Shipyard wastewater treatment using electrocoagulation-sedimentation process: RSM optimization

The use of electrocoagulation-sedimentation is one of the advanced oxidation methods can be used for water and wastewater treatment. The aim of this study was optimization of electrocoagulation-sedimentation in treatment of wastewater from shipyard using central composite design and response surface methodology. The samples of this experimental study were collected from shipyard factory in Iran monthly during two seasons. Measuring of the study parameters, were carried out based on the standard reference method for experiments in water and wastewater. To optimize of the removal of COD, color, turbidity and TSS was conducted using central composite design and response surface methodology. The results showed the independence variables including pH and potassium ferrate concentration and their interaction relationship had a significant effect on the removal of chemical oxygen demand (COD), methylene blue active substances (MBAS), and turbidity. It was optimized using the critical operational parameters such as applied current (۱-۲ A), electrolysis time (۳۰-۹۰ min) and pH (۵-۹). The removal efficiencies of COD, turbidity and MBAS were found to be ۹۴.۵%, ۹۵% and ۹۵.۲% in the optimal condition, respectively. ۴.۲ kWh/m۳ and ۰.۲۳ US$/m۳ were determined for energy consumption and costs, respectively. Overall, this hybrid treatment system is proven as an economic and environmentally friendly technique to remove high contaminants from shipyard wastewater. Central composite design (CCD) and response surface methodology (RSM) was a good method for experimental design and to optimize of the pollutants removal in this study.