Options for Utilization of Tannery Sludge

At global level, the India has amassed the largest livestock and their skins and hide are used for the manufacture of large scale leather and 75% of tanneries in India are the small scale tanneries. The leather industry in India with annual turnover of more than 12 Billion dollar has a cumulative annual growth of about 3.09% in the last five years and 2nd highest manufacture of footwear and garments in the entire world, which leads to foreign exchange. Tannery sludge generation about 150000 TPA causes chromium pollution and contaminates water bodies & soil and risk to eco-system. Further, that affects the agricultural productivity and therefore, Tannery has been classified under the red category. The Supreme Court finding of fact resulting in the closure of polluting tanneries has led to unemployment problem and affecting national GDP. The present tannery sludge disposal methods like Composting, landfill, anaerobic digestion systems are not providing the satisfactory result. Reuse of industrial waste is advocated worldwide and in some of the countries as a remedial measure solidification and stabilization concept is adopted for reducing heavy metals from industrial waste. In this review the outcome of various research on the properties natural clay, ceramic and cement based stabilization of the tannery sludge has been discussed and the research gap is also identified .