Shot in the arm for leather industry in Tamil Nadu as tannery residual salt can be processed, marketed
The State was staring at a major environmental hazard as nearly one lakh tonnes of residual salt produced by tanneries piled up at Common Effluent Treatment Plants.
In India, Tamil Nadu is the only State that enforced Zero Liquid Discharge (ZLD) on leather processing units in 2001. Though the measure was taken by the Tamil Nadu Pollution Control Board (TNPCB) to prevent untreated effluents polluting the waterbodies, it has resulted in accumulation of residual salt over the years, and has become a big cause of concern.
B Chandrasekaran, Director, CLRI, told Express on the sidelines of the Commemoration Day celebrations, about 15 common effluent treatment plants that are stocking close to one lakh tonnes of salt, which is a mixture of sodium chloride and sodium sulphate. This salt is used during rawhide stage, and has no direct market. “We can neither keep the stock nor dispose it off. It is a huge burden on the industry and a storm like Vardah has drained this stock leading to environment disaster. So, we came out with a solution to separate sodium chloride and sodium sulphate using a simple technique and market them separately,” he said.
Laboratory trials have proved successful, and now a pilot project is envisaged with the help of the industry represented by the All India Skin & Hide Tanners & Merchants Association (AISHTMA) for which a Memorandum of Understanding (MoU) was signed recently.
Amitsava Das, Director, CSMCRI, said that trials have given the desired purity (98.8) acceptable for the industry. The technology has proved very economical. The pilot unit is planned at salt farms in Bhavnagar, and once technology is developed into a commercial product, it will be implemented in CETPs.
Chandrasekaran said the salt can be converted into raw material and sold within a year. AISHTMA president, Rafeeq Ahmed, expressed gratitude to scientists for developing such a cost-effective technology.