Simultaneous pollutant removal and PHB accumulation in simple anaerobic treatment of oily wastewater

Abstract

Oil and grease is one of the complicated pollutants to be removed due to oil-in-water emulsions content. This research is a treatment of oily wastewater from an edible oil factory. Addition to pollutant removal, accumulation of PHB (Polyhydroxybutyrate) is investigated simultaneously. Objectives of this research are to obtain the optimum operating conditions for removal of COD and oil, grease, and accumulation of PHB. Operating parameters are acclimatization period (3-7 days), pH (6-8) and sludge concentration (25-75%). Anaerobic treatment was conducted in a bottle and put on a shaker. The wastewater from the edible oil factory was fed to reactors as the substrate and the sludge was added. The result shows that this treatment removed 59.4-90.4% of COD and 65.3-85.2% of oil and grease. Overall PHB accumulation was 0.67-6.00% of PHB/VSS, which is much lower than the pure culture. The influence of pH (6-8) is less significant to both pollutant removal and PHB accumulation. The COD removal efficiency increased with the period of acclimatization and 5 days of acclimatization shows the highest yield of PHB. 50% sludge concentration shows the highest yield of PHB, which is 6.0% PHB/VSS.