Treatment of Waste Water of Automobile Service Station

Abstract

Poor management practices related to generation and disposal of untreated wastewater causes pollution of both surface and ground water bodies. Raw wastewater disposal from industry are some of the sources causing water pollution. Automobiles industry particularly cleaning operations produce thick layered greasy wastewater that contains very high level of organic loads. Automobile cleaning is an important process for organization involved in manufacture, repair/maintenance of automobile and shipping facility. Parts are generally covered with heavy oils and solids which are removed during washing of vehicles. An automobile washing pit facility located in 33 Supply and Transport Battalion at Risalpur cantonment was selected as case study. Samples were collected from the facility and tests were performed on the wastewater. These wastewater contained oil, high COD and solids. The study aimed at characterization of wastewater from automobile cleaning operation, designing a treatment system and study of economic effects of proposed system. Two types of oil contents were encountered i.e. free and emulsified oil. Wastewater generated at locations where vehicles were being cleaned contained free and emulsified oil. Separation of this oil was achieved using skimming tank and chemical emulsion breaking. Solids removal was achieved through coagulation. Alum was used as coagulant. Over 95 percent removal of contaminants was achieved in the treatment process. Results revealed that wastewater from the source is treatable and pollution of water bodies can be minimized to NEQS limits. Moreover recycling of wastewater, after treatment, can achieve significant water conservation. Finally a treatment plant design was proposed for installation in the facility after considering its economic feasibility.