Recovery, Purification and Reuse of Contaminated Sodium Chloride Obtained from Tanneries for Raw Goat Skin Preservation

Abstract

Large quantity of sodium chloride is used for raw skin preservation. Significant amount of salt is removed from raw skin through a mechanical process before taking for further processing in tanneries. This recovered salt is contaminated with various dirt, proteinous materials and microorganisms and gets accumulated, which creates a serious waste disposal problem for tanneries. In this study the recovered contaminated waste salt was purified and reused for skin preservation. The recovered contaminated salt from tannery was dissolved in water, filtered, treated with activated charcoal to remove the undesired components and subjected to ozone treatment for the removal of microbial contamination. The ozonized solution was subjected to solar evaporation. Improved evaporation techniques were employed to facilitate evaporation of salt solution. Dried purified salt obtained was checked for microbial contamination. Then the dry salt was used for the preservation of a fresh batch of animal skin. After a minimum storage period of 21 days, the skins were processed into leather as per the usual procedure and compared with the leathers obtained by conventional fresh salt preserved skins. The physical tests, chemical analysis and organoletic properties of experimental leathers show that the quality of leather obtained from animal skins preserved using purified salt was comparable to leathers obtained from conventional pure salt preserved skins. The approach minimizes salinity concerns of tanning by providing simple and practical solution.