The objective of this study was to investigate the nitritation performance in a biofilm reactor for treating domestic wastewater.The reactor was operated in continuous feed mode from phases 1 to 3.The dissolved oxygen...The objective of this study was to investigate the nitritation performance in a biofilm reactor for treating domestic wastewater.The reactor was operated in continuous feed mode from phases 1 to 3.The dissolved oxygen(DO)was controlled at 3.5–7 mg/L throughout the experiment.The biofilm reactor showed excellent nitritation performance after the inoculation of nitrifying sludge,with the hydraulic retention time being reduced from 24 to 7 hr.Above 90%nitrite accumulation ratio(NAR)was maintained in phase 1.Afterwards,nitratation occurred with the low NH4^+–N concentration in the reactor.The improvement of NH4^+–N concentration to 20–35 mg/L had a limited effect on the recovery of nitritation.However,nitritation recovered rapidly when sequencing batch feed mode was adopted in phase 4,with the effluent NH4^+-N concentration above 7 mg/L.The improvement of ammonia oxidizing bacteria(AOB)activity and the combined inhibition effect of free ammonia(FA)and free nitrous acid(FNA)on the nitrite oxidizing bacteria(NOB)were two key factors for the rapid recovery of nitritation.Sludge activity was obtained in batch tests.The results of batch tests had a good relationship with the long term operation performance of the biofilm reactor.展开更多
The aim of the present work was to evaluate the anaerobic ammonium oxidation (anammox) activity of simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm with different substrate concentrat...The aim of the present work was to evaluate the anaerobic ammonium oxidation (anammox) activity of simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm with different substrate concentrations and pH values. Kaldnes rings taken from the SNAD biofilm reactor were incubated in batch tests to determine the anammox activity. Haldane model was applied to investigate the ammonium inhibition on anammox process. As for nitrite inhibition, the NH4-N removal rate of anammox process remained 87.4% of the maximum rate with the NO2-N concentration of 100 mg/L. Based on the results of Haldane model, no obvious difference in kinetic coefficients was observed under high or low free ammonia (FA) conditions, indicating that ammonium rather than FA was the true inhibitor for anammox process of SNAD biofilm. With the pH value of 7.0, the rmax, KS and K of ammonium were 0.209 kg NO2-N/kg VSS/day, 9.5 mg/L and 422 rag/L, respectively. The suitable pH ranges for anammox process were B.0 to 9.0. These results indicate that the SNAD biofilm performs excellent tolerance to adverse conditions.展开更多
基金funded by the National Water Pollution Control and Management Technology Major Projects(No.2014ZX 07201-011)the Beijing Natural Science Foundation(No.8122005)of Chinathe Beijing Municipal EducationCommission General Program(No.KM2012-10005028)
文摘The objective of this study was to investigate the nitritation performance in a biofilm reactor for treating domestic wastewater.The reactor was operated in continuous feed mode from phases 1 to 3.The dissolved oxygen(DO)was controlled at 3.5–7 mg/L throughout the experiment.The biofilm reactor showed excellent nitritation performance after the inoculation of nitrifying sludge,with the hydraulic retention time being reduced from 24 to 7 hr.Above 90%nitrite accumulation ratio(NAR)was maintained in phase 1.Afterwards,nitratation occurred with the low NH4^+–N concentration in the reactor.The improvement of NH4^+–N concentration to 20–35 mg/L had a limited effect on the recovery of nitritation.However,nitritation recovered rapidly when sequencing batch feed mode was adopted in phase 4,with the effluent NH4^+-N concentration above 7 mg/L.The improvement of ammonia oxidizing bacteria(AOB)activity and the combined inhibition effect of free ammonia(FA)and free nitrous acid(FNA)on the nitrite oxidizing bacteria(NOB)were two key factors for the rapid recovery of nitritation.Sludge activity was obtained in batch tests.The results of batch tests had a good relationship with the long term operation performance of the biofilm reactor.
基金supported by the National Water Pollution Control and Management Technology Major Projects(No.2014ZX 07201-011)and(No.2015ZX 07202-013)the National Natural Science Foundation of China(No.51308010)the Research Fund for the Doctoral Program of Higher Education(No.20131103120017)
文摘The aim of the present work was to evaluate the anaerobic ammonium oxidation (anammox) activity of simultaneous partial nitrification, anammox and denitrification (SNAD) biofilm with different substrate concentrations and pH values. Kaldnes rings taken from the SNAD biofilm reactor were incubated in batch tests to determine the anammox activity. Haldane model was applied to investigate the ammonium inhibition on anammox process. As for nitrite inhibition, the NH4-N removal rate of anammox process remained 87.4% of the maximum rate with the NO2-N concentration of 100 mg/L. Based on the results of Haldane model, no obvious difference in kinetic coefficients was observed under high or low free ammonia (FA) conditions, indicating that ammonium rather than FA was the true inhibitor for anammox process of SNAD biofilm. With the pH value of 7.0, the rmax, KS and K of ammonium were 0.209 kg NO2-N/kg VSS/day, 9.5 mg/L and 422 rag/L, respectively. The suitable pH ranges for anammox process were B.0 to 9.0. These results indicate that the SNAD biofilm performs excellent tolerance to adverse conditions.