Biodegradation of Polycyclic Aromatic Hydrocarbon in Diesel

Abstract

This study was aims to investigating the optimum condition to treat naphthalene by mixed culture of diesel degradation bacteria including Achromobacterinsolitus (D2), Candida spp (D5), and Xanthobactorpolyaromaticiyorans (D6). The experiment was operating in varied ratio of synthetic solution and diesel with surfactant at 0:100, 20:80, 40:60, 60:40, 80:20 and 100:0. The experiment was operated in aeration mode with DO concentration above 2 mg/L at room temperature. The obtained results showed that the mixed culture bacteria used in this study was high efficiency to remove COD from wastewater (96-100%). Thus, it can be indicated that the ratio of N:D did not affect the degradation of COD by mixed culture bacteria but affect the degradation time. The different of nutrient added was affected the biomass growth in reactor. The highest biomass yield was found in batch E with 20% of synthetic solution and 80% of diesel and surfactant. It can be indicated that this ratio was optimal for bacteria for growth up and used for the other experiment. The optimal initial concentration of naphthalene was investigated by varied the initial naphthalene concentration at 20, 40, 60, 80 and 100 mg/L. The concentration of naphthalene was detected by HPLC. The result showed that the different initial concentration of naphthalene was affected degradation time and biomass growth. The optimal initial concentration of naphthalene was 20 mg/L which can apply in membrane bioreactor to degrade naphthalene.