AWWA ACE56288

The Louisville and Jefferson County Metropolitan Sewer District (MSD) and Louisville Water Company (LWC) provide sewer and water service in the Greater Louisville, Kentucky area. MSD serves more than 198,000 customers with a service area of approximately 390 square miles. LWC serves approximately 247,000 customers with a service area of about 600 square miles. All water utilities, including the LWC, regularly dispose of chlorinated water associated with routine operation and maintenance activities, such as water main flushing and repairs. Large discharges to sanitary sewers can potentially overload sewers and small wastewater treatment plants (WWTPs), and even cause dry weather combined sewer overflows (CSOs) and wet weather sanitary sewer overflows (SSOs). Where sanitary sewers are not available, chlorinated water must be discharged to storm drainage-ways and could potentially harm aquatic life. Because of common goals held by both agencies to improve discharge procedures, prevent upsets in MSD operations, and conform to Clean Water Act (CWA) requirements, a partnership developed a set of best management practices (BMPs) for disposal of chlorinated water. The identified procedures and practices are based on limitations determined by the receiving wastewater system. Available dry weather capacities of WWTPs, pump stations and CSOs are calculated to determine the peak flow rate acceptable for each location within the sewer system. Locations of wet weather SSOs are also delineated. This information, along with data on the sewer pipes (i.e., diameter, material, slope, invert elevation, etc.) is available to the LWC digitally through the LOJIC geographic information system. The BMP also reviews equipment and techniques, dechlorinating agents, and monitoring and notification procedures for LWC and MSD staff. The result is more efficient and effective procedures for planning and conducting chlorinated water discharges, along with a positive partnership between the agencies. Includes tables, figures.