ABSTRACT
This chapter presents information on tannery effluent characteristics, water pollution aspects of tannery effluents and on a demonstration plant installed at a tannery in Ranipet to treat its effluent. The treatment of tannery effluent would consist of: segregation of salt bearing wastes; equalization; primary treatment (sedimentation); and secondary treatment (usually biological). The wastewater discharged from a semitanned to finishing units comprise mainly of wash waters after each unit operation such as stripping, souring, retanning, dyeing and fat liquoring and the periodic discharge of concentrated wastes from each unit operation. Many municipalities have adopted distant upstream locations in the river, farther from their areas, as water supply sources, to avoid possible pollution from tannery effluents. The demonstration plant at Ranipet built on design criteria is providing excellent performance. In order to minimize the adverse impacts of the tannery effluents on the environment especially pollution of surface water and groundwater, it is necessary that tanneries provide sufficient treatment of their effluents.
