Electrocoagulation Treatment of Abattoir Wastewater for Reuse Potential in Sokoto State

Abattoir operations in Sokoto State, North West Nigeria, discharge large volumes of high-strength wastewater rich in blood, faeces, and organic solids into open drains and irrigation canals, posing public health risks. This study evaluates electrocoagulation using aluminium electrodes as a treatment technology for abattoir wastewater from the Sokoto Central Abattoir, with a focus on achieving effluent quality suitable for non-potable reuse in agricultural irrigation. A batch electrocoagulation reactor with parallel aluminium electrode pairs was operated at applied current densities of 5 to 30 mA/cm2, operating times of 10 to 90 minutes, and initial pH values of 5 to 9. Response surface methodology was employed to optimise operating conditions for maximum chemical oxygen demand, total suspended solids, and colour removal. Raw wastewater characterisation revealed chemical oxygen demand of 6,840 mg/L, total suspended solids of 3,210 mg/L, and turbidity of 420 NTU, all substantially exceeding NESREA discharge standards. Under optimised conditions of 20 mA/cm2 current density, 60 minutes treatment time, and pH 7, chemical oxygen demand removal reached 89.7%, total suspended solids removal was 94.3%, and colour removal was 97.8%. Treated effluent met WHO irrigation water quality guidelines for faecal coliforms after secondary disinfection with chlorine. Energy consumption was estimated at 4.8 kWh/m3, which is economically competitive with conventional coagulation. Electrocoagulation is recommended as a decentralised treatment solution for abattoirs in Sokoto State. Keywords: electrocoagulation, abattoir wastewater, Sokoto State, COD removal, agricultural reuse