Emerging Technologies

 for Wastewater Treatment and In-Plant

Wet Weather Management

EPA 832-R-06-006 FEBRUARY 2008
Emerging Technologies February 2008

6-16 Wastewater Treatment and In-Plant Wet Weather Management

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Emerging Technologies

for

Wastewater Treatment and 

In-Plant Wet Weather Management

Prepared for:

Office of Wastewater Management

U.S. Environmental Protection Agency

Washington, D.C.

EPA 832-R-06-006

Under Contract

68-C-02-111

Prepared by:

Parsons Corporation

Fairfax, Virginia

February 2008
Emerging Technologies February 2008

ii Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies for Wastewater Treatment and In-Plant Wet Weather 

Management

EPA 832-R-06-006

February 2008

Produced under U.S. EPA Contract No. 68-C-02-111

Prepared by the Parsons Corporation

Fairfax, Virginia

Technical review was provided by professionals with experience in wastewater treatment. 

Technical reviewers of this document were:

Dr. Charles Bott, Assistant Professor, Virginia Military Institute (VMI)

Dr. Sudhir Murthy, Manager, Process Development, Washington, D.C. Water and Sewer 

Authority (WASA)

Dr. Krishna Pagilla, Professor, Illinois Institute of Technology (IIT)

Tyler Richards, Deputy Director of Operations and Environmental Services, 

Gwinnett County, GA

Tom Sadick, CH2M HILL

Terry Krause, CH2M HILL

Mark Bishop, Hazen and Sawyer

Recycled/Recyclable

Printed with vegetable-based ink on paper that contains a minimum of 50 percent postconsumer fiber content, chlorine free.

Electronic copies of this handbook can be downloaded from the

U.S. EPA Office of Wastewater Management web site at:

www.epa.gov/owm

Cover photo credit: Veolia Water North America 

Photo inserts credit: Parsons Corporation
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

iii

February 2008

Preface

The U.S. Environmental Protection Agency (U.S. EPA) is charged by Congress with 

protecting the nation’s land, air, and water resources. Under a mandate of environmental 

laws, the Agency strives to formulate and implement actions leading to a balance between 

human activities and the ability of natural systems to support and sustain life. To meet this 

mandate, the Office of Wastewater Management (OWM) provides information and 

technical support to solve environmental problems today and to build a knowledge base 

necessary to protect public health and the environment well into the future. 

This publication has been produced, under contract to the U.S. EPA, by the Parsons 

Corporation, and it provides current state of development as of the publication date. It is 

expected that this document will be revised periodically to reflect advances in this rapidly 

evolving area. Except as noted, information, interviews, and data development were 

conducted by the contractor. Some of the information, especially related to embryonic 

technologies, was provided by the manufacturer or vendor of the equipment or technology, 

and could not be verified or supported by full-scale case study. In some cases, cost data 

were based on estimated savings without actual field data. When evaluating technologies, 

estimated costs, and stated performance, efforts should be made to collect current and 

more up-to-date information.

The mention of trade names, specific vendors, or products does not represent an actual 

or presumed endorsement, preference, or acceptance by the U.S. EPA or Federal 

Government. Stated results, conclusions, usage, or practices do not necessarily represent 

the views or policies of the U.S. EPA.
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iv Wastewater Treatment and In-Plant Wet Weather Management

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Contents

Page

Preface .................................................................................................................................. iii

List of Acronyms and Abbreviations..................................................................................... viii

List of Technologies ...............................................................................................................xi

Overview.............................................................................................................................O-1

1. Introduction and Approach .......................................................................................... 1-1

1.1 Introduction .....................................................................................................................1-1

1.2 Approach.........................................................................................................................1-2

1.2.1 Information Collection and New Process Identification.....................................1-3

1.2.2 Initial Screened Technologies ...........................................................................1-3

1.2.3 Development of Technology Summary Sheets .................................................1-5

1.2.4 Evaluation of Technologies .............................................................................1-15

1.3 Guidance Document Format and Use...........................................................................1-17

1.4 Chapter References ......................................................................................................1-17

2. Physical/Chemical Treatment Processes.................................................................... 2-1

2.1 Introduction .....................................................................................................................2-1

2.2 Technology Assessment..................................................................................................2-1

3. Biological Treatment Processes.................................................................................. 3-1

3.1 Introduction .....................................................................................................................3-1

3.2 Technology Assessment..................................................................................................3-1

4. In-Plant Wet Weather Management Processes .......................................................... 4-1

4.1 Introduction .....................................................................................................................4-1

4.2 Technology Assessment..................................................................................................4-1

5. Process Monitoring Technologies ............................................................................... 5-1

5.1 Introduction .....................................................................................................................5-1
Emerging Technologies February 2008

vi Wastewater Treatment and In-Plant Wet Weather Management

Contents

Page

5.2 Technology Assessment..................................................................................................5-1

6. Research Needs.......................................................................................................... 6-1

6.1 Introduction .....................................................................................................................6-1

6.2 Research Needs .............................................................................................................6-1

6.2.1 Upgrading Old WWTPs.....................................................................................6-1

6.2.2 Removal of Nutrients and Other Contaminants ................................................6-2

6.2.3 Use of Smart Technologies ...............................................................................6-3

6.2.4 Security of Water Systems................................................................................6-3

6.2.5 Other Research Focus and Developments.......................................................6-4

6.2.6 Research Needs and Prioritization per 

Water Environment Research Foundation (WERF)..........................................6-4

6.3 Chapter References ........................................................................................................6-4

Appendix A Trade Associations........................................................................................A-1

A.1 Introduction .................................................................................................................... A-1

A.2 Trade Associations......................................................................................................... A-1
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February 2008

List of Tables

Page

Table 1.1 Summary of Treatment Technologies 

Chapter 2 – Physical/Chemical Treatment Processes.................................. 1-6

Table 1.2 Summary of Treatment Technologies 

Chapter 3 – Biological Treatment Processes................................................ 1-9

Table 1.3 Summary of Treatment Technologies 

Chapter 4 – In-Plant Wet Weather Management Processes ...................... 1-13

Table 1.4 Summary of Treatment Technologies 

Chapter 5 – Process Monitoring Technologies ........................................... 1-14

Table 1.5 Descriptive Evaluation Criteria.................................................................... 1-16

Table 2.1 Physical/Chemical Treatment Processes – State of Development............... 2-2

Table 3.1 Biological Treatment Processes – State of Development............................. 3-2

Table 4.1 In-Plant Wet Weather Management Processes – State of Development ..... 4-2

Table 5.1 Process Monitoring Technologies – State of Development........................... 5-2

List of Figures

Page

Figure 1.1 Flow Schematic for Guide Development....................................................... 1-2

Figure 2.1 Evaluation of Innovative Physical/Chemical Treatment Technologies .......... 2-3

Figure 3.1 Evaluation of Innovative Biological Treatment Technologies ........................ 3-4

Figure 4.1 Evaluation of Innovative In-Plant Wet Weather Management 

Technologies................................................................................................. 4-2

Figure 5.1 Evaluation of Innovative Process Monitoring Technologies.......................... 5-3

List of Exhibit

Page

Exhibit 6.1 Paper from WERF Workshop on Nutrient Removal...................................... 6-5
Emerging Technologies February 2008

viii Wastewater Treatment and In-Plant Wet Weather Management

A/O Anaerobic/Oxic (Phoredox)

A2/O Anaerobic/Anoxic/Oxic

AACE American Association of Cost Engineers International

ABW® Automatic Backwash Filters

AEBR Anaerobic Expanded Bed Reactor

AGAR® Attached Growth Airlift Reactor

AGRS Advanced Grit Removal System

AGSP Aerobic Granular Sludge Process

AIZ Air Intercept Zone

AMBR® Anaerobic Migrating Blanket Reactor

ANFLOW Anaerobic Fluidized Bed Reactor

AN-MBR Anaerobic Membrane BioReactor

AOP Advanced Oxidation Process

ASBR® Anaerobic Sequencing Batch Reactor

ASCE American Society of Civil Engineers

atm Atmosphere

AT3 Aeration Tank 3

AWTP Advanced Wastewater Treatment Plant

AWWA American Water Works Association

BABE Bio-Augmentation Batch Enhanced

BAF Biological Aerated Filters

BAR Bio Augmentation Regeneration and/or Reaeration

BCFS Biological-Chemical Phosphorus and Nitrogen Removal

BCDMH 1-Bromo-3 Chloro-5,5 DiMethylHydantoin

BHRC Ballasted High Rate Clarification

BioMEMS Biological Micro-Electro Machine System

BNR Biological Nutrient Removal

BOD Biological/Biochemical Oxygen Demand

BOD/N Biochemical Oxygen Demand Ratio to Nitrogen

BOD/P Biochemical Oxygen Demand Ratio to Phosphorus 

CASSTM Cyclic Activated Sludge System

CCASTM CounterCurrent Aeration System

CDS Continuous Deflection Separator

cfu Colony forming unit

CMAS Complete Mix-Activated Sludge

CMF® Compressed Media Filter (WWETCO CMF®)

CMOM Capacity, Management, Operations, and Maintenance

COD Chemical Oxygen Demand

CSO Combined Sewer Overflow

CSS Combined Sewer System

CWA Clean Water Act

DAF Dissolved Air Flotation 

DEMON DEamMONification

DEPHANOX DE-nitrification and PHosphate accumulation in ANOXic

DF Disc Filter 

DO Dissolved Oxygen

EBPR Enhanced Biological Phosphorus Removal

EDC Endocrine Disrupting Compound

List of Acronyms and Abbreviations 

Acronym/

Abbreviation Definition
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

ix

February 2008

ELISA Enzyme-Linked ImmunoSorbent Assay

EMS Environmental Management Systems

FBBR Fluidized Bed BioReactor

FISH Fluorescence In Situ Hybridization

GAC Granular-Activated Carbon

GPD Gallons per day

gpm/ft2 Gallons per minute per square foot

HANAA Handheld Advanced Nucleic Acid Analyzer

HFMBfR Hydrogen-based hollow-Fiber Membrane Biofilm Reactor

HFO Hydrous Ferric Oxide

HPO High-Purity Oxygen

HRC High-Rate Clarification

HRT Hydraulic Retention Time

ICAAS Immobilized Cell-Augmented Activated Sludge

ICEASTM Intermittent Cycle Extended Aeration System

IFAS Integrated Fixed-film Activated Sludge

IIT Illinois Institute of Technology

ISE Ion Selective Electrode

LOT Limit Of Technology

IWA International Water Association

MAB Multi-stage Activated Biological 

MABR Membrane-Activated BioReactor

MAUREEN Main-stream AUtotrophic Recycle Enabling Enhanced N-removal

MBR Membrane BioReactor

MBRT Mobile-Bed Reactor Technology

MFC Microbial Fuel Cell

MGD Million Gallons per Day

mg/L Milligram per Liter

MISS Moderate Isotope Separation System

MLE Modified Ludzack-Ettinger

MLSS Mixed Liquor Suspended Solids

mph Miles per hour

MSABPTM Multi-Stage Activated Biological Process

MUCT Modified University of Cape Town

NACWA National Association of Clean Water Agencies

NADH Nicotinamide Adenine Dinucleotide

NF NanoFiltration

NOB Nitrite Oxidizing Bacteria

ntu Nephelometric turbidity unit

O&M Operation and Maintenance

ORP Oxidation Reduction Potential

OWM Office of Wastewater Management (U.S. EPA)

PAC Powdered Activated Carbon

PAO Phosphorus Accumulating Organisms 

PBDE PolyBrominated Diphenyl Ether

PCR Polymerase Chain Reaction

PeCODTM Photo-electro Chemical Oxygen Demand

PhACs Pharmaceutically Active Compounds

List of Acronyms and Abbreviations (Contd)

Acronym/

Abbreviation Definition
Emerging Technologies February 2008

x Wastewater Treatment and In-Plant Wet Weather Management

POTW Publicly Owned Treatment Works

PPCP Pharmaceutical and Personal Care Products

ppm Parts per million

PVC Poly Vinyl Chloride

psig Pounds per square inch (gauge)

RAS Returned Activated Sludge

RBC Rotating Biological Contactor

R-DN Regeneration DeNitrification

rDON Refractory Dissolved Organic Nitrogen

SBR Sequencing Batch Reactor

SCFM Standard Cubic Feet per Minute

SHARON Single reactor High-activity Ammonia Removal Over Nitrite

SHARON – ANAMMOX Single reactor High-activity Ammonia Removal Over Nitrite – 

ANaerobic AMMonia OXidation

SNdN Simultaneous Nitrification deNitrification

SRBC Submerged Rotating Biological Contactor

SRT Sludge Retention Time; Solids Retention Time

SSO Sanitary Sewer Overflow

STRASS Similar to SHARON named after Strass, Austria

SVI Sludge Volume Index

TDH Total Dynamic Head

TDS Total Dissolved Solids

TF Trickling Filter

TF/PAS Trickling Filter and Pushed Activated Sludge

TF/SC Trickling Filter and Solid Contactor

TMP Trans Membrane Pressure

TOC Total Organic Carbon

TSS Total Suspended Solids

U.S. EPA United States Environmental Protection Agency

UASB Upflow Anaerobic Sludge Blanket

UCT University of Cape Town

UV UltraViolet

VIP Virginia Initiative Plant

VIS Visibility 

VMI Virginia Military Institute

VRM® Vacuum Rotation Membrane

WAS Waste Activated Sludge

WASA Water and Sewer Authority

WEF Water Environment Federation

WEFTEC Water Environment Federation’s Annual Technical Exhibition and Conference

WERF Water Environment Research Foundation

WPAP Water Pollution Abatement Program

WPCF Water Pollution Control Facility

WRF Water Reuse Facility

WWEMA Water and Wastewater Equipment Manufacturers Association

WWPF WasteWater Production Flow

WWTF WasteWater Treatment Facility

WWTP WasteWater Treatment Plant

List of Acronyms and Abbreviations (Contd)

Acronym/

Abbreviation Definition
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

xi

February 2008

Physical/Chemical Treatment Processes

Compressible Media Filtration............................................. Innovative.............................................................. 2-5

Nanofiltration ....................................................................... Innovative.............................................................. 2-7

Actiflo® Process ................................................................... Innovative Use of Established Technology ........... 2-9

DensaDeg® Process............................................................ Innovative Use of Established Technology ......... 2-11

Microwave UV Disinfection.................................................. Innovative Use of Established Technology ......... 2-13

Blue CATTM..........................................................................Embryonic........................................................... 2-15

Blue PROTM.........................................................................Embryonic........................................................... 2-17

CoMagTM .............................................................................Embryonic........................................................... 2-19

Solar Disinfection.................................................................Embryonic........................................................... 2-21

Biological Treatment Processes

Bioaugmentation.................................................................. Innovative.............................................................. 3-5

EXTERNAL BIOAUGMENTATION ..........................................Innovative .......................................................................3-5

Seeding from Commercial Sources of Nitrifiers.......................Innovative .......................................................................3-5

Tricking Filter and Pushed Activated Sludge (TF/PAS) 

Process....................................................................................Innovative .......................................................................3-5

Seeding from External Dispersed Growth Reactors

Treating Reject Waters (Chemostat Type)...............................Innovative .......................................................................3-6

In-Nitri® Process.......................................................................Innovative .......................................................................3-6

Immobilized Cell-Augmented Activated Sludge (ICASS)

Process....................................................................................Innovative .......................................................................3-7

Seeding from Parallel Processes.............................................Innovative .......................................................................3-8

Seeding from Downstream Process ........................................Innovative .......................................................................3-9

IN SITU BIOAUGMENTATION ................................................Innovative .......................................................................3-9

DE-nitrification and PHosphate accumulation in ANOXic

(DEPHANOX) Process ............................................................Innovative .......................................................................3-9

Bio-Augmentation Regeneration/Reaeration (BAR) Process ..Innovative .....................................................................3-10

Bio-Augmentation Batch Enhanced (BABE) Process..............Innovative ..................................................................... 3-11

Aeration Tank 3 (AT3) Process ................................................Innovative ..................................................................... 3-11

Main stream AUtotrophic Recycle Enabling

Enhanced N-removal (MAUREEN) Process............................Innovative ..................................................................... 3-11

Regeneration-DeNitrification (R-DN) .......................................Innovative .....................................................................3-12

Cannibal®............................................................................. Innovative............................................................ 3-15

CATABOLTM......................................................................... Innovative............................................................ 3-17

Deep Shaft Activated Sludge/VERTREATTM ...................... Innovative............................................................ 3-19

Integrated fixed-Film Activated Sludge (IFAS) 

Systems............................................................................... Innovative............................................................ 3-21

SUBMERGED MOBILE MEDIA IFAS......................................Innovative .....................................................................3-21

AGAR® (Attached Growth Airlift Reactor) ................................Innovative .....................................................................3-21

Captor® ...................................................................................Innovative .....................................................................3-21

List of Technologies

PROCESS TYPE PAGE
Emerging Technologies February 2008

xii Wastewater Treatment and In-Plant Wet Weather Management

Biological Treatment Processes (Contd)

LINPOR® .................................................................................Innovative .....................................................................3-21

SUBMERGED FIXED MEDIA IFAS.........................................Innovative .....................................................................3-21

CLEARTEC® ...........................................................................Innovative .....................................................................3-21

AccuWeb® ...............................................................................Innovative .....................................................................3-22

BioMatrixTM .............................................................................Innovative .....................................................................3-22

HYBASTM.................................................................................Innovative .....................................................................3-22

BioWebTM.................................................................................Innovative .....................................................................3-22

RINGLACE® ............................................................................Innovative .....................................................................3-22

Membrane BioReactor (MBR) ............................................. Innovative............................................................ 3-25

Mobile-Bed Reactor Technology (MBRT) Process .............. Innovative............................................................ 3-31

Bardenpho® (Three Stage) with Returned

Activated Sludge (RAS) Denitrification................................ Innovative Use of Established Technology ......... 3-33

Biological-Chemical Phosphorus and Nitrogen Removal

(BCFS) Process................................................................... Innovative Use of Established Technology ......... 3-35

Modified University of Cape Town (MUCT) Process ........... Innovative Use of Established Technology ......... 3-37

Modified Anaerobic/Oxic (A/O) Process .............................. Innovative Use of Established Technology ......... 3-39

Trickling Filter/Solids Contactor (TF/SC)............................. Innovative Use of Established Technology ......... 3-41

Aerobic Granular Sludge Process (AGSP) .........................Embryonic .......................................................... 3-43

ANaerobic Membrane BioReactor (AN-MBR) ....................Embryonic........................................................... 3-45

Anaerobic Migrating Blanket Reactor (AMBR®) ..................Embryonic........................................................... 3-47

DEamMONification (DEMON) .............................................Embryonic .......................................................... 3-49

Hydrogen-based hollow-Fiber Membrane Biofilm ..............Embryonic........................................................... 3-51

Reactor (HFMBfR)

Membrane-Aerated BioReactor (MABR).............................Embryonic........................................................... 3-53

Microbial Fuel Cell (MFC) Based Treatment System ..........Embryonic........................................................... 3-55

Multi-Stage Activated Biological Process (MSABPTM).........Embryonic........................................................... 3-57

NeradaTM .............................................................................Embryonic........................................................... 3-59

SHARON (Single reactor High-activity Ammonia

Removal Over Nitrate).........................................................Embryonic........................................................... 3-61

SHARON – ANAMMOX (ANaerobic

AMMonia Oxidation)............................................................Embryonic........................................................... 3-63

STRASS Process (Nitritation and Denitritation

in SBR) ...............................................................................Embryonic........................................................... 3-65

List of Technologies (Contd)

PROCESS TYPE PAGE
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Emerging Technologies

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February 2008

List of Technologies (Contd)

PROCESS TYPE PAGE

Vacuum Rotation Membrane (VRM®)..................................Embryonic........................................................... 3-67

In-Plant Wet Weather Management Processes

Continuous Deflection Separator (CDS).............................. Innovative.............................................................. 4-3

HYDROSELF® Flushing Gate.............................................. Innovative.............................................................. 4-5

Tipping Flusher® ................................................................. Innovative.............................................................. 4-7

TRASHMASTERTM Net Capture System ............................ Innovative.............................................................. 4-9

WWETCO Compressed Media Filtration® or

WWETCO CMF® System .................................................... Innovative............................................................ 4-11

Alternative Wet Weather Disinfection ..................................Embryonic........................................................... 4-15

Process Monitoring Technologies

Ammonia and Nitrate Probes .............................................. Innovative.............................................................. 5-5

ChemScan N-4000 ..................................................................Innovative .......................................................................5-5

Hach Evita In Situ 5100 ...........................................................Innovative .......................................................................5-5

Myratek Sentry C-2..................................................................Innovative .......................................................................5-5

Hach NITRATAX......................................................................Innovative .......................................................................5-5

NitraVis® System......................................................................Innovative .......................................................................5-5

Royce 8500 Series Multi-Parameter........................................Innovative .......................................................................5-5

Fluorescence In Situ Hybridization (FISH) 

for Filamentous and Nitrifying Bacteria ............................... Innovative.............................................................. 5-9

Microwave Density Analyzer................................................ Innovative............................................................ 5-11

Microtox®/Online Microtox® ................................................. Innovative............................................................ 5-13

SymBioTM – Nicotinamide Adenine Dinucleotide

(NADH) Probes.................................................................... Innovative............................................................ 5-15

Online Respirometry............................................................ Innovative............................................................ 5-17

NITROXTM – Oxidation Reduction Potential (ORP) 

Probe................................................................................... Innovative............................................................ 5-19

Biological Micro-Electro-Mechanical Systems

(BioMEMS) ..........................................................................Embryonic........................................................... 5-21

Fluorescence In Situ Hybridization (FISH) for

Phosphorus Accumulating Organisms (PAOs)....................Embryonic........................................................... 5-23

Handheld Advanced Nucleic Acid Analyzer

(HANNA)..............................................................................Embryonic........................................................... 5-25

Immunosensors and Immunoassays ..................................Embryonic........................................................... 5-27

Photo-electro Chemical Oxygen Demand

(PeCODTM) ..........................................................................Embryonic........................................................... 5-29
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xiv Wastewater Treatment and In-Plant Wet Weather Management

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February 2008

Overview

In 2004, there were 16,583 municipal wastewater treatment plants operating in the United 

States. These plants ranged in size from a few hundred gallons per day (GPD) to more 

than 800 million gallons per day (MGD). Early efforts in water pollution control began in 

the late 1800s with construction of facilities to prevent human waste from reaching drinking 

water supplies. Since the passage of the 1972 Amendments to the Federal Water Pollution 

Control Act (Clean Water Act [CWA]), municipal wastewater treatment facilities have been 

designed and built or upgraded to abate an ever-increasing volume and diversity of 

pollutants. The CWA requires that municipal wastewater treatment plant discharges meet 

a minimum of secondary treatment. However, in 2004, nearly 30 percent of the municipal 

facilities produced and discharged effluent at higher levels of treatment than the minimum 

federal standards for secondary treatment.

This document provides information regarding emerging wastewater treatment and inplant wet weather management technologies organized into four categories of 

development:

1. Embryonic – Technologies in the development stage and/or have been tested at 

a laboratory or bench scale only.

2. Innovative – Technologies that have been tested at a demonstration scale, have 

been available and implemented in the United States for less than five years, or 

have some degree of initial use (i.e., implemented in less than 1 percent of 

treatment facilities).

3. Established – Technologies that have been used at more than 1 percent of 

treatment facilities throughout the United States or have been available and 

implemented in the United States for more than five years.

4. Innovative Uses of Established – Some wastewater treatment processes 

have been established for years, but they are not static. In some cases, an 

established technology may have been modified or adapted resulting in an 

emerging technology. In other cases, a process that was developed to 

achieve one treatment objective is now being applied in different ways or to 

achieve additional treatment objectives. During the operation of treatment 

systems using these established technologies, engineers, and operators have 

altered and improved their efficiency and performance. This document includes 

established technologies that have undergone recent modifications or are used in 

new applications.
Emerging Technologies February 2008

O-2 Wastewater Treatment and In-Plant Wet Weather Management

This document also provides information on each technology, its objective, its description, 

its state of development, available cost information, associated contact names, and 

related data sources. For each innovative technology, this document further evaluates 

technologies against various criteria, although it does not rank or recommend any one 

technology over another. Research needs are also identified to guide development of 

innovative and embryonic technologies and improve established ones.
Chapter

Wastewater Treatment and In-Plant Wet Weather Management 1-1

1.1 Introduction

In 2004, there were 16,583 municipal wastewater treatment plants operating in the United 

States. These plants ranged in size from a few hundred gallons per day (GPD) to more 

than 800 million gallons per day (MGD). Early efforts in water pollution control began in 

the late 1800s with construction of facilities to prevent human waste from reaching drinking 

water supplies. Since the passage of the 1972 Amendments to the Federal Water Pollution 

Control Act (Clean Water Act [CWA]), municipal wastewater treatment facilities have been 

designed and built or upgraded to abate an ever-increasing volume and diversity of 

pollutants. The CWA requires that municipal wastewater treatment plant discharges meet 

a minimum of secondary treatment. However, in 2004, nearly 30 percent of the municipal 

facilities produced and discharged effluent at higher levels of treatment than the minimum 

federal standards for secondary treatment.

To meet the challenge of keeping progress in wastewater pollution abatement ahead of 

population growth, changes in industrial processes, and technological developments, 

EPA is providing this document to make information available on recent advances and 

innovative techniques. 

The goal of this document is straight forward—to provide a guide for persons seeking 

information on innovative and emerging wastewater treatment technologies. The guide 

lists new technologies, assesses their merits and costs, and provides sources for further 

technological investigation. This document is intended to serve as a tool for wastewater 

facility owners and operators. 

Emerging technologies typically follow a development process that leads from laboratory 

and bench-scale investigations to pilot studies and to initiate use or “full-scale 

demonstrations” before the technology is considered established. Not all technologies 

survive the entire development process. Some fail in the laboratory or at pilot stages; 

others see limited application in the field, but poor performance, complications, or 

unexpected costs may cause them to lose favor. Even technologies that become 

established may lose favor in time, as technological advances lead to obsolescence. In 

short, technologies are subject to the same evolutionary forces present in nature; those 

that cannot meet the demands of their environment fail, while those that adapt to changing 

technological, economic and regulatory climates can achieve long-standing success and 

survival in the market.

Introduction and Approach

1
Emerging Technologies February 2008

1-2 Wastewater Treatment and In-Plant Wet Weather Management

Some wastewater treatment processes have been established for many years, but that 

does not mean that they are static. During the operation of treatment systems using 

these established technologies, engineers and operators have altered and improved 

efficiency and performance. In other cases, established technologies applied to one 

aspect of treatment have been modified so that they can perform different objectives. 

Often, better performance can be achieved by linking established processes in innovative 

ways. This document includes established technologies that have undergone recent 

modifications or are used in new applications. These technologies are evaluated in the 

chapters alongside the innovative and embryonic technologies. 

1.2 Approach

To develop this guide, the investigators sought information from a variety of sources, 

identified new technologies, prepared cost summaries, where information was available, 

for all technologies, and evaluated technologies deemed to be innovative. This method is 

described below and in Figure 1-1.

Collect Information

Identify Process

Prepare Process

Summary Sheets

Has Innovative

Modications

Prepare Process

Evaluation Matrix

Screen

Established

No Further Action

Embryonic

Innovative

No Further Action

Embryonic or Innovative

Screen

745043_WWT-01..ai

Figure 1.1—Flow Schematic for Guide Development
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

1-3

February 2008

1.2.1	 Information Collection and New Process Identification

The collection of information and identification of new technology provided the foundation 

for subsequent work. To identify new treatment process technologies, investigators 

gathered information and focused on relevant Water Environment Federation (WEF) and 

American Society of Civil Engineers (ASCE) conference proceedings, as well as monthly 

publications from these and other organizations such as International Water Association 

(IWA).

“Gray” Literature – Vendor-supplied information, Internet research, and consultants’ 

technical reports comprise the information collected in this category. 

Technical Associations – Investigators contacted a variety of professional and 

technical associations in the United States to identify emerging wastewater treatment 

technologies.

Interviews and Correspondence – Individuals known to the project investigation 

team, including consultants, academics, and municipal wastewater treatment plant 

owners and operators, were consulted.

Technologies identified through search of the above sources were screened to determine 

their classification as described below.

1.2.2 Initial Screened Technologies

This project focuses on emerging technologies that appear to be viable, but have not yet 

been accepted as established processes in the United States. Specific screening criteria 

used to define the state of development for processes are described in the following 

paragraphs. This screening resulted in:

23 embryonic technologies

52 innovative technologies

8 established technologies with innovative modifications

Embryonic – These technologies are in the development stage and/or have been tested 

at laboratory or bench scale. New technologies that have reached the demonstration 

stage overseas, but cannot yet be considered to be established there, are also considered 

to be embryonic with respect to North American applications.

Innovative – Technologies that meet one of the following criteria were classified as 

innovative:

They have been tested as a full-scale demonstration.

They have been available and implemented in the United States for less than five 

years.

They have some degree of initial use (i.e., implemented in less than 1 percent of 

municipalities throughout the United States).












Emerging Technologies February 2008

1-4 Wastewater Treatment and In-Plant Wet Weather Management

They are established technologies from overseas.

Established – In most cases, these processes are used at more than 1 percent of fullscale facilities in North America; but there are some exceptions based upon specific 

considerations. The established category may include technologies that are widely used 

although introduced more recently in North America. Due to the extensive number of 

established technologies and variations in each technology, only established technologies 

are listed. None are described in depth in this document and Technology Summary sheets 

are not provided for established technologies. 

Innovative Uses of Established – In some cases, an established technology such 

as the UCT (University of Cape Town) process may have been modified or adapted, 

resulting in an emerging technology such as the Modified UCT. In other cases, a process 

like Actiflo® was developed to remove solids from wet weather flows but is now also being 

used to polish final effluent.

The focus of this document is on Innovative Technologies along with preliminary 

information of Embryonic Technologies. Early in the development process (the laboratory 

stage), data was usually insufficient to prove or disprove technology viability at full scale. 

Available information on these embryonic technologies is presented in this document. 

Technologies on the other end of the developmental scale, those defined as established 

in North America, are excluded from the detailed assessments on the assumption that 

they are proven, although still relatively new.

The differentiation between technologies established in Europe or Asia and those that 

have reached similar status in the United States can be critical since technologies that 

have been applied successfully in other countries have not always flourished here in the 

United States. Because the viability of imported technologies is not guaranteed, 

established processes from overseas are classified as innovative technologies for this 

project, unless they are proven in North American applications.

Some technologies fall into a “gray area” between the embryonic and innovative 

categories. Technologies that fall into this category are incorporated into the innovative 

category. The screening assessment is summarized by chapter in Tables 1.1 through 

1.4. 

Table 1.1 summarizes the treatment technologies for Chapter 2 – Physical/Chemical 

Treatment Processes. 

Table 1.2 summarizes the treatment technologies for Chapter 3 – Biological

Treatment Processes. 

Table 1.3 summarizes the treatment technologies for Chapter 4 – In-Plant Wet 

Weather Management Processes. 

Table 1.4 summarizes the treatment technologies for Chapter 5 – Process Monitoring 

Technologies.

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Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

All the cost estimates provided in this document contain a certain degree of expert 

judgment or educated guesswork concerning the various cost elements that comprise 

the estimates. This is true when cost estimates are based on limited or no information 

where in some cases little more than process type, location, and plant capacity are known. 

Therefore, cost estimates are at best order-of-magnitude level per American Association 

of Cost Engineers (AACE) International classification. However, numerous peripheral 

factors that could also interfere with the accuracy of the order-of-magnitude level cost 

estimates. Considering these facts, the reader should keep in mind that site-specific 

applications and local requirements should be considered to increase the accuracy of 

cost estimates provided in this document.

1.2.3 Development of Technology Summary Sheets

Technologies defined as embryonic or innovative are each summarized on an individual 

Technology Summary sheet. Each process includes the following information:

Objective – Description of the goal of the technology.

State of Development – Where and how the technology has been applied (i.e., 

laboratory study, demonstration scale, full scale, etc.).

Description – A brief overview of the technology.

Comparison to Established Technologies – Advantages and disadvantages 

of innovative and embryonic technologies are compared to more commonly used 

technologies.

Available Cost Information – Approximate range of capital and operations and 

maintenance costs, and assumptions made in developing them (when reliable 

information was available).

Vendors Name(s) – Name, address, telephone numbers, web address, and other 

contact information for equipment manufacturers and suppliers.

Installation(s) – Name, address, telephone numbers, and other contact 

information for utilities and facilities where the technology has been used (full or pilot 

scale).

Key Words for Internet Search – Because this document is not intended to 

provide a comprehensive list of vendors for these technologies, key words have 

been added to aid the reader in finding additional vendors and current product 

information on the Internet. 

Data Sources – References used to compile the technology summary.

