Treatment of leather industrial effluents by filtration and coagulation processes

This study focused on effluents characterization and accessing physical and chemical treatment by filtration and coagulation processes. The analysis results of the raw effluents reveal that the effluents were yellowish-brown color, having basic pH, very high values of BOD5, COD, TDS, TSS, TS and high concentrations of Cr, Na, SO42- and other organic and inorganic constituents. After settling and a subsequent filtration of raw tannery effluents through sand-stone, the filtered effluents were treated with various doses of FeCl3. The study observed that coagulant (FeCl3) of 150 mg/L dose near neutral pH showed the best removal efficiencies for major physico-chemical parameters. The analysis results illustrate that most of the physical and chemical parameters were found well below the prescribed permissible limits for effluent discharged. The study suggests that untreated tannery effluents would be treated by a combined process consisting of settling, filtering and coagulating with FeCl3. (C) 2013 The Authors. Published by Elsevier B.V.