can be limiting for bacterial growth because
they are often removed during the coagulation/sedimentation process. They can
promote contaminant removal and improve hydraulic performance. Nutrient
addition should be tailored to fit facility-specific water quality requirements.
Typical ratios are 1:10:100 of C:N:P3.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Metrics for evaluation
Rating
5
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 75
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
Water Quality
Nutrients (e.g., orthophosphate)
EPA Method 300, or equivalent
(Continued)
A water sample is introduced into an IC and anions are separated and analyzed
using a guard column, analytical column, suppressor device, and conductivity
detector.
Nutrient concentrations can provide insight into biological community health.
0-5 mg/L2
Method interferences may be caused by contaminants in the reagent water,
reagents, glassware, and other sample processing equipment that lead to discrete
artifacts or elevated baselines in an IC. These interferences can lead to false
positive results for target analytes as well as reduced detection limits.
For field grab sampling, a 100 mL plastic bottle is required. The sample should be
held at 4˚C prior to analysis.
For EPA Method 300, samples must be filtered through a 0.45-μm filter prior to
introduction to the IC to prevent damage to the instrument column and flow
systems. ACS grade reagents and deionized water are required.
Orthophosphate concentrations should be measured as this is the faction that is
bioavailable.
IC, spectrophotometer, or use of outside laboratory. Several vendors are available
for these instruments; several field test kits are available and many outside labs
perform this analysis.
1. Pfaff, J. D. 1993. Method 300.0 Determination of inorganic anions by IC
Revision 2.1 Environmental Monitoring Systems Laboratory, Office of
Research and Development, Environmental Protection Agency.
2. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
3. Lauderdale, C.V., J.C. Brown, P.A. Chadik, and M.J. Kirisits. 2011.
Engineered Biofiltration for Enhanced Hydraulic and Water Treatment
Performance. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
76 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Water Quality
pH
Online pH probe
Criterion
Usefulness
Data Quality
Implementability
Cost
Recommendations
Explanation
Ranges in values at 14 full-scale
utilities were between 5 and 11
standard units2.
Correlations to treatment
2
No direct correlation to treatment
objectives
objectives but can affect biological
activity.
Ability to control
5
Highly controllable.
Response/turnaround time
4
Analysis possible within minutes
Precision
5
Well established method with
reproducible results.
Accuracy
5
+/- 0.1 pH unit
Span
5
0-14 standard units.
Representativeness
5
Direct measure.
Selectivity/specificity
5
Direct measure.
Technology maturity
5
Standard method.
Training requirements
5
Minimal training required.
Ease of use
5
Easy to use.
Data acquisition requirements
5
Online
Applicability to small utilities
5
Required at all utilities.
Capital
4
Approximately $300-$400 for pH
sensor, $1,000 for a controller.
Operating and maintenance
4
Cleaning and calibration required as
frequently as monthly depending on
water quality characteristics. The first
calibration should be during
instrument set up.
This is a standard analyte that most facilities are required to monitor and could
easily be incorporated into a monitoring plan for BF.
Metrics for evaluation
Rating
5
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
4 = favorable/low cost
5 = very favorable/very low cost
3 = average
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
(continued)
Summary Tables | 77
Method Description:
Treatment Objectives:
Water Quality
pH
Online pH probe (Continued)
Water pH should be within a biologically relevant range, otherwise biological
activity and the rate of biological reactions will be compromised (e.g. 6 to 9
standard units). This method includes use of a pH electrode that measures the
activity of hydrogen ions in solution.
pH is used to assess if conditions are conducive to biological activity.
Typical Range:
Interferences:
6 to 9 standard units2
Electrical interference is potentially the most significant source of interferences in
an online pH monitoring system. The most important characteristic of the pH
electrode is its very high impedance, of the order of 109 ohms. This is compounded
by background electrical noise and by long distances between the electrode and the
controller. A typical pH measuring device would be normally configured to operate
in the single ended mode, also known as the asymmetrical mode. This
configuration works very well as long as the environment is electronically noisefree.
