ENVIRONMENTALLY SOUND DISPOSAL OF TANNERY SLUDGE

The challenging problems faced by the tannery based countries are the safe disposal of the sludge generated by the effluent treatment plants. In this work, the disposal of the sludge at various generation points such as beam house (BHS) and after tertiary treatment process (TS) is studied. The FT-IR of the beam house sludge confirmed the presence of organic matter at 2880.31cm-1 and calcined products due the process of deliming. The TGA of BHS confirmed dominance of organic matter in the sludge with about 91.88% of residual mass at 292oC, whereas the inorganic salts present in the TS lead to a residual mass of 32.92%. The characterization of various parameters such as pH, hardness, Chlorides, TDS, COD, BOD, TS for the leaching studies and mortar curing studies were also performed. The high values of hardness of the two sludge samples were due to the presence of calcium and magnesium salts. The EPTOX leaching studies of the raw sludges and the leachate studies from the mortar curing were also conducted. These results confirmed the unsafe disposal of tannery sludges. An effective disposal of the tannery sludge by composting and solidification/stabilization (S/S) is suggested and is to be carried out in future. The S/S of the raw tannery sludge without the addition of admixtures were tested for compressive strength. The14th day compressive strength of BHS and TS were 2.2 N/mm 2 and 0.50 N/mm 2 for BHS and TS respectively