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CSO Mitigation

Client: City of Goshen

Location: Goshen, Indiana

The City of Goshen retained Donohue & Associates for a CSO abatement project, which was designed to enable the City to accomplish all of its LTCP requirements within a single 5-year discharge permit cycle. The project comprised five separately bid and constructed facilities, including a wet weather detention facility, a CSO diversion pump station, CSO river crossing, 90-inch CSO trunk line sewer, and water/wastewater SCADA upgrades.

The services provided by Donohue resulted in CSO conveyance, storage and treatment facilities capable of storing 6 million gallons of wet weather flow with a peak influent flow capacity of 212 million gallons per day (mgd). This project was one of the first in the state of Indiana to be designed in full compliance with IDEM’s Nonrule Policy Water-016, which allows communities to implement a CSO treatment basin instead of more costly CSO abatement alternatives. Based on the success of this project, several Indiana municipalities have sought develop their Long Term Control Plans using this methodology.

The WWTP and CSO facilities are fully automated—including dewatering of storage tanks, pump station wet wells, and force mains. The wet weather detention facility was designed for multiple operation modes in order to provide flexibility; they can be operated in series or separately filled to achieve a higher level of solids removal and to minimize the formation of disinfection byproducts. The facility also includes three of the largest wastewater grinders manufactured to date for protecting four 53-mgd pumps.

This project received an Honor Award in the 2013 ACEC Indiana Engineering Excellence competition.