Enhanced peroxi-coagulation process for the treatment of anaerobically-treated palm oil mill effluent (POME)

Abstract

This study investigated the effectiveness of the peroxi-coagulation (PC) process in removing dissolved organic impurities from palm oil mill effluent (POME). Key experimental parameters assessed in this study included wastewater pH, electrolysis duration, and the dosage of H₂O₂. After a five-hour treatment period, maximum breakdown of organic contaminants and removal of suspended particles were achieved, with around 86 % of soluble COD (SCOD), 91 % of total COD (TCOD), 99 % of true colour, and 84 % of turbidity were removed under optimal operating conditions (pH 3 and external dosing of 31.09 mM H₂O₂). These outcomes can be attributed to two removal mechanisms: the predominant Fenton oxidation reaction at low pH which promoted effective •OH generation from the dosed H₂O_2, and the simultaneous coagulation activity by the electrochemically produced Fe(OH)₃ coagulant. This PC process was governed by the pseudo-first-order kinetic model, which achieved a maximum kinetic rate of 0.5321 min⁻¹ under ideal operating conditions. The estimated energy consumption for POME degradation ranged from 0.461 to 1.874 kWh per kg of COD reduced, indicating low electrical energy intake. These findings demonstrate the potential of the PC process as a pre- or post- treatment step that can enhance the removal of COD and pigmentation in integrated POME treatment systems.