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Emerging Technologies February 2008

1-6 Wastewater Treatment and In-Plant Wet Weather Management

Table 1.1—Summary of Treatment Technologies

Chapter 2 – Physical/Chemical Treatment Processes

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Established Technologies

Air Stripping l l

Screening

 Fine Screening l

 Micro Screening l

 Rotary Screening l

 Step Screening l

 Microsieves l l l

Grit Removal

 Travelling Bridge l

Fine/Advanced Grit Removal System (AGRS)

HEADCELLTM  l

GRITKINGTM  l

PISTAGRITTM  l

HYDROGRITTM  l

Flocculation l

Chemical Precipitation*

 Alum Addition l l

 Iron Salts Addition l l

 Zeolite l

High Rate Dissolved Air Flotation (DAF) Treatment/Settling l

Chemically Enhanced Primary Treatment l l

Solids Contact Clarifier for P Removal l l l

Ion-Exchange l

Chemical Oxidation*

 Hydroxyl Radical l l

 Oxygen (Atomic and Molecular) l l

 Ozone l l

 Hydrogen Peroxide l l

 Hypochlorite/Chlorine/Chlorine Dioxide l l

Note:

* Chemical phosphorus removal is limited by kinetic factors as well as stoichiometric factors and excessive inorganic precipitant 

requirements need to be reduced.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Established Technologies (Contd)

Advanced Oxidation Processes

 Supercritical Water Oxidation l l

 Catalytic Oxidation l l

Photo Catalysis (UV + TiO2  ) l l

Fenton’s Reagent (H2O2  + Ferrous Ion) l l

Electodialysis l l

Filtration through Membranes

 Reverse Osmosis l l l

 Microfiltration l l l

 Ultrafiltration l l l

Filtration through Media

 Cloth Media

– Disc Filter (DF) l l

– Drum Filter l l

– Diamond-Shaped Filters l l

 Silica Media (One- and Two-Stage)

– Conventional Downflow l l

– Deep-Bed Downflow Filters l l

– Deep-Bed Upflow Continuous Backwash Filters l l

 Activated Alumina Media l

 Powdered Activated Carbon (PAC) l l

 Granular-Activated Carbon (GAC) l l l

Denitrification Filters l l l

Automatic Backwash Filters (ABW®) l l

Pulsed Bed Filter l l

Disinfection

 Ozone l

 Chlorine/Chlorine Dioxide/Liquid Chlorine/Dechlorination l

 Halogens (Bromine) l

 UltraViolet (UV) Disinfection l

Table 1.1—Summary of Treatment Technologies (Contd)

Chapter 2 – Physical/Chemical Treatment Processes
Emerging Technologies February 2008

1-8 Wastewater Treatment and In-Plant Wet Weather Management

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Innovative Technologies

Compressible Media Filtration l l l

Nanofiltration l l l

Innovative Use of Established Technologies

Ballasted High Rate Clarification (BHRC) Processes* 

Actiflo®  Process l l

Densadeg®  Process l l

Microwave UV Disinfection l

Embryonic Technologies

Blue CATTM l l l

Blue PROTM l l

CoMagTM l l

Solar Disinfection l

Table 1.1—Summary of Treatment Technologies (Contd)

Chapter 2 – Physical/Chemical Treatment Processes

Note:

* Chemical phosphorus removal is limited by kinetic factors as well as stoichiometric factors and excessive inorganic precipitant 

requirements need to be reduced.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Table 1.2—Summary of Treatment Technologies

Chapter 3 – Biological Treatment Processes

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Established Technologies

BOD Removal and Nitrification 

 Biolac-Aerated Lagoon l l

 Complete Mix-Activated Sludge (CMAS) Process l l

 Contact Stabilization l l

 Conventional Extended Aeration l l

 Countercurrent Aeration System (CCASTM) l l l

 Cyclic Activated Sludge System (CASSTM) l l l

 High-Purity Oxygen (HPO) l l

Intermittent Cycle Extended Aeration System (ICEASTM  ) l l l

 Kraus Process l l

 Oxidation Ditch/Aerated Lagoons l l

 Sequencing Batch Reactor (SBR) l l l

 Staged Activated-Sludge Process l l

 Step Feed l l

 Step Feed (Alternating Anoxic and Aerobic) l l l

Biological Nutrient Removal (BNR)

Bardenpho®  (Four Stage) l l l

BiodenitroTM  l l l

 Ludzack-Ettinger l l l

 Modified Ludzack-Ettinger (MLE) l l l

OrbalTM  Process l l l

SchreiberTM  Process l l l

 Simultaneous Nitrification denitrificatioN (SNdN) Process l l l

 Step Feed BNR Process l l l

 Wuhrman l l l

Enhanced Biological Phosphorus Removal (EBPR)

 Anaerobic/Anoxic/Oxic (A2/O) l l l l

Bardenpho®  (Five Stage) l l l l

 Johannesburg Process l l l l

 Phoredox (Anaerobic/Oxic [A/O]) l l

 Phostrip l l

 University of Cape Town (UCT) l l l l

 Virginia Initiative Plant (VIP) l l l l
Emerging Technologies February 2008

1-10 Wastewater Treatment and In-Plant Wet Weather Management

Table 1.2—Summary of Treatment Technologies (Contd)

Chapter 3 – Biological Treatment Processes

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Established Technologies (Contd)

Other Biological Processes 

 Fluidized Bed Bioreactor (FBBR) l l

 Rotating Biological Contractor (RBC) l l

 Submerged Rotating Biological Contactor (SRBC) l l

 Trickling Filter (TF) l l

Anaerobic Processes

 Anaerobic Attached Growth System 

– Upflow Packed-Bed Attached Growth Reactor l

– Upflow Attached Growth Anaerobic l

Expanded-Bed Reactor (Anaerobic Expanded Bed 

Reactor [AEBR])

– l

– Downflow Attached Growth Process l

 Anaerobic Contact Process l

Anaerobic Sequencing Batch Reactor (ASBR®  ) l

 Upflow Anaerobic Sludge Blanket (UASB) l

 ANFLOW (ANaerobic FLuidized Bed Reactor) l

Biological Aerated Filters (BAF)

Biofor®  l l l

Biostyr®  l l l

Innovative Technologies

Bioaugmentation

 External Bioaugmentation 

– Seeding from Commercial Sources of Nitrifiers l l l

Trickling Filter and Pushed Activated Sludge (TF/PAS) 

Process

– l l l

Seeding from External Dispensed Growth Reactors 

Treating Reject Waters (Chemostat)

– l l l

In-Nitri® – Process l l l

Immobilized Cell-Augmented Activated Sludge 

(ICASS) Process

– l l l

– Seeding from Parallel Processes l l l

– Seeding from Downstream Process l l l
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Table 1.2—Summary of Treatment Technologies (Contd)

Chapter 3 – Biological Treatment Processes

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Innovative Technologies (Contd)

 In Situ Bioaugmentation 

DE-nitrification and PHosphate accumulation in 

ANOXic (DEPHANOX) Process

– l l l

Bio-Augmentation Regeneration/Reaeration (BAR) 

Process – l l l

– Bio-Augmentation Batch Enhanced (BABE) Process l l l

– Aeration Tank 3 (AT3) Process l l l

Main stream AUtotrophic Recycle Enabling Enhanced 

N-removal (MAUREEN) Process

– l l

– Regeneration DeNitrification (R-DN) Process l l l

Cannibal® l l l

CATABOLTM l l l

Deep-Shaft Activated Sludge/VERTREATTM l

Integrated fixed-Film Activated Sludge (IFAS)

 IFAS – Submerged Mobile Media 

Attached Growth Airlift Reactor (AGAR® – ) l l

Captor® – l l

LINPOR® – l l

 IFAS – Submerged Fixed Media 

CLEARTEC® – l l

AccuWeb® – l l

BioMatrixTM – l l

HYBASTM – l l

– BioWebTM l l

RINGLACE® – l l

Membrane Bioreactor (MBR)

 Tubular l l l l

 Hollow-Fiber l l l l

 Spiral Wound l l l l

 Plate and Frame l l l l

 Pleated Cartridge Filters l l l l

Mobile-Bed Reactor Technology (MBRT) Process

Kaldnes®  HYBASTM/ Active CellTM l l l

 Hydroxyl-F3R l l l

GeoReactor®  l l l
Emerging Technologies February 2008

1-12 Wastewater Treatment and In-Plant Wet Weather Management

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Innovative Use of Established Technologies

Bardenpho® (Three Stage) with Returned Activated Sludge 

(RAS) Denitrification l l l l

Biological-Chemical Phosphorus and Nitrogen Removal 

(BCFS)* l l l l

Modified University of Cape Town (MUCT) Process l l l l

Modified Anaerobic/Oxic (A/O) Process l l l l

Trickling Filter/Solids Contactor (TF/SC) l l

Embryonic Technologies

Aerobic Granular Sludge Process (AGSP) l l l l

ANaerobic Membrane BioReactor (AN-MBR) l l

Anaerobic Migrating Blanket Reactor (AMBR®) l

DEamMONification (DEMON) Process l l l

Hydrogen-based hollow-Fiber Membrane Biofilm Reactor 

(HFMBfR) l l

Membrane-Aerated BioReactor (MABR) l l l l

Microbial Fuel Cell (MFC) Based Treatment System l l

Multi-Stage Activated Biological Process (MSABPTM) l l l

NeredaTM l

Single reactor High-activity Ammonia Removal Over Nitrite 

(SHARON) l l l

SHARON – ANAMMOX (ANaerobic AMMonia OXidation) l l l

STRASS Process l l l

Vacuum Rotation Membrane (VRM®) System l l l

Table 1.2—Summary of Treatment Technologies (Contd)

Chapter 3 – Biological Treatment Processes

Note

* Chemical phosphorus removal is limited by kinetic factors as well as stoichiometric factors and excessive inorganic precipitant 

requirements need to be reduced.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Table 1.3—Summary of Treatment Technologies

Chapter 4 – In-Plant Wet Weather Management Processes

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Established Technologies

Dispersed Air Flotation l l

Dissolved Air Flotation (DAF) l l

Enhanced Clarification/High Rate Clarification (HRC)

Ballasted Flocculation (Actiflo® and Microsep®  ) l l

 Lamella Plate Settlers l l

Screening l

Vortex Separation l

Innovative Technologies

Continuous Deflection Separator (CDS) l

HYDROSELF® Flushing Gate l

Tipping Flusher® l

TRASHMASTERTM Net Capture System l

WWETCO Compressed Media Filtration® or WWETCO CMP® 

System l l

Innovative Use of Established Technologies

None at this time

Embryonic Technologies

Alternative Wet Weather Disinfection l
Emerging Technologies February 2008

1-14 Wastewater Treatment and In-Plant Wet Weather Management

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Established Technologies

Ammonia and Nitrate Probes 

 ChemScan l

 Myratek l

 Hach Evita l

 Hach NITRATAX l

NitraVis®  System l

Dissolved Oxygen Analyzer l

Online Cl2 Residual l

pH Probes l

Sludge Blanket Level Detector l

Solids Retention Time (SRT) Controller l

Total Suspended Solids Analyzer l

Innovative Technologies

Ammonia and Nitrate Probes

 ChemScan N-4000 l l

 Hach Evita In Situ 5100 l l

 Hach NITRATAX l l

 Myratek Sentry C-2 l l

NitraVis®  System l l

 Royce 8500 Series Multi-Parameter l l

Fluorescence In Situ Hybridization (FISH) for Filamentous 

and Nitrifiying Bacteria l

Microwave Density Analyzer l l

Microtox®/Online Microtox® l

SymBioTM – Nicotinamide Adenine Dinucleotide (NADH) 

Probes l

Online Respirometry l

NitroxTM – Oxidation Reduction Potential (ORP) Probe l

Table 1.4—Summary of Treatment Technologies

Chapter 5 – Process Monitoring Technologies
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Technology and Advancements

(Listed in process flow sequence)

Applications

C-BOD RemovalPhosphorus RemovalNitrification-Ammonia RemovalDenitrification – Nitrogen RemovalSolids – Liquid Separation (TDS and TSS)Targeted Contaminants RemovalDisinfectionPhysical/Chemical MonitoringBiochemical Monitoring

Innovative Use of Established Technologies

None At This Time

Embryonic Technologies

Biological Micro-Electro Machine System (BioMEMS) l

FISH for Phosphorus Accumulating Organisms (PAOs) l

Handheld Advanced Nucleic Acid Analyzer (HANNA) l

Immunosensors and Immunoassays l

Photo-electro Chemical Oxygen Demand (PeCODTM) l

Table 1.4—Summary of Treatment Technologies (Contd)

Chapter 5 – Process Monitoring Technologies

1.2.4 Evaluation of Technologies

Technologies defined as innovative in the initial screening were subjected to a detailed 

evaluation. Each technology was evaluated with respect to the descriptive and comparative 

criteria described below. Descriptive criteria include:

State of Development – Describes the stage of development for each technology, 

ranging from development to full-scale operations.

Applicability – Qualitatively assesses in which market the technology is designed 

to be used.

Effluent Reuse – Discusses the reuse of treated effluent.

Benefits – Considers the benefits gained (e.g., capital or operational savings) from 

implementation of the technology.

Designations for each descriptive criterion are presented in Table 1.5.

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Emerging Technologies February 2008

1-16 Wastewater Treatment and In-Plant Wet Weather Management

Criterion Designation Description

State of Development B Bench scale

P Pilot scale

I Full-scale industrial applications

M Full-scale municipal applications

O Full-scale operations overseas

N Full-scale operations in North America

Applicability I Industrywide

F Few plants

S Primarily small plants

L Primarily large plants

Effluent Reuse Dp Direct potable

Dn Direct nonpotable

Ip Indirect potable

In Indirect nonpotable

Potential Benefits C Capital savings

O Operational/maintenance

Table 1.5—Descriptive Evaluation Criteria

Comparative criteria include:

Impact on Existing Facilities or Other Processes – Describes whether or 

not the technology requires the involvement of extensive design changes, and the 

degree to which the existing facilities will be disturbed.

Complexity – Considers the installation, startup, and shutdown methods for the 

technology. 

Air/Odor Emissions – Considers if the process has impacts on air and odor 

emissions for the facility.

Energy – Considers the amount of energy required to adequately maintain the 

process and if any energy saving is possible.

Footprint – Considers how the footprint helps to identify the land needed to expand 

a facility for increased capacity. 

Retrofitting – Considers if the process can be used to modify old treatment plants 

without extensive reconstruction.

The above criteria compared individual technologies with other technologies in the same 

category, and were scored positive, neutral/mixed, or negative.

The criteria and ratings were applied to each innovative technology and the results are 

presented in matrix format. Where available information was insufficient to rate a 

technology for a criterion, no rating is given. The project team and reviewers assessed 

each technology based on the limited information gathered and their collective judgment, 

experience, and opinions. Results of the evaluation are presented in subsequent 

chapters.

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February 2008

1.3 Guidance Document Format and Use

The remainder of the document is divided into chapters based upon general technologies, 

one chapter is dedicated to each of the following categories:

Chapter 2 – Physical/Chemical Treatment Processes

Chapter 3 – Biological Treatment Processes

Chapter 4 – In-Plant Wet Weather Management Processes

Chapter 5 – Process Monitoring Technologies

Each chapter provides an overview of the appropriate technologies, discusses the state 

of development for each, presents an evaluation matrix for innovative technologies, and 

concludes with a Technology Summary Sheet for each embryonic and innovative 

technology.

The technology summaries and evaluation matrices are the cornerstones of each chapter, 

broadly overviewing the innovative technologies. Neither the summaries nor the matrices 

should be considered definitive technology assessments. Rather, they should be 

considered stepping stones to more detailed investigations.

Chapter 6 discusses research needs and Appendix A contains applicable trade 

associations.

This document will be updated from time to time. Technologies were reviewed in mid2006 to early 2007.

1.4	 Chapter References

U.S. EPA, 2004 Report to Congress: Impacts and Control of CSO and SSOs, EPA 833-

R-04-001, Office of Water.

U.S. EPA, Clean Watershed Needs Survey 2004 Report to Congress, EPA 832-R-07-

001, Office of Water, 2007.

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Chapter

Wastewater Treatment and In-Plant Wet Weather Management 2-1

2

Physical/Chemical Treatment Processes

2.1 Introduction

For the purpose of this report, physical and chemical treatment processes are defined as 

treatment technologies that do not include any biomass in the process to achieve the 

treatment objective. Physical processes remove solids from wastewater by flowing 

through screens or filter media, or solids are removed by gravity settling. Particles 

entrapped with air float to the surface and can be removed. Chemicals are used in 

wastewater treatment to create changes in the pollutants that increase the ability to 

remove them. Changes may include forming floc or a heavier particle mass to improve 

removal by physical processes. As a result, chemical addition and physical processes 

are usually employed together to provide treatment. This chapter focuses on advances in 

basic physical and chemical treatment processes.

2.2 Technology Assessment

A summary of innovative, embryonic, and established technologies for physical and/or 

chemical treatment processes is provided in Table 2.1. A comparative evaluation among 

innovative technologies is provided in Figure 2.1. Most of the physical chemical processes 

are established, and they are still very essential unit processes that are widely used in 

various applications in wastewater treatment.

Innovative development in physical and chemical technologies includes membrane 

filtration and compressible media filters. These technologies focus on the separation of 

liquids and solids. Advanced solids separation is critical as a preliminary process step 

and as an advanced treatment step to reduce suspended solids, plus nutrients and other 

compounds, in the effluent. The application of these technologies has promoted the reuse 

of wastewater by providing a very high-quality effluent. 

This chapter also discusses some of the innovative uses or unique applications of already 

established technologies. For example, the Ballasted High Rate Clarification (BHRC) 

process is a high-rate chemical/physical clarification process that involves the formation 

of suspended solids onto a ballast particle with the aid of a coagulant and polymer. The 

BHRC process includes the patented DensaDeg® and Actiflo® processes. Embryonic 

technologies currently under development include solar disinfection and Blue PROTM for 

phosphorus removal. These technologies are discussed in the technology summaries in 

this chapter. Chemical phosphorus removal is limited by kinetic factors as well as 

stoichiometric factors and excessive inorganic precipitant requirements need to be 

reduced. 
Emerging Technologies February 2008

2-2 Wastewater Treatment and In-Plant Wet Weather Management

Table 2.1—Physical/Chemical Treatment Processes – State of Development

Established Technologies

Air Stripping

Screening

 Fine Screening

 Micro Screening

 Rotary Screening

 Step Screening

 Microsieves

Grit Removal

 Traveling Bridge

Fine/Advanced Grit Removal System (AGRS)

HEADCELLTM 

GRITKINGTM 

PISTAGRITTM 

HYDROGRITTM 

Flocculation

Chemical Precipitation*

 Alum Addition

 Iron Salts Addition

 Zeolite

High Rate Dissolved Air Flotation (DAF) Treatment/Settling

Chemically Enhanced Primary Treatment

Solids Contact Clarifier for P Removal

Ion-Exchange

Chemical Oxidation*

 Hydroxyl Radical

 Oxygen (Atomic and Molecular)

 Ozone

 Hydrogen Peroxide

 Hypochlorite/Chlorine/Chlorine Dioxide

Advanced Oxidation Processes

 Supercritical Water Oxidation

 Catalytic Oxidation

Photo Catalysis (UV + TiO2  )

Fenton’s Reagent (H2O2  + Ferrous Ion)

Electodialysis

Filtration through Membranes

 Reverse Osmosis

 Microfiltration

 Ultrafiltration

Established Technologies (Contd)

Filtration through Media

 Cloth Media

– Disc Filter (DF)

– Drum Filter

– Diamond-Shaped Filters

 Silica Media (One- and Two-Stage)

– Conventional Downflow

– Deep-Bed Downflow Filters

– Deep-Bed Upflow Continuous Backwash Filters

 Activated Alumina Media

 Powdered Activated Carbon (PAC)

 Granular-Activated Carbon (GAC)

Denitrification Filters

Automatic Backwash Filters (ABW®)

Pulsed Bed Filter

Disinfection

 Ozone

 Chlorine/Chlorine Dioxide/Liquid Chlorine/Dechlorination

 Halogens (Bromine)

 UltraViolet (UV) Disinfection

Innovative Technologies

Compressible Media Filtration

Nanofiltration

Innovative Use of Established Technologies

Ballasted High Rate Clarification (BHRC) Processes* 

Actiflo®  Process

Densadeg®  Process

Microwave UV Disinfection

Embryonic Technologies

Blue CATTM

Blue PROTM

CoMagTM

Solar Disinfection

Note:

* Chemical phosphorus removal is limited by kinetic 

factors as well as stoichiometric factors and excessive 

inorganic precipitant requirements need to be 

reduced.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-3

February 2008

Figure 2.1—Evaluation of Innovative

Physical/Chemical Treatment Technologies

Process

Evaluation Criteria

DevelopmentApplicabilityBenefitsImpact on ProcessesComplexityAir/Odor EmissionsReuseEnergyFootprintRetrofitting

Compressible Media Filters I, M, N I C y y y Dn y p p

Nanofiltration I, M, N F O p y y Ip, Dp q p p

Comparative Criteria

p Positive feature

y Neutral or mixed

q Negative feature

Effluent Reuse

Dp = Direct potable

Dn = Direct nonpotable

Ip = Indirect potable

In = Indirect 

nonpotable

Applicability

F = Few plants

I = Industrywide

L = Primarily large plants

S = Primarily small plants

Potential Benefits

C = Capital savings

I = Intense operational demand

O = Operational/maintenance savings

S = Shock load capacity

W= Wet weather load capacity

Statement of Development

B = Bench scale

I = Full-scale industrial applications

M = Full-scale municipal applications

O = Full-scale operations overseas

P = Pilot

N = Full-scale operations in North America

Key
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Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-5

February 2008

Technology Summary

Compressible Media Filtration

Objective:

Enhanced filtration where the porosity of the media can 

be adjusted.

State of Development:

Innovative. This technology has gained widespread use and may 

be approaching an established process. 

Description:

This synthetic medium was developed in Japan. The porosity of the filter bed can be adjusted by compressing the filter 

medium and the size of the filter bed can be increased mechanically to backwash the filter. It is an enhanced filtration process 

where the filtration media is more effective in capturing more solids per filter volume than other media. The filtration unit is 

designed such that the porosity of the media can be adjusted and the solids can be removed by air scouring.

Comparison to Established Technologies:

Effluent to be filtered flows through the media as opposed to flowing around the media as in sand and anthracite filters. This 

feature permits higher hydraulic loadings of 30 gpm/ft2 of media and higher as opposed to other filtration systems with 2 to 6 

gpm/ft2.

Available Cost Information:

Approximate Capital Cost: $80,000 to $90,000 for a 3-ft by 3-ft filter operating at 0.25 to 0.55 MGD.

Approximate O&M Costs: Not disclosed.

Vendor Name(s):

Fuzzy Filters

Schreiber Corporation

100 Schreiber Drive

Trussville, AL 35173

Telephone: 205-655-7466 or 800-535-0944

Email: larryw@schreiberwater.com

Installation(s):

University of California, Davis, CA

Columbus CSO Facility, Columbus, GA

Clayton County Northeast WPCF, GA

Yountville Sanitary District, Yountville, CA

Rogersville, MO

Golden Poultry/Gold Kist, Sanford, NC

Orange County Sanitary District, Fountain Valley, CA

King County, Seattle, WA 

Key Words for Internet Search:

Compressible media filter, wastewater treatment, fuzzy

Data Sources:

Metcalf and Eddy, Wastewater Engineering Treatment and Reuse, 4th Edition, 2003.

http://www.schreiberwater.com/
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Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-7

February 2008

Technology Summary

Nanofiltration

Objective:

Nanofiltration is used as an advanced treatment system 

to remove priority organic pollutants and biodegradable 

organics, Total Suspended Solids (TSS) and Total 

Dissolved Solids (TDS), bacteria, and viruses.

State of Development:

Innovative.

Description:

The nanofiltration process uses membranes with an operating pore size range of 0.01 to 0.2 micron in a pressure-driven 

separation. Operating pressures are 75 to 150 psig. Nanofiltration is used for the removal of priority organic pollutants, 

biodegradable organics, TSS, bacteria, some viruses, and proteins from wastewater. It is used in certain municipal treatment 

plants for disinfection purposes and softening of wastewater or it is used in process where the reuse of water is the treatment 

goal. Typically, microfiltration or ultrafiltration is used as a pretreatment process for water that is required to be treated through 

nanofiltration or reverse osmosis. The membranes are typically made of cellulose acetate or aromatic polyamides and are 

spiral wound and hollow fiber.

Comparison to Established Technologies:

The nanofiltration process helps eliminate TSS, TDS, and other pathogens better than the ultrafiltration process. 

Available Cost Information:

Approximate Capital Cost: Not available.

Approximate O&M Costs: Not available.

Vendor Name(s):

GE Infrastructure Water and Process Technologies

4636 Somerton Road

Trevose, PA 19053

Telephone: 215-355-3300

www.gewater.com

Koch Membrane Systems, Inc.

850 Main Street

Wilmington, MA 01887

Telephone: 888-677-5624

Email: info@kochmembrane.com

Installation(s):

Clifton Water District, CO

Key Words for Internet Search:

Nanofiltration, wastewater treatment, NF

Data Sources:

Metcalf and Eddy, Wastewater Engineering Treatment and Reuse, 4th Edition, 2003.

www.eurodia.com/html/index.html
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Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-9

February 2008

Technology Summary

Actiflo® Process

Objective:

Treatment of primary and tertiary effluents.

State of Development:

Innovative Use of Established Technology.

Description:

The Actiflo® process is a high-rate chemical and physical clarification process that involves the formation of suspended solids 

onto a ballast particle (microsand) followed by lamellar settling. It is considered an established process for the treatment of 

wet weather flows, but is also being applied to primary and tertiary effluents. The process starts with the addition of a 

coagulant to destabilize suspended solids. The flow enters the coagulation tank for flash mixing to allow the coagulant to take 

effect then overflows into the injection tank where microsand is added. The microsand serves as a “seed” for floc formation, 

providing a large surface area for suspended solids to bond to and is the key to Actiflo®. It allows solids to settle out more 

quickly, thereby requiring a smaller footprint than conventional clarification. 

Polymers may either be added in the injection tank or at the next step, the maturation tank. Mixing is slower in the maturation 

tank, allowing the polymer to help bond the microsand to the destabilized suspended solids. Finally, the settling tank effectively 

removes the floc with help from plate settlers allowing the tank size to be further reduced. Clarified water exits the process by 

overflowing weirs above the plate settlers. The sand and sludge mixture is collected at the bottom of the settling tank with a 

conventional scraper system and pumped to a hydrocyclone, located above the injection tank. The hydrocyclone converts the 

pumping energy into centrifugal forces to separate the higher density sand from the lower density sludge. The sludge is 

discharged out of the top of the hydrocyclone while the sand is recycled back into the Actiflo® process for further use. 

Screening is required upstream of Actiflo® so that particles larger than 3 to 6 mm do not clog the hydrocyclone. 

Several startup modes may be used for a full scale Actiflo® system. If a wet weather event is expected within 7 days of a 

previous wet weather event, the units should be shut down, but not put on standby. Wastewater would remain in the tanks 

and a wet startup would ensue at the time of the next wet weather event. In summer months, when freezing is not possible, 

the intermittent flush standby mode could be used; and when freezing is possible, the continuous flush standby mode should 

be used. These standby modes should results in a successful wet method, dry startup. 

Comparison to Established Technologies:

Fundamentally, this process is very similar to conventional coagulation, flocculation, and sedimentation water treatment 

technology. Both processes use coagulant for the destabilization and flocculent aid (polymer) for the aggregation of suspended 

materials. These materials are then subsequently removed by settling for disposal. The primary technical advance made in 

the Actiflo® process is the addition of microsand as a “seed” and ballast for the formation of high-density flocs that have a 

relatively high-density microsand nucleus and are easily removed by settling. Chemical phosphorus removal is limited by 

kinetic factors as well as stoichiometric factors and excessive inorganic precipitant requirements need to be reduced.

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Kruger USA

401 Harrison Oaks Blvd.

Suite 100

Cary, NC 27513

Telephone: 919-677-8310

Fax: 919-677-0082

Email: krugerincmarketing@veoliawater.com

Web site: http://www.krugerusa.com

Installation(s):

City of Greenfield, IN

Lincolnton, NC

Lawrence WWTP, IN

Williamette WTP, OR

Fort Worth, TX
Emerging Technologies February 2008

2-10 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Actiflo® Process (Contd)

Key Words for Internet Search:

Actiflo®, Ballasted High Rate Clarification, BHRC

Data Sources:

Web site owned by Kruger USA.

Keller, John, et al., “Actiflo®: A Year’s Worth of Operating Experience from the Largest SSO System in the U.S.,” Water 

Environment Federation’s Annual Technical Exhibition and Conference (WEFTEC), 2005.

Ponist, Jeffrey B., David Scheiter, “Ballasted High Rate Clarification Process Removes City of Greenfield, Indiana as a CSO 

Community.” 

Sigmund, Thomas, et al., “Operating Chemically Enhanced Clarification for Optimum Disinfection Performance,” WEFTEC, 

2006.

Actiflo® Process Diagram

Microsand and Sludge to Hyrdocyclone

Microsand

Coagulant

Coagulation Injection Maturation

Tube Settler

with Scraper

Clarified

Water

Raw

Water

Hyrdocyclone

Polymer

Sludge

745043_WWT-02..ai
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-11

February 2008

Technology Summary

DensaDeg® Process

Objective:

Treatment of primary and tertiary effluents and wet 

weather flows.

State of Development:

Innovative Use of Established Technology.

Description:

The DensaDeg® process is a high-rate chemical and physical clarification process that combines sludge ballasted clarification 

and lamellar filtration, both established processes. The DensaDeg® process starts with the addition of a coagulant to destabilize 

suspended solids. The flow enters the rapid-mix tank for flash mixing to allow the coagulant to take effect then overflows into 

the reactor tank where sludge and polymer are added. A draft tube and mixer in the reactor allow for thorough mixing of the 

wastewater with the recirculated sludge and added chemicals. The sludge serves as a “seed” for floc formation providing a 

large surface area for suspended solids to bond to and is the key to DensaDeg®, allowing solids to settle out more quickly, 

thereby requiring a smaller footprint than conventional clarification. 

Wastewater flows over a weir from the reactor tank through a transition zone before entering the clarifier. The clarifier 

effectively removes the flow with help from settling tubes, allowing the tank size to be further reduced. Clarified water exits 

the process by overflowing weirs above the settling tubes. Sludge is collected at the bottom of the clarifier with a conventional 

scraper system and recirculated back to the reactor tank. Periodically, a separate sludge pump energizes and wastes a small 

portion of the sludge from the system. Scum is removed from the process at the top of the transition zone by a cylindrical 

collector that automatically rotates periodically. 

Several startup modes may be used for a full-scale DensaDeg®. If a wet weather event is expected within 6 hours of a 

previous wet weather event, the units should be shut down, but not drained. After 6 hours, the units may be drained except 

for three feet of depth in the clarifier. Both of these scenarios, which would include keeping the sludge collector running while 

the system is idle, would maintain a sludge inventory and a wet startup would ensue at the time of the next wet weather event. 

After 12 hours the tanks should be completely drained to prepare for a dry startup.

Comparison to Established Technologies:

Fundamentally, this process is very similar to conventional coagulation, flocculation, and sedimentation treatment technology. 

Both processes use coagulant for the destabilization and flocculent aid (polymer) for the aggregation of suspended materials. 

These materials are then subsequently removed by settling for disposal. The primary technical advance made in the 

DensaDeg® process is the recirculated sludge as a “seed” for the formation of high-density flocs for easy removal by settling. 

Chemical phosphorus removal is limited by kinetic factors as well as stoichiometric factors, and excessive inorganic precipitant 

requirements need to be reduced.

Available Cost Information:

Approximate Capital Cost: Cost estimates are dependent upon local requirements and specific applications.

Approximate O&M Costs: Cost savings are linked to the relative ease of installation, operational flexibility, and lowenergy consumption.

Vendor Name(s):

Infilco Degremont Inc.

P.O. Box 71390

Richmond, VA 23255-1930

Telephone: 804-756-7600

Web site: http://www.infilcodegremont.com 

Installation(s):

Turlock, CA

Gainsville, GA

Toledo, OH

Halifax, Nova Scotia

Shreveport, LA
Emerging Technologies February 2008

2-12 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

DensaDeg® Process (Contd)

Key Words for Internet Search:

DensaDeg®, High Rate Clarification, HRC

Data Sources:

Web site owned by Infilco Degremont.

http://www.infilcodegremont.com/separations_4.html

Sigmund, Thomas, et al., “Operating Chemically enhanced Clarification for Optimum Disinfection Performance,” WEFTEC, 

2006.

Process Diagram of the DensaDeg® High-Rate Clarifier and Thickener

Treated

Water

Raw

Water

Sludge Recirculation Thickened Sludge

Extraction

Coagulant Polymer Floated Matter

745043_WWT-03.ai

Coagulation Flocculation Clarication
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-13

February 2008

Technology Summary

Microwave UV Disinfection

Objective:

Tertiary Disinfection of Wastewater Effluent.

State of Development:

Innovative Use of Established Technology.

Description:

Ultraviolet (UV) disinfection transfers electromagnetic energy from a mercury arc lamp to wastewater. Electromagnetic 

radiation, between the ranges of 100 to 400 nm (UV range), penetrates bacterial cells, and works as a bactericide. Lamps 

containing mercury vapor, which are charged by striking an electric arcs emits UV radiation. Currently, the disinfection lamp 

has three main categories: (1) low-pressure, low-intensity; (2) low-pressure, high-intensity, and (3) medium-pressure, highintensity. All of these lamps contain electrodes that facilitate the generation of UV radiation. These electrodes are of delicate 

construction and their deterioration is the primary source of failure in UV disinfection systems. Microwave UV disinfection 

technology eliminates the need for electrodes by using the microwave-powered electrodeless mercury UV lamp. In this 

technology, microwave energy is generated by magnetrons and directed through wave guides into the quartz lamp sleeves 

containing argon gas. The directed microwave energy excites the argon atoms, which in turn excite the mercury atoms to 

produce radiation as they return from excited states to lower energy states, as is the case with other mercury UV lamps. 

