Aerobic biodegradation of gasoline oxygenates MTBE and TBA

MTBE degradation was investigated using a continuously stirred tank reactor (CSTR) with biomass retention (porous pot reactor) operated under aerobic conditions. MTBE was fed to the reactor at an influent concentration of 150 mg/l (1.70 mmol/l). A second identical reactor was operated as a control u nder the same conditions with the addition of 2.66 g/l of sodium azide, to kill any biological activity. Results from these experiments suggest that b iomass retention is critical to the degradation of MTBE. The rate of MTBE r emoval was shown to be related to the VSS concentration. MTBE removal excee ded 99.99% when the VSS concentration in the reactor was over 600 mg/l. Res ults obtained from batch experiments conducted on mixed liquor samples from the porous pot reactor indicate that the individual rates of biodegradatio n of MTBE and TEA were higher for initial concentrations of 15 mg/l than fo r concentrations of 5 mg/l. The presence of TEA at tower concentrations did not effect the rate of MTBE degradation, however higher concentrations of TEA did reduce the rate of biodegradation of MTBE. Denaturing Gradient Gel Electrophoresis (DGGE) analysis reveals that the culture consisted of a com munity of bacterial organisms of about 6 species.