3 Review(s)

A large portion of the world?s tanning industry operates in low- and middle-income countries, and the percentage of these countries contributing to light and heavy leather materials increased from 35% to 56% and 26% to 56%, respectively, between 1970 and 1995. Many of these tannery sites are clustered together, creating heavily polluting industrial areas in many countries. These pollutants are responsible for the contamination of all nearby surface and groundwater systems with severely high levels of chromium The discharge of solid waste and wastewater containing chromium is the main environmental problem of tannery industry. Chromium is a highly toxic compound and the dumping of chromium containing material is in most countries restricted to a few special dumping grounds. Emissions into the air are primarily related to energy use, but also the use of organic solvents and dyes causes emissions into the air.The production of fresh hides has been estimated at about 8-9 million tonnes per year. During the processing of these hides a total of 1.4 million tonnes of solid waste is produced. This means that in all likelihood ca 16% of the processed hides is leather waste. This is almost the same amount of waste produced as meat from fleshing activities (7 - 23%). These figures show that the solid waste produced per ton of raw hide is about 450-600 kg. About half of this contains 3% chrome on a dry matter basis. Collection and safe disposal of solid waste especially chrome containing solid waste and sludge is normally monitored by environmental authorities and associated with costs. Conversion of solid waste into by-products not only reduce pollution load, it can also be commercially beneficial. This represents great potential for producing increased returns to tannery processing through deriving value from wastes. In any event, reduction of waste is essential in order to meet demands for reduced pollution load from tanneries.?As for the production of wastewater, over 80 per cent of the organic pollution load in BOD terms emanates from the beamhouse (pretanning); much of this comes from degraded hide/skin and hair matter. The beamhouse is also the source of all non-limed and limed solid waste such as fleshing, trimming and waste split Because of the changing pH, these compounds can precipitate and contribute to the amount of solid waste or suspended solids.Every tanning process step, with exception of the crust finishing operations, produces wastewater. An average of 35 m is produced per ton of raw hide. This wastewater contains:- salts (Cl), fat, protein, preservatives (soaking); lime and ammonium salts, ammonia, protein (hair), and sulphides (fleshing, trimming, bating); chromium(salts) and polyphenolic compounds (tanning); and dye and solvent chemicals (wet-finishing). For the present study industrial town of Kanpur (Uttar Pradesh) was choosen. Kanpur is a metropolitan city, sprawling over an area of 260 sq km. According to the census 2001, Kanpur has a population of 25.51 lakhs. It is administratively divided into 6 zones and 110 wards with an average ward population range of 19000 to 26000. It is situated on the southern bank of Ganga River and has been an important place in the history of modern India. Kanpur is the biggest city of the State of Uttar Pradesh and is main centre of commercial and industrial activities. The City formerly known as Manchester of the country is now also called the Commercial capital of the state. It is known for its cotton and woolen textile and leather industries. Kanpur is one of the biggest producers of Textile and Leather products. Apart from leather and textile industry, the fertilizer, chemicals, two wheelers, soaps, Pan Masala, hosiery and engineering industries are also operating prominently in the city. Present book focuses on the pollution caused by the tanneries of Kanpur town.