Modeling and optimization of electrocoagulation process for removal of Cr(VI) and total suspended solids from tannery effluent

Hexavalent chromium [Cr(VI)] is one of the toxic heavy metals and total suspended solids both present in different industrial effluents. The key objective is to adopt best and design suitable methods either to reduce or to prevent heavy metals from wastewater. This present study concerns with EC (electrocoagulation) technique which was a robust technique used to treat polluted tannery effluent without using any chemicals and easy to operate and generate less by-products after wastewater treatment. In electro coagulation electric current is applied to both electrodes (anodes and cathodes) whereby sacrificial anodes corrode to create free ions for coagulations in the solution. This study also optimize process variables like current density, operating time and initial pH for electro coag-ulation for removal of Cr(VI) and total suspended solids (TSS). The response surface methodology (RSM) with central composite design (CCD) used in the development of modelling and statistical analysis of tannery wastewater by EC where RSM is a best mathematical and statistical tool for opti-mizing the solutions and identify the best solution and artificial neural network which is a robust technique of optimization, validate the RSM prediction. A CCD was executed for suitable and ade-quate measurement and predicted two factor interaction model were design for %Cr(VI) removal efficiency for both aluminium and iron electrode. The most significant model for %TSS removal effi-ciency for aluminium and iron electrode, respectively, was quadratic and linear. These models gave coefficient of determination R-squared value, adjusted R-squared value and predicted R-squared values for Cr(VI) and TSS for both Al and Fe electrode, respectively. The optimum condition for predicted maximum Cr(VI) removal was found to be 53.93% and 57.72% for Al and Fe electrodes, respectively, similarly 89% and 86% for %TSS removal.