The input voltage and reaction time from dielectric barrier discharge treatment affect the biogas production and the reduction of pollutants in palm oil mill effluent

The performance of dielectric barrier discharge (DBD) treatment was investigated to demonstrate the potential use for palm oil mill effluent (POME) treatment in terms of biogas production and chemical oxygen demand (COD) and total solids (TS) reduction. The treatment was undergone by applying the different input voltage of 15, 20 and 25 kV for 3 hours of reaction time with a frequency of 50 Hz in a DBD glass reactor. The experiment was carried out at room temperature and under normal air pressure. The results showed that the biogas concentration increased with the increase of input voltage. The concentration of hydrogen, methane, carbon monoxide and carbon dioxide increased from the initial values by 85%, 10%, 33% and 99%, respectively, for the input voltage of 15 kV. Biogas concentration also increased with the prolonged reaction time, indicated that more energy was supplied to convert the organic pollutants to form biogas. The high reduction of pollutants in POME was achieved to 48% for COD and 42% for TS when the input voltage increased to 25 kV. The low reduction of COD and TS was probably caused by the high pH value of POME used in this study, resulting a poor degradation and agglomeration of COD and TS.