By-products of palm oil mill effluent treatment plant – A step towards sustainability

The current wastewater treatment system for palm oil mill effluent (POME) regularly fails to treat the effluent efficiently. The growing demand for palm oil has caused a substantial increase in the generation of POME. To meet the discharge limit proposed by the Department of the Environment, the POME must be treated effectively before being released into the receiving water bodies. The open pond system is presently being used to treat the POME because the open pond system is cheap and less maintenance is required. However, the failure of this technique in the current scenario has spurred the research into new technologies to explore their applicability in treating POME. Although the discovery of new technologies is commendable, the financial infeasibility of these new treatment techniques has stagnated their progress. In this work, a role for the by-products of the treatment systems in implementing the new technologies with return of investment has been revealed. A thorough review of the characteristics and recent trends for producing polyhydroxyalkanoate (PHA), a by-product, is also discussed in this work. Moreover, the opportunities available to further enhance the production of PHA in POME wastewater have been addressed and are presented in this work. Production of biohydrogen, another by-product, is also discussed in this review. In a nutshell, the enhancement of PHA production coupled with biohydrogen production as a by-product may provide a new dimension to the POME treatment plant by generating revenue. Production of PHA and biohydrogen from POME contributes significantly towards the cause of sustainability.