Improving the Quality of Anaerobically-Pretreated Palm Oil Mill Effluent Using Electrocoagulation

Abstract

The palm oil extraction process generates large amounts of effluents with very high concentrations of pollutants, even though they are subjected to anaerobic pretreatment. Further treatment is needed in order to ensure that the effluent is safe for disposal or reuse. This work was conducted to evaluate the performance of an electrocoagulation process in removing pollutants from the anaerobically-pretreated palm oil mill effluent. A 1000 ml beaker glass equipped with a magnetic stirrer was used as an electrocoagulation reactor with four plates of aluminum electrode @ 12×2 cm and an effective area of 0.1 m 2 arranged in a bipolar configuration. The experiments run in a batch mode were carried out at various voltage levels and contact times, namely 10, 15, and 20 V for 15, 30, 45 and 60 min. The level of pollutant removal and electrical energy consumption were determined. The electrocoagulation process at 15 V for 30 min produced the highest level of pollutant removal for TSS, turbidity, color, COD, and BOD 5 , i.e. 90%, 86%, 93%, 87%, and 97%, respectively. The estimated operating costs for these process conditions are 1.48 USD/m 3. A second order empirical model was developed to describe the TSS removal in the POME electrocoagulation process. The electrocoagulation with aluminum electrodes can significantly reduce various types of pollutants of anaerobically-pretreated POME, such as TSS, turbidity, color, COD, and BOD 5. The estimated cost of EC operation is cheaper than the chemical coagulation process.