Electrodless lamps operate at higher pressures than medium-pressure lamps, in the range of 5 to 20 atm, compared to 1 to 

2 atm for medium-pressure lamps. Microwave UV lamps allow greater flexibility for variations in parameters such as lamp 

diameter, operating pressures, and fill materials due to the absence of electrodes. This allows for greater optimization of 

radiation at specific wavelength regions. The intensity of the radiation increases when the applied microwave power is 

increased.

Comparison to Established Technologies:

The lamps warm up quickly and are capable of disinfection within 12 seconds compared to startup times of 20 seconds to 

three minutes for electrode lamps. Eliminating the electrode using from the lamp eliminates the primary deterioration process 

associated with UV lamps, resulting in a lamp life approximately three times that of electrode-using lamps. Furthermore, 

elimination of the electrodes allows for narrower lamps, which reduces the amount of reabsorption, as well as the heat 

capacity and infrared radiation generated. The lamp has very low residual radiation of energy, thus almost instant shut-off 

capability, which prevents overheating heat-sensitive materials near the lamps. Radiation is produced through the entire 

length of the lamp and there is no energy loss associated with electrodes. Nevertheless, the electrodeless lamp system has 

more components than the conventional electrode-using system, including the magnetron, wave guides, and cooling fans. 

Magnetron life is limited and requires replacement. Magnetrons usually are warranted for up to 10,000 hours of operation. 

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor as cost estimates are dependent upon local requirements and vary 

with specific applications. 

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Severn Trent Services

3000 Advance Lane

Colmar, PA 18915

Telephone: 215-997-4000

Fax: 215-997-4062

Email: info@severntrentservices.com

Web site: www.severntrentservices.com

Installation(s):

Scotland WWTP, UK 
Emerging Technologies February 2008

2-14 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Microwave UV Disinfection (Contd)

Key Words for Internet Search:

Microwave UV disinfection of wastewater, electrodeless UV lamps

Data Sources:

Gutierrez, Richard L., et al., “Microwave UV – A New Wave of Tertiary Disinfection,” WEFTEC Proceedings, 2006.

Microwave UV Technology, a Presentation by MicroDynamicsTM, Severn Trent Services.

Vendor-supplied information.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-15

February 2008

Technology Summary

Blue CATTM

Objective:

Remove emerging contaminants, such as endocrine 

disruptors, pharmaceuticals, and other complex organics 

from wastewater; simultaneously accomplish removal of 

contaminants such as phosphorus and disinfection.

State of Development:

Embryonic. Pilot studies of the Blue CATTM system have been 

conducted at 10 gpm. Results include Total Organic Compound 

(TOC) reduction from 4 to 1.5 mg/L, disinfection to <2 cfu/100 mL, 

turbidity reduction to 0.1 to 0.3 ntu, and 95% total phosphorus 

removal.

Description:

The Blue CATTM process is a combination of the Blue PROTM process with an Advanced Oxidation Process (AOP) for advanced 

treatment of effluent. The Blue PROTM process optimizes adsorption of contaminants such as phosphorus in an up-flow sand 

filter with hydrous ferric oxide-coated media and a proprietary pre-reactor.

The occurrence of chlorination byproducts, such as trihalomethanes, in environmental waters has led to enhanced concern 

and regulatory interest about chlorine disinfection of wastewater. This concern has lead to significant research into alternative 

AOPs in water treatment. AOPs can provide a mechanism for destructive removal of micropollutants and pathogens. AOPs 

are applied to water treatment UV, ozone, hydrogen peroxide, Fenton’s reagent (Fe2 + H2O2), acoustic or hydrodynamic 

cavitation, photocatalytic oxidation (UV + TiO2), and super critical water oxidation among the other processes. In recent years 

some of these technologies, such as ozonation, have seen wider implementation in municipal wastewater treatment plants 

(WWTPs). 

There are two ways to increase the rate of AOPs. These are by combining multiple AOPs or by adding catalysis. Manufacturer 

of the Blue CatTM has not disclosed the type of AOP used.

Current pilot test results are promising that significant reductions of turbidity, fecal coliforms, phosphorus, and endocrine 

disrupters or TOC can be achieved.

The residual Blue CATTM waste stream may be recycled to the head of the plant to accomplish additional contaminant 

removals and other secondary process enhancements. For increased contaminant-removal rates, destruction of organics, or 

disinfection, two passes through Blue CATTM may be combined in series.

Comparison to Established Technologies:

Based on recent investigations, there is some evidence that Blue CATTM requires less power than other AOPs due to the 

catalytic configuration of the system to maximize oxidative capability. The only metal salt chemical used is a small amount of 

iron reagent (4–10 mg/L Fe) for the Blue PROTM process. No polymer is used. The process appears to require lower chemical 

dosing than typical chemical wastewater treatment processes and consequently produces fewer solids. The iron-based 

reactive agent also provides odor control.

The Blue CATTM system is suitable for smaller plants (less than 10 MGD) since it would be difficult to operate and maintain 

due to sheer number of modules required for treatment.

Available Cost Information:

The following estimates are for a 1.0 MGD system. Economies of scale are expected for larger systems. Systems may be 

designed with a minimum flow of 5 gpm; intermittent flow systems are also possible at small installations.

Approximate Capital Cost: $463,800 – This price includes pre-reactor and filter assemblies, chemical pumps, air 

compressor, controls and electronics, sand, and freight to the site.

Approximate O&M Costs: $66,330 per year – This annual O&M expense includes $8,700 for energy (108,834 kWh), 

$48,500 for chemicals (ferric sulfate and liquid oxygen), and $9,130 for labor (1 manhour 

per day).
Emerging Technologies February 2008

2-16 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Blue CATTM (Contd)

Vendor Name(s):

Blue Water Technologies, Inc.

10450 North Airport Drive

Hayden, ID 83835

Telephone: 888-710-BLUE (2583)

Web site: www.blueh2o.net 

Installation(s):

Hayden Area Regional Wastewater Treatment Plant, Hayden, ID

Key Words for Internet Search:

Blue CATTM, catalytic oxidation, advanced phosphorus removal, endocrine disruptors

Data Sources:

Blue PROTM, “Hydrous Ferric Oxide (HFO) Coated Sand, Adsorptive Media Technical Summary,” 2006.

CH2M Hill, Technical Memorandum, “Evaluation of Blue PRO Process at the Hayden Wastewater Research Facility – Final 

Summary Report,” 2006.

Newcombe, R.L., B.K. Hart, and G. Möller, “Arsenic Removal from Drinking Water by Moving Bed Active Filtration,” Journal 

Environmental Engineering, 132(1): 5–12, 2006.

Newcombe, R.L., R.A. Rule, B.K. Hart, and G. Möller, “Phosphorus Removal from Municipal Wastewater by Hydrous Ferric 

Oxide Reactive Filtration and Coupled Chemically Enhanced Secondary Treatment: Part I. Performance,” In review, 2007.

Newcombe, R.L., D.G. Strawn, T.M. Grant, S.E. Childers, and G. Möller, “Phosphorus Removal from Municipal Wastewater 

by Hydrous Ferric Oxide Reactive Filtration and Coupled Chemically Enhanced Secondary Treatment: Part II. Mechanism,” 

In review, 2007.

Pilot-scale Blue CATTM equipment, 

including pre-reactor assembly on the 

left and reactive filter in the middle
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-17

February 2008

Technology Summary

Blue PROTM

Objective:

Remove phosphorus from tertiary wastewater.

State of Development:

Embryonic. Pilot studies of the Blue PROTM system have been 

conducted at a 1.2 MGD wastewater treatment plant in 

Hayden, ID.

Description:

The Blue PROTM filtration system includes moving-bed filtration technology preceded by chemical addition and the proprietary 

pre-reactor zone. This is used to remove phosphorus from tertiary wastewater and it combines co-precipitation and adsorption 

in an up-flow sand filter with reactive filter media and a proprietary pre-reactor. Hydrous ferric oxide-coated sand media 

accomplish phosphorus removal by adsorption rather than coagulation and filtration. This process does not require the media 

to be changed, as it has continuous regeneration via a patent-pending process and is continuous flow without the need to 

backwash. After adsorption, the iron and phosphorus are abraded from the sand grains. The iron and phosphorus passes out 

in a waste stream while the sand is retained in the system.

The Blue PROTM system is considered under the continuous backwash filter category, which is suitable for smaller plants 

(less than 10 MGD), and relatively by small modules are usually available. For a larger plant, it would be difficult to operate 

and maintain due to sheer number of modules required for treatment. The Blue PROTM process may be run in series to 

achieve lower phosphorus removal. The residual waste stream may be recycled to the head of the plant to accomplish 

chemically enhanced primary treatment. It has been demonstrated that chemical sand can achieve monthly average effluent 

total phosphorus levels varying between 0.06 μg/L and 0.009 μg/L.

Comparison to Established Technologies:

A testing program conducted by an independent party for evaluation of the Blue PROTM system against direct filtration 

systems using the same chemicals for phosphorus removal indicated that the short-term and long-term testing by Blue Water 

Technologies, Inc., produced promising results for phosphorus removal from tertiary wastewater. The long-term steady-state 

test of 0.25 MGD through the system produced effluent phosphorus levels equivalent to the best technologies currently 

available for phosphorus removal in the wastewater industry.

Available Cost Information:

Approximate Capital Cost: 1 MGD $178,300.

3 MGD $494,000 uninstalled.

Approximate O&M Costs: 1 MGD $29,380.

3 MGD $84,000 annually.

Vendor Name(s):

Blue Water Technologies, Inc.

10450 North Airport Drive

Hayden, ID 83835

Telephone: 208-209-0391

Web site: http://www.blueH2O.net

Installation(s):

Hayden Area Regional Wastewater Treatment Plant, Hayden, ID
Emerging Technologies February 2008

2-18 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Blue PROTM (Contd)

Key Words for Internet Search:

Blue PROTM, advanced phosphorus removal, phosphorus adsorption

Data Sources:

Blue PROTM, “Hydrous Ferric Oxide (HFO) Coated Sand. Adsorptive Media Technical Summary,” 2006.

Blue Water Technologies, Cleaning the World’s Waterways One Treatment Plant at a Time, Brochure, 2006. 

CH2M Hill, Technical Memorandum, “Evaluation of Blue PROTM Process at the Hayden Wastewater Research Facility – Final 

Summary Report,” 2006.

Newcombe, R.L., B.K. Hart, and G. Möller, “Arsenic Removal from Drinking Water by Moving Bed Active Filtration,” Journal 

Environmental Engineering, 132(1): 5–12, 2006.

http://www.blueh2o.net 

Blue Water Blue PROTM Phosphorus Removal System
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-19

February 2008

Technology Summary

CoMagTM

Objective:

Enhanced phosphorus and suspended-solids removal.

State of Development:

Embryonic.

Description:

The process uses magnetite for ballasted flocculation, solids contact, and high-gradient magnetic separation to meet treatment 

objectives. Metal salts are added to the wastewater and pH is adjusted. The wastewater is mixed with fine magnetic ballast 

to increase floc density and permit floc removal using magnetic separator. 

The ballasted floc settles rapidly in a small clarifier. 

Comparison to Established Technologies:

High-gradient magnetic separation has not been applied to treat wastewater prior to this technology development. Magnetite 

is denser than sand, so it creates a heavy floc that settles rapidly in a small clarifier. Its magnetic properties allow the effluent 

to be further polished using a magnetic filter, and the magnetite seed is recovered from sludge using a magnet instead of 

gravity. Chemical phosphorus removal is limited by kinetic factors as well as stoichiometric factors and excessive inorganic 

precipitant requirements need to be reduced.

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Cambridge Water Technology

Ray Pepin, PE

41 Hutchins Drive

Portland, ME 04102

Telephone: 207-774-2112, x3349

Fax: 207-774-6635

Installation(s):

City of Concord, MA

Key Words for Internet Search:

CoMagTM, Cambridge Water Technology, Concord WWTP

Data Sources:

Cambridge Water Technology 

Woodard and Curran
Emerging Technologies February 2008

2-20 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Secondary

Euent

Clean

Water

Magnetic

Separator

Sludge

Processing

Magnetic

Ballast

Recovery

Sludge Recycle

Clarier

Chemical

Treatment Recovered Ballast

Sludge

Backwash

Metal Salt

Magnetic

Ballast

745043_WWT-04.ai

pH Control

Polymer

CoMagTM Process Flow Diagram

CoMagTM (Contd)
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

2-21

February 2008

Technology Summary

Solar Disinfection

Objective:

Use of solar energy for low-cost, low-maintenance, and 

effective disinfection system for the improvement of 

wastewater before discharge.

State of Development:

Embryonic.

Description:

Several portable, low-cost, and low-maintenance solar units to disinfect treated wastewater have been designed and tested 

by researchers at the Department of Chemical Engineering in Lafayette College, PA. The solar disinfection unit was tested 

with both river water and partially processed water from two wastewater treatment plants. In less than 30 minutes in mid-day 

sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. This 

is similar to chlorination with a standard 20-minute contact time, but it is cheaper to operate and uses no hazardous chemicals. 

May only be applicable in the Sun Belt region of the United States.

Comparison to Established Technologies:

The process uses the cheapest source of energy (solar); and it is, therefore, favorable in regions of the nation were there is 

ample sunshine. 

Available Cost Information:

Approximate Capital Cost: Cost range not known at this time for commercial purposes.

Approximate O&M Costs: Cost range not known at this time for commercial purposes.

Vendor Name(s):

Lafayette College

Department of Chemical Engineering

Easton, PA 18042

Telephone: 610-330-18042

Email: tavakoli@lafayette.edu 

Installation(s):

There are no installations at this time.

Key Words for Internet Search:

Solar disinfection, wastewater treatment, portable solar units

Data Sources:

Archer, A., Fischer, E., Turnheim, R., Manor, Y., “Ecologically Friendly Wastewater Disinfection Techniques,” Water Research 

(WATER RES), Vol. 31, No. 6, pp. 1,398–1,404, June 1977. 

Caslake, Laurie F., Daniel J. Connolly, Vilas Menar, Catriona M. Duncanson, Ricardo Rojas and Joavad Tavakoli, “Disinfection 

of Contaminated Water by Using Solar Irradiation,” Applied and Environmental Microbiology, February 2004. 

Journal of Environmental Systems, Issue, Volume 26, No. 2, 1997–1998.
Emerging Technologies February 2008

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Chapter

Wastewater Treatment and In-Plant Wet Weather Management 3-1

3

Biological Treatment Processes

3.1 Introduction

Biological treatment processes are systems that use microorganisms to degrade organic 

contaminants from wastewater. In wastewater treatment, natural biodegradation 

processes have been contained and accelerated in systems to remove organic material 

and nutrients. The microorganisms metabolize nutrients, colloids, and dissolved organic 

matter, resulting in treated wastewater. Excess microbial growth is removed from the 

treated wastewater by physical processes. 

In the last decade, there have been major advancements in the area of biological treatment 

processes. Biological processes are now the preferred way of treatment as they have 

become cost effective in terms of energy consumption and chemical usage. For example, 

biological nutrient removal (BNR) has emerged as the preferred approach for nutrient 

removal. BNR processes involve modifications of biological treatment systems so that 

the microorganisms in these systems can more effectively convert nitrate nitrogen into 

inert nitrogen gas and trap phosphorus in solids that are removed from the effluent.

3.2 Technology Assessment

Table 3.1 presents a categorized list of emerging and established biological treatment 

technologies. The list includes most established biological treatment processes and 

recent developments in cost-effective methods to retrofit older systems or result in 

systems with smaller footprints. Experience in operation of biological systems and the 

ongoing effort to maximize process performance has resulted in established biological 

treatment processes undergoing modifications that warrant discussion in this chapter on 

emerging technologies. Generally, the improvements in established biological treatment 

processes provide treatment of recycle streams, optimize recycle, and maximize nutrientremoval capabilities.

An evaluation of the innovative technologies identified for biological treatment processes 

relative to their state of development, applicability, potential for effluent reuse and the 

potential benefits of the technology is presented in Figure 3.1. Summary sheets for each 

innovative and embryonic technology are provided at the end of the chapter. The 

innovative technologies are as follows: Bioaugmentation, Cannibal®, CATABOLTM, DeepShaft Activated Sludge/VERTREATTM, Integrated fixed-Film Activated Sludge (IFAS), 

Membrane BioReactor (MBR), and Mobile-Bed Reactor Technology (MBRT) processes. 

The innovative use of established technologies are as follows: Bardenpho® (Three Stage) 
Emerging Technologies February 2008

3-2 Wastewater Treatment and In-Plant Wet Weather Management

with Returned Activated Sludge (RAS) Denitrification, Biological-Chemical Phosphorus 

and Nitrogen Removal (BCFS) Process, Modified University of Cape Town (MUCT) 

Process, Modified Anaerobic/Oxic (A/O) Process, and Trickling Filter/Solids Contactor 

(TF/SC). These processes have various configurations and modules to fit the specific 

needs of any individual treatment plant. Most of these technologies can be easily retrofitted 

into existing treatment systems that enable treatment processes to achieve better nutrient 

removal. 

This chapter also lists a number of biological processes that are in embryonic stages of 

development. Processes like Single Reactor High-activity Ammonia Over Nitrite 

(SHARON), Single Reactor High-activity Ammonia Over Nitrite – ANaerobic AMMonia 

OXidation (SHARON – ANAMMOX), and Vacuum Rotation Membrane (VRM®) are now 

being used in full-scale application in the United States after being selected as a preferred 

technology in Europe and other parts of the world. These processes provide energyefficient biological nutrient removal with reduced external carbon requirements. Another 

advantage of these processes is a reduced footprint, although footprint reduction has not 

been a priority in the United States as much as in the rest of the world, where availability 

of land is often more restricted.

Other embryonic technologies included at the end of this chapter are as follows: Aerobic 

Granular Sludge Process (AGSP), ANaerobic Membrane BioReactor (AN-MBR), 

Anaerobic Migrating Blanket Reactor (AMBR®), DEamMONification (DEMON) Process, 

Hydrogen-based hollow-Fiber Membrane Biofilm Reactor (HFMBfR), Membrane-Aerated 

BioReactor (MABR), Microbial Fuel Cell (MFC) Based Treatment System, Multi-Stage 

Activated Biological Process (MSABPTM), NeradaTM, and STRASS Process (Nitrification 

and Denitrificaiton in SBR).

Established Technologies

BOD Removal and Nitrification 

 Biolac-Aerated Lagoon 

 Complete Mix-Activated Sludge (CMAS) Process

 Contact Stabilization 

 Conventional Extended Aeration 

 Countercurrent Aeration System (CCASTM) 

 Cyclic Activated Sludge System (CASSTM) 

 High-Purity Oxygen (HPO) 

Intermittent Cycle Extended Aeration System (ICEASTM  )

 Kraus Process 

 Oxidation Ditch/Aerated Lagoons 

 Sequencing Batch Reactor 

Table 3.1—Biological Treatment Processes – State of Development

Established Technologies (Contd)

 Staged Activated-Sludge Process 

 Step Feed 

 Step Feed (Alternating Anoxic and Aerobic) 

Biological Nutrient Removal (BNR)

Bardenpho®  (Four Stage) 

BiodenitroTM  

 Ludzack-Ettinger 

 Modified Ludzack-Ettinger (MLE) 

OrbalTM  Process 

SchreiberTM  Process 

 Simultaneous Nitrification denitrificatioN (SNdN) Process

 Step Feed BNR Process 

 Wuhrman 
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-3

February 2008

Established Technologies (Contd)

Enhanced Biological Phosphorus Removal (EBPR)

 Anaerobic/Anoxic/Oxic (A2/O) 

Bardenpho®  (Five Stage) 

 Johannesburg Process 

 Phoredox (Anaerobic/Oxic [A/O])

 Phostrip 

 University of Cape Town (UCT) 

 Virginia Initiative Plant (VIP)

Other Biological Processes 

 Fluidized Bed Bioreactor (FBBR) 

 Rotating Biological Contractor (RBC) 

 Submerged Rotating Biological Contactor (SRBC)

 Trickling Filter (TF) 

Anaerobic Processes

 Anaerobic Attached Growth System 

– Upflow Packed-Bed Attached Growth Reactor

– Upflow Attached Growth Anaerobic

Expanded-Bed Reactor (Anaerobic Expanded Bed Reactor 

[AEBR])

–

– Downflow Attached Growth Process 

 Anaerobic Contact Process 

Anaerobic Sequencing Batch Reactor (ASBR®  ) 

 Upflow Anaerobic Sludge Blanket (UASB) 

 ANFLOW (ANaerobic FLuidized Bed Reactor) 

Biological Aerated Filters (BAF)

Biofor® 

Biostyr® 

Innovative Technologies

Bioaugmentation

 External Bioautmentation

– Seeding from Commercial Sources of Nitrifiers

Trickling Filter and Pushed Activated Sludge (TF/PAS) 

Process

–

Seeding from External Dispensed Growth Reactors 

Treatment Reject Waters (Chemostat)

–

In-Nitri® – Process

Immobilized Cell-Augmented Activated Sludge (ICASS) 

Process

–

– Seeding from Parallel Processes

– Seeding from Downstream Process

 In Situ Bioaugmentation 

DE-nitrification and PHosphate accumulation in ANOXic 

(DEPHANOX) Process

–

Table 3.1—Biological Treatment Processes – State of Development (Contd)

Innovative Technologies (Contd)

Bio-Augmentation Regeneration/Reaeration (BAR) 

Process

–

– Bio-Augmentation Batch Enhanced (BABE) Process

– Aeration Tank 3 (AT3) Process

Main stream AUtotrophic Recycle Enabling Enhanced Nremoval (MAUREEN) Process

–

– Regeneration DeNitrification (R-DN) Process

Cannibal® 

CATABOLTM 

Deep-Shaft Activated Sludge/VERTREATTM

Integrated fixed-Film Activated Sludge (IFAS)

 IFAS – Submerged Mobile Media 

Attached Growth Airlift Reactor (AGAR® – )

Captor® –

LINPOR® –

 IFAS – Submerged Fixed Media 

CLEARTEC® –

AccuWeb® –

BioMatrixTM –

HYBASTM –

– BioWebTM

RINGLACE® –

Membrane Bioreactor (MBR)

 Tubular 

 Hollow-Fiber 

 Spiral Wound 

 Plate and Frame 

 Pleated Cartridge Filters

Mobile-Bed Reactor Technology (MBRT) Process

Kaldnes®  HYBASTM/ Active CellTM 

 Hydroxyl-F3R 

GeoReactor®  

Innovative Use of Established Technologies

Bardenpho® (Three Stage) with Returned Activated Sludge (RAS) 

Denitrification

Biological-Chemical Phosphorus and Nitrogen Removal (BCFS)* 

Process

Modified University of Cape Town (MUCT) Process

Modified Anaerobic/Oxic (A/O) Process

Trickling Filter/Solids Contactor (TF/SC)

Note:

* Chemical phosphorus removal is limited by kinetic factors 

as well as stoichiometric factors and excessive inorganic 

precipitant requirements need to be reduced.
Emerging Technologies February 2008

3-4 Wastewater Treatment and In-Plant Wet Weather Management

Table 3.1—Biological Treatment Processes – State of Development (Contd)

Embryonic Technologies

Aerobic Granular Sludge Process (AGSP)

ANaerobic Membrane BioReactor (AN-MBR)

Anaerobic Migrating Blanket Reactor (AMBR®)

DEamMONification (DEMON) Process

Hydrogen-based hollow-Fiber Membrane Biofilm Reactor 

(HFMBfR)

Membrane-Aerated BioReactor (MABR)

Microbial Fuel Cell (MFC) Based Treatment System

Multi-Stage Activated Biological Process (MSABPTM)

NeredaTM 

Figure 3.1—Evaluation of Innovative Biological Treatment Technologies

Process

Evaluation Criteria

DevelopmentApplicabilityBenefitsImpact on ProcessesComplexityAir/Odor EmissionsReuseEnergyFootprintRetrofitting

Bioaugmentation I, M, N, O F C, O y y y In y y p

Cannibal® M, N F C, O p y y In p p p

CATABOLTM M, N F C, O y y p In y y p

Deep-Shaft Activated Sludge/VERTREATTM M, N, O F C, O p y y In p p y

Integrated Fixed-Film Activated Sludge (IFAS) I, M, N I C, O p y y In p p p

Membrane Bioreactor (MBR) I, M, N, O I, F C, O p y y In p p p

Mobile-Bed Reactor Technology (MBRT) Process I, N, O F C, O p y y In p p p

Comparative Criteria

p Positive feature

y Neutral or mixed

q Negative feature

Effluent Reuse

Dp = Direct potable

Dn = Direct nonpotable

Ip = Indirect potable

In = Indirect 

nonpotable

Applicability

F = Few plants

I = Industrywide

L = Primarily large plants

S = Primarily small plants

Potential Benefits

C = Capital savings

I = Intense operational demand

O = Operational/maintenance savings

S = Shock load capacity

W= Wet weather load capacity

Statement of Development

B = Bench scale

I = Full-scale industrial applications

M = Full-scale municipal applications

O = Full-scale operations overseas

P = Pilot

N = Full-scale operations in North America

Key

Embryonic Technologies (Contd)

Single reactor High-activity Ammonia Removal Over Nitrite 

(SHARON)

SHARON – ANAMMOX (ANaerobic AMMonia OXidation)

STRASS Process 

Vacuum Rotation Membrane (VRM®) System
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February 2008

Technology Summary

Bioaugmentation

Objective:

Achieve higher kinetic rates by addition of bacteria and 

enhance nitrification and denitrification

State of Development:

Innovative.

Description:

In Biological Nutrient Removal (BNR) plants designed for nitrogen and phosphorus removal, reactor volumes dedicated to 

nitrification constitute majority of reactor volume. Bioaugmentation aims to reduce the volume dedicated to nitrification by 

decreasing the required aerobic Sludge Retention Time (SRT) by increasing the rate of nitrification. There are two types of 

bioaugmentation schemes; these are (1) external bioaugmentation and (2) in situ bioaugmentation. External bioaugmentation 

includes addition of external-source nitrifiers, whereas in situ bioaugmentation provides internal process enhancements that 

increase activity or enrich nitrifier population. The advantage of external bioaugmentation schemes is that the promotion of 

nitrification within the main stream process can be decoupled from its aerobic SRT. The advantage of in situ schemes is that 

there is less concern about the loss of activity of the seed nitrifiers when transferred to the mainstream process because their 

conditions of growth are similar to those prevalent in the mainstream process. 

External Bioaugmentation

Examples of external bioaugmentation includes seeding from commercial sources of nitrifiers, Trickling Filter and Pushed 

Activated Sludge (TF/PAS) process, seeding from external dispersed growth reactors treating reject waters, seeding from 

external activated sludge reactors treating reject waters, seeding from parallel processes, and seeding from downstream 

processes. Some facilities having both air-activated sludge systems and high-purity oxygen systems have proven that 

nitrification in the high-purity oxygen can be significantly enhanced by seeding with nitrification solids from the parallel aerated 

BNR system. This procedure is not patented. External bioaugmentation is performed in Hagerstown, MD, Henrico County, 

VA, and Hopewell, VA. Note, nitrification in high-purity oxygen plants is typically limited due to pH inhibition.

Seeding from Commercial Sources of Nitrifiers: Although early attempts at bioaugmentation with commercial seed 

sources within wastewater treatment plants have produced controversial results, bioaugmentation for nitrification has 

readily measurable success. Adding external nitrifiers’ sources has shown some success at both laboratory and field scale 

and allows operation at colder temperatures where nitrifiers would normally washout but required dosages of the nitrifiers 

were very high. Therefore, most investigators diverted to onsite production of seed organisms within the treatment plant.

TF/PAS Process: The earliest example of external bioaugmentation with nitrifiers generated within the plant from a 

wastewater source is likely that of the TF/PAS process, whereby the total organic loading on the trickling filter is adjusted to 

achieve about 50 percent nitrification, thereby seeding nitrifiers to a down-stream activated sludge step with a low SRT of 2 

to 4 days. It appears that the enhanced nitrification rates achieved may be due to both the effect of seeding as well as 

removing toxicants in the wastewater by pretreatment of the trickling filter.

Aeration Tank

TF Partly Nitrifies, Seeding

Nitrifiers to Activated Sludge Step

Trickling Filter

Second Clarifier

745043_WWT-05.ai

Process Flow Diagram for Trickling Filter/Pushed Activated Sludge
Emerging Technologies February 2008

3-6 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Bioaugmentation (Contd)

Seeding from External Dispersed Growth Reactors Treating Reject Waters (Chemostat Type): There has been some 

success reported with chemostats seeding batch reactors simulating mainstream processes. Nitrifiers grown in batch-fed 

sidestream chemostats were more effective in stimulating the process efficiency in the simulated main-stream reactors than 

were those grown in continuously fed chemostats. It has been shown that the specific nitrifier types grown in the sidestream 

chemostats were able to replace the microbial population in the mainstream reactors, suggesting that population diversity 

leads to more robust mainstream reactors. 

Process Flow Diagram for Seeding from External Dispersed Growth

In-Nitri® Process: Growing the nitrifiers in an external activated sludge plant using ammonia-laden digester filtrate has 

proven to be successful as it appears that the nitrifiers are protected within activated-sludge flocs. A process known as the 

Short SRT or In-Nitri® process used this principle and several bench or pilot-scale studies have proven its effectiveness.

In-­Nitri® consists of supplemental nitrifying bacteria constantly added to the main-stream activated-sludge process to replenish 

nitrifiers removed with the waste activated sludge. The nitrifiers are grown in a separate sidestream aeration tank using 

ammonia available either in the digested sludge dewatering liquid and in the digester supernatant or from commercial 

ammonia addition. The process has the advantage of achieving year-round nitrification by reducing the SRT by adding only 

a small aeration tank and clarifiers for growing nitrifiers.

Equalized Ammonia Laden

Filtrate From Dewatering

Dispersed Growth Reactor (e.g., SHARON Process)

Waste Sludge

Clarifier

Primary

Effluent

Return Activated Sludge

745043_WWT-06.ai
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-7

February 2008

Technology Summary

Bioaugmentation (Contd)

Process Flow Diagram for Inexpensive Nitrification

Immobilized Cell-Augmented Activated Sludge (ICAAS) Process: Immobilized cells are maintained for a specific treatment 

activity and are enriched in a reactor for bioaugmentation. The ICAAS process employs the immobilized cells that are activated 

and maintained for their specific treatment activity in an off-line enricher reactor for bioaugmentation. The process has been 

effectively used in bench-scale reactors for treating hazardous-compound shock loads, to achieve enhanced nitrate removal 

and to increase general performance of the treatment process. 

Aeration

Tank

Primary Sludge

Thickening

Primary

Sedimentation

Tank

WAS

Thickening

Digester

Sludge

Dewatering

Side-Stream

Nitrification

Secondary

Sedimentation

Tank

Thickened

Primary

Sludge

Dewatering

Return

Stream

Treated

Effluent

Supernatant

Sludge for

Disposal Alkalinity

Excess

Nitrification

Sludge

Nitrified

Dewatering

Liquid

Raw

Wastewater

745043_WWT-07..ai
Emerging Technologies February 2008

3-8 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Bioaugmentation (Contd)

Seeding from Parallel Processes: Two schemes have been proposed to grow nitrifiers in a MBR and seed a high-rate BNR 

process. However, results on pilot or full-scale trials have not yet been reported. Another approach included two parallel 

activated-sludge processes, tertiary nitrifying MBR seeding parallelling a high-rate activated sludge process. Some process 

issues in this scheme are as follows: membranes select for filtering, not settling biomass; seeding effectiveness is likely 

impacted by predation; and the process only fits some nutrient-removal flow diagrams.

Process Flow Diagram for Tertiary Nitrifying MBR Seeding Parallel High-Rate BNR Process

Process Flow Diagram for High Rate BNR Seeded by Parallel MBR Reactor

Low SRT

(2–3 Days)

Complete Nitrification

Membrane

Bioreactor

(High SRT)

Donor Plant

Effluent

Receiver Plant Effluent

Nitrifier Enriched Membrane Bioreactor WAS

AmmoniaRich

Stream

WAS

Digested

Sludge

Centrate

Supernatant

Raw

Influent

Primary

Sludge

Low SRT

(2–3 Days)

Complete Nitrification

WAS

Primary

Sludge

745043_WWT-08..ai

Base-Loaded

MBR

High-Rate BNR

(also treats

peak flows)

WAS

745043_WWT-09..ai
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Emerging Technologies

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February 2008

Technology Summary

Bioaugmentation (Contd)

Seeding from Downstream Process: There are two seeding processes developed for the main treatment plant in Vienna, 

Austria. The plant is a two-stage plant, whereby carbon is removed in the first stage and nitrification occurs in the second 

stage. In this scheme, nitrifying mixed liquor is wasted to the first stage resulting in some nitrification in that stage. Effluent 

from the second stage is also recycled during dry weather for denitrification in the first stage while 10 to 40 percent of the 

influent is bypassed to the second stage to obtain additional denitrification. An alternative to the bypass mode is termed the 

hybrid mode, which includes exchange of mixed liquors between the stages.

In Situ Bioaugmentation

Separate-stage nitrification processes, where carbon is removed in an initial biological stage and then followed by a separatestage nitrification process, are the first examples of in situ bioaugmentation. A three-sludge system incorporating separatestage nitrification, was promoted as a preferred technology in 1970s. Main reason for this was that the separate steps of 

carbon removal, nitrification and denitrification could each be optimized. There have also been fixed-film systems employed 

for separate stage nitrification. Purpose of these systems was three-fold and as follows: (1) use of media with high-masstransfer rates; (2) use of recirculation to improve media-wetting and gain maximum nitrifying biofilm coverage and minimization 

of influent solids to avoid competition for oxygen from heterotrophs; and (3) the control of predators with flooding and alkaline 

treatment.

