A palm oil mill produces an average of 0.65 tons of raw palm oil mill effluent (POME) from every ton of FFB processed. POME is the main cause of environmental pollution due to its high acidity, high biological oxygen demand (BOD) and chemical oxygen demand (COD). Conventionally, anaerobic digestions in ponding systems or aerobic treatments are able to bring the BOD levels to below 100 mg L-1. Open steel tank digesters are used for tapping the biogas for power consumption. In Malaysia, certain areas have more stringent requirements (BOD of less than 20 mg L-1. Tertiary systems have been developed as new systems to provide effluent treatment in a more sustainable manner, as well as achieving the standards required by regulatory bodies. These include biological sequencing batch reactors, bio-filtration systems, systems with high aeration rates, activated sludge plants with aerobic reactors, bio-flow polishing plants, as well as membrane bioreactors. More palm oil plantations are investing into these technologies to harvest the biogas for fuel, and re-use other biomass materials for fertilizers, bio-composite materials, etc.