The City of Elkhart, Indiana, officially broke ground earlier this month on new wastewater treatment plant (WWTP) capacity upgrades. The upgrades, designed by Donohue & Associates, incorporate the latest technology to increase peak flow capacity from 40 million gallons per day (mgd) to a sustained flow rate of 60 mgd as required by the City’s federal Consent Decree (CD) for combined sewer overflow.
Prior to the design, Donohue proposed innovative Cloth Media Disk Filtration (CMDF) technology for CSO flow treatment, although this technology was not available as a CSO treatment during previous CD negotiations. The CMDF process was pilot-tested and Donohue assisted the City in preparing documentation for federal agencies to review and approve the CMDF process. This the first successful CD renegotiation for an improved, innovative technology in Indiana and the first use of non-biological treatment as a secondary treatment equivalency in both Indiana and US EPA Region 5.
With a capacity of 30 mgd, the CMDF process will treat flowrates from 30 to 60 mgd, while the flowrate through the WWTP’s existing activated sludge and biological treatment system is up to 30 mgd. This will allow the system to be sustainable for as long as the peak wet weather induced flowrates may last. All 60 mgd flow will pass through screening and grit removal, downstream of which flows above 30 mgd will be diverted to the CMDF process. After the wet weather flow is filtered through the CMDF process, the CMDF effluent recombines with the WWTP’s biologically treated secondary effluent and the combined effluent is disinfected with an existing UV (ultra-violet light) disinfection process, reaerated, sampled for NPDES compliance, and discharged to the St. Joseph River.
In addition to the innovative use of CMDF technology for CSO flow through a wastewater treatment plant, the project also includes two new primary sludge pumping systems, new drives and baffling floor six existing primary clarifiers, new primary effluent flow control and metering, three new energy-efficient magnetic bearing turbo blowers, new return activated sludge pumping system and distribution control, new diffusers in five aeration tanks, new air headers to the 25 diffuser drop points, new chemical storage and feed facilities, and a new two-story operations building for city monitoring and control of wastewater, collection system, water treatment plants, and distribution systems from one central location.
Construction completion is expected in November 2023.
Pictured above (left to right) are Jeremy Roschyk, Donohue South Bend Area Manager; Tory Irwin, City Engineer; Mayor Rod Roberson; Richard Claus, Donohue Project Manager; and Aaron Mishler, City Councilman.