Detoxification and decolorization of Moroccan textile wastewater by electrocoagulation: energetic and toxicological evaluation

Abstract

In Morocco the textile industry, representing 31% of all Moroccan industries, is accompanied by high water consumption and important wastewater discharges rejected without any treatment. The focus of this study was to characterize the effluent from the local textile industry and to carry out the treatment by electrocoagulation (EC).The effect of electrode materials, pH, applied current density and treatment time on decolorization, COD removal and toxicity aspect of the effluent. Results have indicated that the treatment efficiency was significantly improved by varying the current density, pH and operating time when Al and Fe electrodes were used for EC. The appropriate electrode type search for EC provided that aluminium supplies more COD removal (78%) than iron electrode (56%) at the end of the 25 min operating time and increased BOD₅/COD index from 0.29 to 0.50.Whereas EC with iron electrodes was more beneficial for color removal 91% after 25 min of EC. The evaluation of toxicity by Daphnia magna test has shown that the effluent have a high toxicity. However electrocoagulation significantly reduced the toxicity of the effluent.

Keywords: daphnia test; toxicity; operating cost; decolorization.