Implementation
Requirements:
Procurement:
Online pH probes should be calibrated prior to being placed online. Only one probe
is needed either on the filter influent or effluent as values do not typically
significantly change between the two locations.
One pH sensor, one controller; multiple vendors provide pH probes.
References:
1.
2.
APHA, AWWA, and WEF (American Public Health Association, the
American Water Works Association, and the Water Pollution Control
Federation). 1999. Standard Methods for the Examination of Water and
Wastewater, 20th Edition. Washington, D.C.: APHA.
Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
78 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Water Quality
Disinfection byproduct formation potential
SM 5710, 6232B, 6232C, or 6200
Criterion
Usefulness
Explanation
Best used for monitoring trends over time as
more research and data are needed for further
evaluation.
Correlations to treatment
5
Directly relates to treatment objectives for
objectives
monitoring disinfection byproduct formation in
the distribution system.
Ability to control
3
Potential to control with reduction of AOC
and/or DOC.
Response/turnaround time
3
2-3 weeks for outside labs
Data Quality
Precision
5
Standard method with reproducible results.
Accuracy
5
Standard method with reproducible results.
Span
5
Sub µg/L to mg/L range.
Representativeness
4
Indirect measure.
Selectivity/specificity
3
Highly specific analysis.
Implementability
Technology maturity
5
Typically used in research studies and nonstandard due to high cost and complexity in
instrumentation required to perform analysis.
Training requirements
2
Requires intensive and specialized laboratory
training.
Ease of use
2
Sample collection is easy but analysis may be
technically challenging.
Data acquisition
1
Requires technical understanding of the method
requirements
and interferences if performed in-house.
Reproducibility is very important since the
method is an indirect measure.
Applicability to small
1
Likely to be too expensive for small utilities to
utilities
perform in-house analysis
Cost
Capital
1
Purchase of gas chromatograph and analytical
instrumentation if performed in-house.
Operating and
3
Frequent preventive maintenance needed for
maintenance
instrumentation. Instruments range from $10,000
to >$100,000. Outside laboratory analysis costs
between $150-$250 per sample
Recommendations
Formation of THMs, haloacetic acids (HAAs) and other brominated or chlorinated
compounds is largely inevitable during the disinfection process. However, since some of
the disinfection byproducts are suspected carcinogens, water utilities must maintain the
effectiveness of the disinfection process while minimizing the formation of such
compounds. Because performing the analysis of these compounds in-house is likely
cost-prohibitive to most utilities, sample collection for outside lab analysis is the most
practical approach to adequate monitoring. BF has been shown to reduce disinfection
byproduct precursors, and this method can be used to assess filter performance.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Metrics for evaluation
Rating
2
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 79
Water Quality
Disinfection byproduct formation potential
SM 6232B, 6232C, or 6200 (Continued)
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
Formation of disinfection byproducts (DBPs) such as THMs and HAAs result from
the reaction of chlorine with organic carbon. Total THMFP is determined as the
difference between the final THM and the initial THM after dosing with a
disinfectant. Disinfectant demand testing is performed after 7 days of incubation at
room temperature. The simulated distribution system (SDS) method can serve as an
indication of the formation potential for site-specific conditions based on water
quality characteristics of the treatment plant’s distribution system such as
temperature, pH, disinfectant dose and residual, bromide ion concentration, and
reaction time. Concentrations may be elucidated by using liquid-liquid or purge-andtrap extraction using SM 6232B or 6200, respectively.
Elevated concentrations of THMs may cause potential health hazards. Such
compounds may be monitored and controlled by reduction or removal of reactive
organic carbon.
