ULTRAFILTRATION TREATMENT OF ENGINE PLANT OILY WASTEWATER A FOUR YEAR PERFORMANCE CASE STUDY

In 1994, a major automotive engine manufacturing plant began evaluation of wastewater treatment technologies that would improve the quality of wastewater discharge, produce treated effluent that would comply with POTW discharge limits, and eliminate the costs and risks associated with the use of hazardous chemical/physical treatment chemicals. Several waste management options were examined, including waste reduction via production modification within the plant, point-source, and end-of-pipe membrane separations technology. This study led to the commissioning of a UF (Ultrafiltration) pilot at the plant using full scale membrane modules with the objective of economically reducing the levels of oil and grease, suspended solids, and total solids contaminants in the plant's discharge. It was found, based on cost, technical, and operating (labor, chemical cost, variability in effluent quality) considerations, that UF met all objectives.The commercial scale membrane system specified for end-of-pipe oily wastewater treatment was an open-channel tubular UF system designed to reduce 58,000 gpd of waste to less than 1,200 gpd of oily waste concentrate. Permeate off the UF, directly discharged to the POTW, contains less than 30 mg/l oil and grease, less than 0.5 mg/l Cu and Zn, and less than 10 mg/l suspended solids. This UF system was commissioned in September of 1997 and since then has continuously met design volume reduction targets and effluent discharge limits. In 2001 a second UF unit of equal capacity was also commissioned at this facility, as plant production and wastewater treatment needs increased, and as UF was well proven. The performance of this UF system since start-up is detailed in this case study.