Proactively seeking a cure for wet weather-related sanitary sewer overflows, the Knoxville Utilities Board (KUB) retained CDM to help determine the best course of action for improving sewer performance during peak flow conditions in Knoxville, Tennessee. CDM utilized MIKE SWMM (stormwater management model) to perform system hydraulic modeling-simulating conditions in the trunk sewers during peak rainfall events. Use of existing flow monitoring information with traffic analysis zone data allowed CDM and KUB to analyze wastewater flow projections for more than 20 years into the future. In conjunction with wet weather hydrographs, these projections were used to produce various scenarios to determine tradeoffs between infiltration/inflow (I/I) reductions as compared to construction of increased sewer capacity and/or storage-defining factors for the utility's permitting approval per the proposed U.S. Environmental Protection Agency's (EPA) wastewater blending policy.
CDM is also assisting KUB with additional comprehensive utility analyses through pilot testing and technology comparisons for managing I/I and resulting peak wet weather flows throughout its system, including development of KUB's consent decree-mandated MOM program (continuing sewer system assessment program), a comprehensive performance evaluation/composite correction program to address wastewater treatment capacity issues, and a capacity assurance program. Each are integral evaluation and documentation components to complete KUB's demonstrated "no feasible alternatives analysis" for compliance with EPA's proposed wet weather blending policy.
CLIENT: Knoxville Utilities Board
LOCATION: Knoxville, Tennessee