Part per million or µg/L range
Water samples should be collected with minimal disturbances to avoid loss of volatile
DBP-precursors. Glassware should be heated to 400 oC for 1 hour to remove any
residual organized adsorbed on the glassware. Temperature, reaction time, chlorine
dose and residual, and pH need to be controlled. Water exposed to free chlorine prior
to analysis may have some precursors converted to DBPs. Volatile organic
compounds and substances that have oxidant demand may cause peak co-elution
during analysis.
The sample should be collected in a 1 L amber glass bottle with Teflon-lined screw
caps and stored at 4 ˚C until analysis. Holding time requirement is 7 days.
Liquid and/or gas chromatograph and complex analytical instrumentations.
1. APHA, AWWA, and WEF (American Public Health Association, the American
Water Works Association, and the Water Pollution Control Federation). 1999.
Standard Methods for the Examination of Water and Wastewater, 20th Edition.
Washington, D.C.: APHA.
2. United States Geological Survey. 2007. Studies on Disinfection By-Products and
Drinking Water. Fact sheet 2004-3032.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
80 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Operational
Head loss/filter run time
Online pressure transducer or level sensor and SCADA system
Criterion
Usefulness
Data Quality
Implementability
Metrics for evaluation
Correlations to treatment
objectives
Ability to control
Response/turnaround time
Precision
Accuracy
Span
Representativeness
Selectivity/specificity
Technology maturity
Training requirements
Rating
4
4
5
5
5
5
5
5
5
5
5
Explanation
Ranges in values at 14 full-scale utilities
were between 0.2 and 6.8 feet1.
Head loss is a direct result of filter
performance.
Controlled by backwashing.
Immediate (online).
Standard practice.
Standard practice.
0-10 feet.
Standard practice.
Standard practice.
Standard practice.
Minimal training.
Ease of use
5
Standard practice.
Data acquisition
5
Online.
requirements
Applicability to small
5
Most facilities already monitor this.
utilities
Cost
Capital
5
Equipment in place.
Operating and maintenance
5
Low O&M.
Recommendations
Head loss can be an important indicator of filter fouling or clogging. This may be
associated with physical removal of particulates but may also be an indicator of
excessive biofilm formation. Filter run time is generally associated with head loss as
backwashing can be triggered by head loss exceeding a set point. Both variables can
be used to monitor the impact of biological growth on hydraulic performance.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Method Description:
Procurement:
This method includes use of a pressure transducer that measures the change in
pressure from the filter influent to the filter effluent.
Changes in pressure from the filter influent to the effluent over time can signal
excessive biofilm formation of EPS.
0-12 feet1, depends on filter height and pressure.
Electrical interferences are probably the most significant.
It may be necessary to have an uninterruptible power supply or surge protection
device installed in-place to prevent damage to and loss of data from the online
pressure transducers or level sensors when there is a significant voltage change.
Online pressure transducer or level sensor.
References:
1.
Treatment
Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich, and
P. K. Jjemba. 2013. A Monitoring and Control Toolbox for Biological Filtration.
Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 81
Operational
Oxidant residual
Chlorine (SM 4500-Cl G), permanganate (SM 4500-KMnO4), ozone (SM 4500-O3), chlorine
dioxide (SM 4500-ClO2), or equivalent
Criterion
Usefulness
Metrics for evaluation
4
Data Quality
Correlations to treatment
objectives
Ability to control
Response/turnaround
time
Precision
Accuracy
5
Span
Representativeness
Selectivity/specificity
5
5
5
Technology maturity
Training requirements
5
5
Highly controllable.
Analysis possible within minutes; samples
should be analyzed right after collection.
Well established method with reproducible
results.
Well established method with reproducible
results.
Depends on oxidant being measured.
Direct measure.
Interference from iodine and turbidity
possible.
Standard method.
Minimal training.
Ease of use
Data acquisition
requirements
Applicability to small
utilities
Capital
Operating and
maintenance
5
3
Easy to use.
Requires sampling.
5
Sampling with standard equipment.
