Advancing Wet Weather Treatment in a Big Way – NEORSD is Getting It Done!

The Northeast Ohio Regional Sewer District (District) is currently implementing pilot- and full-scale demonstrations for the chemically enhanced primary treatment (CEPT) and high rate disinfection (HRD) of its wet weather flows at its three wastewater treatment plants in the Greater Cleveland Metropolitan area in response to a Consent Decree (CD) entered into with the Environmental Protection Agency (EPA). The project includes two full-scale and one pilot-scale CEPT facility with each including pilot-scale HRD facilities to assess the performance during wet weather flows. Operations began in July 2013 and will continue into 2015. During wet weather conditions, operations staff members are deployed to operate and measure the performance at each of the facilities. A number of challenges exist, including inherent intermittent operations, unpredictable wet weather, and changing influent water quality characteristics, all of which can adversely impact performance of these facilities. Despite these challenges, the facilities have performed well at the midpoint of the program and have met targeted effluent requirements over a range of events tested. To date, performance results demonstrate an average effluent TSS of less than 40 mg/L at all three plants, which meets the discharge requirements identified in the Consent Decree. Similarly, HRD testing results conducted to date show the capability to achieve 126 CFU/100 mL at dosages of 6 mg/L of chlorine at contact times of less than 10 minutes.