SI NDH UNIVERSITY RESEARCH JOURNAL (SCIENCE SERIES) Analysis and Treatment Wash off Water from Vehicular Service Station in Hyderabad S. BHATTI, Z. SIDDIQUI*, S. MEMON, I. KANDHIR, M. A. MEMON, A. W. MAHESAR** Institute of Environmental and Engineering, Mehran University of Engineering and Technology, Jamshoro Received 16 th January 2017 and Revised 20 th July 2017 1. INTRODUCTION The untreated disposal of contaminated water increases the water pollution levels in receiving water reservoirs. Due to continuous increase in pollution level, buffering capacity of natural water bodies is significantly reducing and causing nuisance to human and natural eco-system. Retrospectively the Environmental regulatory authorities are taking measures to reduce the pollutional strength of wastewater before disposal into sewerage or any other direct disposal. Several studies have already been conducted to treat the wastewater of vehicular service stations, mining industries and petroleum industries specifically to reduce main contents i.e. oil and grease, turbidity, and suspended solids. The vehicle service is preferred to increase the comfort level and vehicle life. Population growth and increased purchasing power have increased the number of vehicles hence a dramatic increase in the number of vehicular service stations. According to survey, roughly 48 service stations are located in Hyderabad city each serving 25 to 30 vehicles per day. These 48 service stations are discharging 380,880 liters of wastewater each day there polluting canals carrying water for agricultural and domestic purposes (Bhatti et al. 2016). This issue is of keen importance, as the service stations require fresh water to wash each vehicle. And no any water cleaning technique is applied which could make this water reusable. The reported issue gets more severe in such regions which are facing fresh water shortage. According to a joint report of WHO and UNICEF about 663 million people are facing serious water shortage issues around the world (WHO and UNICEF, 2015). Simultaneously 80% of the wastewater in developing countries is discharged untreated in to river water and other water sources and becomes a chief reason for diseases. Approximately 3.575 million people die of various diseases caused by polluted water around the world (Dahal, 2012). The waste water of vehicular service station is contaminated with high turbidity values, oil and grease particles, high number of settle able solids and many other impurities. Yasin et al. (2014) reported high levels of BOD, COD, suspended solids and oil & grease contents in the wash off water of service stations in Pakistan and were significantly above the National Environmental Quality Standards (NEQs) (Yasin et al. 2012). Several wastewater treatment methods are being explored by scientists around the world. The researchers have been working to develop water cleaning methods to reuse wastewater after removing the organic contaminants. DAF is found to be efficient for removal of micro-pollutants from solution and illuminating minor level of turbidity; it is also applicable to treat wash off water to separate oil, chemically treated waste water, and refinery wastewater (Gregory, 1990). DAF enhances the buoyancy of oily water by attaching small air bubbles to the oils and grease mixed in the water thereby raising them to the surface (Zouboulis and Avranas, 2000). Typically during the DAF process the air bubbles are formed by dissolving the air in water at high pressure (nearly 5 bar) and releasing that water at lower air pressure. The size of the air bubbles is set to be 10-100 μm. The bubble size is a significant factor; it Abstract: The number of vehicular service stations is increasing significantly all around the world as the number of vehicles is increasing. These service stations are a major organic source of water pollution. There are total 48 service stations in Hyderabad, Sindh. These service stations discharge 380,880 liters of waste water each day, mainly into canals carrying water for irrigation and drinking purposes. Considering the serious water shortage issues, it is necessary to treat this wastewater for reuse purpose. This research focuses upon developing the wastewater treatment method to make the water reusable for washing purpose. The wastewater is treated with Dissolved Air Floatation (DAF) method followed by wool fiber filtration to reduce turbidity, oil and grease particles and settleable solids. The proposed method successfully removed the turbidity of wastewater by 97%; oil and grease particles 98.75% and an improvement of 68% was observed in the number of settleable solids. Keywords: wastewater, vehicular service station, oil and grease, DAF, wool fiber ++ Corresponding author. E-mail address: sheerazahmed.memon@faculty.muet.edu.pk *Department of Environmental Engineering, NED University of Engineering and Technology, Karachi *IICT,University of Sindh, Jamshoro Sindh Univ. Res. Jour. (Sci. Ser.) Vol.49 (3) 473-478 (2017)