Production of biogas from palm oil mill effluent: From laboratory scale to pilot scale

Abstract

An anaerobic closed system using a pilot-scale digester tank has been developed in recent years at Universit as Sumatera Utara. The system was built for the purpose of producing biogas from the fermentation process of palm oil industry effluent obtained from a wastewater treatment plant of the palm oil mills owned by Sisirau Mill. The digester tank used was a reactor with the type of continuous stirred tank reactor has a volume of 3,000 liters equipped with electrical heaters, insulators, and baffles in it. Feed input was performed intermittently so that the operation occurred continuously. In this research, a series of experiments at pilot scale were conducted with 616 liters palm oil mill effluent/day feed rate, the temperature of feed tank 70oC, digester tank temperature of 55oC, stirring rate of 37.5 rpm, and six days of hydraulic retention time. The results were compared to the results of laboratory scale, under the same condition and same POME. Based on the results, fermentation process at laboratory scale showed the better performance than at pilot scale. Therefore, the process should be improved in order to be scaled up to the higher scale.