Three pure bacterial cultures degrading methyl t-butyl ether (MTBE) were isolated from activated sludge and fruit of the Gingko tree. They have been classified as belonging to the genuses Methylobacterium, Rhodococcus, and Arthrobacter. These cultures degraded 60 ppm MTBE in 1-2 weeks of incubation at 23-25 degrees C. The growth of the isolates on MTBE as sole carbon source is very slow compared with growth on nutrient-rich medium. Uniformly-labeled [14C]MTBE was used to determine 14CO2 evolution. Within 7 days of incubation, about 8% of the initial radioactivity was evolved as 14CO2. These strains also grow on t-butanol, butyl formate, isopropanol, acetone and pyruvate as carbon sources. The presence of these compounds in combination with MTBE decreased the degradation of MTBE. The cultures pregrown on pyruvate resulted in a reduction in 14CO2 evolution from [14C]MTBE. The availability of pure cultures will allow the determination of the pathway intermediates and the rate-limiting steps in the degradation of MTBE.

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In this study, the characteristics partial nitrifying biomass in the Sequencing Batch Reactor (SBR) for aerobic granulation was investigated based on experiments and simulation modeling. The reactor operation was carried out at high concentration of ammonium (200~850 mg N/L) which favored Ammonia-Oxidizing Bacteria (AOB) growth over Nitrite-Oxidizing Bacteria (NOB) growth. In partial nitrifying granulation, both Free Ammonia (FA) and Free Nitrous Acid (FNA) simultaneously influenced the activity of NOB much more than that of AOB. According to the simulation results, thE Dissolved Oxygen (DO) concentration and oxygen affinity affect the growth competition and can influence the species that are predominant in the reactor. Both AOB and NOB can have growth potential under toxicants (FA and FNA) inhibition and limited oxygen condition. The AOB growth forms inner part of granule's biofilm, but the NOB growth does not engage in the formation of granules.

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A thermal alkali pre-treatment anaerobic digestion elutriated phased treatment (T-ADEPT) was developed by combining the thermal-alkali pre-treatment (TAP) with the anaerobic digestion elutriated phased treatment (ADEPT) for the anaerobic codigestion of food waste (FW) and dewatered sewage sludge (SS). To improve the solubilization efficiency and methane yield, the optimal conditions for the TAP and ADEPT processes were identified. The soluble chemical oxygen demand (SCOD) solubilization, volatile suspended solids (VSS) reduction rate, volatile fatty acid (VFA) concentration, and methane yield all improved with our proposed process. The variations of the physical properties of the FW and SS mixtures confirm that the TAP process enhances the solubilization of organic matter. The methane yield of the T-ADEPT process was 0.368 L CH 4 /g VS added , which was approximately 1.4 and 1.2 times higher than the values for a conventional two-stage anaerobic digestion (AD) process and an AD process with pre-treatment, respectively. These results show that the application of TAP and ADEPT processes using granular sludge can be an effective approach for the anaerobic co-digestion of FW and SS. The proposed technique is more tolerant of the inhibitory effects of high concentrations of toxic compounds compared with a conventional two-stage AD system. Modifying a conventional anaerobic digester has the potential to deliver low hydraulic retention times (HRTs) and high organic loading rates (OLRs).