DE-nitrification and PHosphate accumulation in ANOXic (DEPHANOX) Process: This process includes a combination 

of suspended growth and fixed-film systems in separate stages. DEPHANOX is based on the phenomenon of phosphate 

accumulation in the anoxic zone while undergoing simultaneous denitrification.

Process Flow Diagram for DEPHANOX Process

Anaerobic

Zone

Influent

RAS

Effluent Nitrification Denitrification Post

Aeration

Primary

Settling

Tank

Final

Settling

Tank

WAS

745043_WWT-10..ai
Emerging Technologies February 2008

3-10 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Bioaugmentation (Contd)

BAR Process: In the Bio-Augmentation R Process, the R stands for regeneration zone in the Czech Republic and in the 

United States the R stands for reaeration. The BAR Process simply recycles the ammonia-laden filtrate or centrate from 

dewatering of aerobically digested sludge to a reaeration (regeneration) tank and receives return activated sludge. The 

stream is fully nitrified and the nitrifiers within activated-sludge flows are then carried forward to charge the main aeration 

tank, thereby reducing the SRT required for complete nitrification. The BAR process was independently developed in the 

United States and Czech Republic.

Process Flow Diagram for BAR Process

Equalized Ammonia Laden

Filtrate From Dewatering

Waste Sludge

Clarier

Primary Euent Iron Addition

Return Activated Sludge

745043_WWT-11.ai
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Emerging Technologies

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February 2008

Technology Summary

Bioaugmentation (Contd)

Bio-Augmentation Batch Enhanced (BABE) Process: Comprised of a Sequencing Batch Reactor (SBR) which is fed with 

the reject water from the sludge dewatering process and the Returned Activated Sludge (RAS) from the treatment system. 

The RAS augments the batch reactor with the nitrifying bacteria from the activated sludge floc. The SBR follows the phases 

of the treatment cycle, i.e, fill and aerate, react, settling, and wasting. Longer sludge age can be achieved in the SBR tank, 

which helps the nitrifying bacteria to adapt and grow in the BABE reactor.

Process Flow Diagram for BABE Process

Aeration Tank 3 (AT3) Process: The AT3 Process is similar to BAR Process but it differs in sending a smaller fraction of the 

RAS to the reaeration tank. The process goal is to stop the nitrification process at nitrite stage by use of dissolved oxygen 

(DO) and pH control to reduce the consumption of carbon and oxygen for denitrification. Addition of an external carbon source 

may be needed to the reaeration tank to accomplish denitrification.

Main stream AUtotropic Recycle Enabling Enhanced N-removal (MAUREEN) Process: The MAUREEN process includes 

a sidestream bioreactor to allow for nitrification and denitrification of the centrate stream. This process was developed for the 

Blue Plains Advanced Wastewater Treatment Plan (AWTP) and provides significant flexibility when applied to the two-sludge 

system at the plant. Configuration includes preferential bioaugmentation of ammonia-oxidizing bacteria from the second to 

the first stage via the sidestream reactor and oxidation of ammonia in reject centrate to nitrite in the enrichment reactor 

resulting in reduced power and chemical consumption. This process has the ability to fortify the second-stage system with a 

combination of primarily ammonia oxidizers and anoxic methanol-degrading bacteria produced in the sidestream reactor 

under conditions that would limit the presence of nitrite-oxidizing bacteria and heterotrophic bacteria. Supernatant from the 

sidestream process can be used for odor and corrosion control in the headworks or within process streams at the plant. Key 

to the success of the process is the physical configuration and selection of operating conditions of the sidestream reactor.

Activated

Sludge Tank

Nitrification

Reactor

~25°C

Secondary Effluent

Centrate (NH3–N) Nitrifiers (NO3–N)

WAS RAS

PC SC

745043_WWT-12..ai
Emerging Technologies February 2008

3-12 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Bioaugmentation (Contd)

Bioreactor

Nitrication/

Denitrication

Bioreactors

WAS

Nitriers and Methanol

Using Dentriers

Return Liquor (Centrate)

Alkalinity

Methanol

Nitrication/

Denitrication

Bioreactors

Raw

Wastewater

WAS

RAS

West Plant

PC SC

Bioreactor

WAS

RAS

RAS

East Plant

PC SC

SC

745043_WWT-13.ai

Process Flow Diagram for MAUREEN Process

Regeneration-DeNitrification (R-DN) Process: The R-DN process is identical to BAR process and also involves filtrate or 

centrate bioaugmentation. It was independently developed in the Czech Republic and the United States.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Technology Summary

Bioaugmentation (Contd)

Comparison to Established Technologies:

The bioaugmentation process helps to achieve higher performance standards because the microorganisms added to the 

reactive phase in the treatment processes boosts microbial activity. These microorganisms are more adapted to the conditions 

in the reactive phase of the treatment process than the microorganisms in the influent. 

Based on simulation results for a highly loaded activated-sludge process as the main treatment stage, use of the BABE 

technology lowers the ammonium concentration in the effluent by 20 to 100 percent, dependent on the temperature in the 

aeration tank and the nitrogen load of the BABE reactor. When the process temperature in the BABE reactor is lower than 20 

degrees C, the volume of the BABE reactor is determined by the process temperature. The necessary reactor volume 

increases significantly with decreasing temperatures. Above a process temperature of 24 degrees C, the temperature has 

only a minor influence on the necessary reactor volume. About 50 percent of the ammonium reduction in the effluent is 

caused by the nitrification of the reject water in the BABE reactor. The remaining 50 percent is removed in the aeration tank 

by nitrifying bacteria washed out from the BABE reactor. This inoculation effect is a main feature of the BABE process 

design. 

Available Cost Information:

Approximate Capital Cost: Costs information not available from vendors. However, bioaugmentation processes 

save capital costs in the main treatment systems due to reduced reactor volumes via the 

augmentation of nitrifying bacteria.

Approximate O&M Costs: The operating costs are mainly related to mixing and aeration requirements and depend upon 

local conditions and the available equipment. Bioaugmentation processes also save operating 

costs in the main treatment through the augmentation of nitrifying bacteria. Actual costs were 

not disclosed.

Vendor Name(s):

DHV Water BV

P.O. Box 484

3800 AL Amersfoort, The Netherlands

Telephone: 0031-33-468-2200

Email: info@wa.dhv.nl

Web site: http://www.dhv.com/water/

Mixing and Mass Transfer Technologies

P.O. Box 315

State College, PA 16804

Telephone: 814-466-6994 or 888-715-9600

Email: rjohansen@m2ttech.com or 

 tgilligan@m2ttech.com

Web site: http://m2ttech.com/index.asp

Eakalak Khan

Associate Professor

Dept. of Civil Engineering 

North Dakota State University

Fargo, ND 58105

Telephone: 701-231-7717

Fax: 701-231-6185

Email: eakalak.khan@ndsu.edu

Installation(s):

BAR Process: Appleton WWTP, Wisconsin; Theresa Street 

WWTP, Lincoln, Nebraska; Woodward Ave. WWTP, Hamilton, 

Ontario, Canada; and 20 plants in Czech Republic

AT3 Process: 26th Ward WWTP, New York City, NY

BABE Process: s’Hertozenbosch WWTP, The Netherlands

MAUREEN Process: Blue Plains AWTP, Washington, D.C.
Emerging Technologies February 2008

3-14 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Bioaugmentation (Contd)

Key Words for Internet Search:

Bioaugmentation, nitrification, wastewater treatment, bacteria

Data Sources:

Constantine, T.A., et al., “New Nitrifier Bioaugmentation Process Configure to Achieve Year Round Nitrification at Low SRTs,” 

Proceedings of WEFTEC, 2001.

Daigger, G.T., et al., “Incorporation of Biological Nutrient Removal (BNR) into Membrane Bioreactors (MRBs),” Proceedings 

of the International Water Association (IWA) Specialized Conference on Nutrient Management in Wastewater Treatment 

Processes and Recycle Streams, Krakow, Poland.

Katehis, D., B. Stinson, J. Anderson, “Enhancement of Nitrogen Removal three Innovative Integration of Centrate Treatment,” 

WEFTEC, 2002.

Parker, Denny S. and Jiri Wanner, “Improving Nitrification through Bioaugmentation,” WEF, Nutrient Removal Conference, 

2007.

Parker, Denny, Brown, and Caldwell, “Nutrient Removal, How low can we go and what is stopping us from going lower? 

Improving Nitrification through Bioaugmentation,” WERF Presentation, 2007.

Stensel, H. David, “Sidestream Treatment for Nitrogen Removal,” 11th Annual Education Seminar Central States Water 

Environmental Association, 2006.

http://m2ttech.com/index.asp 

http://www.dhv.com/water/ 

Telephone conversation and email communication with Mixing and Mass Transfer Technologies. 

Email communication with Tim Constantine of CH2M HILL.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-15

February 2008

Technology Summary

Cannibal® Process

Objective:

Biosolids volume reduction without digestion, thickening, 

dewatering, or polymer addition.

State of Development:

Innovative. A 1 MGD sequential batch reactor wastewater 

treatment plant in Georgia began using the Cannibal® solids 

reduction process in October 1998. The plant has purged solids 

once in 5 years to relieve the plant of extremely fine, inert material 

buildup. The plant removed 8,000 pounds of waste biosolids by 

using this process between January 2000 and September 2003. 

Favorable results also have been realized at other full-scale 

operations within the United States. This process also has been 

successful at the Alpine Cheese Factory in Holmes County, Ohio, 

and it has been the subject of bench-scale research at Virginia 

Polytechnic Institute and State University, Virginia.

Description:

A portion of sludge from the main treatment process is pumped to a sidestream bioreactor where the mixed liquor is converted 

from an aerobic-dominant bacterial population to a facultative-dominant bacterial population. Aerobic bacteria are selectively 

destroyed in this sidestream reactor, while enabling the facultative bacteria to break down and use the remains of the aerobes 

and their byproducts. 

Mixed liquor from the bioreactor is recycled back to the main treatment process. There, the facultative bacteria, in turn, are 

out-competed by the aerobic bacteria and subsequently broken down in the alternating environments of the aerobic treatment 

process and the sidestream bioreactor. 

Trash, grit, and other inorganic materials are removed from the process by a patented solid-separation module on the return 

sludge line. All of the return sludge is pumped through this module and recycled back to the main treatment process. Only a 

portion of this flow is diverted to the sidestream bioreactor for the selection and destruction process.

Comparison to Established Technologies:

Not similar to any established technology.

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

According to the vendor, a 1.5 MGD WWTP could recognize an approximate net annual operating cost savings of $245,600 

using the Cannibal® process.

Vendor Name(s):

Envirex Products

1901 S. Prairie Ave.

Waukesha, WI 53189

Telephone: 262-521-8570

Fax : 262-547-4120

Email: roehlm@usfilter.com

Web site: www.usfilter.com

Installation(s):

Alpine Cheese Factory, Inc.

 1504 U.S. 62

 Wilmont, OH 44689

 Telephone: 330-359-5454

 Fax: 330-359-5049

Bryon WWTP, Bryon, IL
Emerging Technologies February 2008

3-16 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Cannibal® Process (Contd)

Key Words for Internet Search:

Cannibal® process, biosolids, sludge

Data Sources:

Novak, J.T., D.H. Chon, B-A. Curtis, and M. Doyle, “Reduction of Sludge Generation using the Cannibal® Process: Mechanisms 

and Performance,” Proceedings of WEF Residuals and Biosolids Management Conference, 2006 and Bridging to the Future 

Conference, Cincinnati, OH, March 12 to 14, 2005.

Sheridan, J. and B. Curtis, “Casebook: Revolutionary Technology Cuts Biosolids Production and Costs,” Pollution Engineering, 

36:5, 2004.

Vendor-supplied information.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-17

February 2008

Technology Summary

CATABOLTM

Objective:

Combined anaerobic and aerobic treatment to achieve 

reduced nitrogen and phosphorus levels in the treated 

wastewater. 

State of Development:

Innovative.

Description:

In the CATABOLTM process, anaerobic microorganisms for phosphorus removal are combined with aerobic and facultative 

microorganisms for nitrogen removal. A schematic of the process for treatment of municipal wastewater is shown in the figure 

on the next page. The principal elements of the process include an anaerobic reactor, and aerobic reactor, sludge separation, 

inert solids removal, alkalinity and pH control, and a sludge conditioner. Additional equalization tanks, multi-stage reactors 

and tertiary treatment processes, as well as other CATABOLTM configurations may be used in particular applications. The inert 

solids are used as an anaerobic sludge conditioner. Solids from the aerobic zone of the CATABOLTM process are separated 

in a clarifier and sent to the anaerobic sludge conditioner for conversion to predominately anaerobic microorganisms with 

some facultative microorganisms prior to being reintroduced into the anaerobic zone of the CATABOLTM process. The 

anaerobic zone followed by the aerobic zone are the key processes for decomposing the wastewater and removing 

phosphorus. Passage through the sludge conditioner also stores the conditioned microorganisms for use as and when 

needed. Excess solids produced by the CATABOLTM process are wasted from the anaerobic sludge conditioner. To avoid 

process upset by acidification of the wastewater, alkalinity and pH must be controlled. 

Comparison to Established Technologies:

This combined anaerobic-aerobic biological process has been developed to lower operating cost. The process also helps to 

eliminate odor problems and reduce sludge disposal costs. 

Available Cost Information:

Approximate Capital Cost: $6.7 M for the upgrade of a 15-MGD plant, increasing capacity to 20 MGD.

Approximate O&M Costs: $600,000/year in operational saving and electricity consumption after the upgrade of the 20 

MGD plant. 

Vendor Name(s):

Khudenko Engineering, Inc.

744 Moores Mill Road

Atlanta, GA 30327

Telephone: 404-261-4452

Fax: 404-816-1611

Email: bkhudenko@comcast.net

Installation(s):

City of Cartersville, GA

Key Words for Internet Search:

Khudenko Engineering, CATABOLTM

Data Sources:

Vendor pamphlet and phone conversation with Khudenko Engineering staff.
Emerging Technologies February 2008

3-18 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

CATABOLTM (Contd)

Anaerobic

Zone

Anaerobic

Sludge

Conditioner

Aerobic

Zone

Solids

Separation

Air

Air Waste

Sludge

Return Sludge

Air + CO2 CH4

Conditioned Sludge

Influent Effluent

Inerts

Aerobic Mixed Liquor

745043_WWT-14.ai

CatabolTM Combined Treatment Process Schematic
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-19

February 2008

Technology Summary

Deep Shaft Activated Sludge/VERTREATTM

Objective:

Increased oxygen transfer in the activated sludge 

process to decrease power requirements, saving both 

capital and operating costs.

State of Development:

Innovative. This technology has a well-established track record in 

Europe and Asia with over 30 years operation in municipal and 

industrial applications. There are a few operating facilities in North 

America in both Canada and the United States.

Description:

The Deep-Shaft Activated Sludge/VERTREATTM process is a modification of the activated-sludge process. VERTREATTM 

essentially uses a vertical “tank” or shaft in place of the surface aeration basins used in a conventional system. The result of 

this vertical configuration is a ten-fold increase in the dissolved oxygen content of the mixed liquor, which increases the level 

of biological activity in the bioreactor. The process can accommodate high-organic loading with lower aeration supply due to 

the enhanced oxygen transfer (a function of both increased pressure at depth and longer bubble-contact time).

Comparison to Established Technologies:

Reduced footprint requirements.

Lower power consumption and simple controls resulting in reduced O&M.

Much higher-rate system due to increased oxygen transfer in process.

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Available Cost Information:

Approximate Capital Cost: $3 to $5 per installed design gallon of flow.

Approximate O&M Costs: Dependent on power costs. Roughly half the aeration power requirement due to increased 

oxygen-transfer efficiency. Lower maintenance costs as a result of having no pumps or 

diffusers in the core system.

Vendor Name(s):

NORAM Engineering and Constructors Ltd.

Suite 1800, 200 Granville Street

Vancouver, BC, Canada V6C 1S4

Telephone: 604-681-2030

Fax: 604-683-9164

Web site: www.noram-eng.com 

Installation(s):

City of Homer – Public Works Department

3575 Heath Street

Homer, AK, USA 99603 

Telephone: 907-235-3174

Fax: 907-235-3178

Email: jhobbs@ci.homer.ak.us
Emerging Technologies February 2008

3-20 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Deep Shaft Activated Sludge/VERTREATTM (Contd)

Key Words for Internet Search:

Deep shaft process, activated sludge, wastewater treatment, oxygen transfer, high rate, BOD, aerobic

Data Sources:

www.noram-eng.com

www.vertreat.com

Email communication with the vendor.

Flow Diagram of VERTREATTM provided by NORAM Engineering and Constructors Ltd.

745043_WWT-15.ai

Influent

Air

Compressor

Oxidation Zone

Mixing Zone

Saturation Zone

Vent Air Head Tank Hold

Tank Flotation

Clarifier

Clarified

Effluent

Waste

Sludge

Return Sludge

Extraction Line

Aerated Shaft

(95 m/300 ft)

Reactor Casing

Air Lines

Influent Lines

Downcomer

Extraction Line
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-21

February 2008

Technology Summary

Integrated fixed-Film Activated Sludge (IFAS) Systems

Objective:

This treatment process aims at increasing the biomass 

in the system without increasing the footprint of the tank 

to achieve higher rates of degradation.

State of Development:

Innovative.

Description:

The IFAS hybrid processes include any activated sludge system that has some type of fixed/film media in a suspended 

growth reactor to increase the amount of biomass available for treatment. The type of media varies in the different IFAS 

systems, which are usually rope, sponge, or plastic carrier. The IFAS systems can be retrofitted into existing activated sludge 

systems. There are two major types of IFAS: (1) Submerged Mobile Media IFAS and (2) Submerged Fixed Media IFAS. 

SUBMERGED MOBILE MEDIA IFAS

The AGAR® (Attached Growth Airlift Reactor) process from Siemens is a fixed-film moving-bed process using thousands of 

special suspended biomass carriers designed to create an enormous total surface area for biofilm growth. The process uses 

the following features: (1) airlift-driven risers and down-comers for a unique mixing pattern; (2) non-clogging wedge-wire 

screens to retain the biomass carriers in the reactor; (3) biomass carriers suspended in the aerobic zones of the reactor;

(4) partitions to create staged cascading reactors; (5) a mechanically mixed denitrification reactor; and (6) an aerobic reactor 

filled with biomass carriers. The carriers are small perforated media typically 2-cm diameter or less and made of rigid material 

designed to be resistant to stress or damage. 

The Captor® process was tested at full-scale operation for three years at the Moundsville/Glen Dale WWTP at 2.3 MGD. The 

results of that test are published in the Water Science and Technology (see Data Sources). Captor® uses polyurethane foam 

media added to the activated-sludge process, raising the equivalent MLSS concentration. It was designed as a separate front 

portion of the activated-sludge process, with one third of the total HRT of the activated-sludge process.

LINPOR® is an activated sludge process and it was developed by Linde AG in the mid-1970s. It was commercially introduced 

in Europe during the early 1980s. LINPOR® uses a suspended porous plastic foam media, in combination with a freely 

suspended biomass portion, which allows substantially higher total biomass concentrations to be effectively maintained in the 

biological reactor. Equipment specific to the LINPOR® system typically includes the carrier media, the screens, screen-air 

system, media airlift pump hoods and piping, air blowers and fine bubble diffusers, internal mixed-liquor recycle pumps, and 

anoxic zone mixers. Based on extensive full-scale operations, LINPOR® systems have demonstrated the capability to 

substantially increase the treatment capacity of existing wastewater treatment facilities while solving biomass settleability and 

effluent quality problems.

SUBMERGED FIXED MEDIA IFAS

The CLEARTEC® system uses textile material arranged as sheets within a rigid frame as the fixed media. The fixed bed is 

made of polyethylene and presents itself as a mass of hollow tubes, each with a diameter of about 5 cm. Depending on the 

dissolved charge in the wastewater (chemical oxygen demand and/or biological oxygen demand [COD/BOD]) the openings 

of the fixed bed can vary and are expressed in square meters of solid support per cubic meter of fixed bed. This factor can 

range from 150 to 200 m2/m3 and, if necessary, 300 m2/m3 of fixed bed. The wastewater flows in cascades through the 

individual modules of the bioreactor and the contaminants are mineralized by the immobilized biomass.
Emerging Technologies February 2008

3-22 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Integrated fixed-Film Activated Sludge (IFAS) Systems (Contd)

SUBMERGED FIXED MEDIA IFAS (Contd)

AccuWeb® uses fixed media modules. The standard modules include AccuWebTM fabric media assembled on structural 

frames with media supports and tensioning rods. The media is fabric mesh with small hexagonal openings of less than 

2-cm diameter. The modules can be assembled in various dimensions to meet aeration basin size and joined for various 

capacities. AccuWebTM was tested in a full-scale demonstration at the City of Greensboro, NC, in 1997. See the WERF 2000 

publication entitled “Collection and Treatment Processes – Investigation of Hybrid Systems for Enhanced Nutrient Control.”

BioMatrixTM is similar to RINGLACE® (see below) in that it is a looped cord media product in multisided shapes (RINGLACE®

uses rings and loops in lace-like shapes). The concept is to hang this rope-like medium attached to metal brackets mounted 

into an overall metal frame. The frames are modular and are immersed in the aerobic zone of a bioreactor. The media is 

fabricated from polyvinyl chloridine (PVC) filaments woven into rope-like strands with protruding (5-mm) loops. This provides 

surfaces on which microorganisms can grow and effectively increase the SRT of an activated-sludge system. Trade names 

include RINGLACE® and BioMatrixTM. Initially used in Japan and Germany, the technology was first applied in the United 

States in Annapolis, MD, in the early 1990s. It has since seen considerable research and development in the northeastern 

United States and southern Ontario, Canada. 

HYBASTM hybrid process is ideal in upgrading municipal treatment plants for nutrient removal. The HYBASTM process needs 

less space because smaller tank volumes can be used because the biocarriers augment the overall amount of biomass in the 

activated sludge tank. The HYBASTM process has in fact two separate biomasses: one with low sludge age (activated-sludge 

flocs), and one with high-sludge age (suspended biofilm). The HYBASTM process can maintain a high overall biomass 

concentration with low loadings to the sedimentation basins. Even if the activated sludge is inhibited due to an influent toxicity 

event, nitrification will recover more quickly.

BioWebTM was designed to optimize process considerations and remove integrity concerns. The BioWebTM structure is 

extremely strong due to its interlocking “honeycomb” design with a break strength in excess of 1,000 pounds per square foot. 

It uses a proprietary knitting process that is self-tensioning during installation and prevents fraying and unraveling even if cut. 

It comes in manufactured-to-order continuous rolls that allow for simple frame designs and installation. It provides for excellent 

substrate and oxygen distribution and diffusion.

RINGLACE® is a flexible-strand medium formed as a linear laced material to support attached biomass. The medium can be 

attached to various frames to fit within specific aeration basin dimensions. RINGLACE® biomedium was developed in Japan 

in the 1970s and became available in the United States in 1990. Ringlace Products, Inc., has been the exclusive distributor 

for the Americas since 1992. They claim over 400 RINGLACE® installations worldwide.

Comparison to Established Technologies:

The advantage of IFAS over a conventional activated-sludge plant is that IFAS allows significant expansion without additional 

aeration basins, which is effective for Biological Nutrient Removal (BNR). The IFAS system also has increased resilience to 

shock loads and significantly increases capacity of existing clarifiers. The higher total biomass concentration of IFAS processes 

allows higher reactor volumetric organic loadings at biomass loadings, which is similar to the conventional air-activatedsludge process, and produces a treated effluent quality equal to or better than the conventional activated-sludge process.

Available Cost Information:

Approximate Capital Cost: $0.10 to $0.60 per gallon/day of plant capacity (Hydroxyl).

$0.30 to $0.50 per gallon treated (AGAR®).

$300,000/MBD (LINPOR®).

Approximate O&M Costs: Cost range depends on wastewater treatment process required, but it is similar to activated 

sludge process.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-23

February 2008

Technology Summary

Integrated fixed-Film Activated Sludge Systems (IFAS) (Contd)

Vendor Name(s):

AGAR®

US Filter, Zimpro Products

301 W. Military Rd.

Rothschild, WI

Telephone: 715-355-3206

Email: carrolj@usfilter.com

CLEARTEC®

EIMCO Water Technologies

2850 S. Decker Lake Drive

Salt Lake City, UT 84119-2300

Telephone: 801-526-2111

Email: info.ewt@glv.com or 

jeff.mcbride@eimcowater.com

LINPOR® and AccuWeb®

Mixing and Mass Transfer Technologies

583 Greenhaven Road

Pawcatuck, CT 06379

Telephone: 860-599-5381

Web site: http://m2ttech.com/index.asp

AccuWebTM

Brentwood Industries

610 Morgantown Road, Reading, PA 19611

Telephone: 610-374-5109

Fax: 610-376-6022

Web site: www.brentw.com

HYBASTM

AnoxKaldnes Inc.

260 West Exchange Street

Suite 301

Providence, RI, 02903 

Telephone: 401-270-3898

Email: usa@anoxkaldnes.com

BioWebTM

Entex Technologies, Inc.

1829 E. Franklin Street, Suite 600

Chapel Hill, NC

Telephone: 919-619-8862

E-mail: wayne.flournoy@entexinc.com

RINGLACE®

Ringlace Products, Inc.

P.O. Box 301157

Portland, OR 97294

Telephone: 503-618-0313

Fax: 503-771-9649

General Information: info@ringlace.com

Installation(s):

Lakeview Wastewater Treatment Facility

 Region of Peel

 Ontario, Canada

3.7 MGD HYDROXYL-iFASTM 

North Buffalo Wastewater Treatment Plant

 P.O. Box 3136

 Greensboro, NC 27402

 Telephone: 336-373-2055

 Fax: 336-412-6305

Westerly, RI 

City of Broomfield, CO
Emerging Technologies February 2008

3-24 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Integrated fixed-Film Activated Sludge Systems (IFAS) (Contd)

Vendor Name(s) (Contd):

HYDROXYL-PAC Media

Hydroxyl Systems, Inc.

1100th Main Road

Westport, MA 02747

Telephone: 508-636-9289

Email: dturner@hydroxyl.com

Key Words for Internet Search:

IFAS, activated sludge, wastewater treatment, fixed film, Cleartec , LINPOR®, Hydroxyl-PAC, BioWeb, AGAR®

Data Sources:

Captor process, Water Science and Technology, Vol. 29, 10–11, pp 175–181, IWA publishing, 1994.

WERF Report, “Collection and Treatment Processes – Investigation of Hybrid Systems for Enhanced Nutrient Control,” Final 

Report, 2000.

Communications with vendor contacts, including emails, web site, and telephone conversations.

Porous plastic foam cubes used as biomass carriers in LINPOR® process.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-25

February 2008

Technology Summary

Membrane BioReactor (MBR)

Objective:

Treatment by filtration of biomass for high-quality effluent 

in a smaller footprint.

State of Development:

Innovative. Various modules are being developed and improved. 

Some of the membrane modules are innovative while some 

modules are in established markets. 

Description:

An MBR is a biological reactor that uses membranes for solid-liquid separation instead of conventional clarifiers. In an MBR 

the fine pores of membranes are used to filter water from the Mixed Liquor Suspended Solids (MLSS) process. This filtered 

water (permeate) leaves as secondary effluent while solids remain in the reactor as MLSS with some solids periodically 

withdrawn as waste solids. Using membranes instead of clarifiers enables an activated sludge system with high MLSS 

concentrations, thereby reducing the required bioreactor volume for a desired Solids Retention Time (SRT). MBR systems 

can operate with MLSS concentrations at 20,000 mg/L or higher. High SRTs allow the development of slow-growing 

microorganisms such as nitrifiers. 

Membranes used in MBRs are comprised of two basic materials: (1) organic polymers and (2) inorganic materials such as 

ceramics. Organic polymer-based membranes are most widely used for municipal wastewater treatment and are formed from 

either modified natural cellulose acetate materials or synthetic materials. The membranes are modular units. The modules 

are of the following types: tubular, hollow-fiber, spiral-wound, plate-and-frame, and pleated cartridge filters, depending on the 

desired application. 

Some MBR systems are designed for membranes, immersed in the reactors. Other applications locate the membranes in a 

separate stage or compartment. Any of the previously listed types of membranes can be used in either application. 

Membrane fouling is the systematic accumulation of suspended solids, colloids, precipitates, and macromolecules on the 

membrane surface or inside the pores, causing a reduction in membrane permeability. Commonly used strategies to control 

fouling includes chemical washing and cleaning as well as air-scour and permeate back-pulsing to prevent cake-layer 

formation. 

Comparison to Established Technologies:

The advantages of MBR systems over conventional biological systems include better effluent quality, smaller space 

requirements, and less sludge generation. Since the MBR acts as a filter and it separates water from the MLSS, it can achieve 

TSS less than 1.0 mg/L and BOD less than 1.5 mg/L. MBRs offer a small footprint; therefore, it is an excellent option for 

expanding existing plants with very limited space. MBR systems provide operational flexibility with respect to flow rates and 

the ability to readily add or subtract modular units as necessary. However, immersed membranes typically require that water 

be maintained a a reasonably constant level so that they remain wet. Throughput limits are required by the physical properties 

of the membrane resulting in the fact that peak design flows should be no more than 1.5 to 2 times the average design flow. 

MBRs have been used with Biological Nutrient Removal (BNR) systems and can achieve total nitrogen levels below 4.0 

mg/L and total phosphorus levels less than 0.5 mg/L.

Available Cost Information:

Approximate Capital Cost: Capital costs vary with the size of plant as the economy of scale applies ($6 million/MGD for 

4 MGD and $3.2 million/MGD for 12 MGD plant).

Approximate O&M Costs: Operating costs are mainly attributed to power due to high mixed liquor concentration in the 

reactor and membrane cleaning costs ($1.23/1,000 gal).
Emerging Technologies February 2008

3-26 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Membrane BioReactor (MBR) (Contd)

Vendor Name(s):

Enviroquip, Inc.

2404 Rutland Drive, Suite 200

Austin, TX

Telephone: 512-834-6019

Email: dennis.livingston@enviroquip.com

Web site: http://www.enviroquip.com/

US Filter/MEMCOR

4116 Sorrento Valley Blvd.

San Diego, CA 92121

Zenon Environmental Services, Inc.

3239 Dundas Street West

Oakville, Ontario, Canada 

Telephone: 905-465-3030

Fax: 905-465-3050

Email: rsccott@zenon.com

Web site: http://www.zenon.com/

Mitsubishi International Corporation

333 South Hope Street West, Suite 2500

Los Angeles, CA 90071

Telephone: 213-687-2853

Fax: 213-626-3739

Email: lei.ge@mitsubishicorp.com

Infilco Degremont Inc.,

P.O. Box 71390 

Richmond, VA 23255-1390

8007 Discovery Drive

Richmond, VA 23229-8605

Telephone: 804-756-7600

Fax: 804-756-7643

Web site: http://www.infilcodegremont.com/index.html 

Ќeppel Seghers Engineering Singapore Pte Ltd./

Toray

31 Shipyard Road

Singapore 628130

Telephone: 32-0-3-880-7704

Fax: 32-0-3-880-7749

Web site: www.keppelsegners.com

Huber Technoogy Inc.

9805 North Cross Center Court, Suite H

Huntersville, NC 28078

Telephone: 704-949-1010

Fax: 704-949-1020

Web site: www.hubertechnology.com

Installation(s):

Chino Valley, AZ

Pumpkinvine, GA

Hamptons, GA

Hyrum City, UT

Traverse City WWTP – 17 MGD, Grand Traverse County, MI

Hampton Creek WWTP – 1.0 MGD, 5235 Hampton Golf Club 

 Drive, Hampton, GA

Stevens Pass WWTP – 0.21 MGD

Cauley Creek – 5.0 MGD, 7225 Bell Road, Duluth, GA 30097

Broad Run Water Reclamation Facility, 

Loudoun County Sanitation District, Ashburn,VA 

Telephone:571-223-3855

Fax: 571-223-3866
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-27

February 2008

Technology Summary

Membrane BioReactor (MBR) (Contd)

Key Words for Internet Search:

Membrane bioreactor, wastewater, tubular, hollow-fiber, spiral wounds, plate and frame, pleated cartridge filters

Data Sources:

Metcalf and Eddy, Wastewater Engineering Treatment and Reuse, 4th Edition, 2003.

Web site data sources are as follows: 

http://www.werf.org/products/MembraneTool/home/

http://www.zenon.com/ 

http://www.enviroquip.com/ 

http://www.infilcodegremont.com/index.html

Picture of MBR Installations
Emerging Technologies February 2008

3-28 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Membrane BioReactor (MBR) (Contd)

MBR Plate and Frame Modules

Pictures courtesy of Enviroquip, Inc. and

Zenon Environmental Services, Inc.

5-mgd Hollow Fiber Plant
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-29

February 2008

Technology Summary

Membrane BioReactor (MBR) (Contd)

Immersed Membrane Suppliers

Zenon Environmental Services, Inc.

Kubota (Enviroquip, Inc.)