Implementability
Cost
Rating
5
5
4
5
Explanation
Ranges in values at 14 full-scale utilities
were between 0 and 0.8 mg/L at filter
influent2.
Affects filter performance.
4
4
Spectrophotometer ($3,500).
For samples measured in-house there are
low disposables. Field test kits that are
equivalent to the Standard Method may
also be used at a cost of $1 to $2/sample.
$50 per sample for outside laboratory
analysis.
Recommendations
This is a standard analyte that most facilities are required to monitor and could
easily be incorporated into a monitoring plan for BF. While the degree of preoxidation can enhance the fraction of biodegradable organic carbon present, the
presence of oxidant residuals on the filter influent can reduce biological activity.
Oxidants may act synergistically to provide more biodegradable carbon to
enhance removal on biological filters.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
(continued)
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
82 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Operational
Oxidant residual
Chlorine (SM 4500-Cl G), permanganate (SM 4500-KMnO4), ozone (SM 4500-O3), chlorine
dioxide (SM 4500-ClO2), or equivalent (Continued)
Method Description:
Treatment Objectives:
Typical Range:
Interferences:
Implementation
Requirements:
Procurement:
References:
Oxidant residual may be measured using a variety of standard methods; a few
common oxidants are presented as follows. Chlorine residual may be measured
using the DPD colorimetric method reacts N,N-diethyl-p-phenylenediamine
(DPD) with the sample. Free chlorine reacts with the DPD indicator, producing a
red color. Total chlorine can be measured using iodide with the DPD indicator.
For total chlorine, combined chlorine oxidizes the iodine to iodide, which then
reacts with the DPD indicator and turns pink; at the same time, free chlorine
reacts with the DPD indicator and turns the solution pink. The degree of pink
coloration is proportional to the concentration of chlorine present in the sample. A
spectrophotometer can quantify concentrations at a wavelength of 515 or 530 nm.
Permanganate may be measured using a spectrophotometric method at 525 nm.
The Cairox test kit uses a modified DPD spectrophotometric method for low
concentrations typical in drinking water.
Ozone is measured colorometrically using an indigo reagent. Indigo is rapidly
oxidized by ozone in an acidic solution and the absorbance at 600 nm is linear
with concentration of ozone.
Chlorine dioxide is measured using the DPD method at 530 nm to one-fifth of the
extent of its chlorine content. It may also be measured using iodometric titration.
Oxidant residual can be used to control the growth of biofilm which may cause
performance issues if allowed to grow too thick. However research has shown
extensive use of chlorine does not result in less EPS.
0-0.5 mg/L2
The most significant interfering substance likely to be encountered in water is
oxidized manganese. The method to compensate for this is listed in SM 4500-Cl.
Chromate in excess of 2 mg/L interferes with end-point determination. Add
barium chloride to mask this interference by precipitation. High concentrations of
combined chlorine can break through into the free chlorine fraction. If free
chlorine is measured in the presence of more than 0.5 mg/L combined chlorine,
use the thioacetamide modification. If this modification is not used, a colordevelopment time in excess of 1 min leads to progressively greater interference
from monochloramine. Adding thioacetamide (0.5 mL 0.25 percent solution to
100 mL) immediately after mixing DPD reagent with sample stops further
reaction with combined chlorine in the free chlorine measurement. Continue
immediately with FAS titration to obtain free chlorine. Obtain total chlorine from
the normal procedure, i.e., without thioacetamide. Because high concentrations of
iodide are used to measure combined chlorine and only traces of iodide greatly
increase chloramine interference in free chlorine measurements, take care to avoid
iodide contamination by rinsing between samples or using separate glassware 1.
The sample should be collected in a 500 mL poly bottle and stored at 4˚C.
Holding time requirement is as soon as possible, but no longer than 48 hours.
Several vendors are available for test kits (Hach, Chemetrics) and for
spectrophotometers.
