Best Practices for the Treatment of Wet Weather Wastewater Flows

During wet weather events, separate and combined wastewater collection systems deliver substantial amounts of storm water runoff to wastewater treatment plants. Often these flows inundate collection systems and treatment works creating bypasses of untreated or partially treated wastewater. The federal Clean Water Act (CWA), its amendments, and associated regulations have been attempting to address these concerns for nearly 30 years. These regulations, coupled with the wastewater treatment standards under the CWA, are posing immense challenges to the owner/operators of wastewater systems, who are also driven to provide the most cost-effective service to customers. This project (WERF Project 00-CTS-6, "Best Practices for the Treatment of Wet Weather Wastewater Flows") undertook a review of currently available technologies to improve the performance and efficiency of wet weather wastewater treatment and also identified potentially beneficial technologies and methodologies that are emerging in this area. The project report includes the types and characteristics of current technologies and methodologies available to ensure treatment of wet weather wastewater flows. The following are the categories of technologies are assessed in report: vortex separation, enhanced clarification, operational enhancements, flushing systems, and disinfection.