Organic Substances Reduction in Palm Oil Mill Effluent (POME) After Cultivation with Locally Isolated Microalgae

Abstract

This work aims to study the ability of locally isolated microalgae to reduce organic substances in Palm Oil Mill Effluent (POME) which was carried out on a laboratory scale. Inoculum with a concentration of 20% was cultivated into POME media with various concentration of LP₁₀₀ (without dilution), LP₇₅ (25% dilution), and LP₅₀ (50% dilution) using aeration and continuous lighting for 15 days in vessels with a lighting intensity of 1300 lux. Biomass of microalgae were observed daily and analyzed in dry weight by means of spectrophotometry using 624 nm wavelength to get their growth by determining the content of algae biomass. The reduction of organic substances in POME was observed by measuring the COD, BOD phosphate, ammonium, nitrate, and fatty oil parameters every 3 hours with the standard method. Results show that the growth of microalgae occurred well in POME media at LP₇₅ and LP₅₀ concentrations with inoculum concentration of 20% under 1300 lux lighting intensity conditions with a continuous 24-hour lighting and aeration cycle that obtained biomass content of  0.92 and 1.08 g-DW/L, respectively. The presence of microalgae in POME at concentration of LP₇₅ for 12 days reduced organic substances and nutrients reaching 80.74% - 99.70%. Some parameters that were reduced include BOD (99.35%), COD (89.57%), TSS (89.68%), Phosphate (97.70%), Ammonium (95.08%), Fatty Oil (99.70%), and Nitrates (80.74%). This study concludes that locally isolated microalgae have ability to treat POME safely for environment and as a growing medium for microalgae followed by a decrease in organic substances.