There are many laboratories that perform this analysis.
1. APHA, AWWA, and WEF (American Public Health Association, the
American Water Works Association, and the Water Pollution Control
Federation). 1999. Standard Methods for the Examination of Water and
Wastewater, 20th Edition. Washington, D.C.: APHA.
2. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2012. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 83
Operational
Oxidant demand
SM 2350
Criterion
Usefulness
Data Quality
Implementability
Cost
Metrics for evaluation
Correlations to treatment
objectives
Ability to control
Response/turnaround
time
Precision
Rating
2
2
Explanation
Few utilities measure this parameter.
Important for optimization of oxidant dose.
2
2
Difficult to control.
Analysis requires several steps.
5
Accuracy
5
Span
Representativeness
Selectivity/specificity
5
5
5
Technology maturity
Training requirements
5
3
Ease of use
Data acquisition
requirements
Applicability to small
utilities
Capital
3
3
Well established method with reproducible
results.
Well established method with reproducible
results.
Depends on oxidant being measured.
Direct measure.
Interference from iodine and turbidity
possible.
Standard method.
Analysis may be complex if ozone demand
is being measured.
Easy to use.
Requires sampling.
3
Sampling with standard equipment.
4
Spectrophotometer may be needed
($3,500).
Operating and
4
For samples measured in-house there are
maintenance
low disposables. Field test kits that are
equivalent to the Standard Method may
also be used at a cost of $1 to $2/sample.
Recommendations
Pre-oxidants are primarily used for disinfection and oxidation of NOM, iron and
manganese, taste and odors compounds, and color. Oxidant demand is the dose
needed to oxidize organic compounds in solution. Oxidant residual is measured in
the sample after all of the demand has been satisfied. This parameter is of interest
during start-up and optimization.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Method Description:
To conduct the test, subsamples are dosed with varying concentrations of a
standard oxidant solution (e.g. chlorine, ozone, permanganate). Oxidant residual,
pH, and temperature are measured after a specified reaction time. Typical reaction
times are 5 minutes, 1 hour, and 24 hours. The demand at these contact times can
provide information on the characteristics of organic carbon present and oxidant
kinetics. At the end of the test, if all the demand has been satisfied, then an oxidant
residual will be present. Oxidants may be measured using standard methods and
field test kits noted in the oxidant residual section.
Treatment
Oxidant demand provides information on the concentration of oxidant needed for
Objectives:
reduction of NOM for control DBP formation, regrowth, taste and odor, and loss of
disinfectant in the distribution system.
Typical Range:
Varies depending on oxidant.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
84 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Control
Oxidant dose
SCADA system; ozone and pre-oxidant control system
Criterion
Usefulness
Ability to control
Correlation to treatment
objectives
Sensitivity of process to
parameter
Established metrics for design
General applicability to all
processes
Applicability to existing
biological filters
Rating
5
5
Explanation
Can be manually or remotely
controlled by a SCADA system.
Has effect on filter performance.
4
Can be specific to the source water.
5
5
Common process used in many plants.
Used to reduce NOM.
3
Requires installation of a chemical
dosing system if one is not already in
place.
Implementability
Technology maturity
5
Standard practice.
Regulatory acceptance
5
Standard practice.
Requirement for major
3
Requires installation of a chemical
modifications
dosing system if one is not already in
place.
SCADA requirements
4
Requires interlock of dosing rate to
plant flow.
Applicability to small utilities
3
Applicable if chemical dosing system
is in place. Capital may be too high for
small utilities that don't have a
chemical dosing system in place.
Cost
Capital
2
Requires purchase and installation of
pumps, storage tanks, piping, and
appurtenances.
Operating and maintenance
3
Chemical supply, equipment
maintenance.
Recommendations
This is a widely accepted control strategy for oxidation of NOM and directly
influences filter performance. Pre-oxidant dose is incorporated into the monitoring
program for most utilities that use pre-oxidants in their process. Moderate to high
capital costs would be required to add this process if it does not already exist.
