Kinetics models of COD degradation,biomass growth of the anoxic-oxic ( A/O) system as well as NH3-N degradation in aerobic phase were presented according to the mass balance theory,reaction-diffusion theory and Fick l...Kinetics models of COD degradation,biomass growth of the anoxic-oxic ( A/O) system as well as NH3-N degradation in aerobic phase were presented according to the mass balance theory,reaction-diffusion theory and Fick law. Then these models were testified by comparson with experimental results. It is demonstrated that the variation trends of theoretical and experimental values for COD degradation and biomass growth are similar. The deviation rate between theoretical and experimental values is always under 20% even it increases along with the fluctuation of influent organic loading. In terms of NH3-N degradation,nitrification can also be well simulated by the model as the substrates of influent are sufficient. It indicates that the model can accurately reflect the reaction in hybrid A/O process. Models presented herein provide a theoretical basis for the design, operation and control of hybrid A/O process.展开更多
In this study,an anaerobic/anoxic/oxic(A^(2)O)wastewater treatment process was implemented to treat domestic wastewater with short-term atrazine addition.The results provided an evaluation on the effects of an acciden...In this study,an anaerobic/anoxic/oxic(A^(2)O)wastewater treatment process was implemented to treat domestic wastewater with short-term atrazine addition.The results provided an evaluation on the effects of an accidental pollution on the operation of a wastewater treatment plant(WWTP)in relation to Chemical Oxygen Demand(COD)and biological nutrient removal.Domestic wastewater with atrazine addition in 3 continuous days was treated when steady biological nutrient removal was achieved in the A^(2)O process.The concentrations of atrazine were 15,10,and 5 mg%L–1 on days 1,2 and 3,respectively.The results showed that atrazine addition did not affect the removal of COD.The specific NH4þoxidation rate and NO3–reduction rate decreased slightly due to the short-term atrazine addition.However,it did not affect the nitrogen removal due to the high nitrification and denitrification capacity of the system.Total nitrogen(TN)removal was steady,and more than 70%was removed during the period studied.The phosphorus removal rate was not affected by the short-term addition of atrazine under the applied experimental conditions.However,more poly-hydroxy-alkanoate(PHA)was generated and utilized during atrazine addition.The results of the oxygen uptake rate(OUR)showed that the respiration of nitrifiers decreased significantly,while the activity of carbon utilizers had no obvious change with the atrazine addition.Atrazine was not removed with the A^(2)O process,even via absorption by the activated sludge in the process of the short-term addition of atrazine.展开更多
To explore the applicability of anoxic-oxic (A/O) activated sludge process for petrochemical wastewater treatment,the relationship between bacterial community structure and pollutants loading/removal efficiencies was ...To explore the applicability of anoxic-oxic (A/O) activated sludge process for petrochemical wastewater treatment,the relationship between bacterial community structure and pollutants loading/removal efficiencies was investigated by gas chromatograph-mass spectrometry (GC-MS),polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and other conventional techniques.It showed that when the concentrations of the influent chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) were 420～560mg/L and 64～100mg/L,respectively,the corresponding average effluent concentra-tions were 160mg/L and 55mg/L,which were 1.6 and 2.2times higher than those of the national standards in China,respectively,demonstrating the inefficient performances of A/O process.Analysis of GC-MS indicated that refractory pollutants were mainly removed by sludge adsorption,but not by biodegradation.PCR-DGGE profile analysis suggested that the biological system was species-rich,but there was apparent succession of the bacterial community structure in different locations of the A/O system.Variations of bacterial community structure and pollutant loadings had obvious influences on pollutants removal efficiencies.Thus,A/O process was inapplicable for the treatment of complicated petrochemical wastewater,and strategies such as the reinforcement of pre-treatment and two-stage A/O process were suggested.展开更多
基金Sponsored by the National Water Plan (2008ZX07207-005-03)
文摘Kinetics models of COD degradation,biomass growth of the anoxic-oxic ( A/O) system as well as NH3-N degradation in aerobic phase were presented according to the mass balance theory,reaction-diffusion theory and Fick law. Then these models were testified by comparson with experimental results. It is demonstrated that the variation trends of theoretical and experimental values for COD degradation and biomass growth are similar. The deviation rate between theoretical and experimental values is always under 20% even it increases along with the fluctuation of influent organic loading. In terms of NH3-N degradation,nitrification can also be well simulated by the model as the substrates of influent are sufficient. It indicates that the model can accurately reflect the reaction in hybrid A/O process. Models presented herein provide a theoretical basis for the design, operation and control of hybrid A/O process.
基金the National Key Science and Technology Special Projects(No.2008ZX07209-003)Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Municipality(No.PHR20090502).
文摘In this study,an anaerobic/anoxic/oxic(A^(2)O)wastewater treatment process was implemented to treat domestic wastewater with short-term atrazine addition.The results provided an evaluation on the effects of an accidental pollution on the operation of a wastewater treatment plant(WWTP)in relation to Chemical Oxygen Demand(COD)and biological nutrient removal.Domestic wastewater with atrazine addition in 3 continuous days was treated when steady biological nutrient removal was achieved in the A^(2)O process.The concentrations of atrazine were 15,10,and 5 mg%L–1 on days 1,2 and 3,respectively.The results showed that atrazine addition did not affect the removal of COD.The specific NH4þoxidation rate and NO3–reduction rate decreased slightly due to the short-term atrazine addition.However,it did not affect the nitrogen removal due to the high nitrification and denitrification capacity of the system.Total nitrogen(TN)removal was steady,and more than 70%was removed during the period studied.The phosphorus removal rate was not affected by the short-term addition of atrazine under the applied experimental conditions.However,more poly-hydroxy-alkanoate(PHA)was generated and utilized during atrazine addition.The results of the oxygen uptake rate(OUR)showed that the respiration of nitrifiers decreased significantly,while the activity of carbon utilizers had no obvious change with the atrazine addition.Atrazine was not removed with the A^(2)O process,even via absorption by the activated sludge in the process of the short-term addition of atrazine.
基金Project supported by the National Basic Research Program(973)of China(No.2004CB418505)the Science and Technology Devel-opment Program of Heilongjiang Province(No.CC05S301),China
文摘To explore the applicability of anoxic-oxic (A/O) activated sludge process for petrochemical wastewater treatment,the relationship between bacterial community structure and pollutants loading/removal efficiencies was investigated by gas chromatograph-mass spectrometry (GC-MS),polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and other conventional techniques.It showed that when the concentrations of the influent chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) were 420～560mg/L and 64～100mg/L,respectively,the corresponding average effluent concentra-tions were 160mg/L and 55mg/L,which were 1.6 and 2.2times higher than those of the national standards in China,respectively,demonstrating the inefficient performances of A/O process.Analysis of GC-MS indicated that refractory pollutants were mainly removed by sludge adsorption,but not by biodegradation.PCR-DGGE profile analysis suggested that the biological system was species-rich,but there was apparent succession of the bacterial community structure in different locations of the A/O system.Variations of bacterial community structure and pollutant loadings had obvious influences on pollutants removal efficiencies.Thus,A/O process was inapplicable for the treatment of complicated petrochemical wastewater,and strategies such as the reinforcement of pre-treatment and two-stage A/O process were suggested.
