Pilot-scale Evaluation of Various Approaches for the Decontamination of Drinking Water Distribution Systems

The safety and security of water supplies have come under reassessment in the United States in recent years. Issues ranging from public safety and health, ecological, and national security are under consideration. The terrorist attacks on the United States on September 11, 2001 and the subsequent delivery of Anthrax-contaminated letters through the mail raised concerns about protecting U.S. citizens and the nation’s critical infrastructure. Presidential Decision Directive 63 (PDD 63) designates the Environmental Protection Agency (EPA) as the lead for securing the national water infrastructure. Therefore, the Agency is working to be proactive in anticipation, detection, and identification of the threat of deliberate or accidental contamination of our water supplies. One of the more important roles of EPA in dealing with a contamination threat is how to treat, contain, and dispose of contaminated water. Depending on where the contaminant is introduced, this may involve actions within source waters, drinking water treatment plants, distribution systems, or points downstream. Any material (including the water) may need to be disposed of properly. Furthermore, the physical infrastructure of water distribution systems will require decontamination before it is reused. To evaluate the efficacy of various decontamination methods, a series of tests were conducted using a unique pilot-scale drinking water distribution system simulator (DSS) located at the EPA Test and Evaluation (T&E) Facility, Cincinnati, Ohio. These studies were aimed to provide information on the efficiencies of various techniques for the proper containment, treatment and decontamination of any material that might result in the deliberate or accidental contamination of U.S. water supplies or water supply systems.