United States
Environmental Protection
Agency
RESEARCH PROJECT
National Risk Management Research Laboratoi
Water Supply and Water Resources Division
Treatment Technology Evaluation Branch
INTEGRATED DISINFECTION BYPRODUCTS (DBFs) MIXTURES RESEARCH: DBF
CONCENTRATION VIA REVERSE OSMOSIS MEMBRANE TECHNIQUES
IMPACT STATEMENT
Production of concentrated natural waters containing whole
mixtures of DBPs enabled the completion of EPA's 4-Lab study
evaluating the health effects of whole mixture DBPs. The health
effects, toxicology, and risk analysis of the whole mixture DBP
study is currently undergoing data analysis and interpretation in
preparation for final publications. The implications to the U.S.
Environmental Protection Agency (EPA) from this project will be
fully realized during the next review cycle for the disinfection
byproduct (DBP) rule. Current phases of this project are working
toward developing a library of freeze-dried natural organic
matter (NOM) that will contribute a source of consistent drinking
water relevant NOM to EPA and the drinking water research
community. This consistent source of concentrated dried NOM
will allow DBP, water reuse, and many other areas of research to
commence in new directions that have never before been possible because of the lack of relevant NOM.
BACKGROUND:
Interest in the health effects of complex DBP mixtures has existed for some time; although, until recently they have
remained largely uncharacterized. Pioneering work done primarily at EPA facilities, has opened the door to more
environmentally realistic characterizations of natural organic matter and disinfection byproducts. EPA scientists and
engineers recently completed a large scale evaluation of the health effects of complex DBP mixtures known as the 4-Lab
project. A key component of this research was the concentration of NOM from natural waters by reverse osmosis
membranes.
The current research aims to continue with the concentration aspect of the 4-lab project, and to further characterize
NOM concentrates and the DBPs formed during chlorination. Furthermore, the effects of lyophilization (freeze-drying)
on NOM concentrate are undergoing investigation. Researchers have historically taken for granted that lyophilization
does not fundamentally alter the character of NOM. This research attempts to provide a factual basis for this
assumption.
DESCRIPTION:
With the completion of the 4-lab project, the NOM concentration aspect of 4-lab is being continued with renewed focus
on creating drinking water relevant freeze-dried NOM concentrates that can be used for many drinking water research
efforts from DBP investigations to water reuse investigations. The first phase of the project involved developing a new
freeze-drying technique to remove the remaining water from the reverse osmosis NOM concentrates. This new
technique was optimized to minimize total organic carbon losses through the process.
The second phase of the project, currently in progress, involves comparing the freeze-dried and reconstituted NOM to
the NOM prior to freeze-drying and concentration in order to demonstrate that the final product is representative of the
National Risk Management Research Laboratory
Water Supply and Water Resources Division
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original natural water. The first recently completed demonstration of this comparison was based on DBP comparisons
before and after concentration and freeze-drying. Follow-up work will include other well documented methods for
characterizing NOM, such as NMR, elemental analysis, and molecular weight fractionation.
The third phase of this project, being conducted concurrently to the second phase, is aimed at concentrating a natural
surface water source on a monthly basis for at least a year to build a library representing the NOM from a single water
source capturing temporal variations. The concentrated and dried NOM from this source represents a consistent source
of NOM that can then be used to research various changes in drinking water treatment and the effects upon DBPs
formed.
The fourth phase of this project includes moving the NOM concentration equipment to various drinking water relevant
water sources and creating a freeze-dried NOM library that can be used for a multitude of drinking water research
projects requiring more than one water source to demonstrate the effects of treatment implements.
EPA GOAL: Goal #2 - Clean & Safe Water; Objective 2.1.1 - Water Safe to Drink
ORD MULTI YEAR PLAN: (DW) Long Term Goal - DW-2 Control, Manage, and Mitigate Health Risks
RESEARCH PARTNERS:
Contractors: Pegasus Technical Services, Inc.; Shaw Group, Inc.
EXPECTED OUTCOMES AND IMPACTS:
Outcomes of this research include new methods for concentrating and freeze-drying NOM that preserve the organic
character and DBP formation characteristics of the original source, a full year of NOM collected monthly from a single
source to capture temporal variations in NOM for further DBP treatment studies, and a novel library of dried NOM from
various water sources that can be used by EPA and the drinking water research community for DBP and related
research.
OUTPUTS:
• Integrated Disinfection By-Products Mixtures Research: Toxicology and Chemical Evaluation of Alternative
Disinfection Treatment Scenarios. Journal of Toxicology and Environmental Health, Part A Current Issues, Volume 71
Issue 17 2008.
• Pressman, J.G., et al. A Preliminary Report on U.S. EPA's Four Lab Study: Concentration, Chlorination, and Chemical
Analysis of Drinking Water Disinfection By-Product Mixtures for Health Effects Research. Project Report (APM 222) -
( Submitted: 9/1/2009)
• Pressman, J.G., et al. Concentration, Chlorination, and Chemical Analysis of Drinking Water for Disinfection
Byproduct Mixtures Health Effects Research: U.S. EPA's Four Lab Study. Environmental Science and Technology,
submitted.
RESOURCES:
NRMRL Treatment Technology Evaluation Branch: http://www.epa.ROv/ORD/NRMRL/wswrd/tteb.htm
Journal Article: Integrated Disinfection By-Products Mixtures Research: Toxicology and Chemical Evaluation of
Alternative Disinfection Treatment Scenarios. (http://www.informaworld.com/smpp/title~db=all~content=R795055525)
CONTACTS:
Jonathan Pressman, Principal Investigator - (513) 569-7625 orpressman.jonathan@epa.gov
Steven Doub, MediaRelations - (513) 569-7503 ordoub.steven@epa.gov
Michelle Latham, Communications - (513) 569-7601 orlatham.michelle@epa.gov
National Risk Management Research Laboratory www.epa.gov/nrmrl EPA/600/F-10/010
Water Supply and Water Resources Division November 2009
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