Effect of operating parameters on the sludge settling characteristics by treatment of the textile dyeing effluent using electrocoagulation

Abstract This study invested the impact of the operational parameters (pH, Current Density (CD) and Electrode Gap (EG)) on the sludge generated after electrocoagulation treatment of textile dyeing effluent (TDE) by studying sludge settleability and filterability characteristics of EC generated sludge. Electrocoagulation treatment evaluated at laboratory scale with aluminum as electrode material at operating condition of parameters of pH, CD and EG. (pH-5.5, CD-105.12 A/m2 and EG-2.5 cm). Under these operating conditions, maximum COD reduction was achieved 88.45 % and maximum color reduction was about 66.92 %. Settling characteristics of TDE was studied by sludge volume index (SVI) and Centrifugal settleability index (CSI). From disposal point of view, filterability characteristic was also studied by simple gravity filtration method. Specific cake resistance, α (m/kg), filter medium resistance, Rm(m−1) was also studied. The specific cake resistance was found in the order of 38.4 × 1013 >34.13 × 1013 >22.25 × 1013 >11.19 × 1013 >7.30 × 1013 (m/kg) at the pH 9.5, 7.5, 1.5, 5.5 and 3.5 respectively. While filter medium resistance was found to be 111.22 × 109, 92.28 × 109, 82.33 × 109, 41.38 × 109 and 13.87 × 109 m−1 at pH 7.5, 9.5, 3.5, 5.5 and 1.5 respectively.