Electrochemical treatment of dye-bath effluent by stainless steel electrodes: multiple response optimization and residue analysis.

The aim of this article is to maximize the chemical oxygen demand (COD) and color removal, and simultaneously minimize the energy consumed per unit mass of COD removed for the treatment of dye-bath effluent (DBE) by electrochemical (EC) method using stainless steel (SS) electrode in a batch EC reactor. Response surface methodology involving central composite design was employed to optimize the multiple responses. The effects of operating parameters such as pH of DBE, and important process parameters such as current density, electrolysis time and inter electrode space were studied. At the optimized condition, 91.7% COD removal and 99.8% color removal was observed with energy consumption of 7.71 kWh/kg of COD removed. Finally, the thermogravimetric analysis of the EC scum and sludge has been done in oxidizing atmosphere so as to evaluate their disposal aspects.