AWWA DSS71296

The U.S. Environmental Protection Agency (USEPA) Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBP Rule) mandates that a utility maintain a maximum contaminant level (MCL) for total trihalomethanes (TTHMs) at 80 parts per billion (ppb) and 60 ppb for haloacetic acid (HAA) at designated sampling sites. The Birmingham Water Works Board (BWWB) has set a goal of 80 percent of the MCL's (64 ppb for TTHM, 48 ppb for HAA) for each Stage 2 site locational running annual average (LRAA). For the purpose of this study, the goal of 80 percent of the MCL was applied to these sample locations. To comply with the Stage 2 DBP Rule, water providers identified the locations with high DBP concentrations in their distribution systems (EPA 2003). These locations will become compliance monitoring sites (EPA 2003). DBPs will be calculated for each monitoring location in the distribution system using a method known as locational running annual average (LRAA) (EPA 2003). The BWWB is taking a proactive approach in anticipating the impending, stricter Stage 2 DBP Rule requirements. The BWWB has implemented over twenty studies involving DBP compliance. This study examines potential DBP formation in finished water storage tanks. It is widely assumed that tank mixing enhances water quality, and slows the creation of DBPs. The BWWB is conducting a study, which examines the correlation between mixing and water age to DBP formation. Includes 4 references, tables, figures.