IMPACT ASSESSMENT OF AUTOMOBILE SERVICE STATIONS EFFLUENT OF KARACHI CITY

Abstract

Since last three decades a significant number of automobiles service stations have been increased creating waste water contamination problem in the mega City Karachi. It was estimated that approximately 255 liters of water was consumed while washing one vehicle (car). An average of 20-25 vehicles was washed on a station every day consuming 5610 liter of water per day at one station. Waste water effluent samples were collected from ten different stations of each district (South, East, Central, North, Malir and Korangi; total sixty samples from six districts) of Karachi city, to calculate the average fresh water consumption and the concentration of different hazardous pollutants in their wastewater and compare these results with Sindh Environmental Protection Agency (SEQS) limits for BOD 80, COD 150 Oil and grease 10 and TSS 200. The obtained results revealed that the concentration of BOD, COD, Oil and Grease, and TSS was 86.2, 90.9, 91.1 and 77.21% in the central area of Karachi city. These higher values may cause serious environmental pollution like stultification in photosynthesis, depletion of dissolved oxygen, disturbance of aquatic life, damaging of sewer system, toxic effects on human and water resources. District central values were highest as compared to other districts due to high population and vehicles. Overall, this study highlights the vehicle service stations of Karachi, about their water consumption, treatment practices and negative impacts on environment. Keywords: Automobile, Service station, Effluent, Water consumption, Karachi city