Novel approach for removal of DOC in samples of raw water using electrocoagulation for drinking water treatment

This study evaluates the performance of a laboratory-scale direct current electrocoagulation reactor for the removal of natural organic matter as a secondary treatment step following chemical coagulation in surface water treatment. The chemical coagulation conditions were pre-optimized and electrocoagulation was operated in a batch mode using mild steel or aluminium sacrificial electrodes. Current density, initial pH and metal doses were optimized to assess removal efficiency and residual metal concentrations in the treated water. The optimal conditions for electrocoagulation were identified at pH 4.75–5.5, inter electrode distance of 0.4 cm, current density of 3.1 mA/cm². Based on total organic carbon measurements, the highest removal efficiencies were 38% for mild steel electrode (dose 8.5 mg/L at initial pH 4.75) and 19% for aluminium electrode (dose 8.5 mg/L at initial pH 6). The specific energy consumption for treating of 1 m³ was 0.322 kWh when using the mild steel electrode. The results demonstrate that direct current electrocoagulation, as a secondary treatment, can achieve effective total organic carbon removal while maintaining low residual metal concentrations, thereby meeting drinking water safety standards.