Mitsubishi International Corporation (GE Water)

US Filter/Memcor

Seghers Keppel/Toray

Huber Technology

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Hollow Fiber MBR

Flat Sheet Plant
Emerging Technologies February 2008

3-30 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Membrane BioReactor (MBR) (Contd)

Common MBR Characteristics

Modular assemblies: Multiple parallel units

Scouring air: Prevent solids deposition

Fine screen pretreatment: 2 mm max solids

Filterable sludge: DO > 0 and SRT > 12 days 

High recirculation Rates: Return > 4 x Influent flow

Periodic relaxation: 1 min no flow every 10

Periodic backflush: Weekly/monthly with NaOCl

Periodic chemical clean: Semiannual/annual

MBR Design Considerations

Membrane design flux: Avg, max, and peak

Flow equalization: Inline or offline

Target MLSS range: SRT > 12 days

Hydraulic retention time (HRT): Adequate to avoid short 

circuit

Air scour requirement: Low O2 transfer

Supplemental aeration: DO > 1 mg/L MBR

Dentrification: Supplemental air reduction

Hollow Fiber versus Flat Sheet

Hollow Fiber

Design flux: 8 to 12 gal/ft2

 x d avg, 

20 to 28 gal/ft2 x d max, <36 gal/ft2 x d peak

Target MLSS: 10,000 to 15,000 mg/L

Scouring air: 0.013 to 0.016 cfm/ft2

Piping: Above liquid, top access

Trans Membrane Pressure (TMP) differential: 5 to 16 ft 

forward, 100 ft back

Flat Sheet

Design flux: 12 to 16 gal/ft2

 x d avg, 

24 to 32 gal/ft2 x d max, <40 gal/ft2 x d peak

Target MLSS: 15,000 to 20,000 mg/L

Scouring air: 0.028 to 0.030 cfm/ft2

Piping: Submerged, piping gallery

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Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

3-31

February 2008

Technology Summary

Mobile-Bed Reactor Technology (MBRT) Process

Objective:

BOD removal, nitrification and denitrification

State of Development:

Innovative.

Description:

The MBRT process consists of small cylindrical polyethylene carrier elements in aerated or nonaerated basins for biofilm 

growth. The mixers in the system continuously keep the elements circulated. A final clarifier is used to settle out the sloughed 

solids.

The process is defined as a hybrid system as it can be easily retrofitted into existing activated-sludge basins. While similar to 

IFAS systems, this technology is different because the process does not include an activated-sludge return. Kaldnes®-

HYBASTM/ActiveCellTM, Hyrdoxyl-F3R, GeoReactor® systems are examples of the MBRT process.

The moving-bed biofilm process combines the technologies of activated-sludge processes and biofilm processes. The 

moving-bed biofilm process is frequently used for upgrading an existing plant, especially when space is an issue, because of 

the retrofit aspects of this technology. High-rate biofilm systems, such as the ones listed, are highly efficient in removing the 

soluble organic and nitrogen loads.

Comparison to Established Technologies:

MBRTs do not recycle activated sludge in the reactor. The media in a reactor are constantly moving to provide better 

aeration. 

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Kaldnes MBBR

Kaldnes North America Inc.

58 Weybosset Street, 4th Floor

Providence, RI 02903

Telephone: 401-270-3898

Fax: 401-270-3908

Email: chj@anoxkaldnes.com

Web site: http://www.kaldness.com

Parkson Corporation

2727 NW 62nd Street

P.O. Box 408399

Fort Lauderdale, FL 33309-8399

Telephone: 800-553-5419 or 954-974-6610

Fax: 954-974-6182

Web site: http://www.parkson.com

Hydroxyl Systems Inc. 

1100 S. Main Road 

Westport, MA 02790

Telephone: 508-636-9289

Fax: 508-636-7823

Web site: http://www.hydroxyl.com/index.php

Installation(s):

AnoxKaldnes-HYBASTM

Broomfield Wastewater Reclamation

2985 West 124th Avenue

Broomfield, CO 80020

HYDROXYL-iMBRTM 

City of Moorehead, MN
Emerging Technologies February 2008

3-32 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Mobile-Bed Reactor Technology (MBRT) Process (Contd)

Key Words for Internet Search:

Mobile-bed reactor, MBR, MBRT, wastewater, biofilm, activated sludge

Data Sources:

Metcalf and Eddy, Wastewater Engineering Treatment and Reuse, 4th Edition, 2003.

http://www.hydroxyl.com/ 

WERF Report, “Collection and Treatment Processes – Investigation of Hybrid Systems for Enhanced Nutrient Control,” Final 

Report, 2000.

http://www.kaldnes.com/process.html
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Technology Summary

Bardenpho® (Three Stage) with Returned Activated Sludge (RAS) Denitrification

Objective:

Enhanced removal of phosphorus and nitrogen from 

wastewater. 

State of Development:

Innovative Use of Established Technology.

Description:

The Three-Stage Bardenpho® with Returned Activated Sludge (RAS) denitrification provides phosphate and nitrogen removal 

efficiently. First, RAS is subjected to an anoxic stage to remove nitrates. While a fraction of the influent wastewater is sent to 

the anoxic reactor, the remaining portion is fed to the anaerobic reactor directly. There is also an internal recycle from the oxic 

reactor to the second-stage anoxic reactor. 

Comparison to Established Technologies:

In the basic Three-Stage Bardenpho® process, the oxic reactor is in tandem with the anaerobic and anoxic reactors. RAS is 

returned to the anaerobic reactor and there is an internal recirculation from the oxic reactor to the anoxic reactor. The ThreeStage Bardenpho® with RAS denitrification process includes the anaerobic reactor sandwiched between the two anoxic 

reactors, with the oxic reactor downstream of the three stages. 

Available Cost Information:

Approximate Capital and O&M Costs: Cost estimates are dependent upon local requirements and specific application 

and economy of scale applies. For example, uniform annual cost of a 100,000 GPD 

plant is estimated about $272,075 based on an interest rate of 6% for a 20-year 

period. 

Vendor Name(s):

N/A

Installation(s):

Used in Kelowna WWTP, British Columbia, Canada

Key Words for Internet Search:

Modified Bardenpho®, three-stage RAS denitrification

Data Sources:

“Design and Retrofit of Wastewater Treatment Plants for Biological Nutrient Removal,” Water Quality Management Library, 

Volume 5, Second Edition, 1998.

Principles and Practice of Nutrient Removal from Municipal Wastewater, Lewis Publishers, Second Edition, 1991.

Clarifier

Effluent

AnoxicAnoxic

Anaerobic

Oxic

Influent Internal Recycle

Returned Activated Sludge

Waste

Sludge

745043_WWT-16.ai

Process Flow Diagram for Three-Stage Bardenpho® with RAS Denitrification Process
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February 2008

Technology Summary

Biological-Chemical Phosphorus and Nitrogen Removal (BCFS) Process

Objective:

Enhanced nutrient removal (nitrogen and phosphorus).

State of Development:

Innovative Use of Established Technology.

Description:

The BCFS process has been developed to achieve low-nutrient effluent concentrations at relatively low Biochemical Oxygen 

Demand Ratio to Nitrogen (BOD/N) and Biochemical Oxygen Demand Ratio to Phosphorus (BOD/P) ratios in the influent. 

The process design is based on the University of Cape Town (UCT) process. In the process, the return sludge is introduced 

at the start of the anoxic zone to prevent the presence of nitrate in the anaerobic zone. Mixed liquor is recirculated from the 

end of the anoxic zone to the anaerobic zone. At the end of the anoxic zone, most of the nitrate is removed. In the anoxic 

zone, the phosphorus is taken up by phosphate-accumulating bacteria in the activated sludge. The anoxic phosphorus 

uptake results in a lower energy and BOD demand as well as lower sludge production. 

Because of the different microorganisms involved in phosphorus and nitrogen removal, the retention times for both removal 

processes are different. For maximum nitrification and availability of COD for denitrification a long sludge-retention time is 

necessary. For biological phosphorus removal, usually shorter retention times are advantageous. In the BCFS process, long 

sludge-retention times that are favorable for the removal of nitrogen are preferred. 

Comparison to Established Technologies:

The BCFS process achieves removal rates for BOD, nutrients, and suspended solids similar to other process designs based 

on the activated-sludge concept. With the BCFS process configuration, a stable and reliable operation is possible. It has been 

demonstrated that the biological phosphorus removal capacity is usually sufficient to comply with effluent standards. The 

settling characteristics of the activated sludge can be enhanced by implementing the BCFS process design. The 

compartmentalization of the process allows low and stable sludge volume index (SVI) to be achieved. At the Holten WWTP, 

SVI is reduced from 150 to 80 mL/mg. Chemical phosphorus removal is limited by kinetic factors as well as stoichiometric 

factors, and excessive inorganic precipitant requirements need to be reduced. 

Available Cost Information:

Approximate Capital Cost: The capital costs for the implementation of a BCFS process in case of upgrading depend on 

the availability of existing tanks and equipment as well as local requirements and specific 

application. Actual costs are not disclosed.

Approximate O&M Costs: Not disclosed.

Vendor Name(s):

N/A

Installation(s):

Holten WWTP, The Netherlands
Emerging Technologies February 2008

3-36 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Biological-Chemical Phosphorus and Nitrogen Removal (BCFS) Process (Contd)

Key Words for Internet Search:

BCFS, nitrogen phosphorus nutrient removal

Data Sources:

Technical University of Delft,The Netherlands.

Waterboard Groot Salland, The Netherlands.

Clarifier

Effluent

Anaerobic

Anoxic/

Anaerobic

AnoxicAnoxic

Oxic

Internal Recycle

Influent

Returned Activated Sludge

Waste

Sludge

745043_WWT-17.ai

Process Flow Diagram for BCFS Process
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Technology Summary

Modified University of Cape Town (MUCT) Process

Objective:

Enhanced removal of phosphorus and nitrogen 

from wastewater. 

State of Development:

Innovative Use of Established Technology.

Description:

The Modified University of Cape Town (MUCT) process provides efficient nitrogen removal by sending the RAS to the anoxic 

zone. The anaerobic reactor, is located upstream of two anoxic reactors. RAS is subjected to the first anoxic reactor stage. 

There is an internal recycle from the first anoxic reactor to the anaerobic reactor, and another internal recycle from the oxic 

reactor to the second anoxic reactor.

Comparison to Established Technologies:

The MUCT process is different from the UCT process. MUCT includes two anoxic stages in series. Influent wastewater is fed 

to the anaerobic reactor, which is located upstream of the anoxic reactors. RAS is returned to the first anoxic reactor. There 

is an internal recirculation from the first anoxic reactor to the anaerobic reactor. Removal of nitrogen in the aeration basin may 

vary from 40 to 100 percent and the effluent nitrate should be sufficiently low so as not to interfere with the anaerobic contact 

zone. Plug flow configuration of the aeration basin allows the anoxic zones in the first section of the plant to be low, while the 

endogenous oxygen demand at the end of the aeration basin and the DO level will increase to allow for the required nitrification 

and phosphate uptake. Nitrates not removed in the aeration basin will be recycled to the anoxic zone. Therefore, efficient 

overall nitrogen removal is achieved more economically.

Available Cost Information:

Approximate Capital and O&M Costs: Cost estimates are dependent upon local requirements and specific application 

and economy of scale applies. For example, uniform annual cost of a 100,000 GPD 

plant is estimated to be about $272,075 based on an interest rate of 6 percent for a 

20-year period.

Vendor Name(s):

N/A

Installation(s):

King County South AWTP, WA

Key Words for Internet Search:

Modified UCT process, RAS anaerobic reactor

Data Sources:

“Design and Retrofit of Wastewater Treatment Plants for Biological Nutrient Removal,” Water Quality Management Library, 

Volume 5, Second Edition, 1998.

Principles and Practice of Nutrient Removal from Municipal Wastewater, Lewis Publishers, Second Edition, 1991.
Emerging Technologies February 2008

3-38 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Modified University of Cape Town (MUCT) Process (Contd)

Clarifier

Effluent

AnoxicAnoxic

Anaerobic

Oxic

Internal Recycle Internal Recycle

Influent

Returned Activated Sludge

Waste

Sludge

745043_WWT-18.ai

Process Flow Diagram for Modified UCT Process
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Technology Summary

Modified Anaerobic/Oxic (A/O) Process

Objective:

Enhanced removal of phosphorus and nitrogen 

from wastewater. 

State of Development:

Innovative Use of Established Technology.

Description:

The modified A/O process provides phosphate and nitrogen removal. If nitrification is not required and the temperatures are 

not high, the simple two-stage, high-rate A/O process may be sufficient. However, with higher temperatures some nitrate 

formation can not be avoided. Therefore, RAS should be subjected to an anoxic stage to remove nitrates before mixing it with 

the influent wastewater. 

Comparison to Established Technologies:

The simple high-rate A/O process uses an anaerobic reactor upstream of the oxic reactor. RAS is returned to the anaerobic 

reactor. The modified A/O process, however, includes an anoxic reactor downstream of the anaerobic reactor where only RAS 

is recycled. Influent wastewater is directly sent to the anaerobic reactor for phosphorus removal. There is an internal 

recirculation from the anoxic reactor to the anaerobic reactor. 

Available Cost Information:

Approximate Capital Cost: Cost estimates are dependent upon local requirements and specific application and economy 

of scale applies. For example, uniform annual cost of a 100,000 GPD plant is estimated about 

$244,000 based on an interest rate of 6 percent for a 20-year period.

Approximate O&M Costs: Unknown.

Vendor Name(s):

N/A

Installation(s):

Fayetteville AWTP, AR

Key Words for Internet Search:

High-rate A/O with RAS dentrification

Data Sources:

“Design and Retrofit of Wastewater Treatment Plants for Biological Nutrient Removal,” Water Quality Management Library,

Volume 5, Second Edition, 1998.

Principles and Practice of Nutrient Removal from Municipal Wastewater, Lewis Publishers, Second Edition, 1991.
Emerging Technologies February 2008

3-40 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Modified Anaerobic/Oxic (A/O) Process (Contd)

Clarier

Euent

Anaerobic

Anoxic

Inuent Internal Recycle

Oxic

Returned Activated Sludge

Waste

Sludge 745043_WWT-19.ai

Process Flow Diagram for Modified Anaerobic/Oxic (A/O) Process
Wastewater Treatment and In-Plant Wet Weather Management

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February 2008

Technology Summary

Trickling Filter/Solids Contactor (TF/SC)

Objective:

Organics and nitrogen removal. 

State of Development:

Innovative Use of Established Technology.

Description:

The TF/SC is comprised of a trickling filter, aerated-solids contact tanks, and a flocculation clarifier with RAS recycled back 

to the solids contact tanks. Final clarification of TF effluent is required. A portion of this treated effluent is recirculated for 

media wetting. This is a hybrid system that combines the low-energy consumption and simple operation of a trickling filter with 

the excellent settling characteristics of a suspended growth system. The benefits include organic removal and nitrification 

through the TF and superior solids flocculation and settling in the aeration component. The aeration component is referred to 

as solids contact tank since its retention time is relatively short (30 minutes or less). There are many important design 

considerations for the TF/SC process, including periodic media flushing, solids contact operation, flocculating clarifier design, 

and reduced hydraulic gradeline and floc disruption to the solids contactor. 

Comparison to Established Technologies:

A number of advances have occurred since the introduction of the trickling filter that makes it a potential candidate for a 

secondary facility with the increasingly stringent effluent requirements. These advances include the development of better 

media and the discovery of new combined processes. The development of new media including vertical filter media, horizontal 

filter media, random media, and cross-flow media has increased the void area available compared to rock media. These new 

types of media provide increased air circulation, higher specific surface area for biological growth, and the ability to slough off 

growth without plugging. 

Available Cost Information:

Approximate Capital Cost: Dependent upon local requirements and specific application.

Approximate O&M Costs: Not available.

Vendor Name(s):

N/A

Installation(s):

Annacis Island WWTP, Vancouver, Canada

Key Words for Internet Search:

Trickling Filter/Solids Contactor

Data Sources:

Brookville Water Pollution Control Centre Upgrade, Class Environmental Assessment Report, Simcoe Engineering Group 

Limited, December 2004.

Metcalf and Eddy, Wastewater Engineering Treatment and Reuse, 4th Edition, 2003.
Emerging Technologies February 2008

3-42 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Trickling Filter/Solids Contactor (TF/SC) (Contd)

Process Flow Diagram for TF/SC Process

Clarifier

Effluent

TF Effluent

Sludge Aeration

Air Air

Returned Activated Sludge

Blower

Waste

Sludge

Effluent

Recycle

Primary Effluent

Trickling

Filter

745043_WWT-20.ai
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Technology Summary

Aerobic Granular Sludge Process (AGSP)

Objective:

The AGSP has the ability to provide comparable 

treatment efficiency to conventional activated sludge at 

lower costs with the compact aerobic granular sludge 

technology. 

State of Development:

Embryonic.

Description:

It has been demonstrated that granular sludge has improved settling characteristics facilitating efficient solid-liquid separation. 

With high biomass retention and biological activity, a granular sludge reactor can be operated at high-volume loading rates. 

The AGSP reactor is operated as a sequenced batch reactor (SBR), which is necessary to achieve process conditions for the 

formation of aerobic granular sludge. Similar to conventional applications of the SBR concept, one treatment cycle in the 

AGSP reactor has four well-defined phases. These are filling, mixing/aerating, settling, and decanting. Batch feeding of the 

reactor induces a high-substrate concentration at the beginning of a treatment cycle. Due to a high concentration gradient, 

substrate can diffuse deeply into the granules preventing starvation of bacteria within the granules. With insufficient feeding 

(diffusion gradient), the bacteria at the center of the granules will be starved and weakened which eventually leads to the 

disintegration of the granules. In general, the size of the granules will increase until the formation of stable granules is limited 

by substrate diffusion. Less stable granules are susceptible to shear forces and will be reduced in size or disintegrate. 

Weakened biomass in the granule center will also decrease the granule density and inhibit settling processes, causing 

washout. Thus, a dynamic equilibrium will eventually be reached between substrate concentration and the average diameter 

of granules. It has been observed that high-shear forces under turbulent flow conditions give selective advantage to the 

formation of stable granules. Research has shown that nitrogen removal rates of more than 80 percent seem feasible. While 

nitrification takes place in the outer, aerobic layer of the granules, denitrification will occur in the anoxic core of the granules 

with the necessary carbon source being supplied by substrate diffused into the granules. 

Comparison to Established Technologies:

In the past, granular sludge was used as part of anaerobic treatment process design concepts. However, recent research has 

shown that granular sludge can also be obtained under aerobic process conditions. Unlike bacteria found in anaerobic 

granular sludge, aerobic bacteria, in general, do not naturally form granules. In order to achieve granulation under aerobic 

process conditions, short-settling times are used to introduce a strong selective advantage for well-settling sludge granules. 

Poor-settling biomass will be washed out under these conditions. Accordingly, appropriate settling and decanting times in 

each treatment cycle are chosen. In pilot trials, the AGSP reactor is operated at settling times that correspond to average 

settling velocities of about 10 to 15 mph. These relatively high settling velocities allow high-volume loadings of the reactor 

resulting in a compact reactor design.

Further development of the aerobic granular-sludge technology may result in the design of compact secondary and tertiary 

treatment units with small footprints, thereby providing cost savings because of reduced space requirements. 

Available Cost Information:

Approximate Capital Cost: Not available.

Approximate O&M Costs: Not available.
Emerging Technologies February 2008

3-44 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

Aerobic Granular Sludge Process (AGSP) (Contd)

Vendor Name(s):

Delft University of Technology 

Department of Biotechnology 

Environmental Biotechnology Group

Delft, The Netherlands

Telephone: 31-15-278-1551

Email: m.dekreuk@tnw.tudelft.nl 

Web site: www.bt.tudelft.nl 

Installation(s):

There are no installations in the United States.

Key Words for Internet Search:

Aerobic granular sludge, aerobic granular reactor technology

Data Sources:

De Kreuk, M. K. and M. C. M. Van Loosdrecht, “Selection of Slow Growing Organisms as a Means for Improving Aerobic 

Granular Sludge Stability,” Water Science Technology, 49, pp. 11–12 and 9–19, 2004.

Etterer, T. and P. A. Wilderer, “Generation and Properties of Aerobic Granular Sludge,” Water Science Technology, 

pp. 3–43, 2001.

Morgenroth, E., T. Sherden, M. C. M. Van Loosdrecht, J. J. Heijnen, and P. A. Wilderer, “Aerobic Granular Sludge in a 

Sequencing Batch Reactor,” Water Resources, Vol. 31, No. 12, 1997.
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

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February 2008

Technology Summary

ANaerobic Membrane BioReactor (AN-MBR)

Objective:

Anaerobic treatment by filtration of biomass for highquality effluent in a smaller footprint. 

State of Development:

Embryonic.

Description:

An AN-MBR is similar to an MBR facility except that the biological processes are done in anaerobic reactions. In the AN-MBR 

process, the mixed liquor of the anaerobic reactor passes through membranes for liquid-solids separation. The membranes 

can be internal, submerged modules or located in an external tank. Different types of membrane material can foul at different 

rates due to struvite formation and other factors. Review of recent information indicates that AN-MBR systems may be able 

to achieve treatment levels comparable to conventional activated sludge processes under moderate temperature conditions. 

Economics may favor an AN-MBR system located upstream of an existing wastewater treatment plant. The idea is to 

withdraw and pre-treat some of the incoming wastewater and reduce the organic loadings into the existing plant.

Comparison to Established Technologies:

Conditions in an AN-MBR are ideal for the formation of struvite, which is reported to contribute significantly to the fouling of 

membranes. Membrane materials, used for anaerobic applications, have hydrophobic characteristics that cause lower 

permeate flux than in aerobic applications. 

The production of biogas with a high content of methane provides an additional benefit with about 22 to 26 megajoules (MJ) 

of energy per cubic meters depending on the carbon dioxide content. Gas in the headspace of an AN-MBR reactor can be 

used for continuously sparging an internal membrane system.

Available Cost Information:

Approximate Capital Cost: Not available.

Approximate O&M Costs: Not available.

Vendor Name(s):

Enviroquip, Inc.

2404 Rutland Drive, Suite 200

Austin, TX 78758

Telephone: 512-834-6019

Web site: http://www.enviroquip.com/

US Filter/MEMCOR

4116 Sorrento Valley Blvd.

San Diego, CA 92121

Zenon Environmental Services, Inc.

3239 Dundas Street West

Oakville, Ontario, Canada

Telephone: 905-465-3030

Fax: 905-465-3050

Email: rsccott@zenon.com

Web site: http://www.zenon.com/

Installation(s):

There are no known large, full-scale AN-MBR systems in 

operation that treat municipal wastewater.
Emerging Technologies February 2008

3-46 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

ANaerobic Membrane BioReactor (AN-MBR) (Contd)

Vendor Name(s) (Contd):

Infilco Degremont Inc.

P.O. Box 71390 

Richmond, VA 23255-1390

8007 Discovery Drive

Richmond, VA 23229-8605

Telephone: 804-756-7600

Fax: 804-756-7643

Web site: http://www.infilcodegremont.com/index.html 

Key Words for Internet Search:

ANaerobic Membrane BioReactor, AN-MBR, anaerobic treatment of lower strength wastewaters

Data Sources:

Membrane Bioreactors for Anaerobic Treatment of Wastewaters, WERF Project 02-CTS-4 Phase 1 Report, 2004.

Membrane Bioreactors for Anaerobic Treatment of Wastewaters, WERF, Phase 2 Report, 2004.

Preliminary Investigation of an Anaerobic Membrane Separation Process for Treatment of Low Strength Wastewaters, WERF, 

2004.
Wastewater Treatment and In-Plant Wet Weather Management

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February 2008

Technology Summary

Anaerobic Migrating Blanket Reactor (AMBR®)

Objective:

Improve wastewater treatment efficiency.

State of Development:

Embryonic. Pilot-scale studies have been performed.

Description:

AMBR® is an anaerobic system like the AEBR with mixing to maintain sludge in the system. The AMBR® is a compartmentalized 

system where the flow of wastewater is reversed on a regular basis. In this process, the influent feed and the effluent 

withdrawal point is changed such that the sludge blanket remains uniform in the anaerobic reactor. This helps maintain the 

sludge in the system without the use of packing or settlers for solids capture.

Comparison to Established Technologies:

AMBR® is an anaerobic system with mixing to maintain sludge in the system without packing and settlers for solids capture. 

This technology improves process efficiency over conventional activated sludge. It has been applied overseas to treat highstrength food-processing wastewater to demonstrate this efficiency.

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Washington University

Hilltop Campus

Campus Box 1198, One Brooking Drive

St. Louis, MO 63130

Telephone: 314-935-5663 

Fax: 314-935-5464

Email: angenent@seas.wustl.edu

Installation(s):

No installation in the United States at this time.

Key Words for Internet Search:

AMBR, migrating blanket reactors, wastewater treatment

Data Sources:

Angenent, Largus T. and Shihwu Sung, “Development of Anaerobic Migrating Blanket Reactor (AMBR), A Novel Anaerobic 

Treatment System,” Water Research, Vol. 35, No. 7, pp. 1,739–1,747, 2001.

Telephone conversation with Lars Angenent, Washington University, St. Louis, MO, August 2004.
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February 2008

Technology Summary

DEamMONification (DEMON)

Objective:

Biological ammonia removal from high-strength streams 

(e.g., sludge liquors, landfill leachate).

State of Development:

Embryonic. Full-scale system was operated in Austria and 

Switzerland for 3 years. A full-scale system was also operated in 

Swizerland for one year (article referenced below). Extensive 

research pilot-scale studies were performed in the United States 

(New York and Alexandria) and Europe. Technology is available 

commercially. 

Description:

DEamMONication comprises two autotrophic reaction steps: (1) partial nitritation (aerobic oxidation of about 50 percent of 

ammonia to nitrite); and (2) anaerobic oxidation of residual ammonia by generated nitrite. The DEMON process is operated 

in a single-sludge SBR system where intermittent aeration is provided. Aeration control is based on the pH-signal that 

corresponds with the production of intermediate nitrite, and allows an optimum interaction of both process steps.

Comparison to Established Technologies:

DEMON, as an exclusively autotrophic process, requires no organic carbon and substantially less aeration energy as 

compared to conventional nitrification/denitrification systems. The patented control system provides stable process 

performance (90 percent ammonia removal) at varying influent loads. Suspended growth biomass of slowly growing anaerobic 

ammonia oxidizers can be easily transferred from one plant to the other to accelerate startup procedure. 

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Grontmij Nederland BV 

Infrastructure and Milieu 

Afdeling Water and Reststoffen 

Postbus 203, 3730 AE De Bilt

Handelsregister 30029428

The Netherlands

Telephone: 31-30-220-79-11

Fax: 31-30-220-01-74

Web site: http://www.grontmij.nl/site/nl-ni/

Cyklar-Stulz

CH-8737 Gommiswald Rietwiesstrasse 39

Switzerland

Email: info@cyklar.ch

Web site: http://www/cyklar.ch

Installation(s):

Full-scale DEMON systems in Strass, Austria and Glarnerland, 

Switzerland. Pilot systems are operated by Alexandria Sanitation 

Authority, Virginia, and by New York City Department of 

Environmental Protection, New York. There are no full-scale 

installations in the United States at this time.

Key Words for Internet Search:

Deammonification, DEMON process, sidestream treatment, ammonia

Data Sources:

Wett, B., “Development and Implementation of a Robust Deammonification Process,” presentation at the Leading Edge 

Technologies Conference, Singapore, 2007.

Wett, B., S. Murthy, et al., “Key Parameters for Control of DEMON Deammonification Process,” presentation at the Nutrient 

Removal Conference in Baltimore, MD, 2007.
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February 2008

Technology Summary

Hydrogen-based hollow-Fiber Membrane Biofilm Reactor (HFMBfR)

Objective:

Treatment to remove oxidized contaminants.

State of Development:

Embryonic.

Description:

The process reactor consists of a hollow-fiber membrane bundle with an inner and outer microporous layer and a nonporous 

layer sandwiched in between. Hydrogen is introduced inside the fibers, which are sealed on one end to prevent escape and 

allowed to diffuse through the nonporous layer. The water in contact with the biofilm layer reacts to reduce the contaminant 

while hydrogen is oxidized. (U.S. Patent – 6,387,262)

The technology can be used for treating wastewater, groundwater, or drinking water. The process is effective in treating water 

with contaminants such as perchlorate, nitrates, chlorinated solvents, selenate, bromate, chromate, and radionuclides. 

Comparison to Established Technologies:

Not comparable to any established technology.

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Biodesign Institute

Arizona State University

1001 South McAllister Avenue

P.O. Box 875701

Tempe, AZ 85287-5701

Telephone: 480-727-0434

Email: rittmann@asu.edu

Applied Process Technology, Inc.

3333 Vincent Road, Suite 222

Pleasant Hill, CA 94523

Telephone: 925-977-1811 or 1-888-307-2749

Fax: 925-977-1818

Email: info@aptwater.com

Web site: http://www.aptwater.com/

Installation(s):

There are no installations in the United States at this time.

Key Words for Internet Search:

HFMBfR, reducing oxidized contaminants 

Data Sources:

http://www.aptwater.com 

http://www.uspto.gov/ 
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February 2008

Technology Summary

Membrane-Aerated BioReactor (MABR)

Objective:

Aeration of membranes to enable the treatment of 

wastewater. 

State of Development:

Embryonic. Commercially not available; extensive research is 

currently being performed in the United States and Europe.

Description:

A Membrane-Aerated BioReactor (MABR) uses a gas-permeable membrane for oxygen transfer to wastewater and does not 

use bubble aeration as used in conventional systems for aeration. The ability to control the contact time between air and 

wastewater enables high-oxygen transfer efficiencies. The oxygen transfer at the membrane enables microbial colonization 

at the membrane surface. Oxygen transfer across the membrane increases due to microbial respiration. The biofilm formed 

on the membrane surface; therefore, the aerobic and anaerobic processes go on at the same time. The MABR can 

simultaneously remove BOD and nitrogen from the wastewater. 

Comparison to Established Technologies:

The MABR, when compared to trickling filter and Membrane BioReactor (MBR), can have lower energy requirements and be 

a single-reactor treatment process. 

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

University of Minnesota

Department of Civil Engineering

500 Pillsbury Drive, SE

Minneapolis, MN 55455

Telephone: 612-625-9857

Email: semme001@amn.edu

Installation(s):

There are no installations in the United States at this time.

Key Words for Internet Search:

Membrane-Aerated BioReactor, MABR, wastewater, gas-permeable membrane

Data Sources:

WERF Report, Treatment Processes – Membrane Technology: Pilot Studies of Membrane-Aerated Bioreactors, Final Report, 

2005.
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February 2008

Technology Summary

Microbial Fuel Cell (MFC) Based Treatment System

Objective:

Generate electricity from wastewater treatment. 

State of Development:

Embryonic. Not available commercially; however, extensive 

research underway.

Description:

The concept of the system is based on using bacteria in a conductive material in which the bacteria can grow. The 

microorganisms present in the wastewater oxidize compounds in the wastewater away from oxygen during the process. The 

electrons gained through oxidation are transferred towards an electrode (anode). The electrons depart through an electrical 

circuit towards a second electrode (cathode). At the cathode, the electrons are transferred towards a high-potential electron 

acceptor, preferably oxygen. As current flows over a potential difference, power is generated as a result of bacterial activity. 

The generation of electricity is based on the respiratory enzymes of the bacteria that span the outer membrane and transfer 

electrons to materials on the surface of the cell.

Comparison to Established Technologies:

Not comparable to any established technology. 

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Research Projects at various universities including: 

Pennsylvania State University 

Hydrogen Energy Center

University Park, PA 16802

Telephone: 814-863-7908

Email: blogan@psu.edu

Washington University

Hilltop Campus

Campus Box 1198, One Brooking Drive

St. Louis, MO 63130

Telephone: 314-935-5663 

Fax: 314-935-5464

Email: angenent@seas.wustl.edu

Installation(s):

There are no installations in the United States at this time.

Key Words for Internet Search:

Microbial fuel cell, MFC, wastewater treatment, energy conversion

Data Sources:

Logan, B.E., “Extracting Hydrogen and Electricity from Renewable Resources,” Environmental Science Technology, 38, 

160A–167A, 2004.

Logan, B.F., et al., “Microbial Fuel Cells: Methodology and Technology,” Environmental Science Technology, 40 (7); 5,181–

5,192, 2006. 

http://www.engr.psu.edu/ce/enve/mfc-logan_files/mfc-logan.htm
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February 2008

Technology Summary

Multi-Stage Activated Biological Process (MSABPTM)

Objective:

Carbon oxidation, nitrification, and denitrification

State of Development:

Embryonic.

Description:

The Multi-Stage Activated Biological Process (MSABPTM) is an embryonic method of domestic and industrial wastewater 

treatment based upon the spatial microorganisms’ succession and the trophic hydrobiont chains. These spatially segregated 

trophic microorganism chains provide proper conditions at which bacteria are used as food source sequentially by first 

primary and then higher level microorganisms in the food chain. Apparently, the spatial microorganism succession provided 

treatment by aerobic and anaerobic microorganisms maintained at different stages of the biological reactor. 

There are eight compartments in the biological reactor. The influent wastewater enters the first compartment and travels 

through the each compartment circulating via the flow pattern created by air diffusers located at the bottom of the tank. 

Wastewater flow is in a looping pattern so that short circuiting is reduced. Removal of organics and nitrification take place in 

the first four compartments. Fifth and sixth compartments are anoxic and denitrification occurs in these compartments. 

Usually 80 percent of the BOD is reduced in these compartments leaving about 20 percent available for nitrification and 

denitrification processes. The seventh and eighth compartments operate in endogenous phase and digest remaining volatile 

solids. 

Comparison to Established Technologies:

The vendor claims that no waste-activated sludge is generated in this system. Total number of compartments and size are 

based on the influent wastewater characteristics and treatment goals.

