A Management Study on Recovery and Recycling of Useful Material in Leather Tanning Industry

Author: Moghira Badar* , Imran Ali** and Muhammad Luqman***

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Abstract

This paper deals with the process development for recycling of waste chemicals. Basic chromium sulfate (BCS) is one of the expensive and widely used chemicals in chrome tanning process. We have economically recovered BCS up to 99 % however 1% is left as impurity in effluents. Sodium sulphide is recovered up to 99.5 from the composite wastewater using the very economical method. This paper also deals with the locally devolved technique of de-liming by the use of CO2. The results show that in case of skins, the use of ammonium sulfate can be completely eliminated where as in case of bovine hides the use of ammonium sulfate can be reduced to 20 to 50% (w/w), depending upon the thickness of the pelt (limed hides or skins). These results in proportional reduction of ammonia gas produced along with the reduction in concentration of BOD, COD and sulfate ions by the same amount.

Keywords

Liming process, Chromium Recovery, Precipitation Agent, Float, Chromium Sulphate

Conclusion

It is concluded that here recycling of chrome lime and pickle are very much effective in reducing the pollution load at the final drain and are equally effective source of chemical land water conservation. All these options are financially feasible without any compromising leather quality. Chrome recycling system results in, 24% basic chromium sulfate cost saving. Whereas with recycling, its concentration lowered down from 87 mg/1 to only 12mg/1 and chromium load reduction was about 60 kg/d. which is still higher than the NEQS limit of 1.0 mg/1 and needs further treatment of comply with this standard. Which is possible by separate treatment of chrome contaminated stream. Sulfate reduction is quite significant, which is about 925 kg /d (73%) and final effluent comply NEQS limit of 600mg/l. It is recommended to adopt further cleaner production options like, slat dedusting, recycling of de-dusted salt in the pickle processes, CO2 Deliming and dye recycling for chemical saving and furthe

References

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How to cite this article

Moghira Badar , Imran Ali** and Muhammad Luqman (2016). A Management Study on Recovery and Recycling of Useful Material in Leather Tanning Industry , Biological Forum – An International Journal 8(2): 379-383.