Baseline study of methane emission from anaerobic ponds of palm oil mill effluent treatment

The world currently obtains its energy from the fossil fuels such as oil, natural gas and coal. However, the international crisis in the Middle East, rapid depletion of fossil fuel reserves as well as climate change have driven the world towards renewable energy sources which are abundant, untapped and environmentally friendly. Malaysia has abundant biomass resources generated from the agricultural industry particularly the large commodity, palm oil. This paper will focus on palm oil mill effluent (POME) as the source of renewable energy from the generation of methane and establish the current methane emission from the anaerobic treatment facility. The emission was measured from two anaerobic ponds in Felda Serting Palm Oil Mill for 52 weeks. The results showed that the methane content was between 35.0% and 70.0% and biogas flow rate ranged between 0.5 and 2.4 L/min/m2. Total methane emission per anaerobic pond was 1043.1 kg/day. The total methane emission calculated from the two equations derived from relationships between methane emission and total carbon removal and POME discharged were comparable with field measurement. This study also revealed that anaerobic pond system is more efficient than open digesting tank system for POME treatment. Two main factors affecting the methane emission were mill activities and oil palm seasonal cropping

Start-up operation of semi-commercial closed anaerobic digester for palm oil mill effluent treatment

Palm oil mill effluent (POME) generated through oil extraction processes has a great impact to the industry. Owing to its chemical properties and volume of discharge, a large wastewater treatment is required to reduce the polluting strength of POME before safe discharge. Thus the selection and performance of the treatment system determine the quality of wastewater discharge. An improved 500 m3 closed digester was constructed to evaluate the POME treatment efficiency for a comparison study with the open digester system. Prior to actual treatment, the closed digester was under gone a start-up operation which is crucial to the overall POME treatment. During the start-up operation, the system demonstrated a remarkable performance of high COD removal efficiency (up to 97%) and satisfactory ratio of volatile fatty acids: alkalinity (VFA:Alk) between 0.1 and 0.3. The lowest hydraulic retention time (HRT) at 17 days was achieved in less than 3 months. Initial biogas production rate was high, however declined during higher organic loading rates (OLR). This was attributed to sudden variations of POME chemical properties that affect the system stability. The start-up strategy used for this process has achieved its objectives by creating an active microbial population which was expressed in terms of key performance parameters such as % COD removal efficiency, pH, VFA:Alk and HRT