Geauga County, Ohio
The McFarland Creek Wastewater Treatment plant has become a model for thousands of other existing conventional wastewater treatment plants considering a conversion to modern MBR technology.
As Ohio’s first large scale public works wastewater treatment plant to utilize the Membrane Bioreactor (MBR) treatment process and the largest retrofit of a conventional treatment facility in North America, this project addressed the unique aspect of introducing the latest treatment technologies into existing facilities of all sizes to meet the ever increasing regulations to protect our environment.
One of the main benefits of MBR technology is the superior effluent quality it produces compared to conventional techniques. Pollutants are reduced significantly and the environmental impact from point source discharges to the receiving streams of the wastewater treatment plants is virtually eliminated.
CT recommended MBR to Geauga County for use at McFarland Creek Wastewater Treatment Plant after studying the system in Japan where the technology has been operational for many years. The MBR treatment system requires less overall operation and maintenance and has resulted in reduction of residual solids production by over 30%.
In addition to serving as a guide for other operators of wastewater treatment facilities considering this new technology, Ohio EPA was able to develop design guidelines by working closely with CT at both the local and state levels since design review criteria had not been established for the new MBR process. The design and approval process involved presentations to agency staff by CT’s project manager, and one-on-one explanation of the process. CT was also required to provide support data of the process performance along with documentation from overseas treatment facilities.
An Expansion and Needs Feasibility Study was prepared for the McFarland Creek Wastewater Treatment Plant. The plant previously had design capacity of 1.2 MGD. Given existing flows to the plant, available capacity that was committed, and growth and development trends in the area, plant flows would be at design capacity within a few years. Although expansion of the plant was the main focus of the study, the scope of the study was also to include a needs analysis of facility components and operation. The service area study indicated a need for a 50% expansion of the plant from 1.2 MGD to 1.8 MGD over a 20-year design plan.
The final design included an MBR installation using the existing aeration tanks. As this process features extremely high mixed liquor concentrations, sufficient capacity for a 50% expansion was available in the existing aeration tanks. All solids separation is accomplished in the existing aeration tanks; therefore a final clarifier expansion was also unnecessary. The existing tertiary filters were converted to standby mode. Surplus tank capacity was available in the aeration tanks and existing final clarifiers for flow equalization. Biological Nutrient Removal (BNR) is accomplished by recirculation of mixed liquor through an anoxic zone.
The McFarland Creek WWTP project was the recipient of the following award:
- National Finalist, 2007 ACEC Engineering Excellence Awards
- Outstanding Achievement Award, 2007 Engineering Excellence Awards, ACEC of Ohio