Evaluating Innovative CSO Treatment Strategies at Metropolitan Sewer District of Greater Cincinnati


  • William Martin PE, W. James Gellner PE - Hazen and Sawyer
  • Daniel Murray PE, Bruce Smith PE - Metropolitan Sewer District of Greater Cincinnati

One evaluated filter unit utilizes a high rate filtration system (HRFS) with floating media, which uses pinwheel shaped floating media for upflow filtration and is an established technology in Japan for primary and overflow filtration.

A summary of pilot unit operations is shown above.

Metropolitan Sewer District of Greater Cincinnati (MSDGC) has implemented a program to identify and evaluate new, emerging technologies for the management and control of combined sewer overflows (CSOs). In 2016 MSDGC, evaluated two pilot-scale media filtration systems from Aqua Aerobics/MetaWater USA (Loves Park, Illinois) to gauge whether the treatment could meet MSDGC criteria for primary equivalent total suspended solids (TSS) removal on CSO discharges. The filtration pilot units were a cloth media filter and pinwheel shaped floating media high rate filtration system (HRFS). Both were installed to capture and treat flows at the influent to one of MSDGC’s existing CSO treatment facilities. Over the course of the study, the cloth media filter pilot unit generally displayed consistent performance and was able to typically achieve primary equivalent treatment TSS removal with an average effluent TSS of 18 mg/L (range from 3 mg/L to 58 mg/L). The average TSS removal was 77%, and ranged from 50% to 95%. The HRFS with floating pinwheel media had more variable performance, with average effluent TSS of approximately 56 mg/L, and range from 5 mg/L up to 370 mg/L. The average TSS removal was 51%, and ranged from 9% to 75%. Both pilot filtration systems were also evaluated for scalability and operability in CSO treatment applications.

For more information, please contact the author at wmartin@hazenandsawyer.com.

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Horizons Fall 2017 (pdf)

Horizons showcases significant water, wastewater, reuse, and stormwater projects and innovations that help our clients to achieve their goals, and can help you achieve yours. Articles are written by top engineers and process group leaders, demonstrating and explaining the beneficial application of a variety of technologies and tools.

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