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Leather tannery wastewater is discharged wastewater in the production process. Typically animal skin with salt or soaked in water to swell, add lime to the meat, off the base, and then use tannins or chrome tanning greasing softening, and finally processed into leather dyeing.
Tannery wastewater characteristics are the following:
①large fluctuations in water quality and quantity;
③high concentrations of suspended solids, perishable produce a large quantity of pollution;
④S2- and wastewater containing chromium and other toxic compounds.
Nonionic polyacrylamide flocculant can NPAM Leather wastewater treatment. Leather industrial wastewater including degreasing wastewater, wastewater liming hair removal, water softening, dyeing wastewater, tanning wastewater, other aspects of wastewater. Processing of raw hide leather industry high protein content, the formation of high concentration organic wastewater, smell great; Coupled after the dyeing process, the higher Wastewater generated by processing complex process, difficult discharge standards; because in leather processing and production process need to use a variety of chemicals, so the leather wastewater contains not only fat, collagen, animal and plant fibers, sulfide and other substances, also contains a variety of pollutants chromium, salts, surfactants, dyes and other harmful and toxic substances . COD content of 4000 + mg / L, BOD content reaches 1500 + mg / L, SS content 2000-4000mg / l, PH weakly alkaline value of about 8-11.
Because complex composition leather waste alone is not an effective treatment process processing, waste water discharge standards, so the general biochemical process and physicochemical treatment processes combine to deal with. Non-ionic polyacrylamide coagulation sedimentation and SBR activated sludge treatment Combination leather waste, non-ionic polyacrylamide flocculant NPAM can effectively out of sewage and toxic substances in some organic matter in wastewater using activated sludge degradation of soluble organic matter. Process low investment, low operating cost, suitable for small leather wastewater treatment.
Tannery wastewater biodegradability is better, in general can be processed using biochemical methods. But wastewater often contain sulphide and chromium ions would inhibit microorganisms, it should give full attention to the role of pre-treatment, so in tannery wastewater, generally adopt "materialized - biochemical" combined process.
Different tannery wastewater, to select a different treatment process, in order to obtain better treatment effect. Such as tannery wastewater containing excessive salts, easy-to-produce inhibition of microbial activity, so choose low salt tolerance load activated sludge, or choose less-salt load in biofilm To weigh determined after; tannery wastewater biochemical general is very good, but the ratio of the integrated wastewater system fur, BOD / COD at 0.2, while the COD content is not high, usually no more than 2000 mg / L, when when using contact oxidation treatment, the pool can not form biofilms filler, so the best in the wastewater treatment process, add a hydrolysis acidification, in order to improve the ratio of its BOD / COD's.