Anodic oxidation of slaughterhouse wastewater on boron-doped diamond: process variables effect

Abstract

A non-sacrificial boron-doped diamond electrode was prepared in the laboratory and used as a novel anode for electrochemical oxidation of poultry slaughterhouse wastewater. This wastewater poses environmental threats as it is characterized by a high content of recalcitrant organics. The influence of several process variables, applied current density, initial pH, supporting electrolyte nature, and concentration of electrocoagulant, on chemical oxygen demand (COD) removal, color removal, and turbidity removal was investigated. Results showed that raising the applied current density to 3.83 mA/cm² has a positive effect on COD removal, color removal, and turbidity removal. These parameters increased to 100%, 90%, and 80% respectively. A low pH of 5 favored oxidants generation and consequently increased the COD removal percentage to reach 100%. Complete removal of COD had occurred in the presence of NaCl (1%) as supporting electrolyte. Na₂SO₄ demonstrated lower efficiency than NaCl in terms of COD removal. The COD decay kinetics follows the pseudo-first-order reaction. The simultaneous use of Na₂SO₄ and FeCl₃ decreased the turbidity in wastewater by 98% due to electrocoagulation.