Bacterial strain Enterobacter aerogenes TJ-D capable of utilizing 2-methylquinoline as the sole carbon and energy source was isolated from acclimated activated sludge under denitrifying conditions. The ability to degr...Bacterial strain Enterobacter aerogenes TJ-D capable of utilizing 2-methylquinoline as the sole carbon and energy source was isolated from acclimated activated sludge under denitrifying conditions. The ability to degrade 2-methylquinoline by E. aerogenes TJ-D was investigated under denitrifying conditions. Under optimal conditions of temperature （35°C） and initial pH 7, 2-methylquinoline of 100 mg/L was degraded within 176 hr. The degradation of 2-methylquinoline by E. aerogenes TJ-D could be well described by the Haldane model （R 2 〉 0.91）. During the degradation period of 2-methylquinoline （initial concentration 100 mg/L）, nitrate was almost completely consumed （the removal efficiency was 98.5%）, while nitrite remained at low concentration （〈 0.62 mg/L） during the whole denitrification period. 1,2,3,4-Tetrahydro-2-methylquinoline, 4-ethyl-benzenamine, N-butyl-benzenamine, N-ethyl-benzenamine and 2,6-diethyl-benzenamine were metabolites produced during the degradation. The degradation pathway of 2-methylquinoline by E. aerogenes TJ-D was proposed. 2-Methylquinoline is initially hydroxylated at C-4 to form 2-methyl-4-hydroxy-quinoline, and then forms 2-methyl-4-quinolinol as a result of tautomerism. Hydrogenation of the heterocyclic ring at positions 2 and 3 produces 2,3-dihydro-2-methyl-4-quinolinol. The carbon-carbon bond at position 2 and 3 in the heterocyclic ring may cleave and form 2-ethyl-N-ethyl-benzenamine. Tautomerism may result in the formation of 2,6-diethyl-benzenamine and N-butyl-benzenamine. 4- Ethyl-benzenamine and N-ethyl-benzenamine were produced as a result of losing one ethyl group from the above molecules.展开更多
Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal(BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, a...Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal(BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, anaerobic anoxic oxic(A2 /O). The ASM2 d implemented on the platform of WEST2011 software and the Bio Win activated sludge/anaerobic digestion(AS/AD) models were used in this study with the aim of consistently achieving the designed effluent criteria at a low operational cost. Four ASM2 d parameters(the reduction factor for denitrification(η NO3, H), the maximum growth rate of heterotrophs( μ H), the rate constant for stored polyphosphates in PAOs(q pp), and the hydrolysis rate constant(k h)) were adjusted. Whereas three Bio Win parameters(aerobic decay rate(b H), heterotrophic dissolved oxygen(DO) half saturation(K OA), and Y P /acetic) were adjusted. Calibration of the two models was successful; both models have average relative deviations(ARD) less than 10% for all the output variables. Low effluent concentrations of nitrate nitrogen(N-NO3), total nitrogen(TN), and total phosphorus(TP) were achieved in a full-scale BNR treatment plant having low influent chemical oxygen demand(COD) to total Kjeldahl nitrogen(TKN) ratio(COD/TKN). The effluent total nitrogen and nitrate nitrogen concentrations were improved by 50% and energy consumption was reduced by approximately 25%, which was accomplished by converting the two-pass aerobic compartment of the plug-flow bioreactor to anoxic reactors and being operated in an alternating mode. Findings in this work are helpful in improving the operation of wastewater treatment plant while eliminating the cost of external carbon source and reducing energy consumption.展开更多
基金supported by the National Natural Science Foundation of China(No.50108009)the Program for New Century Excellent Talents in University(No.NCET-08-0403)the Fundamental Research Funds for the Central Universities(No.2012KJ019)
文摘Bacterial strain Enterobacter aerogenes TJ-D capable of utilizing 2-methylquinoline as the sole carbon and energy source was isolated from acclimated activated sludge under denitrifying conditions. The ability to degrade 2-methylquinoline by E. aerogenes TJ-D was investigated under denitrifying conditions. Under optimal conditions of temperature （35°C） and initial pH 7, 2-methylquinoline of 100 mg/L was degraded within 176 hr. The degradation of 2-methylquinoline by E. aerogenes TJ-D could be well described by the Haldane model （R 2 〉 0.91）. During the degradation period of 2-methylquinoline （initial concentration 100 mg/L）, nitrate was almost completely consumed （the removal efficiency was 98.5%）, while nitrite remained at low concentration （〈 0.62 mg/L） during the whole denitrification period. 1,2,3,4-Tetrahydro-2-methylquinoline, 4-ethyl-benzenamine, N-butyl-benzenamine, N-ethyl-benzenamine and 2,6-diethyl-benzenamine were metabolites produced during the degradation. The degradation pathway of 2-methylquinoline by E. aerogenes TJ-D was proposed. 2-Methylquinoline is initially hydroxylated at C-4 to form 2-methyl-4-hydroxy-quinoline, and then forms 2-methyl-4-quinolinol as a result of tautomerism. Hydrogenation of the heterocyclic ring at positions 2 and 3 produces 2,3-dihydro-2-methyl-4-quinolinol. The carbon-carbon bond at position 2 and 3 in the heterocyclic ring may cleave and form 2-ethyl-N-ethyl-benzenamine. Tautomerism may result in the formation of 2,6-diethyl-benzenamine and N-butyl-benzenamine. 4- Ethyl-benzenamine and N-ethyl-benzenamine were produced as a result of losing one ethyl group from the above molecules.
基金Supported by the College of Scientific Innovation Significant Cultivation Fund Financing Projects(No.708047)the Key Special Program for the Pollution Control(No.2012ZX07101-003)+1 种基金the National Natural Science Foundation of China(No.51208173)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Two mathematical models were used to optimize the performance of a full-scale biological nutrient removal(BNR) activated treatment plant, a plug-flow bioreactors operated in a 3-stage phoredox process configuration, anaerobic anoxic oxic(A2 /O). The ASM2 d implemented on the platform of WEST2011 software and the Bio Win activated sludge/anaerobic digestion(AS/AD) models were used in this study with the aim of consistently achieving the designed effluent criteria at a low operational cost. Four ASM2 d parameters(the reduction factor for denitrification(η NO3, H), the maximum growth rate of heterotrophs( μ H), the rate constant for stored polyphosphates in PAOs(q pp), and the hydrolysis rate constant(k h)) were adjusted. Whereas three Bio Win parameters(aerobic decay rate(b H), heterotrophic dissolved oxygen(DO) half saturation(K OA), and Y P /acetic) were adjusted. Calibration of the two models was successful; both models have average relative deviations(ARD) less than 10% for all the output variables. Low effluent concentrations of nitrate nitrogen(N-NO3), total nitrogen(TN), and total phosphorus(TP) were achieved in a full-scale BNR treatment plant having low influent chemical oxygen demand(COD) to total Kjeldahl nitrogen(TKN) ratio(COD/TKN). The effluent total nitrogen and nitrate nitrogen concentrations were improved by 50% and energy consumption was reduced by approximately 25%, which was accomplished by converting the two-pass aerobic compartment of the plug-flow bioreactor to anoxic reactors and being operated in an alternating mode. Findings in this work are helpful in improving the operation of wastewater treatment plant while eliminating the cost of external carbon source and reducing energy consumption.
