Evaluation of POME-biogas production system for eco-efficiency improvement in palm oil mills

The release of massive amount of methane gas into the atmosphere from the palm oil mill effluent (POME) treatment ponds has made many realize that the industry must be sustainable if its national and international market is to be safeguarded. Malaysian palm oil millers have been encouraged to implement biogas facilities in the mills to capture the methane gas and used it for power generation. However, different configurations of biogas capture technology and biogas utilization pathway currently adopted in palm oil mills may lead to a great variance of outcomes from both environmental and economic point of views. This situation could subsequently affect the selection and decision on an appropriate anaerobic digestion (AD) system among the palm oil industry players. The objectives of this study are 1) to evaluate the environmental and economic performance of Malaysian palm oil mills with current POME-biogas AD systems using Life Cycle Assessment (LCA) and Environmental Life Cycle Costing (ELCC), and 2) to provide best management option of palm oil operations associated with feasible biogas configuration for a better decision making among the palm oil industry players using Eco-costs Value Ratio (EVR) model. Several methodologies were used in this study that included LCA, ELCC and EVR model. The four imperative steps in the LCA framework were conducted: goal and scope definition, Life Cycle Inventory (LCI) analysis, Life Cycle Impact Assessment (LCIA) and interpretation. As ELCC is known as the economic counterpart and complimentary to LCA, most of the steps remain unchanged except for the impact assessment. This step was covered by a financial appraisal through capital budgeting analysis, of which the future values for net present value (NPV), internal rate of return (IRR), benefit cost ratio (BCR) and payback period (PBP) of the interest palm oil mills were analyzed. The acquired information from palm oil mills was collected through a specific data collection sheet. Results obtained from LCA and ELCC were used for EVR model. From the environmental point of view, a total of 11 impact categories have been determined in palm oil mills. Of these, respiratory inorganics, climate change and fossil fuels depletion are identified as the most significant impact categories. The contributing factors to these impact categories are primarily derived from the application of chemical fertilizers in plantations, highly energy (diesel)-dependent transportation and machinery