Effectiveness of Carbon Electrode Electrolysis Effluent Treatment System in Textile Dyeing

The electrolysis process is an easy alternative for the treatment of textile dyehouse wastewater. To study the effectiveness of the carbon electrode electrolysis method in dyehouse effluent treatment is the main objective of this research. In most cases, the metal electrode used in the electrolysis system becomes decayed and needs to be replaced after a certain time. In this study, an inert carbon electrode has been chosen to treat the cotton dyehouse wastewater that can function longer than a metal electrode. Hence, the process is named as Carbon Electrode Electrolysis (CEE) method. In this method, a combined effect of electro-coagulation and electro-reduction has occurred. Electro-coagulation happens by direct charge supplied from a carbon electrode and then neutralizing negative effluent charges using positive charge. The color chromophore becomes broken down by a reduction in the cathode. Through electrolysis of sodium chloride in the effluent, sodium hypochlorite is produced, which later oxidizes organic compounds and reduces BOD. The effects of different treatment parameters of the CEE method like salt concentration and operating time have been studied and found that higher salt concentration and around 65 minutes operating time is effective. The results are analyzed based on four criteria: Color change, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Total Dissolved Solids (TDS). Results show that the CEE method minimizes effluents’ color and reduces BOD and COD within the acceptable limits of the Department of Environment (DoE), Bangladesh. Moreover, the CEE Effluent Treatment Plant (ETP) needs less space than the other existing biological and chemical ETP. However, this method is failed to remove TDS from wastewater.

Keywords:Textile effluents; Carbon electrode electrolysis; Coagulation; Flocculation; Oxidation