Treatment of coffee wastewater by a hybrid system of electrocoagulation and continuous ozonation

Abstract

    Coffee processing wastewater was treated by a combined system of electrocoagulation and continuous ozonation with suitable operating conditions, including pH 6, current intensity 2,5 A, conductivity 2,5 mS/cm, water retention time 16,7 minutes in the electrocoagulation tank, and in the ozonation reaction column: pH 5, 2 liters of ozone/minute, dosage 10 g/h, HRT 60 min. The treatment efficiency of the system was impressive, removing COD (Chemical Oxygen Demand), color over 92% and TSS (Total Suspended Solids) reaching over 62%. The COD, color, and TSS remaining were 29 mg/L, 45 Pt-Co, and 38 mg/L, respectively, less than column A QCVN 40:2025/BTNMT.