Research Description	Affiliated Faculty
Membrane Processes for DBP Precursor Control: Effects of Colloid Stability and Membrane Surface Chemistry on Flux and Rejection	Dr. Chip Kilduff
Acquisition of Instrumentation for research on the Continuum of Aqueous Colloids and Particles in Natural and Engineered Environmental Systems	Dr. Chip Kilduff
Brominated DBP Formation and Speciation Based on the specific UV Absorbance Distribution of Natural Waters	Dr. Chip Kilduff
Settling Characteristics of As-Deposited Cryptosporidium Oocysts	Dr. Sim Komisar
Fate (and transport) of hydrophobic Organic Compounds in natural and engineered systems	Dr. Marianne Nyman
Sediment Remediation	Dr. Marianne Nyman
Aquatic Chemistry	Dr. Marianne Nyman
Method development for HOCs	Dr. Marianne Nyman
Sorption/Desorption Processes	Dr. Marianne Nyman
Modeling and Mass Spectrometry	Dr. Marianne Nyman

Project Title: Membrane Processes for DBP Precursor Control: Effects of Colloid Stability and Membrane Surface Chemistry on Flux and Rejection

Sponsor:

NSF

Background:

The use of synthetic polymer membranes in water treatment is increasing worldwide. Membrane processes for removing disinfection by-product precursors and pathogens (e.g. viruses) from potable waters have been designated Best Available Technologies by the U.S. EPA. Membrane processes are also promising for controlling risk of highly mobile groundwater contaminants such as perchlorate and methyl tert-butyl ether. Membrane processes are distinguished by, and derive their unique properties from, polymeric microporous materials. However, these materials are vulnerable to fouling by organic macromolecules and other colloids (organic and inorganic). In both municipal and industrial applications, the efficiency, reliability, and cost (design and operation) of these processes is controlled by such fouling. Research to understand mechanisms of fouling and to develop strategies to control it is needed.

Objectives:

The goals of this research are to:

• understand the interactions between organic macromolecules and other natural organic and inorganic colloids in nanofiltration systems, to elucidate how colloid stability influences the performance of membrane processes designed to control the risk posed by anthropogenic contaminants and naturally-occurring disinfection by-product precursors; and,
• understand how membrane flux and rejection are related to membrane surface chemistry, and identify the efficacy of UV photomodification as a route to produce nanofiltration membranes that exhibit a resistance to fouling under water treatment conditions.

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Acquisition of Instrumentation for research on the continuum of Aqueous Colloids and Particles in Natural and Engineered Environmental Systems

Sponsor:

US Bureau of Reclamation, Desalination Research and Development Program

Co-investigator:

Dr. Georges Belfort, Professor & Howard P. Isermann Department of Chemical Engineering

Membrane fouling by colloidal substances can significantly reduce membrane performance, increase operating costs, and shorten membrane life. Understanding fouling mechanisms and developing ways to control them are critical for the economical development of membrane desalting technologies. Naturally occurring dissolved and colloidal organic matter.

(NOM) is considered a major contributor to membrane fouling in water treatment applications. Our goal is to understand how organic matter properties affect the adhesion of these foulant materials to membrane surfaces, and to develop a procedure to modify commercially available membranes to reduce their fouling characteristics by NOM. Performance will be evaluated by measuring flux decline as a function of time, and the adhesion of NOM to membrane surfaces, as measured by flux recovery after backwashing and chemical cleaning (NaOH).

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Brominated DBP Formation and Speciation Based on the specific UV Absorbance Distribution of Natural Waters

Sponsor:

US EPA

Co-investigator:

Tanju Karanfil, Ph.D., Clemson University, Clemson, SC

Understanding the factors that influence disinfection byproduct (DBP) formation and bromine incorporation during disinfection with chlorine is critical for providing safe water and for meeting current drinking water regulations (e.g. the D/DBP rule). A good deal of research has been done showing the effects of primary factors (dissolved organic carbon, chlorine residual, and bromide concentrations) on DBP formation and bromine incorporation; however, little is known about how natural organic matter composition influences such reactions. An important route to elucidating organic matter composition involves fractionation and characterization of the reactivity of individual fractions. Another approach is to use bulk water parameters such as the specific ultraviolet absorbance (SUVA).

Dr. Kilduff and his team propose to combine these two approaches, under the hypothesis that fractionation of whole water is required to gain insight into the reactivity of different components, and that SUVA is a reliable and robust predictor of reactivity. Current application of the SUVA measurement yields a single value that represents the response of a distribution of chromophores within a single organic molecule and among different molecules. Dr. Kilduff’s proposed approach will better define how SUVA is distributed in natural waters, and how the distribution of SUVA in natural waters influences DBP formation and speciation (including bromine incorporation). Such information will be critical for optimizing treatment goals, understanding the effects of treatment processes, and devising strategies to comply with the D/DBP rule.

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Settling Characteristics of As-Deposited Cryptosporidium Oocysts

Cryptosporidia are pathogenic protozoa found in natural waters from sources as diverse as small mammals, birds, livestock and humans. The organisms have a unique life cycle and, outside of the intestinal tract, form a spore-like body called an "oocyst." The oocyst is resistant to heat andcold and can stay viable in the environment for months. It is also resistant to disinfectants like chlorine and is very hard to remove from water during conventional treatment using filtration. Because of these characteristics, Cryptosporidia may be the leading cause of waterborne disease in the US. Although the symptoms of the disease (intestinal distress and severe diarrhea) are just unpleasant for most healthy individuals, they may be life threatening for those with an impaired immune response including the very young, the very old, patients receiving chemotherapy and those with AIDS.

Dr. Komisar and his team are studying the fundamental behavior of the oocyst particle in numerous waters in order to understand its basic hydraulic properties including its settling velocity. They are especially concerned about the design and implementation of best management practices for agricultural wastes (like those typically generated at dairy farms) and hope to use their understanding of Cryptosporidia to protect important drinking water sources.

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