Additional data are needed to evaluate the sensitivity of dose changes to filter
performance.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Method Description:
Pre-oxidants are primarily used for disinfection and oxidation of NOM, iron and
manganese, taste and odors compounds, and color. Pre-oxidants increase the
biodegradability of NOM and in turn reduce DBP formation and stability issues in
the distribution system if followed by BF. The ratio of oxidant to TOC can be used
as a control parameter to assess impact on other BF monitoring parameters
including AOC, carboxylic acids, and BDOC. Dose can be optimized to maximize
water quality and minimize cost.
Treatment
Oxidant dose is used to reduce NOM in order to control DBP formation, regrowth,
Objectives:
taste and odor, and loss of disinfectant in the distribution system.
Typical Range:
Varies depending on oxidant.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 85
Control
Nutrient dose (e.g., orthophosphate)
SCADA system
Criterion
Usefulness
Implementability
Ability to control
Rating
5
Correlation to treatment
objectives
4
Sensitivity of process to
parameter
3
Established metrics for
design
3
General applicability to all
processes
3
Applicability to existing
biological filters
Technology maturity
Regulatory acceptance
Requirement for major
modifications
SCADA requirements
3
4
3
4
Explanation
Can be manually or remotely controlled by a
SCADA system.
Can impact biological activity if
concentrations are below sustainable growth
requirements1.
Additional data are needed to determine
sensitivity of filter performance to dose
changes.
Not a common process used in many plants
and requires standard design but has
potential for process enhancement.
Will be source water quality and process
specific. Encouraging data on effectiveness
is available but warrants further
investigation.
Requires installation of chemical dosing
system if one is not already in place.
Emerging technology.
Emerging technology.
Relatively simple modifications.
4
Requires interlock of dosing rate to plant
flow.
Applicability to small
5
Simple chemical dosing system is applicable
utilities
to small utilities.
Cost
Capital
2
Requires purchase and installation of pumps,
storage tanks, piping, and appurtenances.
Operating and maintenance
3
Chemical supply, equipment maintenance.
Recommendations
Nutrients, especially orthophosphate, can be limiting for bacterial growth because
they are often removed during the coagulation/sedimentation process. Nutrient
addition of a typical ratio (1:10:100 of C:N:P) can promote contaminant removal and
improve hydraulic performance
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Method Description: Nutrients, especially orthophosphate, can be limiting for bacterial growth because
they are often removed during the coagulation/sedimentation process. Addition of
nutrients can promote contaminant removal and improve hydraulic performance.
Treatment
Nutrients can be used to promote biological activity resulting in better contaminant
Objectives:
removal and better hydraulic performance.
Typical Range:
0.1-2 mg/L, depends on nutrient requirements1
References:
1. Lauderdale, C. V., J. C. Brown, P. A. Chadik, and M. J. Kirisits. 2011.
Engineered Biofiltration for Enhanced Hydraulic and Water Treatment
Performance. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
86 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
Control
Flow rate/contact time
SCADA system, control valve/flow meter/number of filters in service
Criterion
Usefulness
Implementability
Cost
Recommendations
Ability to control
Correlation to treatment
objectives
Sensitivity of process to
parameter
Established metrics for
design
General applicability to all
processes
Applicability to existing
biological filters
Technology maturity
Regulatory acceptance
Requirement for major
modifications
SCADA requirements
Rating
3
5
5
4
2
2
4
4
1
4
Explanation
Ability to control may be limited based on
plant capacity.
Increased contact time increases
contaminant removal.
Directly impacts process capacity and
effectiveness.
Quantitative relationships between NOM
removal and contact time are plant-specific.
Limited applicability because contact time
is established during design.
May only be practicable where excess/spare
filters are available to reach plant capacity.
Standard practice as part of design.
Standard practice as part of design.
