Innovative ecological processes with recovery of chemicals and water for reuse in leather sector - an economical and sustainable approach

Abstract

The effluent discharged from conventional process in textile dyeing and tanneries are unable to meet some of the discharge parameters such as Total Dissolved Solids (TDS) in the existing physiochemical & biological treatment units. In addition to TDS management the control of volatile solids in hazardous category sludge is also becoming a necessity. To overcome these challenges faced by tanneries in the world leather, improved cleaner production, segregation of saline soak liquor and separate treatment, modified chrome recovery system and recovery of chromium & sodium chloride salt in the form of powder and quality water with TDS less than 500mg/l for reuse by tanneries have been developed for field application. Physiochemical treatment is converted into total biological treatment with sulphide oxidation using enzyme and biomass which resulted in 50% reduction in sludge generation. The secondary treated effluent and supernatant from chrome recovery system are processed with membrane units for recovery of high saline stream and quality salt for reuse in pickling process and other industrial requirement. These developments are being implemented at field level for cluster of nearly 400 tanneries in India which is first of its kind in the world.