Available Cost Information:

Approximate Capital Cost: Dependent upon local requirements and specific application.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Aquarius Technologies, Inc. 

1103 Mineral Springs Drive, Suite 300 

Port Washington, WI 53074

Telephone: 262-268-1500 

Fax: 262-268-1515 

Email: info@aquariustechnologies.com

BioScape Technologies, Inc.

Tim Bossard, Jack Akin

816 Bennett Avenue

Medford, OR 97504

Telephone: 541-858-5774

Fax: 541-858-2771

Email: info@bioscapetechnologies.com

Installation(s):

Beijing Eizen Lubao Oil Co., China

Johnson and Johnson Ltd., China

Salatey Shamir Foods, Israel

Pigs grow farm, Spain

Marugan WWTP, Spain

Delta Textile Factory, Israel

Shtrauss Dairy Foods, Israel

Key Words for Internet Search:

Multi-Stage Activated Biological Process, MAB, MSABPTM, trophic hydrobiont chains 

Data Sources:

http://www.aquariustechnologies.com/

http://www.bioscapetechnologies.com/index.html
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February 2008

Technology Summary

NeredaTM

Objective:

Treating domestic or industrial wastewater by means of 

aerobic pellets.

State of Development:

Embryonic.

Description:

The NeredaTM process is based upon cultivating aerobic bacteria in conditions that cause the bacteria to form an adhesive 

material that bonds the bacteria into concentrated “pellets.” The adhesive material and the conditions that produce it are not 

disclosed by the vendor. Nereda’s claim is that forming pellets allow large concentrations of bacteria to be contained in less 

space than conventional activated-sludge bacteria that are more dispersed and less concentrated. The pellets are also 

easier to settle in clarifiers because of their higher density. Bacteria in the pellets are as capable of decomposing the 

wastewater as dispersed bacteria in conventional activated sludge; however, the advantages of higher concentrations and 

better settling may be able to reduce the costs of aeration basins and clarifiers. The pellets may also be less prone to bulking 

and poor solids settling episodes. 

Comparison to Established Technologies:

The NeredaTM process offers important advantages when compared to conventional water purification processes. All the 

processes can occur in one reactor; therefore, this process eliminates the need for a clarifier. This process needs only a 

quarter of the space required by conventional installations. 

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Andreas Giesen

DHV Water BV 

P.O. Box 1132

3800 AL Amersfoort

The Netherlands

Telephone: 0031-33-468-22 00

Fax : 0031-33-468-28 01

Email: andreas.giesen@dhv.nl

Web site: http://www.dhv.com

Installation(s):

There are no installations in the United States at this time.

Key Words for Internet Search:

NeredaTM, DHV Water BV

Data Sources:

http://www.nereda.net

http://www.dhv.com
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February 2008

Technology Summary

SHARON (Single reactor High-activity Ammonia Removal Over Nitrite)

Objective:

Nitrogen removals from digested-sludge-processing 

recycle flows.

State of Development:

Embryonic. One full-scale application is under construction in 

Wards Island, New York City, New York. Six facilities are in 

operation worldwide.

Description:

SHARON is a sidestream process that has been developed to remove nitrogen biologically from recycle flows of anaerobically 

digested solids. The SHARON process takes place in a simple, completely mixed reactor without biomass retention. Compared 

to the conventional conversion of ammonium via the nitrification/denitrification route, the SHARON process converts ammonia 

nitrogen to nitrite nitrogen, which is then converted to nitrogen gas. The oxidation of ammonia is stopped at nitrite by creating 

favorable process conditions for nitrifying bacteria. Further oxidation of the nitrite can be prevented since at higher temperatures 

the ammonia oxidizers, such as nitrosomonas, grow significantly faster than the nitrite oxidizing bacteria, such as nitrobacter. 

This is used in the SHARON process design, which is characterized by the absence of sludge retention. By choosing a 

sufficiently short hydraulic retention time, the slow-growing nitrite oxidizers are washed out of the system and ammonia 

oxidation is stopped at nitrite. The microbiological activity in the SHARON reactor results in significant heat production, which 

causes a temperature rise of about 5 to 8 degrees C. Due to high process temperature of between 30 to 40 degrees C, 

relatively short retention times can be realized. Since the inflowing reject water from dewatering can be expected to be 

relatively warm, additional heating is only required in winter time.

Comparison to Established Technologies:

The removal efficiency is strongly dependent on the ammonium influent concentration and the Hydraulic Retention Times 

(HRTs). Generally the removal efficiency increases with higher influent concentrations and longer HRT. Considerable savings 

in carbon source and aeration capacity are reported when the SHARON process is compared to the conventional nitrogen 

conversion within the context of overall nitrogen removal. Based on European data, average nitrogen removal efficiency is in 

the range of 80 to 90 percent. On average, 70 percent of the nitrogen load is converted via nitrite. The presence of suspended 

solids is not reported to have influence on the removal efficiencies and operation of the process as it operates without sludge 

retention. The pH has to be controlled carefully due to high concentrations and the high-reaction rates involved in the process. 

The bicarbonate in the sludge liquor and the denitrification process compensate the acidifying effect of the nitrification. In the 

process, the CO2 stripping needs to be sufficient to allow for full use of the bicarbonate. The process is highly dynamic and 

has to be designed for rapid response.

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.
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Technology Summary

SHARON (Single Reactor High-activity Ammonia Removal Over Nitrite) (Contd)

Vendor Name(s):

Mixing and Mass Transfer Technologies

Southeastern Region

8833 North Congress Ave., Suite 818

Kansas City, MO 64153

Telephone: 816-854-1969

Email: arawakomski@m2ttech.com or 

tgilligan@m2ttech.com

Website: http://www.m2ttech.com

Delft University of Technology

Prof. Dr. Ir. Mark van Loosdrecht 

Department of Biotechnology

Julianalaan 67, 2628 BC Delft, The Netherlands 

Telephone :31-15-278 1618

Email: mark.vanLoosdrecht@tnw.tudelft.nl

Installation(s):

There are no installations in the United States at this time.

Key Words for Internet Search:

SHARON process, wastewater treatment, sidestream process, biological treatment

Data Sources:

Metcalf and Eddy, Wastewater Engineering Treatment and Reuse, 4th Edition, 2003.

Communication with Mixing and Mass Transfer Technologies, 23 May 2005. 
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Technology Summary

SHARON – ANAMMOX (ANaerobic AMMonia OXidation)

Objective:

Nitrification, denitrification, and ammonia removal.

State of Development:

Embryonic. Bench-scale and pilot-scale studies have been 

performed throughout the world. The United States and Europe 

are performing extensive research. The technology is not yet 

available commercially.

Description:

This process is a modification of the SHARON process. The process removes ammonia from the wastewater. The principle 

of these combined processes is that the NH4-N in the sludge digester effluent is oxidized in the SHARON reactor to NO2-N 

for only 50 percent of NH4-N. The mixture of nitrite and ammonia is ideally suited as influent for the ANAMMOX process, and 

ammonium and nitrite are anaerobically converted to nitrogen gas and water.

Comparison to Established Technologies:

SHARON – ANAMMOX process allows a reduction of up to 60 percent of the oxygen and energy demand as compared to 

the traditional nitrification/denitrification route via nitrate. The process combination does not require the presence of organic 

COD for denitrification. It is considered to be more sustainable than conventional treatment because of the reduced CO2

emissions associated with energy savings. An overall nitrogen removal efficiency of 90 to 95 percent can be achieved 

depending on process conditions and influent characteristics.

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Mixing and Mass Transfer Technologies

Southwestern Region

8833 North Congress Ave., Suite 818

Kansas City, MO 64153

Telephone: 816-854-1969

Email: arawakomski@m2ttech.com 

Web site: http://www.m2ttech.com

Mixing and Mass Transfer Technologies

Northeast Region

583 Greenhaven Road

Pawcatuck, CT 06379

Telephone: 860-599-5381

Email: tgilligan@m2ttech.com 

Web site: http://www.m2ttech.com

Installation(s):

There are no installations in the United States at this time.

Key Words for Internet Search:

ANAMMOX, SHARON process, wastewater treatment, ammonia

Data Sources:

Communication with Mixing and Mass Transfer Technologies.

http://www.bt.tudelft.nl/r_proj/mic/P_Dongen.htm
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February 2008

Technology Summary

STRASS Process (Nitritation and Denitritation in SBR)

Objective:

Biological ammonia removal from high-strength streams 

(e.g., sludge liquors, landfill leachate).

State of Development:

Embryonic. Two full-scale systems in Strass and Salzburg, Austria, 

have been successfully implemented in 1997 and 1999 

respectively. In 2004 it was transformed to the superior DEMON 

technology. In Salzburg, Austria, 1,000 kg N/d sidestream 

treatment is still in operation. Extensive pilot-scale studies 

performed in the United States at Alexandria Sanitation Authority, 

Virginia. 

Description:

The STRASS process uses a high-sludge sequencing bench reactor to oxidize ammonia to nitrite (nitritation) followed by 

reduction of the produced nitrite to nitrogen gas (denitritation). A supplemental carbon source, such as primary sludge is used 

to drive the denitritation process. The key feature of the STRASS process is that the pH based control mechanism is highly 

effective to control the intermittent aeration system. During an aeration, interval acidification occurs because of nitritation. 

When the lower pH setpoint is reached, the aeration stops and alkalinity/pH recovers. At the upper pH setpoint, aeration is 

switched on again resulting in a characteristic sawtooth profile of the pH course. Following this control strategy, frequency and 

length of aeration intervals is self adjusting to the feed rate and concentration of sidestreams. Proper selection of pH setpoints 

helps to control Nitrite Oxidizing Bacteria (NOB) inhibition and inorganic carbon limitation. 

Comparison to Established Technologies:

The STRASS process is an equivalent technology compared to the SHARON process, and it was developed in the same 

year. The main difference is that SHARON process is operated as a chemostat without sludge retention (to keep a short SRT 

to maintain inhibition of NOBs), while STRASS process is operated in an SBR with sludge retention. NOB inhibition is reliably 

maintained by pH-controlled intermittent aeration (aeration stops immediately after available ammonia has been transformed 

to nitrite and H+

), low Dissolved Oxygen (DO), and elevated temperature. 

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

Cyklar-Stulz

CH-8737 Gommiswald Rietwiesstrasse 39

Switzerland

Telephone: 41-55-290-11-41

Fax: 41-55-290-11-43

Email: info@cyklar.ch 

Web site: http://www.cykar.ch

Installation(s):

Full-scale STRASS systems are in Strass and Salzburg, Austria. 

Pilot systems are operated by Alexandria Sanitation Authority, 

Virginia, United States. There are no full-scale installations in the 

United States at this time.

Key Words for Internet Search:

STRASS, sidestream treatment, ammonia, pH-control, Air Intercept Zone (AIZ)

Data Sources:

Wett, B., et al., “pH Controlled Reject Water Treatment,” Water Science Technology, 1998.
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February 2008

Technology Summary

Vacuum Rotation Membrane (VRM®) System

Objective:

Filtration of biomass for high-quality effluent with smaller 

footprint, lower energy demand, and more effective 

scouring of the membrane surface.

State of Development:

Embryonic. Systems are in operation in Europe.

Description:

The new membrane system employs flat-sheet ultra-filtration membranes rotating around a horizontal shaft. Scouring air is 

introduced next to the shaft at about half the water depth, providing high-intensity scouring of a small section in the 12 o’clock 

position. The membranes rotate through this scouring section several times per minute. Operating results showed that neither 

back-pulsing nor regular cleaning is required to maintain an average flux of at least 10 gal/ft2 with a suction head of less than 

10 feet.

Comparison to Established Technologies:

The vendor claims that the VRM® system reduces aeration tank volume by 70 percent and energy consumption.

Available Cost Information:

Approximate Capital Cost: $1/gallon (based on overseas operations).

Approximate O&M Costs: $100,000/year/1 MGD (based on overseas operations).

Vendor Name(s):

Huber Technology, Inc.

9805 North Cross Center Court, Suite H

Huntersville, NC 28078

Telephone: 704-949-1010 

Email: christian@hhusa.net

Web site: http://www.huber.technology.com or

http://www.huber.de

Installation(s):

There are no installations in the United States at this time.

Key Words for Internet Search:

VRM®, membrane bioreactor, wastewater, vacuum, rotation

Data Sources:

http://www.huber.de
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Chapter

Wastewater Treatment and In-Plant Wet Weather Management 4-1

4

In-Plant Wet Weather Management Processes

4.1 Introduction

Chapter 4 in-plant wet weather management processes include the storage and treatment 

of wastewater with infiltration/inflow entering a WWTP or storm-related flows in combined 

sewer systems entering a WWTP. This chapter focuses on storage and treatment 

technologies that can be used to manage the volume of wastewater during wet weather 

events.

4.2 Technology Assessment

Table 4.1 includes a categorized list of emerging and established technologies for wet 

weather management. The innovative wet weather management technologies are as 

follows: Continuous Deflection Separator (CDS), HYDROSELF® Flushing Gate, Tripping 

Flusher®, TRASHMASTERTM Net Capture System, and WWETCO Compressed Media 

Filtration® or WWETCO CMP® System. Alternative wet weather disinfection is the 

embryonic in-plant wet weather management embryonic technology, which is highlighted 

at the end of this chapter. 

Wet weather flows can be better managed if the conveyance systems to a facility are well 

maintained. However, new technologies are needed to overcome the wet weather issues 

more efficiently. Emerging technologies used to rehabilitate conveyance systems to 

reduce wet weather flows are described in the U.S. EPA document “Emerging Technologies 

for Conveyance Systems – New Installations and Rehabilitation Methods” (EPA 832-R06-004, July 2006). An evaluation of the innovative technologies identified for in-plant wet 

weather management processes is presented in Figure 4.1.
Emerging Technologies February 2008

4-2 Wastewater Treatment and In-Plant Wet Weather Management

Figure 4.1—Evaluation of Innovative In-Plant Wet Weather Management Technologies 

Table 4.1— In-Plant Wet Weather Management Processes – State of Development

Process

Evaluation Criteria

DevelopmentApplicabilityBenefitsImpact on ProcessesComplexityAir/Odor EmissionsReuseEnergyFootprintRetrofitting

Continuous Deflection Separator (CDS) P, N S, F W p p y Dn p y p

HYDROSELF® Flushing Gate M, N S, F W p y y Dn p y p

Tipping Flusher® M, N S, F W p y y Dn p y p

TRASHMASTERTM Net Capture System M, N S, F W p y y Dn p y p

WWETCO Compressed Media Filtration® or 

WWETCO CMF® System

P, N S, F W p p y Dn p y p

Comparative Criteria

p Positive feature

y Neutral or mixed

q Negative feature

Effluent Reuse

Dp = Direct potable

Dn = Direct nonpotable

Ip = Indirect potable

In = Indirect 

nonpotable

Applicability

F = Few plants

I = Industrywide

L = Primarily large plants

S = Primarily small plants

Potential Benefits

C = Capital savings

I = Intense operational demand

O = Operational/maintenance savings

S = Shock load capacity

W= Wet weather load capacity

Statement of Development

B = Bench scale

I = Full-scale industrial applications

M = Full-scale municipal applications

O = Full-scale operations overseas

P = Pilot

N = Full-scale operations in North America

Key

Established Technologies

Dispersed Air Flotation

Dissolved Air Flotation (DAF)

Enhanced Clarification/High Rate Clarification (HRC)

Ballasted Flocculation (Actiflo® and Microsep®  )

 Lamella Plate Settlers

Screening

Vortex Separation

Innovative Technologies

Continuous Deflection Separator (CDS)

HYDROSELF® Flushing Gate

Tipping Flusher®

TRASHMASTERTM Net Capture System

WWETCO Compressed Media Filtration® or

WWETCO CMF® System

Innovative Use of Established Technologies

None at this time

Embryonic Technologies

Alternative Wet Weather Disinfection
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February 2008

Technology Summary

Continuous Deflection Separator (CDS)

Objective:

Separates debris, sediments, oil, and grease from 

stormwater runoff. 

State of Development:

Innovative.

Description:

CDS works by continuous deflection of the stormwater runoff. The CDS unit has a diversion chamber where the flow of water 

is diverted to the separation chamber. The flow and screening controls prevents the re-suspension and release of separated 

solids. During flow events, the diversion weir bypasses the separation chamber to avoid already trapped solids to be washed 

into the flow. 

The CDS units are available either precast or cast- in-place, and offline units can treat flows from 1 to 300 cubic feet per 

minute (cfm). The inline units treat up to 6 cfm, and internally bypass flows in excess of 50 cfm. 

Comparison to Established Technologies:

Operation of CDS is independent of flow for a wide treatment ranges.

Available Cost Information:

Approximate Capital Cost: Not disclosed by vendor.

Approximate O&M Costs: Not disclosed by vendor.

Vendor Name(s):

CONTECH® Construction Products Inc.

9025 Centre Pointe Drive, Suite 400

West Chester, OH 45069

Telephone: 800-338-1122 or 513-645-7000

Web site: http://www.contech-cpi.com/contract

Installation(s):

Cincinnati, OH

Key Words for Internet Search:

CONTECH®, Continuous Deflection Separation, CDS

Data Sources:

Vendor web site: http://www.contech-cpi.com/
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February 2008

Technology Summary

HYDROSELF® Flushing Gate

Objective:

Wet weather management, cleaning of Combined Sewer 

Overflows (CSOs) and storage tanks.

State of Development:

Innovative.

Description:

The Hydroself® flushing gate system is a method of removal of accumulated sediments and debris in the combined sewer 

retention systems, stormwater runoff, and balancing tank. The operating principle for the Hydroself® flushing system is that 

the flush water is held in reserve and as released there is a high-energy wave. The wave removes the accumulated debris 

from the retention chamber and interceptors along the flushway lengths. 

Comparison to Established Technologies:

The Hydroself® flushing gate system is not similar to established wastewater technology, but is similar to other innovative 

technologies that restore the capacity of collection systems. Removing accumulated sediment may be accomplished manually. 

The system lessens manpower needs and improves employee safety over manual cleaning.

Available Cost Information:

Approximate Capital Cost: Approximately $350,000.

Approximate O&M Costs: Approximately $250/event.

Cost information taken from the WERF Manual, Best Practices for Wet Weather Wastewater Flows, 2002.

Vendor Name(s):

Steinhardt GmbH Wassertechnik

Roderweb 8-10-D-65232

Taunusstein, Germany

Telephone: 49-6128-9165-0

Email: info@steinhardt.de

Web site: http://www.steinhardt.de/htm_en/fset_e.html

Installation(s):

Gabriel Novac and Associates, Inc.

 3532 Ashby

 Montreal, Quebec H4R 2C1, Canada

 Telephone: 514-336-5454

 Email: gnacso@gnacso.com

Clough Creek CSO Treatment Facility

 Cincinnati, OH

Key Words for Internet Search:

Flushing gate system, wastewater, high-energy wave, Hydroself®

Data Sources:

WERF Manual, Best Practices for Wet Weather Wastewater Flows, 2002.

http://www.copa.co.uk

http://www.epa.gov/ednnrmrl/repository

http://www.steinhardt.de/htm_en/fset_e.html
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February 2008

Technology Summary

Tipping Flusher®

Objective:

Wet weather management, cleaning of CSOs, and 

storage tanks.

State of Development:

Innovative.

Description:

The system generally includes filling pipes and valves, a pumping system, and wet well (where restricted by the site conditions), 

and the tipping flusher vessels. The tipping flusher is a cylindrical stainless steel vessel suspended above the maximum water 

level on the back wall of the storage tank. Just before overtopping the vessel with water, the center of gravity shifts and 

causes the unit to rotate and discharge its contents down the back wall of the tank. A curved fillet at the intersection of the 

wall and tank floor redirects the flushwater (with minimum energy loss) horizontally across the floor of the tank. The fillet size 

depends on the size of the flusher. The flushing force removes the sediment debris from the tank floor and transports it to a 

collection sump located at the opposite end of the tank.

Comparison to Established Technologies:

The Tipping Flusher® is not similar to established wastewater technology, but it is similar to other innovative technologies that 

restores the capacity of collection systems. Removing accumulated sediment may be accomplished manually. The system 

lessens manpower needs and it improves employee safety over manual cleaning.

Available Cost Information:

Approximate Capital Cost: Approximately $525,000

Approximate O&M Costs: Not disclosed by vendor.

Costs information taken from the WERF Manual, Best Practices for Wet Weather Wastewater Flows, 2002.

Vendor Name(s):

Steinhardt GmbH Wassertechnik

Roderweb 8-10-D-65232

Taunusstein, Germany

Telephone: 49-6128-9165-0

Email: info@steinhardt.de

Website: http://www.steinhardt.de/htm_en/fset_e.html

Installation(s):

Gabriel Novac and Associates, Inc.

 3532 Ashby

 Montreal, Quebec H4R 2C1, Canada

 Telephone: 514-336-5454

Saginaw, MI

Key Words for Internet Search:

Sewer, tank, flushing tipping flusher, wet weather management, wet well

Data Sources:

WERF Manual, Best Practices for Wet Weather Wastewater Flows, 2002.

http://www.copa.co.uk 

http://www.epa.gov/ednnrmrl/repository

http://www.steinhardt.de/htm_en/fset_e.html
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February 2008

Technology Summary

TRASHMASTERTM Net Capture System

Objective:

Wet weather management of trash and debris removal 

from CSOs and stormwater systems.

State of Development:

Innovative.

Description:

The TRASHMASTERTM Net Capture System is a process that removes accumulated trash, sediments, and debris in a 

combined sewer system (CSS) or stormwater collection system. The operating principle of the TRASHMASTERTM Net Capture 

System is to capture trash, debris, and sediment in special removable nets as the water flows through the unit. No electrical 

connections are required. It is used in low-flow applications (5 cubic feet per second [cfs] or less) and inserts in-line on the 

outflow piping. It is a light weight, roto-molded, fiberglass unit that is very easy to install on pipes that are 24 inches or less in 

size by using onsite equipment. No special construction is necessary. The unit can be installed in two days or less to depths 

of ten feet. The unit can also accommodate special chemical feed systems to treat waterborne impurities. 

Comparison to Established Technologies:

The TRASHMASTERTM Net Capture System is a unique solution to remove trash and debris in low flowing water. The vendor, 

Fresh Creek Technologies, produces similar, established technologies (e.g., Netting Trash TrapTM system). Other established 

technologies require extensive engineering, special installation equipment, a more expensive product, and a week or longer 

to install. 

Available Cost Information:

Approximate Capital Cost: Approximately $40,000.

Approximate O&M Costs: Approximately $110 per event.

Vendor Name(s):

Fresh Creek Technologies, Inc.

1425 Pompton Avenue

Suite 1–2

Cedar Grove, NJ 07009

Telephone: 973-237-9099

Fax: 973-237-0744

Web site: www.freshcreek.com

Installation(s):

Kingston, Ontario, Canada

Harrington, WA

Key Words for Internet Search:

TRASHMASTERTM Net Capture System, netting systems, Fresh Creek Technologies, freshcreek 

Data Sources:

Email and telephone conversations with vendor.

http://www.freshcreek.com 
Emerging Technologies February 2008

4-10 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

TRASHMASTERTM Net Capture System from Fresh Creek Technologies

Cross Section of a TRASHMASTERTM Net Capture System

TRASHMASTERTM Net Capture System (Contd)
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

4-11

February 2008

Technology Summary

WWETCO Compressed Media Filtration® or WWETCO CMF® System 

Objective:

Wet weather management.

State of Development:

Innovative.

Description:

The patent pending WWETCO Compressed Media Filtration®, also known as WWETCO CMF® System, consists of detached 

fibrous lump media that is hydraulically compressed by a flexible housing with the fluid filtered in a lateral direction, which 

provides a porosity gradient from uncompressed highly permeable media zone to an adjustable lesser porous media zone in 

the direction of flow. The result allows the removal of larger particles in the upper zone and the penetration and removal of 

smaller particles in the lower zones. This flexibility allows the application of the WWETCO CMF® at publicly owned treatment 

works (POTW) in a dual-use mode as a dry weather tertiary filter, then as a wet weather filter to treat either excess primary 

clarifier flows or excess screened and degritted flows. 

Filter TSS removals are adjustable with compression provided. Up to 95 percent TSS removal can be achieved as a tertiary 

filter with effluent TSS consistently less than 1 mg/L and turbidities consistently under 1 ntu. Filter performance when treating 

screened and degritted wet weather flow can be 75 to 90 percent TSS removal. Hydraulic loadings in this application are 

typically 8 to 10 gpm/ft2 with backwash quantities in the range of 5 to 10 percent of the filtered water volume. Filter performance 

when treating primary effluent flows during wet weather can generally be 65 to 75 percent. Pilot plant test results indicate that 

WWETCO CMF® proved to be effective in removing solids at various ranges of primary effluent flow. Typically, as hydraulic 

and solids loading rates increased, filter run times decreased requiring a balance of run time and loading rates for optimum 

performance. One pilot study indicated that 64 percent removal of solids at loading rates of 12 to 15 gpm per ft2 is achievable 

for a primary effluent flow of 182 MGD with 100 mg/L solids concentration. 

The WWETCO CMF® System incorporates a patent pending backwash method that uses low head air (10 standard cubic feet 

per minute [SCFM] per ft2 at 7 ft Total Dynamic Head [TDH]) to circulate and scrub the filter media and lift the backwash water 

and solids to be wasted. The backwash method maximizes the use of the air and minimizes the amount of water to clean the 

filter. Backwashing is accomplished within a 20-minute period cleaning a filter cell was used to treat raw sewage or secondary 

clarifier effluent. Backwash solids are typically sent to biological treatment or directly to solids processing facilities. 

No mechanical equipment is required to provide the filter compression, and this makes the system ideal for passive operation, 

which is often needed in wet weather treatment systems. The filter is left dry and can sit idle for extended periods with no odor 

or operational issues. When excess wet weather flows occur, the filter is immediately brought online and has no ramp-up 

requirements. Chemicals are not required. The filter can tolerate moderate screenings and grit loadings without impacting 

performance or cleaning operations.

Comparison to Established Technologies:

The WWETCO CMF® technology is comparable in performance with the ballasted flocculation systems being marketed for 

use at POTW to treat excess wet weather flows. Ballasted flocculation systems can typically achieve 85 percent TSS removals, 

but they require flocculation chemicals and ramp-up time (15 to 30 minutes) to achieve performance objectives. The WWETCO 

CMF® can meet similar or better removals, it requires no chemicals, and it immediately achieves performance objectives. The 

WWETCO CMF® starts dry and ends dry without odor issues, without special startup protocols, and without special attention 

to mechanical Equipment. 

The ballasted flocculation systems generally require a footprint of approximately 40 to 80 ft per MGD of capacity and are 

generally 23- to 29-ft deep. This footprint does not include chemicals and sludge handling and processing requirements. The 

WWETCO CMF® requires a total footprint of approximately 150 ft2

 per MGD for treating primary clarifier effluent. The WWETCO 

CMF® for POTW application is 12-ft deep. 
Emerging Technologies February 2008

4-12 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

WWETCO Compressed Media Filtration® or WWETCO CMF® System (Contd)

Available Cost Information:

Approximate Capital Cost: The capital cost is a function of hydraulic and solids loading rate. Higher solids wastewaters 

require lower hydraulic loading rates, shorter run times, thus more filters. General capital 

costs are as follows for complete systems including filter, appurtenant equipment, and 

concrete structures:

Approximate O&M Costs: O&M costs include power for low-head blower air for backwashing. As the filter requires no 

other equipment other than valving, no chemicals and no additional solids handling, and it 

comes online passively, with little personnel attention required. Power costs are as follows:

Vendor Name(s):

WWETCO, LLC

800 Lambert Drive, Suite F

Atlanta, GA 30324

Telephone: 404-307-5731 

Email: mark@wwetco.com

Website: http:/www.wetco.com

Installation(s):

Atlanta, GA 

Columbus, GA

Key Words for Internet Search:

Compressed media filtration, WWETCO, Advanced Demonstration Facility at Columbus, Georgia, CSO filter, tertiary filter, 

wet weather filter

Data Sources:

ARCADIS, “Water Pollution Control Station Secondary By Pass Treatability Study Phase III,” City of Akron, OH, February 

2006.

Arnett, C.A., M. Boner and J. Bowman, “Bacteria TMDL Solution To Protect Public Health And Delisting Process In Columbus, 

GA,” WEFTEC, 2006.

Boner, M. et al., “Atlanta CSO Pilot Plant Performance Results,” WEFTEC, 2004.

Frank, D. A. and T. F. Smith III, “Side by Side by Side, The Evaluation of Three High Rate Process Technologies for Wet 

Weather Treatment,” WEFTEC, 2006.

WERF, Peer Review: Wet Weather Demonstration Project in Columbus, Georgia, Co-published: Water Environment Research 

Foundation, Alexandria, VA, and IWA Publishing, London, UK, 2003.

Application

Capital Cost Estimate

($ per gallon capacity)

Tertiary Filter $0.05 to $0.06

Primary Effluent Filtration $0.06 to $0.08

Wastewater and CSO Filtration $0.10 to $0.15

Application

Power Cost

(per million gallons treated)

Tertiary Filter $0.30 

Primary Effluent Filtration $2.93 

Wastewater and CSO Filtration $12.80 
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

4-13

February 2008

Technology Summary

WWETCO Compressed Media Filtration® or WWETCO CMF® System (Contd)

WWETCO CMF® Patents Pending

Synthetic Filter Media with Air Supply (Center) and Flexible Membrane
Emerging Technologies February 2008

4-14 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary

WWETCO Compressed Media Filtration® or WWETCO CMF® System (Contd)

Backwash Troughs

Filter Housing Filter Membrane

Compressible Media

Perforated Plates

Air Supply for Backwashing

Patent Pending

Filtered Water Underdrain

Filter Basin

745043_WWT-21.ai

WWETCO CMF® Drained of Liquid at Ready Position (Patent Pending)

Filter in Backwash Mode
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

4-15

February 2008

Technology Summary

Alternative Wet Weather Disinfection

Objective:

High-rate alternative to wet weather disinfection flows by 

using disinfection products such as peracetic acid, 

ferrite, or Bromo Chloro Dimethylhydantoin (1-Bromo-3-

Chloro-5,5 Dimethylhydantoin [BCDMH]).

State of Development:

Embryonic. A pilot-scale test was performed in Akron, Ohio, on 

three wet weather test events. BCDMH was found to be an 

effective disinfectant at doses of 3 mg/L, 6 mg/L, and 12 mg/L.

Description:

Alternative disinfectants are being applied to wet weather flows because of their ability to act as high-rate disinfectant. 

Although not yet approved by the U.S. EPA specifically as a wastewater disinfectant, peroxyacetic acid (peracetic acid 

[CH3CO3H]) is an oxidizing agent that can be used as a disinfectant. Peracetic acid is produced 5, 15, and 35 percent 

solutions and is widely used in the food industry. 

BCDMH is a chemical disinfectant used in treating drinking water. It is a crystalline substance, insoluble in water, but soluble 

in acetone. It reacts slowly with water releasing hypochlorous acid and hypobromous acid. EBARA has devised a system to 

liquefy the BCDMH powder in a mixer with an injection device. The solution is injected directly into the wastewater and it relies 

on the turbulence of the process to mix into the disinfection process.

Comparison to Established Technologies:

As compared to disinfection with chlorine compounds, peracetic acid does not form harmful byproducts after reacting with 

wastewater. However, a residual of acetic acid will be present and will exert an oxygen demand. The concentration used for 

disinfection of secondary effluent depends on the target organism, the water quality, and the level of inactivation required. For 

example, a concentration of 5 mg/L peracetic acid, with contact time of 20 minutes, was able to reduce fecal and total coliform 

by 4 to 5 logs in secondary effluent (Morris, 1993). 

BCDMH has a small footprint and is easier to store than chlorine disinfection products. BCDMH is comparable to sodium 

hypochlorite, but it acts in contact a shorter amount of time. The shorter contact time is typically 3 minutes instead of 5 

minutes for sodium hypochlorite, and it reduces the size of the contact chamber and may result in capital cost savings of 

about 54 percent. 

Available Cost Information:

Approximate Capital Cost: Unknown.

Approximate O&M Costs: The cost of peracetic acid is about 3 to 5 times the cost of sodium hypochlorite.

Vendor Name(s):

Peracetic Acid

Microbial Control

FMC Corporation

1735 Market Street

Philadelphia, PA 19103

Telephone: 609-951-3180 

Web site: http://www.microbialcontrol.fmc.com

BCDMH

EBARA Engineering Service Corporation

Shinagawa, NSS-11 Building

2-13-34 Konan, Minato-Ku, Tokyo, Japan

Telephone: 81-3-5461-6111 (switchboard) 

Web site: http://www.ebara.co.jp/en/

Installation(s):

Columbus Water Works, Columbus, GA

Water Pollution Control Station, City of Akron, OH

Key Words for Internet Search:

Alternative disinfectant, wet weather, peracetic acid, PAA, BCDMH
Emerging Technologies February 2008

4-16 Wastewater Treatment and In-Plant Wet Weather Management

Alternative Wet Weather Disinfection (Contd)

Data Sources:

Columbus Georgia Water Works, CSO Technology Testing web site: http://www.cwwga.org/NationalPrograms/Index.htm

Combined Sewer Overflow Technology Fact Sheet Alternative Disinfection Methods web site: 

www.epa.gov/owmitnet/mtb/altdis.pdf

Gehr, R., Wagner, M., P. Veerasubramanian, and Payment, P. “Disinfection Efficiency of Peracetic Acid, UV and Ozone After 

Enhanced Primary Treatment of Municipal Wastewater,” Water Research, 37, 19, pp.4,5734586, 2003.

