DBP CONTROL IN DRINKING-WATER - COST AND PERFORMANCE

The U.S. Environmental Protection Agency (U.S. EPA) is currently attem pting to balance the complex trade-offs in chemical and microbial risk s associated with controlling disinfection and disinfection by-product s (D/DBP) in drinking water. In attempting to achieve this balance, th e U.S. EPA will propose three rules: an information collection (ICR); an enhanced surface water treatment rule (ESWTR) and a two-stage D/DBP rule. Controlling D/DBP will have a major impact on drinking water ut ilities in the United States. There are several options for D/DBP cont rol, including moving the point of disinfection, removal of by product s once they are found, removing precursor material or natural organic matter before it interacts with the disinfectant, or use of a disinfec tant that minimizes the formation of by-products. The least-expensive approach to D/DBP control is to move the point of disinfection or the use of an alternative disinfectant. The least-desirable approach is to remove disinfection by-products once they are formed. Overall, the mo st effective approach to D/DBP control is to remove precursor before i t reacts with the disinfectant. The choice of any given strategy is ve ry site specific.