Electrochemical treatment of Ayurveda pharmaceuticals wastewater: Optimization and characterization of sludge residue

In present study, we have investigated the treatment of Ayurveda pharmaceutical wastewater (APW) by electrocoagulation (EC) treatment method to minimize the energy consumed per unit mass of COD removed and maximize the color and COD removals by using the stainless steel (SS) and aluminum (Al) electrodes. Response surface methodology (RSM) was used to optimize the multiple responses during the batch mode study of APW treatment. A full factorial central composite experimental design has been used to determine the experiments for each factors and optimize the responses: color removal (R-1), COD removal (R-2), and energy consumed per unit mass of COD removed (R-3). At optimized conditions, R-1 = 97.83%, R-2 = 58.35% and R-3 = 27.12 kWh/kg COD removed for Al electrodes and R-1 = 95.35%, R-2 = 78.88% and R-3 = 28.32 kWh/kg COD removed for SS electrodes, respectively were obtained. Field emission scanning electron microscopy (FESEM) and thermo-gravimetric analysis (TGA) have been used to determine the EC treatment mechanism and disposal aspects of EC solid residue (scum and sludge). EC treatment mechanism of APW seems to be a combination of electro-floatation, electro-oxidation, and electro-coagulation. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.