This Project is Completed

These TOC Research Reports Are Now Available for Download

     BOD5:TOC Correlation Study

Solve Waste Loading Upsets
Using Total Organic Carbon (TOC)
ITAs Newest Research Project

ITA is launching a new research program to investigate the performance of online total organic carbon (TOC) instruments and to demonstrate a correlation between laboratory 5-day biochemical oxygen demand (BOD5) analysis and TOC measurements to improve the accuracy of waste load monitoring.

Variations in organic waste loading at wastewater treatment plants can create problems for operators by causing upsets in the treatment process. Operators respond to these upsets by initiating adjustments to the treatment processes, such as altering flow, aeration, and food/microorganism ratios (F/M). 

Most operators do not have early warning of waste load upsets since traditional BOD5 analysis takes five days to determine biochemical waste loading changes.  Waste load upsets may pass through the plant without effective treatment.


Comparing Waste Loading Tests

The BOD5 analysis by its standard laboratory procedures and dilution method is a costly, labor intensive test that has a lower detection limit of only 2 mg/L (APHA, 1998), a reproducibility only in the order of +/- 10 to 20% (Constable, 1979) and an uncertainty of 15 to 20% (Bourgeois W, 2001).  Although the BOD test is still a widely accepted parameter for characterizing water quality, it cannot be used for process control or real-time monitoring, due to the time it takes to receive test results, at least 5 days (Constable, 1979).  The following table provides a comparison of BOD5, COD, and TOC test.  The comparison matrix shows that TOC analysis, as an alternative to BOD5, is a more cost effective, accurate and timely test, with less interferences, that also has the capability to be used for process control and real-time monitoring.


The wastewater industry and ITA has recognized the need for a new approach that provides quantifiable and precise measurements of wastewater loadings and process control capabilities.  Global regulations allow chemical oxygen demand (COD) or total organic carbon (TOC) to be substituted for BOD5 when a long-term BOD:COD or BOD:TOC correlation has been demonstrated (40 CRF 133.104 (b)).

City of Santa Cruz Success

The City of Santa Cruz, California was successful in demonstrating to the California State Water Resources Control Board and the U.S. EPA Region 9 NPDES permit sections a definitive correlation between BOD and TOC at their wastewater treatment plant. The City of Santa Cruz now reports a monthly average of TOC and uses the TOC results to report their percent BOD removal efficiency for compliance purposes (Babatola, 2006).  In addition, percent TOC removal efficiencies were calculated using TOC test results. The City of Santa Cruz BOD:TOC correlation report recommended a nationwide study be conducted to develop the percent TOC removal efficiencies that can be used to replace percent BOD removal efficiencies.


Research Team Looking for 50 Wastewater Treatment Plants (WWTPs)

ITA has teamed with Dr. Krishna Pagilla of Illinois Institute of Technology (IIT) who will be leading the task of performing long-term correlations of TOC to BOD5 and COD.

Dr. Pagilla's research expertise includes developing sustainable technologies for nutrient control, aerobic and anaerobic membrane bioreactors for wastewater treatment, and improving bacteria for bioremediation of organic pollutants.

The research team's goal is to collect correlation data for up to 50 WWTP's over a period of 6 to 12 months starting in 2011. ITA is looking for wastewater treatment plants who are interested in receiving specific correlation algorithms for their treatment plant and who routinely measure BOD5, TOC and/or COD.   

All participating treatment plant correlation data will remain confidential and will be reported anonymously in a final report.  All participating treatment plants will receive acknowledgement and a full copy of the project report.

How Can Your Wastewater Treatment Plant Benefit?
Having reliable and accurate measurements of waste loading can save wastewater treatment plants thousands of dollars in labor, energy, chemical costs and provide real-time monitoring and process control capabilities.  These savings are not currently available with the standard practice of measuring the 5-day biochemical oxygen demand (BOD5). ITA is looking for wastewater treatment plants who are interested in receiving specific correlation algorithms for their treatment plant and who routinely measure BOD5, TOC and/or COD.  All participating treatment plants will receive acknowledgement and a full copy of the project final report. 

Treatment Plant Benefits of Participation?

Your wastewater treatment plant can benefit by:

  • Receiving specific BOD5 correlation algorithms for your plant

  • Increasing plant operations efficiency and response to waste loading upsets.

  • Reducing energy, chemical and operating costs.

  • Providing the potential to operate and control your treatment process automatically using online TOC measurements.

