Electro-Chemical Treatment of Wastewater

Abstract

This study aims to investigate the treatment of wastewater from rubber reclaiming industry and first extraction stage effluent from a pulp and paper mill using electrocoagulation and electro-flocculation. Removal of color, turbidity, chemical oxygen demand (COD), oil and grease and total solids from the effluents was investigated at different pHs and different electrolyte doses by using two types of electrodes Aluminum (Al) and Stainless Steel respectively at various electrolysis times (5.0 to 35 minutes at 5 minutes interval). In case of rubber sample, among Stainless steel and Aluminum electrodes, maximum removal efficiency was found with Stainless steel electrodes. it was observed that the experiments carried out at pH 7, voltage 4V, an electrolysis time of 15 minutes and electrolyte dose (NaCl) of 0.8 g/l were sufficient for the maximum removal of these pollutants with Stainless steel electrodes. The maximum removal efficiency of various parameters by Stainless steel electrodes found were: COD 70%, total solids 60% and oil and grease 80%. In case of bleach effluent, maximum removal efficiencies were found with Aluminum electrodes in comparison to Stainless steel electrodes. It was observed that the experiments carried out at 5V, an electrolysis time of 15 minutes and at pH 2 were sufficient for maximum removal of these pollutants with Aluminum electrodes. The maximum removal efficiency of color, turbidity and COD by Aluminum electrodes were 98%, 76% and 86% respectively. In both the cases, It was found that 15 minutes of electrolysis time was sufficient for maximum removal of pollutants and further increase in residence time for electro-chemical treatment imposes no further positive effect on the pollutants removal.