Treating Car Wash Wastewater by Ceramic Ultrafiltration Membranes for Reuse Purposes

Abstract

In this study, a three-stage ceramic ultrafiltration system was created to treat two car wash wastewater effluents to produce water with class A recycled water quality for the purpose of reuse at car washing facilities. Pre-treatment included coagulation, flocculation and sedimentation followed by sand filtration. The successive treatment of ceramic ultrafiltration was employed with an effective pore size of 0.02 µm. The results indicated that coagulation produces a dramatic reduction in turbidity (83–94%) and the additional sand filtration aided with the removal of suspended solids of up to 100%, in turn, reducing the likelihood of membrane fouling. Analysis suggests that the chosen coagulant of FeCl3 aids complete removal of phosphorus with an initial concentration of 15.5 mg/L of \({\text{PO}}_{4}^{3 - } - {\text{P}}\). Additionally, there is a reduction in N concentrations after the coagulation stage with up to 31% reduction of nitrate and 74% reduction of nitrite. The system has minimal influence on the removal of both heavy metal and dissolved solid concentrations, suggesting that metal and dissolved ions may only be removed with additional reverse osmosis treatment. The results obtained show that the system is robust enough to treat a large range of car wash wastewater effluents to a standard that reflects class A water with respect to turbidity and suspended solids.