A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Engineering and Technology

Thesis (M.Sc.) - Asian Institute of Technology, 1994

This study envisaged assessment of the total number of industries, total wastewater discharge, BOD load and the toxicity of industrial wastewaters in Pakistan. The industrial sector has been found to be a major contributor of water pollution with BOD, heavy metals and toxic compounds. Only 30 industries have had some kind of water pollution control equipment, but most of them are working at very low levels of treatment. For the effective utilization of scarce resources and to apply a systematic approach for water pollution control, the existing industries have been prioritized. Major priority industries identified are textiles and chemicals among the medium to large scale industries, while tanneries and electroplating are from small scale industries. Large quantities of water are used during textile dyeing and bleaching operations leading to almost equal amount of wastewater generation. While electroplating industry have been found to be discharging highly toxic and hazardous wastewaters into the sewer system without any treatment. The water consumption earl be reduced through in-plant modifications such as water consumption monitoring, controlling the leakage and spillage, optimizing the use of chemicals and using specially designed washers and rinsing equipment and replacing old machinery and equipment with the new ones. To encourage the la_rge and medium scale industries to control the water pollution, economic incentives like tax rebates, subsidies and soft loans should be provided. Combined/central treatment plants should be constructed for small scale industries. In the present circumstances they should have pretreatment at factory site before discharging into the sewer system. The estimated costs for the treatment of textile and electroplating wastewaters are US$ 0. 55 and 1. 27 per m3 respectively. The legislative structure has been found to be insufficient for industrial water pollution control and needs not only revision of existing laws but also inclusion of few more laws and regulations to improve the situation. The enforcement agencies need to be strengthed in terms of trained manpower, equipment and legislative support for effective pollution control.