The City of Euclid completed a Sewer Study to examine feasible alternatives to eliminating WWTP wet weather bypasses for a typical year rainfall and entered into a Consent Decree with USEPA/OEPA for the implementation of improvements. Limitations of treatment plant’s existing clarifiers restrict the maximum flow through the WWTP. These limitations had allowed a peak daily flow (PDF) of 28-32 MGD through the WWTP while the design peak daily flow (PDF) through the WWTP was at 66 MGD.
A major challenge and constraint to the project was limited land available at the existing WWTP located in a densely populated area within residential neighborhoods and businesses in close proximity. High rate treatment technologies were investigated and included various ballasted flocculation systems, high rate filtration, and chemical enhancement of swirl concentration. WWTP improvements were also reviewed to maximize secondary treatment including flow equalization, enhanced clarification, and membrane bioreactor conversion.
Based on a comparison of Wet Weather Auxiliary Treatment Facility (WWATF) activation reductions, effluent discharge pollutant percent removals, Operations and Maintenance Costs and life-cycle Total Present Worth (TPW), a final recommendation was made to move forward with a MBR High-Rate Secondary Treatment Upgrade plus Flow Equalization. This $90 million program includes the installation of a new MBR high-rate biological activated sludge treatment process within the existing WWTP tanks making it the 5th largest MBR plant in the world. Peak flows greater than 66 MGD are captured in an equalization basin. The WWATF provides pretreatment of peak flows prior to the 25 MG equalization basin(s). The 25 MG will be provided in two (2) separate tanks with the first phase tank sized to accommodate 15 MG and limit activations to four (4) in a typical year.
Due to the poor condition and operation of the existing WWTP’s headworks, a new headworks treatment facility is also be included in the plant upgrade including screening, grit removal and influent flow metering for preliminary treatment.