  • Reducing or eliminating BOD5 measurements which are a labor intensive and time consuming.

  • Reducing the impact of waste loading discharged to the environment.

  • Providing a more precise and quantifiable measurement for regulatory reporting and process control with TOC measurements in the lab or with an online instrument.

How to Join The Research Team
Joining the TOC research team is easy.  Simply fill-in the project commitment form to identify your interest and participation level. 

Remember, the research team is seeking participation from at least 50 treatment plants for the correlation study and invites you to join. 

Joining the research team's Advisory panel is ITA Board member Paul Lagasse Wastewater Engineer for the City of Winnipeg and Bob Bastian of the US EPA.

The research team is also looking for organizations to contribute funding. 


Contribute Funding
The research team is looking for organizations to contribute funding for this very important research project.  Help further ITAs mission by supporting and encouraging research and development.  Contribute to help meet the growing need for instrumentation and automation research. All funding organizations will receive acknowledgement and a full copy of the project final report.


APHA, A. a. (1998). Standard Methods for the Examination of Water and Wastewater 20th Edition.

Babatola, A. (2006). TOC NPDES Limit Letter. Santa Cruz, California: City of Santa Cruz.

Bourgeois W, B. J. (2001). On-line monitoring of wastewater quality: a review. Journal of Chemical Technology and Biotechnology , pp. 337-348.

Boyles, W. (1997). The science of chemical oxygen demand. Hach Lange, Loveland, Colorado.

Constable. (1979). BOD/TOC Correlations and Their Application to Water Quality Evaluation. Water, Air and Soil Pollution , 363-375.

Stevens, R. et. al. (2006). TOC analysis correlation with other environmental parameters. Teledyne Instruments, Mason, Ohio.

USEPA. (2000). Progress in Water Quality, An Evaluation of the National Investment in Municipal Wastewater Treatment EPA-832-R-00-008, Chapter 2, An Examination of BOD Loadings Before and After the CWA. Washington, D.C.: US EPA Office of Water.

About ITA

ITA has been successfully conducting cooperative testing of online instruments used in the water and wastewater industry, for more than 26 years.  ITA draws from its members' expertise and organizations past experiences in testing by using its five-step testing process.  The following provides a description of ITAs testing process.

Volunteer Test Site and Equipment Procurement

Test Protocol Development and Test Site Visit

Instrument Installation and Test Start-up

Test Performance and Data Collection for up to 3 Months per Test Site

Data Analysis and Report Development

Please contact ITA to learn more about the TOC research project and ITA.


Laboratory BOD5 Instrument

(Photo courtesy of AQUALYTIC)


Taking a Wastewater Sample for an ITA Test

Krishna R. Pagilla, PhD, PE

Professor, ENVE

Environmental Engineering

Illinois Institute of Technology


ITA Online TOC Analyzer Field Test

As part of this research project, ITA will be field-testing online TOC  analyzers to critically assess performance and reliability and to demonstrate monitoring and control capabilities. ITA has contacted several online TOC manufacturers that have expressed interest to participate in the field test portion of the project at volunteer wastewater treatment facilities. The following is a list of interested online TOC manufacturers:

BioTector Analytical Systems Limited

Hach Company & Hach Lange

GE Water & Process Technologies

Liquid Analytical Research (LAR)  



ITA Field Test Instrument Installation

Paul Lagasse, P.Eng., ITA Board Member and Wastewater Engineer for the City of Winnipeg, receiving an ITA award, has volunteered to serve on the TOC project Advisory Panel.

The following is an initial list of treatment facilities and organizations that have expressed interest or joined in support of the project research team:

Town of Quispamsis, New Brunswick, Canada

Gulf Coast Waste Disposal Authority, Houston, Texas

Charleston Water Systems, Charleston, South Carolina

City of Winnipeg, Manitoba, Canada

Padre Dam Municipal Water District, Santee, California

Hopewell Regional Wastewater Treatment Facility, Hopewell, Virginia

Stamford Water Pollution Control Authority, Stamford, Connecticut

Sacramento Regional County Sanitation District, Elk Grove, California

East Bay Municipal Utility District, Oakland, California

San Francisco Public Utilities Commission, San Francisco, California

Orange County Florida

Metropolitan Water Reclamation District of Greater Chicago

Prince William County Sanitation Authority

City of Edmonds, Washington

Muscatine WPCP, Iowa

U.S. EPA Headquarters Office of Wastewater Management