Dairy Wastewater Treatment in Continuous Stirred Tank Electrochemical Reactor (Cster): Parametric Optimization and Kinetics

Abstract

Dairy wastewater has been a major environmental concern because of massive effluents characterized by high pollution load. This study reports the influence of initial pH (pHi), residence time (τ) and elapsed time (t) on the %COD removal (Y1) and specific energy consumed (kWh per kg of COD removed, Y2) for real dairy industry wastewater treatment in continuous stirred tank electrochemical reactor (CSTER) using aluminum electrodes. Central composite design (CCD) was applied for designing the experiments, analyzing the experimental data and optimizing the process parameters to maximizing Y1 and simultaneously minimizing Y2. Important design parameters for continuous reactors like steady state time (tS), mass transfer coefficient (km) and kinetic parameters were also estimated. Modified pseudo-first-order kinetic model was used for kinetic modeling with non-linear regression technique. Experiments conducted at optimal process parameters for CSTER (pHi= 4.5, τ= 141 min; t= 52 min) showed Y1 = 71.21%, Y2 = 4.