Moffa, Peter E., Daniel P. Davis, Chris Somerlot, Dan Sharek, Brian Gresser and Tom Smith. “Alternative Disinfection 

Technology Demonstrates Advantages for Wet Weather Applications,” Water Environment and Technology, January 2007.

Morris, R., “Reduction of Microbial Levels in Sewage Effluents using Chlorine and Peracetic Acid Disinfectants,” Water 

Science and Technology, Vol. 27, 1993.

WERF, Wet Weather Demonstration Project in Columbus, Georgia, 98-WWR1P.

Rossi, S., et al., “Peracetic Acid Disinfection: A Feasible Alternative to Wastewater Chlorination,” Water Environment Research, 

79 (4): 341–350, 2007.

Kitis, M., “Disinfection of Wastewater with Peracetic Acid: A Review,” Environment International, 30:47–55, 2004.
Chapter

Wastewater Treatment and In-Plant Wet Weather Management 5-1

5

Process Monitoring Technologies

5.1 Introduction

Process monitoring technologies are now a critical component in the improvement of 

wastewater treatment. Those included in this report as process monitoring technologies, 

not only help prevent upsets in treatment systems and help facilities stay within the 

compliance limits during upset conditions, but also could potentially save energy and 

chemicals used by maximizing process efficiency. 

5.2 Technology Assessment

Table 5.1 includes a categorized listing of emerging and established technologies for 

process monitoring. An evaluation of the innovative technologies identified for process 

monitoring is presented in Figure 5.1. Summary sheets for each innovative technology 

are provided at the end of this chapter.

The innovative monitoring technologies listed in this chapter are focused on online 

monitoring in wastewater treatment systems, which help to prevent any upset to the 

system. These monitoring systems usually are probes or sensors that can detect change 

in physical, chemical and biological activity, and they can be installed at the influent, 

effluent, or in the main basin or the process tank. These monitoring devices are also 

helpful in saving energy and reducing operation and maintenance cost. These monitoring 

devices are also helpful in saving energy and reducing operation and maintenance cost. 

The innovative process monitoring technologies are as follows: Ammonia and Nitrate 

Probes (ChemScan N-4000, Hach Evita In Situ 5100, Myratek Sentry C-2, Hach 

NITRATAX, NitraVis® System, and Royce 8500 Series Multi-Parameter), Fluorescence In 

Situ Hybridization (FISH) for Filamentous and Nitrifying Bacteria, Microwave Density 

Analyzer, Microtox®/Online Microtox®, SymBioTM – Nicotinamide Adenine Dinucleotide 

(NADH) Probes, Online Respirometry, and NITROXTM – Oxidation Reduction Potential 

(ORP) Probe. The embryonic process monitoring technologies are as follows: Biological 

Micro-Electro-Mechanical Systems (BioMEMS), FISH for Phosphorus Accumulating 

Organisms (PAOs), Handheld Advanced Nucleic Acid Analyzer (HANNA), Immunosensors 

and Immunoassays, and Photo-electro Chemical Oxygen Demand (PeCODTM). The 

innovative and embryonic process monitoring technologies follow at the end of summarized 

in the technology summary sheets. 
Emerging Technologies February 2008

5-2 Wastewater Treatment and In-Plant Wet Weather Management

Table 5.1—Process Monitoring Technologies – State of Development

Established Technologies

Ammonia and Nitrate Process

 ChemScan

 Myratek

 Hach Evita

 Hach NITRATAX

NitraVis®  System

Dissolved Oxygen Analyzer

Online Cl2 Residual

pH Probes

Sludge Blanket Level Detector

Solids Retention Time (SRT) Controller

Total Suspended Solids Analyzer

Innovative Technologies

Ammonia-Nitrate Probes

 ChemScan N-4000

 Hach Evita In Situ 5100

 Myratek Sentry C-2

Innovative Technologies (Contd)

 Hach NITRATAX

NitraVis®  System

 Royce 8500 Series Multi-Parameter

Fluorescence In Situ Hybridization (FISH) for Filamentous 

and Nitrifiying Bacteria

Microwave Density Analyzer

Microtox®/Online Microtox®

SymBioTM – Nicotinamide Adenine Dinucleotide (NADH) 

Probes

Online Respirometry

NitroxTM – Oxidation Reduction Potential (ORP) Probe

Innovative Use of Established Technologies

None At This Time

Embryonic Technologies

Biological Micro-Electro-Mechanical Systems (BioMEMS) 

FISH for Phosphorus Accumulating Organisms (PAOs) 

Handheld Advanced Nucleic Acid Analyzer (HANNA)

Immunosensors and Immunoassays

Photo-electro Chemical Oxygen Demand (PeCODTM)
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

5-3

February 2008

Figure 5.1—Evaluation of Innovative Process Monitoring Technologies

Process

Evaluation Criteria

DevelopmentApplicabilityBenefitsImpact on ProcessesComplexityAir/Odor EmissionsReuseEnergyFootprintRetrofitting

Ammonia and Nitrate Probes I, M, N I, F C, O, S p p y y p y p

Fluorescence In Situ Hybridization (FISH) for 

Filamentous and Nitrifying Bacteria

I, M, N I, F C, O, S p p y y y y p

Microwave Density Analyzer I, M, N F C, O, S p p y y y y p

Microtox®/Online Microtox® I, M, N I, F C, O, S p y y y y y y

SymBioTM – Nicotinamide Adenine Dinucleotide (NADH) 

Probes

I, M, N I, F C, O p p y y p y

Online Respirometry I, M, N F C, O, S p p y y p y p

NITROXTM – Oxidation Reduction Potential (ORP) Probe M, N I, F C, O, S p p y y p y p

Comparative Criteria

p Positive feature

y Neutral or mixed

q Negative feature

Effluent Reuse

Dp = Direct potable

Dn = Direct nonpotable

Ip = Indirect potable

In = Indirect 

nonpotable

Applicability

F = Few plants

I = Industrywide

L = Primarily large plants

S = Primarily small plants

Potential Benefits

C = Capital savings

I = Intense operational demand

O = Operational/maintenance savings

S = Shock load capacity

W= Wet weather load capacity

Statement of Development

B = Bench scale

I = Full-scale industrial applications

M = Full-scale municipal applications

O = Full-scale operations overseas

P = Pilot

N = Full-scale operations in North America

Key
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Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

5-5

February 2008

Technology Summary

Ammonia and Nitrate Probes 

Objective:

Automatic online analysis of dissolved nutrients and 

halogens for water and wastewater process monitoring 

and control, including nitrification, denitrification, 

phosphorus removal, disinfection, dechlorination, and 

choramination. In situ, real-time measurement of 

ammonia and/or nitrate concentration. 

State of Development:

Innovative.

Description:

ChemScan N-4000: Online multiple parameter analyzer using full-spectrum UV-visible detection with chemometric analysis 

of spectral data. The analyzer is script driven and has the capability of performing rapid sequential analysis with or without 

the assistance of chemical reagents. Nitrate analysis and/or a separate analysis of nitrite are performed based on the direct 

analysis of spectra from the sample. Ammonia analysis is reagent-assisted using bleach and hydroxide reagents. The 

analyzer contains an internal manifold to provide automatic zeroing, cleaning, and managing multiple sample lines. A variety 

of accessories are available, including sample pumps, filters, and external controllers.

Hach Evita In Situ 5100: Nitrate analyzer using UV absorption to measure nitrate concentration. Probe is immersed in 

wastewater and the ion specific membrane allows the appropriate ions to be transferred to the carrier solution so no sample 

preparation is necessary and interference from bacteria and particles is virtually eliminated. Uses deionized water that needs 

to be refilled every 10 weeks. Measuring range is 2 to 50 mg/L NO3-N with accuracy of ±10 percent. Readings approximately 

every 13 minutes are possible.

Myratek Sentry C-2: Based on Ion Selective Electrode (ISE) technology. A sample is isolated in the measuring chamber and 

ammonia and nitrate values established. Calibration using the standard addition method is performed automatically at userset intervals. Installation takes less than 1 hour; maintenance less than 15 minutes per week. 

Hach NITRATAX: Probe-style analyzer based on UV light absorption. Photometer measures primary UV 210 beam while a 

second beam at 350 nm provides a reference standard. Measuring range is 0.1 to 50 mg/L NO3-N. 

NitraVis® System: In situ, real-time spectral measurement (UV and Visibility [VIS] range of 200 to 750 nm) of nitrate 

concentration without filtering. Interferences, such as those caused by turbidity, are detected and compensated for. Operates 

in media at temperatures of at least 32°F, with a pH between 4 and 9, and contains less then 5,000 mg/L chloride. Automatic 

cleaning with compressed air prior to each measurement. Measuring range is 0.1 to 100 mg/L NO3-N with accuracy of 

±3 percent. 

Royce 8500 Series Multi-Parameter: Patented, in situ xenon-based optical sensor allows virtually continuous monitoring. 

Automatic cleaning system available. Individual models address varying combinations of the following parameters: turbidity, 

total suspended solids, COD, TOC, BOD, nitrate, nitrite, color, phenols, and hydrocarbons.

Comparison to Established Technologies:

Traditionally monitoring was performed by taking samples and analyzing them for various parameters in laboratories. 

Performing lab analyses are time-consuming steps that do not resolve a problem until the results are gathered. These 

monitoring technologies provide real-time or near real-time conditions in the treatment system through continuous monitoring. 

Immediate feedback helps operators take corrective action in the event of a shock or toxic load immediately.
Emerging Technologies February 2008

5-6 Wastewater Treatment and In-Plant Wet Weather Management

Technology Summary Technology Summary

Ammonia and Nitrate Probes (Contd)

Available Cost Information:

Approximate Capital Cost: $25,000 to $45,000 (ChemScan and Myratek);

$11,000 for Hach Evita In situ 5100 (probe only; 

USC Controller and Communications add $3,100).

Approximate O&M Costs: $2,800 to $4,000 annually;

Costs vary with frequency of calibration. Includes O&M time. Replace electrodes every 

6 months. WTW claims no O&M cost for NitraVis® as there are no chemicals or other 

consumables use.

Vendor Name(s):

ASA/ChemScan

2325 Parklawn Drive

Waukesha, WI 53186

Telephone: 262-717-9500

Email: info@chemscan.com

Web site: http://www.chemscan.com

Myratek, Inc. – BioChem Technology, Inc.

100 Ross Road, Suite 201

King of Prussia, PA 19406-2110

Telephone: 610-265-8620

Email: rick@myratek.com

Web site: http://www.biochemtech.com

WTW Inc.

6E Gill Street

Woburn, MA 08801

Telephone: 800-645-5999

Email: info@wtw-inc.com

Web site: http://www.wtw.com

Royce Technologies

14125 South Bridge Circle

Charlotte, NC 28273

Telephone: 800-347-3505

Email: royce@itt.com

Web site: www.roycetechnologies.com

Hach Company

P.O. Box 389

Loveland, CO 80539-0389

Telephone: 800-227-4224

Web site: www.hach.com

Installation(s):

South Cross Bayou WRF

St. Petersburg, FL

Telephone: 727-582-7015

Wastewater Treatment Plant

Enfield, CT

Telephone: 860-253-6450

Wastewater Treatment Plant

Abington, PA

Telephone: 215-884-8329

Key Words for Internet Search:

Water monitoring, wastewater, ammonia, nitrates, probe, online analysis
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

5-7

February 2008

Technology Summary

Ammonia and Nitrate Probes (Contd)

Data Sources:

Misiti, John Hach, “UV Spectrum Based NOx Monitors,” paper.

Web site sources are as follows:

http://www.chemscan.com

http://www.myratek.com

http://biochemtech.com

http://www.hach.com

http://www.wtw.com

http://www.roycetechnologies.com

Vendor-supplied information.
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February 2008

Technology Summary

Fluorescence In Situ Hybridization (FISH) for Filamentous and Nitrifying Bacteria

Objective:

Identify and quantify specific microorganisms in 

wastewater. 

State of Development:

Innovative.

Description:

Bacteria in activated sludge contains DNA as unique genetic material. DNA sequences unique to individual groups of 

microorganisms can be used to identify specific microorganisms in a sample containing a mixture of many different types of 

microorganisms. The process of identifying specific microorganisms is part of the full-cycle 16S Ribosomal Ribonucleic Acid 

(rRNA) approach by using FISH. Fluorescently labeled 16S rRNA probes are hybridized, stained, and observed under an 

epifluorescent microscope. 

Comparison to Established Technologies:

The microbial detection process is able to positively identify specific microorganisms in a mixed culture. Previously, 

microbiological tests performed in a laboratory were necessary to identify and enumerate bacteria. This process provides 

real-time feedback, over laboratory tests that take hours or even days for results.

Available Cost Information:

Approximate Capital Cost: Unknown.

Approximate O&M Costs: Unknown.

Vendor Name(s):

Department of Civil and Environmental Engineering at 

the following universities:

University of Illinois, Urbana-Champaign

University of Cincinnati

North Carolina State University

Installation(s):

There are no known installations.

Key Words for Internet Search:

Fluorescence In Situ Hybridization, FISH, 16S rRNA, full-cycle 16S rRNA approach, phylogeny

Data Sources:

Department of Civil and Environmental Engineering, University of Illinois, Urbana-Champaign, University of Cincinnati, and 

North Carolina State University.

Technology Summary
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Emerging Technologies

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February 2008

Technology Summary

Microwave Density Analyzer

Objective:

Solids measurement.

State of Development:

Innovative.

Description:

The microwave sludge density transmitter uses microwave-phase difference measurements to determine the density of solids 

flowing through pipes. This method exploits the way that fluid density affects the propagation of microwaves when they pass 

through it. The Microwave Density Analyzer allows reliable measurement of the sludge density and monitors the difference in 

microwave phase between the original wave and one wave that passed through the measured fluid. Unlike the method of 

monitoring the attenuation of a transmitted wave, measuring flow density by observing a wave’s phase difference is not 

affected by flow velocity and is resistant to the effects of contamination, scaling, fouling, and gas bubbles. It uses no moving 

mechanical parts or mechanism that is often used in other measuring methods for cleaning, sampling, or defoaming. It 

permits continuous measurement. The density meter measures density in electric current, which is suitable for an application 

in a process for monitoring and controlling.

Comparison to Established Technologies:

This density meter has adapted a new measuring method called “phase difference method by microwaves.” When microwaves 

go through a substance and come out of it, This density measures the phase lag of the waves and obtains a certain physical 

property of the substance that is proportional to the density. 

Available Cost Information:

Approximate Capital Cost: 8-inch density meter is about $75,000 to $100,000 depending upon the specific application. 

Approximate O&M Costs: Not disclosed.

Vendor Name(s):

Toshiba 

Instrumentation Marketing Logistics Services

9740 Irvine Blvd.

Irvine, CA 92618-1697

Telephone: 800-231-1412, x3693 or 949-461-4400

Fax: 949-859-1298

E-mail: instrument@tic.toshiba.com

Web site: http://www.toshiba/com/ind/product_display

Installation(s):

Blue Plains AWTP, Washington, D.C.

Key Words for Internet Search:

Microwave Density Analyzer, LQ500, LQ300, LQ510

Data Sources:

Engineering Program Management Consultancy Services, CH2M HILL, Parsons, “Evaluation of the Test Results for the 

Microwave Sludge Density Meter at the Gravity Sludge Thickener (GST) No. 7,” Blue Plains AWTP, Interoffice Memorandum, 

2006.

Toshiba web site: http://www.toshiba.com/ind/product_display
Emerging Technologies February 2008

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Emerging Technologies

5-13

February 2008

Technology Summary

Microtox®/Online Microtox®

Objective:

Acute toxicity analysis for wastewater, water, soil, and 

other hazardous waste applications.

State of Development:

Innovative.

Description:

The toxicity test is based on indigenous bioluminescence of a marine bacterium (Photobacterium phosphoreum to Vibrio 

fischeri strain, NRRL B-11177). The aqueous samples are incubated for controlled time and luminators are used to compare 

the reduction in light of the sample with a control culture of the bacterium. The proportional reduction in bioluminescence is 

indicative of toxicity of the sample. The Microtox® instrumentation systems are available for online and offline toxicity 

analysis.

Comparison to Established Technologies:

Microtox® monitoring is a biosensor based on a toxicity measurement system. The Microtox® process can provide near realtime monitoring of water and wastewater and is much faster than other laboratory based analysis.

Available Cost Information:

Approximate Capital Cost: $17,895. 

Approximate O&M Costs: $2.50 to $7 per test.

Cost information includes the cost for the software for the unit. The O&M cost varies 

depending on the dilution range of toxicity tests.

Vendor Name(s):

Strategic Diagnostics, Inc.

111 Pencader Drive

Newark, DE 19702

Telephone: 302-456-6789 or 800-544-8881

Email: sales@sdix.com

Web site: http://www.sdix.com

Installation(s):

Petersburg, VA

Key Words for Internet Search:

Microtox®, toxicity test, wastewater, online

Data Sources:

WERF Report, Collection and Treatment – A Review and Needs Survey of Upset Early Warning Devices, Final Report, 

2000.

Web site sources are as follows:

http://www.sdix.com/

http://www.azurenv.com/
Emerging Technologies February 2008

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February 2008

Technology Summary

SymBioTM – Nicotinamide Adenine Dinucleotide (NADH) Probes

Objective:

SymBioTM process probe is used for simultaneous 

nitrification and denitrification in the same basin. The 

nicotinamide adenine dinucleotide and dissolved oxygen 

(NADH/DO) monitoring probe provides an effective tool 

for strict aeration control to maintain simultaneous 

nitrification and denitrification conditions.

State of Development:

Innovative.

Description:

The SymBioTM process monitors the NADH level in the biomass along with the dissolved oxygen level in the wastewater to 

precisely predict the changes in the biological oxygen demand. Based on the results of the NADH levels, the aeration is 

controlled to maintain low dissolved oxygen (<1.0 parts per million [ppm]) for Simultaneous Nitrification and deNitrification 

(SNdN) in the same basin.

Comparison to Established Technologies:

The SymBioTM Process monitors are newly available sensors that can measure NADH in wastewater in real-time. Based on 

the reading, aeration in the tank can be adjusted to enhance nitrification or denitrification processes. This maximizes aeration 

efficiency and reduces energy for aeration.

Available Cost Information:

Approximate Capital Cost: About $100,000 for one sensor with monitoring and process control setup. 

Approximate O&M Costs: No additional cost for O&M incurred (energy consumption reduced 20 to 25 percent).

The cost for the SymBioTM system is based on the setup of the NADH sensor and the monitoring system. (The cost reflects 

the estimate for the year 2005.)

Vendor Name(s):

Enviroquip, Inc.

2404 Rutland Drive, Suite 200

Austin, TX 78758

Telephone: 512-834-6015

Email: hiren.trivedi@enviroquip.com

Web site: http://www.enviroquip.com

Installation(s):

Big Bear, CA

Rochelle, IL

Lake Elsinore, CA

Pflugerville, TX

Stonington, CT

Perris, CA

Bend, OR

New Philadelphia, OH

Key Words for Internet Search:

Aeration, NADH, fluorescence, nitrification, BOD

Data Sources:

Metcalf and Eddy, Wastewater Engineering Treatment and Reuse, 4th Edition, 2003.

Enviroquip, Inc., Email, brochures, and telephone conversation, July 8, 2005.

Enviroquip, Inc. web site is as follows: http://www.enviroquip.com 
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Emerging Technologies

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February 2008

Technology Summary

Online Respirometry

Objective:

Measures cellular respiration or oxygen uptake rate.

State of Development:

Innovative.

Description:

Respirometry devices are used for biotreatment process control. The device can be set up and operated in different modes. 

For oxygen uptake-based respirometers, oxygen is measured either in closed headspace gas or liquid phases. The 

respirometry rate measurement can also determine the shock-load measurement and toxicity in a system when the baseline 

respirometry rate has been set for a system.

Respirometer’s sensors can also be calibrated to measure other gases of concern like carbon monoxide, hydrogen sulfide, 

and methane.

Comparison to Established Technologies:

Traditionally, respirometric studies or kinetic parameters for wastewater treatment have been performed in laboratories with 

use of dissolved oxygen probes. During the stabilization of probes in the laboratory, sensitive information was lost, which was 

critical for measuring oxygen uptake rates and dissolved oxygen rates. The real-time feedback using the probes provides 

more reliable information on oxygen uptake. 

Available Cost Information:

Approximate Capital Cost: 1 unit of the respirometer Respicond V for about $60,000 U.S.

Approximate O&M Costs: Unknown.

Cost based on the published cost for the Respicond V on the web site of A. Nordgren Innovations AB, Sweden.

Vendor Name(s):

A. Nordgren Innovations AB

Djakneboda 99

SE915 97 Bygdea, Sweden

Telephone: 46-934-31260

Email: a.nordgren@respicond.com

Web site: http://www.respicond.com

Columbus Instruments

950 N. Hague Avenue

Columbus, OH 43204

Telephone: 614-276-0861 or 800-669-5011

Email: sales@colinst.com

Web site: http://www.colinst.com

Respirometry Plus, LLC

P.O. Box 1236, Fond du Lac, WI 54935-1236

Telephone: 800-328-7518

Email: operations@respirometryplus.com

Web site: http://www.respirometryplus.com

Installation(s):

There are no known installations.

Key Words for Internet Search:

Cellular respiration, online respirometry, biotreatment process control, oxygen respirometer

Data Sources:

WERF web site and publications.

Research journals and publications.

Technology Summary
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February 2008

Technology Summary

NITROXTM – Oxidation Reduction Potential (ORP) Probe

Objective:

NITROXTM process is used to achieve denitrification of 

wastewater in an oxidation ditch by continuously 

monitoring the Oxidation Reduction Potential (ORP) of 

the wastewater.

State of Development:

Innovative.

Description:

This monitoring technology uses an ORP probe that constantly monitors and controls aeration to achieve anoxic and anaerobic 

conditions for Simultaneous Nitrification-deNitrification (SNdN). Nitrogen removal levels, from this unique process, are 

equivalent to systems that use anoxic tanks in front of the aeration basins. Effluent total inorganic nitrogen concentrations of 

less than 10 mg/L are common, and do not require preanoxic tanks and internal recycle pumps. Denitrification process 

involves the cycling of a single oxidation ditch through anoxic and aerobic periods. At selected intervals, the aeration system 

is turned off and the mixer(s) are turned on. Denitrification system consists of an ORP converter and a NITROXTM 

controller.

Comparison to Established Technologies:

ORP probes have not been traditionally used in the wastewater to regulate the nitrification and denitrification processes. The 

use of the ORP probe provides better process control over previous options. This maximizes aeration efficiency and reduces 

energy for aeration.

Available Cost Information:

Approximate Capital Cost: Approximately $100,000/MGD.

Approximate O&M Costs: 20 percent reduction in O&M.

Vendor Name(s):

United Industries

2380 O’Neal Lane, Suite 1

Baton Rouge, LA 70816

Telephone: 225-755-0724

Email: info@ui-inc.com

Web sites: http://www.ui-inc.com/ or 

http://www.ui-inc.com/nitrox.htm

Installation(s):

Grand Coulee, WA

Diamondhead, MS

Key Words for Internet Search:

NITROXTM, nitrification, wastewater, Oxidation Reduction Potential, ORP, monitoring

Data Sources:

Metcalf and Eddy, Wastewater Engineering Treatment and Reuse, 4th Edition, 2003. 

Telephone conversation with United Industries.
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February 2008

Technology Summary

Biological Micro-Electro-Mechanical Systems (BioMEMS)

Objective:

Biological Micro-Electro-Mechanical Systems 

(BioMEMS) are aimed at rapid testing of biomolecules 

that are indicative of an upset process.

State of Development:

Embryonic.

Description:

BioMEMS are being developed for the faster detection of upset signs in a bioprocess by using microchips or integrated 

circuits that can detect and quantify the biomolecules that cause process upsets. The systems aim at detecting the changes 

in the microbial activities that are caused by a shock load or toxicity. BioMEMS can be a very useful in predicting operational 

problems before they occur, such as bulking, foaming, and detecting, which cause operational problems because of changes 

to microbial population.

Comparison to Established Technologies:

Not similar to any established technology.

Available Cost Information:

Approximate Capital Cost: Unknown.

Approximate O&M Costs: Unknown.

Vendor Name(s):

University of Cincinnati

Water Quality Biotechnology Program

Room 765, Baldwin Hall, Box 210071

Cincinnati, OH 45221-0071

Telephone: 513-556-3670

Email: daniel.oerther@uc.edu or chong.ahn@uc.edu

Web sites: www.wqb.uc.edu or www.biomems.uc.edu

Installation(s):

There are no installations in the United States at this time.

Key Words for Internet Search:

BioMEMS, wastewater, biomechanics, biological micro-electro-mechanical systems 

Data Sources:

Web site sources are as follows:

www.biomems.uc.edu 

www.memsnet.org
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February 2008

Technology Summary

Fluorescence In Situ Hybridization (FISH) for Phosphorus Accumulating Organisms 

(PAOs)

Objective:

Identify specific microorganisms in wastewater.

State of Development:

Embryonic.

Description:

Bacteria in activated sludge contain DNA as unique genetic material. DNA sequences unique to individual groups of 

microorganisms can be used to identify specific microorganisms in samples that contain a mixture of many different types of 

microorganisms. The process of identifying specific PAOs is part of the full-cycle 16S rRNA approach using FISH. Fluorescently 

labeled 16S rRNA probes are hybridized, stained, and observed under an epifluorescent microscope.

Comparison to Established Technologies:

The FISH for PAOs microbial detection process is able to positively identify specific microorganisms in a mixed culture. 

Previously, microbiological tests performed in a laboratory were necessary to identify and enumerate bacteria. This process 

provides real-time feedback, over laboratory tests that take hours or even days for results.

Available Cost Information:

Approximate Capital Cost: Unknown.

Approximate O&M Costs: Unknown.

Vendor Name(s):

Department of Civil and Environmental Engineering at 

the following universities:

University of Illinois at Urbana-Champaign

University of Cincinnati

North Carolina State University

Installation(s):

There are no known installations.

Key Words for Internet Search:

Fluorescence In Situ Hybridization (FISH), 16S rRNA, full-cycle 16S rRNA approach, phylogeny

Data Sources:

Amann, R. I., L. Krumholz, and D. A. Stahl, “Fluorescent-Oligonucleotide Probing of Whole Cells for Determinative, 

Phylogenetic, and Environmental Studies in Microbiology,” Department of Veterinary Pathobiology, University of Illinois, 

Urbana, IL 61801, Journal of Bacteriology, 172(2), pp. 762–770, February 1990.

Amann, Rudolf, “Monitoring the Community Structure of Wastewater Treatment Plants: A Comparison of Old and New 

Techniques,” Max-Planck Institut für Marine Mikrobiologie, Arbeitsgruppe Molekulare Ökologie, Celsiusstr. 1, D-28359 

Bremen, Germany, FEMS Microbiology Ecology, Volume 25, Issue 3, p. 205, March 1998.

Daims, Holger, Niels B. Ramsing, Karl-Heinz Schleifer, and Michael Wagner, “Cultivation-Independent, Semiautomatic 

Determination of Absolute Bacterial Cell Numbers in Environmental Samples by Fluorescence In Situ Hybridization,” Lehrstuhl 

für Mikrobiologie, Technische Universität München, 85350 Freising, Germany, and Department of Microbial Ecology, Institute 

of Biological Sciences, University of Aarhus, 8000 Aarhus, Denmark, Applied and Environmental Microbiology, pp. 5,810–

5,818, Vol. 67, No. 12, December 2001.

Technology Summary
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February 2008

Technology Summary

Handheld Advanced Nucleic Acid Analyzer (HANAA)

Objective:

Real-time detection of pathogens in water and 

wastewater.

State of Development:

Embryonic.

Description:

HANAA uses the genetic material of microorganisms in wastewater by performing a Polymerase Chain Reaction (PCR) to 

detect pathogens. PCR is a technique for enzymatically replicating DNA without using a living organism, such as E. coli or 

yeast. Like amplification using living organisms, this technique allows for a small amount of DNA to be amplified exponentially. 

The HANAA is miniature thermal cycler, which can perform PCR in real time. 

Commercially these products are available as Bio-SeeqTM and RAZOR®, although they are mostly being used for bioterrorism 

monitoring purposes. 

Comparison to Established Technologies:

HANAA can be compared to a thermal cycler that is used in laboratories performing extensive molecular biology work. 

HANAA is a portable version of the thermal cycler and therefore, has the benefit of being used in field where monitoring needs 

to be performed, without extensive sampling and laboratory analysis time. 

Available Cost Information:

Approximate Capital Cost: Unknown.

Approximate O&M Costs: Unknown.

Vendor Name(s):

Smiths Detection

Telephone: 1-908-222-9100 

Web site: www.smithsdetection.com/

Idaho Technology Inc.

390 Wakara Way

Salt Lake City, UT 84108

Telephone: 801-736-6354 or 800-735-6544

Fax: 801-588-0507

Email: it@idahotech.com

Web site: www.idahotech.com/

Installation(s):

Information not available about the installations.

Key Words for Internet Search:

Bio-SeeqTM, Smiths Detection, Handheld Advanced Nuclei Acid Analyzer, HANNA 

Data Sources:

Higgins, James, “Handheld Advanced Nucleic Acid Analyzer (HANAA) for Waterborne Pathogen Detection,” WERF publication, 

USDA, 2001.

www.smithsdetection.com 

Telephone conversation with the vendor.

Technology Summary
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February 2008

Technology Summary

Immunosensors and Immunoassays

Objective:

Use antigen- antibody interaction to identify the presence 

of toxins in wastewater. 

State of Development:

Embryonic.

Description:

Immunosensors and immunoassays involve antibodies that bind to a specific antigen noncovalently. Sensors and assays are 

designed to detect these interactions through a range of transducer options. The most popular immunoassay system in use 

is the Enzyme-Linked ImmunoSorbent Assay (ELISA). Environmental application includes analyzing selected contaminants 

such as pesticides and polyaromatic hydrocarbons. ELISAs include an antibody or antigen bound on a titer plate and an 

unbound reagent labeled with an enzyme that produces a signal in the presence of a specified substrate. 

Comparison to Established Technologies:

This is not similar to any established technology.

Available Cost Information:

Approximate Capital Cost: Unknown.

Approximate O&M Costs: Unknown.

Vendor Name(s):

Not available commercially for wastewater applications.

Installation(s):

There are no known installations.

Key Words for Internet Search:

ELISA, antibody-antigen, immunosensors, and immunoassays

Data Sources:

Love, Nancy and Charles Bott, “A Review and Needs Survey of Upset Early Warning Devices,” WERF publication, 2000.
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February 2008

Technology Summary

Photo-electro Chemical Oxygen Demand (PeCODTM)

Objective:

Determine Chemical Oxygen Demand (COD) of 

wastewater without extensive laboratory process.

State of Development:

Embryonic.

Description:

Photo-electro Chemical Oxygen Demand (PeCODTM) technology can measure photo-current charge originating from the 

oxidization of organic species contained in a sample. The PeCODTM technology is able to photo-electrochemically generate 

an electrical signal that directly correlates, via mass balance, with the oxidizable organic species contained in wastewater 

samples. The core of the technology is the ability of the UV-activated nano-particulate photocatalyst semi-conductive electrode 

to create a high-oxidation potential that ensures complete oxidation of all oxidizable organic species. This technology has the 

ability to capture and measure the resultant photo-current. The PeCODTM online analyzer has been used to monitor COD in 

municipal wastewater treatment plants. Real-time COD event-monitoring enables efficient secondary treatment and reduces 

operational and discharge costs in regional plants vulnerable to COD surges from industrial sources. 

Comparison to Established Technologies:

The photoelectric COD sensor has short analysis time, is simple to use, has low impact to the environment, and has a long 

sensor life. It provides real-time results in as low as 30 seconds to overcome the problems of time delay encountered by 

chemical oxidation methods. High sensitivity and wide linear range is obtained by direct signal acquisition. 

Available Cost Information:

Approximate Capital Cost: Not available.

Approximate O&M Costs: Not available.

Vendor Name(s):

Aqua Diagnostic Pty Ltd.

Level 1, 159 Dorcas Street 

South Melbourne, Victoria 3205 

Australia

Telephone: 61 3 8606 3424 

Fax: 61 3 9686 9866

Email: info@aquadiagnostic.com

Web site: http://www.aquadiagnostic.com

East China Normal University

Litong Jin

Department of Chemistry

Shanghai 200062

People’s Republic of China

Installation(s):

There are no installations.

Key Words for Internet Search:

Photo-electro Chemical Oxygen Demand, PeCODTM, Aqua Diagnostic

Data Sources:

Aqua Diagnostic, “PeCODTM COD Analyzer Delivers Rapid, Reliable and Accurate On-Line COD Monitoring, Technology.”

Journal Abstract, “Ti/TiO2 Electrode Preparation Using Laser Anneal and its’ Application to Determination of Chemical Oxygen 

Demand,” Electroanalysis, Volume 18, Issue 10, pp. 1,014–1,018.

Technology Summary
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Chapter

Wastewater Treatment and In-Plant Wet Weather Management 6-1

6

Research Needs

6.1 Introduction

In order to develop new technologies or process improvements for any technology that is 

considered to be innovative or embryonic, additional research and field demonstration 

projects are necessary. This chapter focuses on specific technologies that may have a 

significant impact on wastewater treatment and wet weather management, and the 

relevant research needs in these areas.

