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Environmental Issues in Leather Products Industry Wastes and chemicals released to water system are the main pollution concerns for the leather industry. They are produced during washing, dehairing and tanning of the leather. The washing of skins removes dirt, salt and some organic matter from the raw material. Lime and sulfides are used to dehair the skins. The waste water from this process is very alkaline, contains toxic sulfides and is the main cause of the high BOD and suspended solids in the waste stream. The second processing step is de-liming to remove the lime in the skins and soften them by enzymatic action. The first dump of this process contains ammonium sulfate, enzymes and some protein. In the third step the skins are tanned using the chrome tanning process, which is standard for the industry. The solutions contain chromium as chromium sulfate salt and some free acid. About 75 per cent of the chromium present combines with the hide. The use of chromium in the tanning process is an environmental problem attracting considerable attention in developing countries. Tanning with soluble chromium salts, basic chromium sulfate, enhances the physical and chemical properties of finished leather. Currently it is the most widely used tanning method in the United States and most other countries. Environmental and health concerns have resulted in a number of initiatives to reduce its presence in the waste stream, improve fixation on the leather, recycle chromium from effluents (EPA 1995a), and use aluminium and titanium as alternatives (EPA 1995b). Environmental and health concerns led Chromium to be banned in leather products for the export market by the Bangladesh government as of June 1, 1990. In the final processing step, colour and fatliquor are employed to colour and oil the leather to make it as soft or as firm as desired. A number of chemicals are used in these steps, and about 90 percent of the load is fixed to the leather. The spent solutions are mildly acidic, with a pH between 4 and 6. BOD and suspended solids are relatively low (US AID 1994) The Indian government has numerous laws in place that effect the leather industry. Although compliance is generally weak, State Pollution Control Boards have in the last few years ordered closures of, and imposed fines on hundreds of tanneries for pollution infractions. Common effluent plants have been a major effort of both Central and State governments, and have been established in all areas of where tanneries are clustered (Jha 1997). Using domestic policy to establish and enforce proper waste treatment is an essential proactive step for the export sector given the emphasis on certain waste streams in eco-labeling programmes, The typical waste streams for leather production are outlined in Table 3 which documents the results of a pilot project on cleaner production in a developing country's tannery. The costs of remedying the pollution problems and the payback period are quantified. Summary of Recommended Pollution Prevention Opportunities
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