AWWA ACE59924

This extended abstract discusses the Proposed Rule and how it was based largely upon an Agreement in Principle, developed by the US Environmental Protection Agency (USEPA), AWWA, and other stakeholders, such as state, environmental and public health organizations, and signed on Sept. 19, 2000. The proposed Stage 2 Disinfection/Disinfectant Byproducts Rule (D/DBP Rule) describes how monitoring locations are to be selected and how compliance will be determined. The stakeholders agreed to split the Stage 2 Rule into two parts: Stage 2a, in which the trihalomethane (THM) and haloacetic acid (HAA) maximum contaminant levels (MCL) will be temporarily increased to 120 ug/L and 100 ug/L respectively; and, Stage 2b in which the MCL's will return to 80 ug/L for THMs and 60 ug/L for HAA5. However, compliance will be based on a Location Running Annual Average rather than the system wide Running Annual Average of the THM Rule, and Stage 1 and 2A D/DBP Rules. The USEPA is expected to formally propose the Stage 2 D/DBP Rule in 2004. The temporary increase in the MCL for Stage 2a is intended to give those utilities which would be in compliance with a system-wide RAA but out of compliance with a location RAA, time to make adjustments to treatment or operations. Includes extended abstract only.