AWWA JAW58671

The proposed and final versions of the Long-term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) have not been published, but water suppliers are already gearing up for the challenges of compliance with the rule. This article discusses LT2ESWTR regulations in terms of their effect and implication for a surface water treatment plant. A case study applied the expected requirements of the LT2ESWTR to the Richmond (Va.) Water Treatment Plant (RWTP). The components of the microbial toolbox were analyzed in terms of cost, feasibility, and applicability to the Richmond facility. For RWPP, the most feasible and cost-effective toolbox alternatives available were: a 0.5-log credit for a watershed control program; a 0.5-log combined filter effluent turbidity credit; a 1.0-log demonstration of performance credit using full-scale aerobic spore monitoring or pilot-scale microbial challenge studies; and, inactivation with ultraviolet light. Although this study is specific to Richmond, the findings can be used by other utilities facing similar situations with similar alternatives available to them resulting from application of the microbial toolbox. An Expanded Summary in this issue offers a condensed review of study findings; a full discussion of the study results can be found online at www.awwa.org/communications/journal/2003/ september.