Electrocoagulation process for oily wastewater treatment and optimization using response surface methodology

Electrocoagulation technique using aluminum electrodes in a batch bi-polar system was investigated to determine the efficiency of removing oil from oily wastewater. The Box-Behnken design was utilized to optimize conditions and the effects of four independent factors, including oil volume (X-1), temperature (X-2), initial pH (X-3), and treatment time (X-4),-were examined to investigate turbidity recovery and conductivity changes. The significant independent variables and their interactions were assessed using ANOVA. The optimal operating conditions for turbidity removal were obtained at an oil volume of 10 ml L-1, a temperature of 28 degrees C, an initial pH of 4, and a coagulation time of 90 min. The results revealed that turbidity removal and conductivity changes are enhanced significantly with increasing treatment time and decreasing oil volume. The application of the treatment process under optimal operating conditions allows promising removal efficiencies of 97.3%, and 73.4% for turbidity and conductivity, respectively. Also, the treated wastewater showed remarkable changes in removal efficiencies of the main oily wastewater pollution loads for COD, NO2, PO4, DO, and BOD. The economic study indicated that oily wastewater treatment by electrocoagulation is a very cost-effective technique.