AWWA JAW55951

This column summarizes a draft proposal of the Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) released last November by the US Environmental Protection Agency (USEPA). The objective of the LT2ESWTR is to ensure that all customers of surface water systems are equally protected against chlorine-resistant crypto by imposing additional treatment requirements on filtered systems with higher-than-normal crypto levels in their source waters and by requiring unfiltered systems to boost their current disinfection performance against Giardia and viruses to kill or otherwise detoxify crypto as well. Although signers of the regulatory agreement were able to recommend quantified log removal and inactivation credits for 15 treatment and management options, they left it up to USEPA to develop specific design and implementation criteria for each option. The draft is the first time the agency has disclosed its conclusions regarding these criteria, which are discussed in this column. Includes tables.