Flow EQ, Pump Station, and Odor Control

  • Client Confidential
  • Type Industrial
  • Services Design, Construction
  • Construction Cost $4 Million
  • Project Manager Steve Troyer, P.E., BCEE


This large Minnesota city owns and operates an industrial wastewater treatment facility which treats wastewater from a hog processing plant. The industrial wastewater facilities consist of flow equalization and an anaerobic contact treatment process which was originally constructed in the late 1950s. The industrial wastewater facilities are capable of handling approximately 2 million gallons per day (MGD). Treated wastewater from the industrial side is combined with partially-treated effluent from the 5 MGD domestic side of the plant then finished with treatment in a nitrification bio-tower and disinfection tank just before discharge to the river.

1a Biogas P1080064


The city retained FOX to prepare plans and specifications for a new two-million gallon flow equalization tank, pump station and odor control system for the equalization tank. Using a unique pre-design evaluation process led by FOX, the project was revised to achieve a very significant cost saving for the city and industry. The first phase of the project consisted of the design of two 1.2-million-gallon anaerobic treatment reactors that serve as flow equalization, biogas collection and handling system, a 6,400 gallons-per-minute (gpm) transfer pump station and control building, control system, associated piping modifications, and miscellaneous construction.

FOX was retained to investigate alternatives for expansion and upgrading of the older portion of the industrial treatment section. Special attention was given to the feasibility of alternative anaerobic processes. The target design flows and loads for the facility, based on an earlier engineering report, were 2.32 mgd and 37,100 lb BOD/day, respectively.

Final construction cost of that phase was $4,031,967, or just 0.8% greater than FOX’s opinion-of-cost from the design stage.

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2a BiogasOutcome

From the study, phase two improvements were identified. The project involved rehabilitation of the older anaerobic digesters, new mixers, degasification system, piping modifications, and digester gas handling.


FOX continues to work with the industry on various projects that bring efficiency and improved performance to the city and industry.