6.2	 Research Needs

Wastewater treatment technologies have shown tremendous growth in the past decade 

and continue to grow. The focus of treatment technologies is to achieve higher levels of 

pollutant removal while minimizing the operation and maintenance costs of the treatment 

system. 

Emerging technologies can provide more cost-efficient solutions to the problems 

associated with deteriorating wastewater treatment and collection systems, growing 

population and urbanization, conservation of non-renewable resources and approaches 

toward cheap and green technology. Emerging technologies may also improve the 

performance of processes and systems. Research and technical issues can be grouped 

into the following areas: (1) upgrading older WWTPs; (2) nutrient removal and recovery; 

(3) use of smart technologies; (4) research and development to solve emerging problems 

in treatment facilities; and (5) security and emergency preparedness of WWTPs in United 

States.

6.2.1 Upgrading Old WWTPs

Most of the treatment plants in the United States were constructed more than two decades 

ago. Many of these treatment facilities need to be upgraded to improve capacity and 

treatment efficiency. The upgraded treatment processes that can best fit the existing 

technologies at Publicly Owned Treatment Works (POTWs) are chosen based upon 

permit requirements and their cost-effectiveness techniques used to achieve water quality 

and protect public health. Such upgrades are often opportunities to employ emerging 

technologies or established technologies in newer and better ways.
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6-2 Wastewater Treatment and In-Plant Wet Weather Management

Some of the areas of current and future interest are as follows:

Determine of the long-term performance and life-cycle cost effectiveness of system 

rehabilitation techniques, including new and existing materials.

Identify emerging and innovative asset inspection technologies and demonstrate of 

these technologies in field settings to improve understanding of cost-effectiveness, 

performance, and reliability. 

Use technologies that are energy-efficient and conserve energy expenditures by 

wastewater utilities.

Use physical adaptation for emerging and innovative technologies within the existing 

constraints of wastewater facilities.

6.2.2	Removal of Nutrients and Other Contaminants

Nutrients in wastewater effluent can stimulate excessive algae growth and ammonia is 

toxic to aquatic life. Increasingly more stringent nutrient discharge limits are promoting 

research into technologies that are capable of improved nutrient removal. 

Compounds that can alter the endocrine system of animals are known as Endocrine 

Disrupting Compounds (EDCs) and have been linked to a variety of adverse effects in 

both humans and wildlife. Pharmaceutical compounds and their metabolites have been 

detected as Pharmaceutically Active Compounds (PhACs). Some PhACs are highly 

persistent and can function as EDCs. 

Some of the areas of current and future interest are as follows:

Processes to achieve low total nitrogen and total phosphorus levels.

Recycle streams for bioaugmentation and enhanced nutrient removal.

Use MBR technology for anaerobic wastewater treatment.

Use Aerobic Granular Sludge Process (AGSP) for aerobic wastewater treatment.

Evaluate availability and effectiveness of new carbon sources for denitrification.

Identify refractory Dissolved Organic Nitrogen (rDON) and determine rDON 

bioavailability.

Evaluate new processes and process modifications that can effectively remove 

rDON.

Improve online nutrient and toxic monitoring techniques.

Improve analytical methods for measuring very low levels of nitrogen and 

phosphorus.

Improve disinfection technologies for control of emerging pathogens of concern 

(Cryptosporidium, Giardia, e-Coli-0157, etc.) without disinfection byproduct issues.

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Wastewater Treatment and In-Plant Wet Weather Management

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February 2008

Recover P, N, and ammonia from wastewater streams (e.g., Struvite precipitation 

and calcium phosphate formation) and study the feasibility of these processes in the 

United States.

Evaluate new technologies for cost-effective removal of EDCs, PhACs, PBDEs, 

Prions, PPCPs, etc.

6.2.3 Use of Smart Technologies 

Real-time information through monitors and automated process controls provide improved 

process performance and treatment response. These recent advances can be further 

developed to yield even greater advances. Some of the smart-technologies are as 

follows:

Biological process modeling and control by using process-modeling tools to control 

plant operations and optimize treatment.

Process automation, improved efficiency, space needs, reduced O&M costs, and 

reduced energy usage. 

Sensors and early warning devices to predict system upset.

Microbiology and molecular tools to better understand and resolve biological 

wastewater treatment issues.

Monitoring technologies development using the molecular approach to achieve realtime monitoring.

Microbial ecology study of reactors, metabolic pathways, and bioengineered 

systems. 

Energy recovery improvement.

6.2.4 Security of Water Systems

With treatment and collection systems valued at more than $2 trillion, the wastewater 

infrastructure of the United States is one of the nation’s most valuable resources. Largescale damage to this national asset would require extensive rebuilding under very 

challenging conditions. While loss of life resulting from this damage might not be 

significant, the discharge of millions of gallons of untreated or partially treated sewage 

into the nation’s rivers and lakes could cause catastrophic damage to aquatic ecosystems 

and the economy. While much attention has been given to the security of the nation’s 

drinking water systems, there has been less emphasis on wastewater security. Research 

for security of wastewater systems includes the following:

Emergency preparedness of WWTPs to deal with pandemics, new strains of viruses 

and bacteria, or spill incidents.

Mitigation strategies for treatment plants after natural calamities (i.e., Katrina).

Prevention and preparedness for bioterrorism.

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6-4 Wastewater Treatment and In-Plant Wet Weather Management

6.2.5	Other Research Focus and Developments

There are many additional areas for further research in the wastewater treatment arena, 

specifically concerning the development of new technologies or in approaches to extend 

the life of wastewater infrastructure and investments in treatment technologies, including 

the following. 

Contact-stabilization and/or quick stabilization of storm water.

Compounds of emerging concern such as EDCs, PPCPs, PBDEs, Prions, etc.

Pathogens and antibiotic-resistant pathogens in water reclamation processes.

Fate of specific organic pollutants.

Sustainable wastewater conveyance and treatment.

Novel advanced treatment processes that enable water reuse.

Odor control and aerosol emission from the wastewater treatment facility. 

Disinfection alternatives to chlorination.

Prevention of membrane fouling through changes in membrane system design, 

materials, and operation.

Kinetic and stoichiometric parameter estimation of biological processes. 

Degradation of xenobiotics and destruction-resistant strains of microorganisms.

Biohydrogen (as fuel-cells for electricity production) and bioethanol production 

through wastewater processes. 

Some technologies can be used in certain regions depending on the climatic conditions. 

These technologies need to be made available to the WWTPs in those regions. One such 

example is the solar disinfection system that can be used in sunnier parts of the United 

States.

6.2.6	Research Needs and Prioritization per Water Environment Research

Foundation (WERF)

The Water Environment Research Foundation (WERF) held a workshop in March of 2006 

for an informed discussion on nitrogen and phosphorus removal at wastewater treatment 

plants. They have since produced the report entitled “WERF Workshop of Nutrient 

Removal: How Low Can We Go and What is Stopping Us from Going Lower?,” 05-CTS1W. The report identifies research needs and prioritizes the results from that workshop; 

see Exhibit 6-1 (report is included with the permission from the WERF).

6.3	 Chapter References

Institute of Environment and Resources – Wastewater Technology University of Denmark; 

web site: http://www.er.dtu.dk/English/

Water Environment Research Foundation (WERF), 2002; web site: www.werf.org/funding/

researchplan.cfm

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Wastewater Treatment and In-Plant Wet Weather Management

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05-CTS-1W

WERF WORKSHOP ON

NUTRIENT REMOVAL:

HOW LOW CAN WE GO & WHAT IS 

STOPPING US FROM GOING LOWER?

by:

Charles B. Bott, Ph.D., P.E.

Virginia Military Institute 

Sudhir N. Murthy, Ph.D., P.E.

 District of Columbia Water and Sewer Authority, D.C. 

Tanya T. Spano, P.E.

 Metropolitan Washington Council of Governments, D.C. 

Clifford W. Randall, Ph.D.

Virginia Tech

2007

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal
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6-6 Wastewater Treatment and In-Plant Wet Weather Management

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

Abstract:

 Based on an expert stakeholder workshop convened in March 2006, this report 

provides a summary of discussions on the state of knowledge on the removal of nutrients 

(nitrogen and phosphorus) from wastewater and their limits of technology (LOT), and to 

help address the questions “how low can we go” and “what is stopping us from going 

lower”. The panelists and participants included many of the key water quality 

professionals from consulting, academia, government, and utilities that have been 

working in this arena for several years and/or decades. The report includes an 

accompanying CD-ROM with the speaker presentations, documents distributed at the 

workshop, research needs and prioritization, as well as the list of participants and results 

from the workshop survey. 

Benefits: 

Ƈ Provides a summary of the state of knowledge through presentations and discussions 

by key experts and practitioners on limits of technology, removal strategies, etc., for 

nitrogen and phosphorus in wastewater

Ƈ Identifies key questions and research needs

Ƈ Informs WERF current nutrient removal challenge (06-NUTR-1)

Keywords: Nitrification, denitrification, boundary conditions, nitrogen, phosphorus, 

EBPR, BNR 

PRIORITY RESEARCH NEEDS IDENTIFIED AT WORKSHOP 

The following three categories of program-based research needs were identified: 

A. Policy and Information Based Research 

B. Experimental Research Targeting LOT Permitting Policy (short-term research) 

C. Experimental Research Targeting LOT Design and Operation 

Within these three categories, there are four priorities established (“Highest”, “High”, 

“Moderate”, and “Long-Range”). See Appendix A for the detailed research needs and 

prioritization.

Table 1: Priority Research Needs Identified at Workshop.

 Program-Based Research Needs Identified Priority 

A Policy and Information Based Research 

This focuses on a forum for LOT policy development 

and disseminating information among WERF industry, 

utility, consulting and regulatory subscriber groups 

 1 Information Exchange and Technology Transfer – 

methods to improve sharing of operational and design 

experience at or near the LOT 

Highest

 2 LOT Permitting Policy – need to develop consensus 

on achievable, realistic, and sustainable nutrient limits 

Highest
Wastewater Treatment and In-Plant Wet Weather Management

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February 2008

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

 3 Long Range Sustainability for Water Reuse and 

Nutrient Recovery – need to understand and measure 

sustainable approaches to LOT nutrient removal 

Long-range

 

B Research Targeting LOT Permitting Policy Short-Term 

Research

Several topics of experimental research that should 

be considered to support the LOT permitting approach 

 1 Refractory Dissolved Organic Nitrogen (rDON) – need 

to better understand the production and sources of 

rDON, removal of rDON in various treatment 

schemes, and the significance of rDON in the 

environment 

Highest

 2 Standard Methods for Low Level P Analysis – develop 

standard methods for LOT phosphorus measurement 

and understand / characterize residual and refractory 

phosphorus fractions 

Highest

 3 Update Nitrification Inhibition EPA List – list of 

chemicals that represent threshold nitrification 

inhibition dosages was developed about 20 years ago; 

it has not been updated since and is incorrect / 

incomplete. Updated list is needed as part of local 

municipality pre-treatment program. 

Highest

 4 Modeling Tools and Procedures – develop forum for 

modeling LOT nutrient removal

Highest

 

C Research Targeting LOT Design and Operation Long-Term 

Research

Focus research targeted at improving the technology 

and design procedures for LOT nutrient removal 

processes based on differing plant size and discharge 

limits. Better understand the impact of LOT nutrient 

removal on sludge treatment and reuse, and the 

related implications for volume and mass of solids 

created.

 1 Better Instrumentation and Application / 

Implementation / Use of Online Instruments – develop 

online instrumentation and control for LOT nutrient 

removal including nitrogen control, phosphorus control 

and supplemental carbon addition and control 

Highest

 2 Substrates for Denitrification and Biological 

Phosphorus Removal – a majority of plants building 

LOT nitrogen and phosphorus removal processes will 

consider supplemental carbon for treatment; much 

work is needed to understand the appropriate use of 

supplemental carbon 

Highest

 3 Methods to achieve Low P Levels – develop novel 

technologies for LOT phosphorus control, while 

simultaneously understand capabilities of current 

simultaneous precipitation, tertiary clarification and/or 

High
Emerging Technologies February 2008

6-8 Wastewater Treatment and In-Plant Wet Weather Management

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

filtration technologies 

 4 Nitrification Process Control, Inhibition and 

Bioaugmentation - develop and refine understanding 

of nitrification impacts on LOT treatment, including 

impacts of chemical and substrate inhibition, cold 

temperature and cold shock, high temperature 

inhibition, BOD/TKN ratios, process 

anaerobic/anoxic/aerobic cycling, etc. 

High

 5 P Limitations of Post-Secondary Denitrification 

Processes – as utilities consider simultaneous low TN 

and TP, phosphorus deficiency becomes an important 

issue for plants. Research is needed to understand 

phosphorus bioavailability in chemically removed 

material versus suspended solids from Bio-P 

processes

High

 6 Enhanced Biological Phosphorus Removal – 

continued research needed in several areas for costeffective application of EBPR, e.g., P uptake and 

release kinetics, pre-fermenters, VFA, PAO, GAO, 

etc.

High

 7 Simultaneous Nitrification-Denitrification (SND) – 

better design and implementation information and 

methodologies to evaluate the amount of “nutrient 

removal credit” that can be expected with a SND 

process for small to medium sized plants 

High

 8 Side Stream Treatment – research on reduction in 

influent loading, bioaugmentation, etc. 

High

 9 Activated Sludge Settling, Selectors, Bulking – 

clarifiers are usually hydraulic bottlenecks for LOT 

nutrient removal; develop protocols for process and 

clarifier operations for LOT treatment 

Highest

 

RESEARCH NEEDS AND PRIORITIZATION 

Overall Goals 

 A research program that will provide utility, industrial, consultant and regulator 

subscribers a battery of tools to help insure that water quality-based nutrient limits are 

achievable, sustainable and cost effective. These tools will address design, operational 

control, measurement and regulatory compliance issues for limit of technology (LOT) 

nutrient removal. A well-defined and standardized approach to identify LOT effluent 

quality based on site-specific influent and receiving water characteristics, operating 

realities and treatability of various nutrient components, and other parameters, is a most 

critical need. 

filtration technologies 

 4 Nitrification Process Control, Inhibition and 

Bioaugmentation - develop and refine understanding 

of nitrification impacts on LOT treatment, including 

impacts of chemical and substrate inhibition, cold 

temperature and cold shock, high temperature 

inhibition, BOD/TKN ratios, process 

anaerobic/anoxic/aerobic cycling, etc. 

High

 5 P Limitations of Post-Secondary Denitrification 

Processes – as utilities consider simultaneous low TN 

and TP, phosphorus deficiency becomes an important 

issue for plants. Research is needed to understand 

phosphorus bioavailability in chemically removed 

material versus suspended solids from Bio-P 

processes

High

 6 Enhanced Biological Phosphorus Removal – 

continued research needed in several areas for costeffective application of EBPR, e.g., P uptake and 

release kinetics, pre-fermenters, VFA, PAO, GAO, 

etc.

High

 7 Simultaneous Nitrification-Denitrification (SND) – 

better design and implementation information and 

methodologies to evaluate the amount of “nutrient 

removal credit” that can be expected with a SND 

process for small to medium sized plants 

High

 8 Side Stream Treatment – research on reduction in 

influent loading, bioaugmentation, etc. 

High

 9 Activated Sludge Settling, Selectors, Bulking – 

clarifiers are usually hydraulic bottlenecks for LOT 

nutrient removal; develop protocols for process and 

clarifier operations for LOT treatment 

Highest

 

RESEARCH NEEDS AND PRIORITIZATION 

Overall Goals 

 A research program that will provide utility, industrial, consultant and regulator 

subscribers a battery of tools to help insure that water quality-based nutrient limits are 

achievable, sustainable and cost effective. These tools will address design, operational 

control, measurement and regulatory compliance issues for limit of technology (LOT) 

nutrient removal. A well-defined and standardized approach to identify LOT effluent 

quality based on site-specific influent and receiving water characteristics, operating 

realities and treatability of various nutrient components, and other parameters, is a most 

critical need. 
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

6-9

February 2008

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

Overview 

Several categories of program-based research needs were identified at the 2005 Nutrient 

Removal Workshop. These include: 

A. Policy and Information Based Research 

B. Experimental Research Targeting LOT Permitting Policy (short-term research) 

C. Experimental Research Targeting LOT Design and Operation 

 Within these three categories, there are four priorities established. These are 

“Highest”, “High”, “Moderate”, and “Long-Range”. It is expected that funding would be 

established for the “Highest” priority research. WERF should first evaluate existing 

projects in these categories. Successful, existing WERF or Subscriber projects should be 

leveraged when possible to minimize WERF costs by providing program oversight, peer 

review or simply by disseminating results through information exchange on a case-bycase basis. 

A. POLICY AND INFORMATION-BASED RESEARCH 

 This sub-program area focuses on a forum for LOT policy development and 

disseminating information among WERF industry, utility, consulting and regulatory 

subscriber groups.

1. Information Exchange and Technology Transfer 

Priority – Highest 

 Methods are needed to improve the sharing of operational and design experiences 

at or near the LOT. This could be in the form of design methodologies, regulatory 

toolkits, standards for influent wastewater characterization, and web-based information 

sharing tools.

i A significant amount of institutional knowledge is available within process simulation 

models that are currently available. There is a need for educational enhancement 

within our field on the understanding, use and application of these models. These 

models represent a platform for sharing design and operational experiences. (also see 

modeling below–Part B-4) 

i There is a need to translate the real world experience of LOT facilities, such as 

effluent variability, operation challenges, back into the design tools and operating 

strategies to test the ability of the toolkits to predict performance. 

i There is a need to better understand what skills are required to operate LOT nutrient 

removal facilities and whether current training/certification programs are adequate. 

Also, to determine specific services and training needs for start-up and debugging of a 

new facility or a renovated facility. 

i There is a need to better understand the costs and benefits of designing and operating 

plants to achieve LOT nutrient removal. 

i This information-based research could be a reasonable forum to follow the 

development and application of membrane bioreactor processes and membrane 

treatment for very low levels of phosphorus removal and possibly the removal of 

refractory nitrogen. 
Emerging Technologies February 2008

6-10 Wastewater Treatment and In-Plant Wet Weather Management

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

i Although other forums could be used, there is a need to update and expand the wellknown EPA Nitrogen Control Manual (EPA/625/R-93/010, 1993) to include current 

information and to include both LOT nitrogen and phosphorus removal and the 

improvements in instrumentation, controls and real time analytical measurement. 

2. LOT Permitting Policy 

Priority – Highest 

 There is an important need to develop consensus among municipalities, industry, 

regulators and consultants on what are achievable, realistic and sustainable limits for 

nutrients. Under what conditions can we achieve near perfection? How close to ideal can 

we permit? This suggests a need for permits that include “Boundary Conditions” or 

“Terms and Conditions” under which discharge limits can and should be reliably met. 

There is a need for policies and regulatory framework to develop these permitting 

strategies. Examples such as excluding refractory dissolved organic nitrogen from massbased limits, accounting for higher influent levels due to industrial sources, water saving 

or conservation measures, statistically-based limits rather than absolute values (such as 

90% of the time), and variances for wet weather flows and inhibition from unusual 

occurrences. WERF should pursue an understanding of environmental benefit and cost 

from different regulatory approaches and the costs and benefits associated with the risk 

mitigation of noncompliance. 

i Assuming that effluent limits are being set based on the LOT, can we develop a 

methodology that will allow designers, operators and regulators to agree to site 

specific LOTs effluent limits? 

i Do we need to develop a “CMOM” (capacity, management, operations and 

maintenance, similar to EPA’s program for collection systems) or “EMS” 

(environmental management systems, similar to the EPA/WEF/NACWA program for 

biosolids) approach to our NPDES limits that incorporate LOT limits? If the system 

were designed to standards that all agree should be able to achieve LOT, the plant 

continuously monitors, operates and maintains the system but LOT limit is not 

achieved, can this provide a defense against monetary violations? Would an 

exceedance cause an action plan similar to a toxicity reduction evaluation, without 

onerous fines and penalties? 

i Can an approach be developed that would define the range in effluent quality 

produced from various treatment technologies, i.e., denitrification filters (0 to 0.x 

mg/l Nitrate)? 

i Evaluate why certain plants may sometimes not be able to meet specific limits 

i There is a need to explore alternate permit limits such as a 12-month rolling average 

for a mass based limit over a strict LOT concentration limit. Trading programs will 

allow flexibility with a LOT limit. This may serve to bridge the operational 

performance deficiencies during process upset or wet weather conditions. 

i There are wet and cold weather conditions that are not practical for wastewater 

treatment plant design that may occur infrequently and would need boundary 

conditions.

i Consider permitting with Boundary Condition

i Interpretation of blending regulations
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

6-11

February 2008

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

3. Long Range Sustainability—Water Reuse and Nutrient Recovery Priority—Long 

Range

 There is a need to understand and measure sustainable approaches to LOT 

nutrient removal. This includes developing a sustainability index and understanding the 

additional energy and chemicals requirements to attain LOT treatment. Metrics for value 

produced from treatment for reuse and reclamation is needed. Other approaches for 

sustainability include decentralized treatment, nutrient recovery, integrated water 

treatment and reclamation, and solids volume reduction. 

B. EXPERIMENTAL RESEARCH TARGETING LOT PERMITTING POLICY 

(SHORT-TERM RESEARCH) 

 There are several topics of experimental research that should be considered to 

support the LOT permitting approach. These projects should receive highest priority for 

WERF funding.

1. Refractory Dissolved Organic Nitrogen (rDON) 

Priority – Highest 

For a plant achieving LOT nitrogen removal, 30-50% of the effluent N is in the form of 

rDON. There is a need to better understand the production and sources of rDON, removal 

of rDON in various treatment schemes, and the significance of rDON in the environment. 

i Do non-biodegradable forms of nitrogen exist in wastewater and if so how can they 

be measured? Should they be excluded from nitrogen discharge mass limits? 

i Occurrence – Removal – Significance? 

i Source? Influent or biological process? Humics? EPS? SMP? 

i Effect of treatment process design/operation on production/removal? 

i Methods to remove – maybe a survey of different treatment systems in place now? 

i Novel methods for removal? 

i Production in suspended growth versus fixed film systems 

i Production in separate stage nitrification/denitrification systems vs. combined 

systems. 

i Differences in production between plug flow combined systems (e.g. Bardenpho) vs. 

those that approach complete mix (e.g. Carrousel systems) vs. “mixed flow” 

processes like Step Feed BNR 

i Borrow from the field of drinking water NOM removal? 

i Fate – bioavailability in the environment (including an assessment of the time scale of 

availability)? 

2. Standard Methods for Low Level P Analysis 

Priority – Highest 

 Develop standard methods for LOT phosphorus measurement and 

understand/characterize residual and refractory phosphorus fractions. 

3. Update Nitrification Inhibition EPA List 
Emerging Technologies February 2008

6-12 Wastewater Treatment and In-Plant Wet Weather Management

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

Priority – Highest 

 U.S. EPA developed a list of chemicals that represent threshold nitrification 

inhibition dosages about 20 years ago and it has not been updated since. This list has 

proven to be incorrect and incomplete. Localities need an updated list that can be used as 

part of their pre-treatment program. 

4. Modeling Tools and Procedures 

Priority – Highest 

 Develop a forum for modeling LOT nutrient removal as well-developed models 

essentially represent current collective knowledge. This forum would evaluate reactor 

staging, wet weather, cold weather, inhibition, sidestream treatment, partial nitrification, 

denitrification and deammonification reaction, biological-P and chemical P removal to 

understand capabilities of plants to achieve LOT. Available data would be reviewed that 

show complete mix systems develop nitrifying bacteria with significantly lower growth 

rates than in plug flow systems; similar data are available comparing “mixed flow” 

systems (Step BNR) and plug flow systems. Also, given the importance of rDON, models 

need to updated to reflect current research results on bioflocculation of colloidal materials 

and to account for rDON removal/transformation and rDON production/end product 

formation during biological treatment. Models will be a primary tool in demonstrating 

LOT limits to regulators and, thus, these models must be “fine-tuned” when it comes to 

LOT limits. Small anomalies, such as reaction time to turn on additional aeration or turn 

off aeration, during the day could, in the case of nitrogen, add 0.1 to 0.5 mg/l TN to the 

effluent.

C. EXPERIMENTAL RESEARCH TARGETING LOT DESIGN AND 

OPERATION (LONG-TERM RESEARCH) 

 There is a need to focus research targeted at improving the technology and design 

procedures for LOT nutrient removal processes based on differing plant size and 

discharge limits. Plants that have very low TP limits without TN limits require different 

strategies as compared to plants that have combined low TN (3-4 mg/L) and moderately 

low TP (0.1-1 mg/L) limits. Research priorities in this category generally depend on the 

size of the plant being considered. Small plants typically have high SRT and HRT and 

large clarifiers, and thus there is a need to understand how to “extract” additional nutrient 

removal from “available volume.” This suggests better information transfer and 

experimental research targeting these design modifications (do more nutrient removal 

with the tank volume available). Large plants already have low available safety factor in 

terms of SRT and HRT. New cost-effective technologies should be considered to further 

extract additional nutrient removal (e.g. breakpoint chlorination, bioaugmentation, side 

stream treatment, etc.) without large capital expenditures. There is also a need to better 

understand the impact of LOT nutrient removal on sludge treatment and reuse, and the 

related implications for volume and mass of solids created. (Note: to be coordinated with 

the concurrent ET challenge on solids volume reduction).

y)

2. Standard Methods for Low Level P Analysis 

Priority – Highest 

 Develop standard methods for LOT phosphorus measurement and 

understand/characterize residual and refractory phosphorus fractions. 

3. Update Nitrification Inhibition EPA List 
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

6-13

February 2008

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

1. Better Instrumentation and Application/Implementation/Use of Online 

Instrument

Priority – Highest 

 Develop online instrumentation and control for LOT nutrient removal including 

nitrogen control, phosphorus control and supplemental carbon addition and control. 

Leverage existing WERF projects including 03-CTS-8 and expand it to phosphorus 

removal and carbon control technologies. This will also improve efficiency and energy 

management at treatment facilities. This one area as with all instrumentation and controls 

has changed dramatically since the 1993 EPA manual was published and needs updating 

to current technology. 

2. Substrates for Denitrification and Biological Phosphorus Removal 

Priority – Highest 

 A majority of plants that will build LOT nitrogen and phosphorus removal 

processes will be considering supplemental carbon for treatment. Much work needs to be 

done to understand the appropriate use of supplemental carbon: 

i Improve understanding of methanol utilization kinetics, microbiology, and 

stoichiometry both in suspended and attached growth systems – and temperature 

dependency

i Glycerol (unrefined byproduct of biodiesel production coupled with possible increase 

in methanol cost with consumption to produce biodiesel) 

i Better understanding of benefit of acetate, ethanol, sugar solutions and other viable 

carbon sources compared to methanol – better understand kinetics, microbiology 

(ability of native organisms to use these substrates), and stoichiometry 

i Evaluate the potential for insitu methanol production using methane derived from 

anaerobic digestion. 

i Improve understanding and application of fermentation processes (using various 

sludge sources) for VFA production and Bio-P versus fermentation for high 

COD/TKN ratio for denitrification 

i Better understanding of capability of denitrification in single-sludge second anoxic 

zone with and without carbon addition 

3. Methods to Achieve Low P Levels 

Priority – High 

 Develop novel technologies for LOT phosphorus control, while simultaneously 

understand capabilities of current simultaneous precipitation, tertiary clarification and/or 

filtration technologies (how well are we doing?). Two areas of research should be 

considered:

i Chemistry at low P concentrations (high Me/P dose ratio) 

i Improvement of solids removal (membranes, filtration, or other) 

4. Nitrification Process Control, Inhibition and Bioaugmentation 

Priority – High

 There is an important need to develop and refine our understanding of nitrification 

impacts on LOT treatment, including impacts of chemical and substrate inhibition, cold 

temperature and cold shock, high temperature inhibition, BOD/TKN ratios, process 
Emerging Technologies February 2008

6-14 Wastewater Treatment and In-Plant Wet Weather Management

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

anaerobic/anoxic/aerobic cycling. Develop molecular techniques to monitor and diagnose 

inhibition. Develop and refine novel techniques to enhance nitrification including 

bioaugmentation and heterotrophic wasting. Leverage existing WERF projects. Develop 

a user friendly system of analysis and evaluation for the end users for trouble shooting 

guide to nitrification inhibition.

5. P Limitations of Post-Secondary Denitrification Processes 

Priority – High

 As utilities consider simultaneous low TN and TP, phosphorus deficiency 

becomes an important issue for plants. Therefore, research is needed to understand 

phosphorus bioavailability in chemically removed material versus suspended solids from 

Bio-P processes. 

6. Enhanced Biological Phosphorus Removal – Continued Research 

Priority – High 

 Several areas of research remain for the cost-effective application of the enhanced 

biological phosphorus removal process at the LOT: 

i P uptake and release kinetics – staging, P concentration and P storage, relationship 

between release and uptake specifically under dynamic loading conditions? 

i Operation and control of pre-fermenters for VFA production? How much does 

fermenter operation affect the production of the different VFA forms, particularly 

acetic and propionic? 

i PAO starvation with diurnal feeding? Need improved understanding of COD uptake 

and stabilization under anaerobic conditions - biochemical mechanisms involved. 

i Improved understanding of secondary P release in anoxic zones and clarifiers? 

i Better understanding of competition between PAOs and GAOs, particularly as related 

to influent wastewater characteristics such as the acetic/propionic acid ratio. Also, 

temperature effects on the competition over the range from 5-40o

C and the 

biochemical mechanisms involved. 

i Better understanding of the interactions of EBPR and chemicals, which can develop a 

tool that will help identify when EBPR versus chemicals should be used to achieve 

LOT.

7. Simultaneous Nitrification-Denitrification (SND) 

Priority – High 

 SND represents a good opportunity for small to medium size plants with available 

safety factor to maximize nutrient removal (both denitrification and potentially bio-P), 

likely as a component of more conventional nutrient removal processes. It seems likely 

that SND alone would not be used to meet LOT permit limits, but it could be part of a 

cost-effective solution for nutrient removal. There is a need for better design and 

implementation information and methodologies for evaluating the amount of “nutrient 

removal credit” that can be expected with a SND process. Several research areas should 

be addressed including nitrification to NO2, improved online instrumentation for process 

control, potential bio-P considerations, nitrification kinetics, and modeling. 

8. Sidestream Treatment – Reduction in Influent Loading and Bioaugmentation 
Wastewater Treatment and In-Plant Wet Weather Management

Emerging Technologies

6-15

February 2008

Priority – High 

 Sidestream treatment is a cost effective method to reduce the use of supplemental 

carbon and aeration energy. An added benefit is the bioaugmentation of nitrifying 

bacteria to the main-stream treatment process. Research areas include: 

i Further develop the Anammox and related processes for autotrophic denitrification. 

i Use molecular methods to evaluate mainstream bioaugmentation efficiency of 

nitrifiers produced in side-stream treatment. Need thorough documentation of fullscale demonstrations. 

9. Activated Sludge Settling, Selectors, Bulking 

Priority – Highest (but should be addressed outside the WERF LOT Nutrient Removal 

Program)

 Clarifiers are usually hydraulic bottlenecks for LOT nutrient removal. Develop 

protocols for process and clarifier operations for LOT treatment, including understanding 

benefits/ drawbacks of anoxic zones, IFAS and phosphorus deficiency from low TP coprecipitation. Given the sporadic performance of anoxic and anaerobic selectors, conduct 

research to understand and improve performance. Through additional surveys and 

experimentation, assess whether some BNR processes, influent compositions, and 

environmental conditions produce mixed liquor qualities that have superior settling and 

compaction characteristics. Building on previous WERF research, there is a need to 

develop a fundamental understanding of the factors leading to or favoring improved 

settling and compaction. 

Exhibit 6.1—Paper from WERF Workshop on Nutrient Removal (Contd)

likely as a component of more conventional nutrient removal processes. It seems likely 

that SND alone would not be used to meet LOT permit limits, but it could be part of a 

cost-effective solution for nutrient removal. There is a need for better design and 

implementation information and methodologies for evaluating the amount of “nutrient 

removal credit” that can be expected with a SND process. Several research areas should 

be addressed including nitrification to NO2, improved online instrumentation for process 

control, potential bio-P considerations, nitrification kinetics, and modeling. 

8. Sidestream Treatment – Reduction in Influent Loading and Bioaugmentation 
Emerging Technologies February 2008

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Wastewater Treatment and In-Plant Wet Weather Management

Appendix

A-1

A

Trade Associations

A.1 Introduction

This chapter lists professional and trade associations that may have significant 

information. These professional and trade associations may provide relevant research 

assistance on wastewater treatment and in-plant wet weather management 

technologies within their respective areas of expertise.

A.2 Trade Associations

American Society of Civil Engineers (ASCE)

1801 Alexander Bell Drive Reston, VA 20191-4400

Telephone: 800-548-2723

Web site: http://www.asce.org

National Association of Clean Water Agencies (NACWA)

1816 Jefferson Place, NW, Washington D.C. 20036

Telephone: 202-833-2672

Web site: http://www.nacwa.org/

Water and Wastewater Equipment Manufacturers Association (WWEMA) 

P.O. Box 17402, Washington, D.C. 20041

Telephone: 703-444-1777

Web site: http://www.wwema.org

Water Environment Federation (WEF) 

601 Wythe Street, Alexandria, VA 22314-1994

Telephone: 703-684-2452

Web site: http://www.wef.org

Water Environment Research Foundation (WERF)

635 Slaters Lane, Suite 300, Alexandria, VA 22314

Telephone: 703-684-2470

Web site: http://www.werf.org
Emerging Technologies February 2008

A-2 Wastewater Treatment and In-Plant Wet Weather Management

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