Increasing contact time would require
additional filters.
Interlock of plant flow to number of filters
in operation.
Applicable to utilities with flow flexibility.
Applicability to small
2
utilities
Capital
1
Would require additional filters.
Operating and
4
Process complexity would only increase
maintenance
because of increased filters.
Contact time can affect biological filter performance and thus must be monitored. If
sufficient capacity is available then it may be used as a control parameter.
Key: 1 = very unfavorable/very high cost 2 = unfavorable/high cost
3 = average
4 = favorable/low cost
5 = very favorable/very low cost
Method Description:
Contact time affects NOM removal and is controlled by the total flow rate and the
number of filters in operation at any given time. The ability to control this
parameter is limited however due to water demand constraints.
Treatment Objectives:
Reducing the flow rate through the filter increases the contact time which may
allow microorganisms to degrade organic carbon more effectively.
Typical Range:
0.5-5.5 gallons per minute per square foot (gpm/ft2)1
References:
1. Evans, P. J., J. L. Smith, M. LeChevallier, O. D. Schneider, L. A. Weinrich,
and P. K. Jjemba. 2012. A Monitoring and Control Toolbox for Biological
Filtration. Denver, Colo.: Water Research Foundation.
©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 87
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©2013 Water Research Foundation. ALL RIGHTS RESERVED.
Summary Tables | 91
ABBREVIATIONS
AOC
ATP
assimilable organic carbon
adenosine triphosphate
BF
BDOC
BQV
BOM
biological filtration
biodegradable dissolved organic carbon
BactiQuant® Value
biodegradable organic matter
CDM Smith
CFU
COD
o
C
CDM Smith, Inc.
colony forming unit
chemical oxygen demand
degrees Celsius
DBP
DNA
DO
DOC
DPD
disinfection byproduct
deoxyribonucleic acid
dissolved oxygen
dissolved organic carbon
N,N-diethyl-p-pheylenediamine
EAWAG
EDC
ELISA
PS
Eidgenössische Anstalt für Wasserversorgung, Abwasserreinigung und
Gewässerschutz
endocrine disrupting compounds
Enzyme-linked immunosuppressant assay
Extracellular polymeric substances
Foundation
Water Research Foundation
GAC
GC-FID
gpm/ft2
g
granular activated carbon
gas chromatography with flame ionization detector
gallons per minute per square foot
gram
HAA
HPC
haloacetic acid
heterotrophic plate count
IC
INT
ion chromatographic
2-para (iodophenyl)-3(nitrophenyl)-5(phenyl) tetrazolium chloride
LDO
LED
luminescent dissolved oxygen
light-emitting diode
mg
mg/L
MIB
milligrams
milligrams per liter
methyl isoborneol
91
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92 | Biological Filtration Monitoring and Control Toolbox: Guidance Manual
MS
mass spectroscopy
nm
NOM
NTU
nanometers
natural organic matter
nephelometric turbidity units
O&M
ORP
operations and maintenance
oxidation-reduction potential
PAC
PCR
pg
PLFA
PPCP
ppm
Project Advisory Committee
polymerase chain reaction
picograms
phospholipid fatty acids
pharmaceutical and personal care products
parts per million
SCADA
SDS
SM
SOUR
SUVA
Supervisory control and data acquisition
simulated distribution system
Standard Method
specific oxygen uptake rate
specific ultraviolet absorbance
TAG
THMs
THMFP
TOC
TRFLP
Technical Advisory Group
trihalomethanes
trihalomethanes formation potential
total organic carbon
terminal restriction fragment length polymorphism
U.S.
US EPA
UV
UV/VIS
UV254
μg acetate-C/L
μm
μg/L
United States
United States Environmental Protection Agency
ultraviolet
Ultraviolet/visible
ultraviolet absorbance at 254 nanometers
micrograms of acetate carbon per liter
micrometer
micrograms per liter
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