Cultivation and application of Scenedesmus sp. strain UKM9 in palm oil mill effluent treatment for enhanced nutrient removal

Abstract Palm oil mill effluent (POME) contains nutrients such as carbon, nitrogen and phosphorus, and poses a threat to the environment especially if released untreated into water bodies. The phylum Chlorophyta contains microalgae from the genus Scenedesmus which are utilised as bioremediation agents. This study was conducted to evaluate the performance of Scenedesmus sp. UKM9 to remove chemical oxygen demand (COD) and nutrients (NH4+ and PO43−) from anaerobic POME by considering photoperiods and pollutant loading rates as environmental parameters. The results showed that the removal of COD (57% removal) and NH4+ (100% removal) was the highest in a 12h:12h (light:dark) photoperiod and a pollutant loading rate of 61.67 mg L−1 day−1 COD. Removal of PO43− (91% removal) was highest in a 16h:8h (light:dark) photoperiod and a pollutant loading rate of 11.67 mg L−1 day−1 COD. The removal of COD, nitrogen and phosphate occurred via the actions of microalgae through assimilation, bacteria through oxidation and precipitation through the formation of calcium phosphate complexes. These findings suggest that Scenedesmus sp. strain UKM9 is a potential bioremediation agent for treating POME.