Investigation of slaughterhouse wastewater treatment by electrochemical oxidation process using different electrodes

Abstract In this study, the treatment of slaughterhouse wastewater by electrochemical oxidation process was investigated. The effects of electrode type, chemical pre-treatment, initial pH, and potential applied to the electrodes were investigated. The highest chemical oxygen demand and color removal were obtained as 91% and 97.8%, respectively, when stainless steel was used as the anode and cathode electrodes at the original pH value of 7.16 and the COD removal efficiency decreased in more acidic and basic conditions. Chemical pre-treatment improved COD and color removal efficiencies using boron doped diamond electrodes at the anode. In case of using different electrodes for raw slaughterhouse wastewater, specific energy consumption values were determined in the range of 3.7–6.1 kW.h/kg COD, and in pre-treated slaughterhouse wastewater, specific energy consumption values were determined in the range of 9.3–37.7 kW.h/kg COD. From these experimental results, it is seen that chemical pre-treatment (coagulation-flocculation using aluminium sulphate) has a negative contribution to specific energy consumption. When a potential in the range of 5–15 V was applied to stainless steel electrodes, no significant change was observed in COD removal efficiency, however, it was determined that specific energy consumption increased by 2–3 times. As a result, it was determined that the electrochemical oxidation process can be applied in the treatment of slaughterhouse wastewater, either alone or in combination with different processes, depending on the final use of the effluent, and that especially by using stainless steel electrodes, both costs can be reduced and effective color and COD removal can be achieved.