The Ford Motor Company Utica Trim Plant is one of the world's largest manufacturers of automotive trim components.   The plant has three major wastewater streams: deionized water (DI), paint wastewater, and sanitary wastewater.

The high strength paint wastewaters had historically been disposed of by hauling offsite through a licensed contractor.   A paint system expansion was completed which was estimated to triple the current production of paint wastewaters.   This, in conjunction with increasing costs for offsite disposal of the paint wastewater, warranted a study and evaluation of alternatives for treatment/disposal of the wastewater streams.

The sanitary wastewater from the Ford Utica Trim Plant was treated in an existing sanitary treatment facility which consisted of primary settling tanks followed by biological treatment with rock trickling filters, followed by secondary clarifiers, before being discharged to polishing ponds, and then to the Clinton River.

HRC was hired to conduct a pilot plant study to determine if a cost effective treatment process could be developed to combine all of the wastewater streams for treatment to meet the current NPDES discharge permit.   During the pilot plant testing, paint and deionized wastewaters were blended and the flow was chemically treated to form an insoluble precipitate.   The precipitate was removed in an upflow solids contact clarifier.   From the clarifier, treated DI and paint wastewater was discharged to an aerated holding tank.   The holding tank contents were blended with sanitary wastewater and biologically treated in the activated sludge tank followed by secondary clarification.   To emulate the use of tertiary filters at a full scale facility, the effluent from the secondary clarifier was filtered prior to analysis.

The high strength paint wastewater had a BOD concentration of approximately 15,000 mg/l but was devoid of phosphorus and nitrogen which are essential to promoting biological growth of bacteria to biologically treat the paint wastewater.   Therefore, sanitary wastewater was blended with the paint wastewater to provide some of the necessary nutrients.   Small amounts of sodium phosphate and ammonia nitrate were added to supplement the nutrients provided by the sanitary flow.

The pilot testing was concluded in four months with the resulting system producing an effluent with an average of 21 mg/l BOD or an overall pilot plant removal of 99.3%.

The successful results of the pilot plant study demonstrated that exceptional treatment is achievable and offered an economical alternative to offsite disposal of a high strength industrial wastewater stream.

This unique and significant project was selected for award by the American Council of Engineering Companies (ACEC).