Leather tanning industry wastes

Globally, it can be estimated that the tanning industry use around 3 million tons of chemicals for the production of leather. The chemicals will end up in the product or waste or will be directly discharged to the water, air or soil. Although a major part of the chemicals are standard organic chemicals and standard inorganic chemicals, it is important for tanneries to have a careful control of the chemicals both for environmental and health reasons. 

This process has been used for petrochemical, textile, pulp and paper mills, leather-tanning, gum, wood-processing, and some other industrial waste streams. 

Commonly enriched in ultramaflc rocks and their associated ore deposits. Much naturally occurring Cr is relatively insoluble chromite. Soluble Cr may occur naturally in evaporative lake sediments or other evaporative environments, as a trace element within other soluble salts. Anthropogenic Cr can occur in soils, sediments, and waters affected by industrial wastes and byproducts (i.e., leather tanning, electroplating., cement use). 

Enriched in many zinc ores, hlack shales, phosphatic shales. Can he enriched in soils, sediments, and waters affected hy emissions from smelters, power plants agricultural applications of sewage sludge mining and industrial wastes and hy-products industrial wastes, hy-products, and trash (i.e., battery production, leather tanning, electroplating, cement use). 

Hexavalent chromium (6 ") is a recognized carcinogen, and industrial exposure to fiimes and dusts containing this metal is associated with increased incidence of lung cancer, dermatitis, and skin ulcers. Environmental health risks arise from soil contamination by Cr " waste disposal sites left by the leather tanning and dyestuff industries. Cr is more efficiently absorbed than Cr " and its toxicity and carcinogenic effects involve reduction to Cr and Cr " by cysteine, with the formation of intracellular DNA adducts. Cr species are relatively nontoxic partly because of their poor intestinal absorption and rapid excretion in urine. 

Gasification of Leather Offal. Chrome-leather tanning scraps or offal are a waste product of the tanning and leather industries. These wastes are usually the result of trimming operations and contain 3.5 wt % chromium and about 50 wt % water. The wastes cannot be incinerated because malodorous substances and carcinogenic chromium-containing particulates are formed. Landfill disposal is presently used. 

MAJOR USES Component in food processing used in environmental applications for pH control, neutralization of waste streams, treatment and general cleaning used in industries of electroplating, leather tanning, steel pickling and photography antiseptic toilet bowl cleaner. 

EXPOSURE ROUTES wind transport from road dust wood treated with copper dichromate leather tanned with chromic sulfate chromate production stainless-steel production chrome plating working in tanning industries chromium waste disposal sites chromium manufacturing and processing plants consumption of food and drinking water inhalation of air... 

Metal ions that are prevalent in industrial effluent and have a considerable environmental impact include Cr(III), Zn(II), and Ni(II) [7]. Waste solutions of these metals are routinely found at levels that are in excess of acceptable disposal limits. Such waste solutions are produced, for example, by electroplating and metal pretreatment [Cr(III), Zn(II), Ni II)], printed board manufacture [Cr(III), Ni(II)], leather tanning and wool scouring [Cr(III)], and anodizing [Cr(III), Zn(II)], among others [7,8]. These three metal ions are studied in detail in this chapter. 

Leather Tanning and Finishing Industry Wastes Industry Description... 

A method is proposed for using chrome tanned leather wastes produced by the footwear and clothing industry as fillers in polymer matrices. A technique for processing the composite obtained by continuous extrusion is also demonstrated. In order to evaluate the technique, a series of PVC-leather fibre composites was prepared and extruded through a flat die to produce sheets. The process produced a leather-like sheet that could be used in several applications. The influence of the filler content on the processability and final properties of the composite sheets was evaluated. The tests revealed that the sheets were flexible and exhibited suitable water absorption levels for several applications in the footwear and clothing industry. Finally, the tests showed that this composite could be formulated and processed at high productivity levels and at a low cost. 28 refs. 

The tanning materials enter the waters by the natural route as well as from wastewaters of the leather industry, and also after elution of the waste deposits from the preparation of tanning leaches and wastes of the wood-working industry. 

The Eprs of B. subtilis and related bacilli are also very relevant for commercial applications. In particular, these enzymes are employed in the manufacture of detergents, tanning of leather, management of industrial and household wastes, bioprocessing of X-ray or photographic films for the recovery of silver, protein hydrolysate preparation in the food industry, synthesis of aspartame, and other applications [102]. Recently, the fibrinolytic activity of Vpr was discovered. Accordingly, Vpr has the potential to work as a thrombolytic agent in medical applications [103, 104]. 

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