AWWA WSC61386

Drinking water distribution systems supplying large population centers must be considered as serious potential targets for terrorists. Contamination of distribution system equipment would result from adherence of contaminants to biofilms, tubercles and other corrosion products lining the pipes, or from permeation of the pipe material itself. Because of their non-toxic, non-corrosive, and environmentally benign properties, enzymes may provide an ideal method for the treatment of agents, pesticides or other chemical contaminants in drinking water systems, as well as the decontamination of pipes and other equipment with contaminant residue. Additionally, enzymes have been demonstrated to function in foams, sprays, lotions, detergents, and other vehicles that can be used in flowing water or on material surfaces. The goal of this project was to identify, develop, and evaluate at least one enzyme-based method for treating flowing contaminated water, and one enzyme-based method for decontaminating drinking water pipes. A literature search was conducted to identify the potential of enzymes to treat contaminated drinking water and/or to decontaminate distribution systems equipment. The literature search considered the potential application of enzymes to a large range of possible water contamination scenarios, from groundwater to drinking water, from toxic industrial chemicals (TIC's) to chemical warfare agents. Enzyme-based decontaminants have been under development for many years at the U.S. Army Edgewood Chemical Biological Center (ECBC) for military use. Enzymes with catalytic activity against nerve agents, related organophosphorus pesticides, sulfur mustard and biological agents have been identified and are in various stages of development. In order to evaluate the potential for enzymes to deal with contaminated water supplies or water distribution systems, two approaches are being taken. The first is a liquid formulation that will consist of soluble stabilized enzymes. The second is a filter system with immobilized enzymes through which contaminated water is passed. Two well characterized enzymes are being used in these studies: Organophosphorus Acid Anhydrolase (OPAA), a bacterial enzyme with the highest known activity against G-type nerve agents (ex. Sarin); and Organophosphorus Hydrolase (OPH), an unrelated bacterial enzyme with excellent activity against organophosphorus pesticides as well as lesser activity against G- and V-type nerve agents. Preliminary results on the stabilization and immobilization of these enzymes is presented. Although also applicable to biological contaminants, this paper only deals with the chemical varieties. Includes 99 references, tables, figures.