Anammox is widely considered as the most cost-effective and sustainable process for nitrogen removal.However,how to achieve the enrichment of anammox biomass remains a challenge for its large-scale application,especia...Anammox is widely considered as the most cost-effective and sustainable process for nitrogen removal.However,how to achieve the enrichment of anammox biomass remains a challenge for its large-scale application,especially in mainstream wastewater treatment.In this study,the feasibility of enrichment of anammox biomass was explored through the realization of partial denitrification and the addition of bio-carriers.By using ordinary activated sludge,a sequencing batch reactor(SBR)followed by an up-fow anaerobic sludge bed(UASB)was operated at 25±2℃ for 214 days.The long-term operation was divided into five phases,in which SBR and UASB were started-up in Phases I and II,respectively.By eliminating oxygen and adjusting the infow ratios in Phases III-V,advanced nitrogen removal was achieved with the effuent total nitrogen being 4.7 mg/L and the nitrogen removal efficiency being 90.5%in Phase V.Both in-situ and ex-situ activity tests demonstrated the occurrence of partial denitrification and anammox.Moreover,16S rRNA high-throughput sequencing analysis revealed that Candidatus Brocadia was enriched from below the detection limit to in biofilms(0.4%in SBR,2.2%in UASB)and the foc sludge(0.2%in SBR,1.3%in UASB),while Thauera was mainly detected in the foc sludge(8.1%in SBR,8.8%in UASB),which might play a key role in partial denitrification.Overall,this study provides a novel strategy to enrich anammox biomass driven by rapid achievement of partial denitrification through the addition of bio-carriers,which will improve large-scale application of anammox processes in mainstream wastewater treatment.展开更多
In order to realize the simultaneous treatment of low C/N municipal and nitrate( NO3^--N) wastewaters,a sequencing batch reactor( SBR) was used to optimize the partial denitrification( PD),which the influent substrate...In order to realize the simultaneous treatment of low C/N municipal and nitrate( NO3^--N) wastewaters,a sequencing batch reactor( SBR) was used to optimize the partial denitrification( PD),which the influent substrate and the anoxic reaction time were appropriately controlled. The carbon and nitrogen removal and the characteristic parameters of PD during long-term operation were studied. Experimental results showed that the PD showed stable characteristics of nitrogen and carbon removal and NO2^--N accumulation after an adaptation of 20 d with municipal wastewater used. The anoxic reaction time was extended from 50 to 70 min with the initial COD/NO3^--N decreased from 3. 0 to about 2. 5. When the influent NO3^--N was 117. 93 mg/L,the effluent NO2^--N and NAR were 23. 10 mg/L and 82. 26%,respectively,and the nitrogen and carbon removal rate reached 91. 76% and 65. 70%,respectively. The effluent NO2^--N/NH4^+ -N meantime reached 1.17-1. 22. Moreover,the cumulative concentration of NO2^--N and the system NAR increased linearly with the consumption of NO3^--N and COD,and the change trend was highly significant within 0-20 min,and gradually flattened.展开更多
The effects of aeration rates and aeration patterns on the oxidation of ammonia-nitrogen into nitrite were investigated. The influent high ammonia-nitrogen synthetic wastewater resembled to those of the catalytic proc...The effects of aeration rates and aeration patterns on the oxidation of ammonia-nitrogen into nitrite were investigated. The influent high ammonia-nitrogen synthetic wastewater resembled to those of the catalytic process of the petrochemical refinery. The method involved the biological shortcut nitrification and denitrification lab-scale’s sequencing batch reactor (SBR) process based on intermittent aerations and aeration patterns. All the operations were carried out in a 20 L working volume SBR bioreactor, and the influent synthetic wastewater’s concentration was always 1000 mg/L ammonia-nitrogen NH<sub>4</sub>-N concentration at a C/N (carbon/nitrogen) ratio of 2.5:1. Effective shortcut nitrification to nitrite was registered at 1.1 mg-O<sub>2</sub>/L (i.e. 9 L-air/min) with 99.1% nitrification efficiency, 99.0% nitritation rate and 2.6 mg-NO<sub>3</sub>-</sup>-N/L nitrate concentration. The best results with 99.3% nitrification efficiency were recorded when operating at 1.4 mg-O<sub>2</sub>/L (i.e. 12 L-air/min). According to these experiments, it results that the nitrite accumulation rate was related to aeration rate and cycle’s duration. However, at 1.7 mg-O<sub>2</sub>/L (i.e. 15 L-air/min), the system was limited by an increase in nitrate concentration with more than 5 mg/L which could be a point of reverse to conventional nitrification. The best total nitrogen (TN) removal was about 71.5%.展开更多
In this study,the effects of soluble readily biodegradable COD(sCOD)and particulate slowly biodegradable COD(pCOD)on anammox process were investigated.The results of the longterm experiment indicated that a low sCOD/N...In this study,the effects of soluble readily biodegradable COD(sCOD)and particulate slowly biodegradable COD(pCOD)on anammox process were investigated.The results of the longterm experiment indicated that a low sCOD/N ratio of 0.5 could accelerate the anammox and denitrification activity,to reach as high as 84.9%±2.8%TN removal efficiency.Partial denitrification-anammox(PDN/anammox)and denitrification were proposed as the major pathways for nitrogen removal,accounting for 91.3% and 8.7% of the TN removal,respectively.Anammox bacteria could remain active with high abundance of anammox genes to maintain its dominance.Candidatus Kuenenia and Thauera were the predominant genera in the presence of organic matter.Compared with sCOD,batch experiments showed that the introduction of pCOD had a negative effect on nitrogen removal.The contribution of denitrification to nitrogen removal decreased from approximately 14%to 3% with increasing percentage of pCOD.In addition,the analysis result of the process data using an optimized ASM1 model indicated that high percentage of pCOD resulted in serious N_(2)O emission(the peak value up to 0.25mg N/L),whichwas likely due to limited mass diffusion and insufficient available carbon sources for denitrification.However,a high sCOD/N ratio was beneficial for alleviating N_(2)O accumulation.展开更多
基金supported by the National Natural Science Foundation of China (No.22176007),the Beijing Natural Science Foundation (No.8212022)the fund of innovation and entrepreneurship leading team project in Guangzhou (No.CYLJTD-201607)the National Key Research and Development Program of China (No.2021YFC3200605)。
文摘Anammox is widely considered as the most cost-effective and sustainable process for nitrogen removal.However,how to achieve the enrichment of anammox biomass remains a challenge for its large-scale application,especially in mainstream wastewater treatment.In this study,the feasibility of enrichment of anammox biomass was explored through the realization of partial denitrification and the addition of bio-carriers.By using ordinary activated sludge,a sequencing batch reactor(SBR)followed by an up-fow anaerobic sludge bed(UASB)was operated at 25±2℃ for 214 days.The long-term operation was divided into five phases,in which SBR and UASB were started-up in Phases I and II,respectively.By eliminating oxygen and adjusting the infow ratios in Phases III-V,advanced nitrogen removal was achieved with the effuent total nitrogen being 4.7 mg/L and the nitrogen removal efficiency being 90.5%in Phase V.Both in-situ and ex-situ activity tests demonstrated the occurrence of partial denitrification and anammox.Moreover,16S rRNA high-throughput sequencing analysis revealed that Candidatus Brocadia was enriched from below the detection limit to in biofilms(0.4%in SBR,2.2%in UASB)and the foc sludge(0.2%in SBR,1.3%in UASB),while Thauera was mainly detected in the foc sludge(8.1%in SBR,8.8%in UASB),which might play a key role in partial denitrification.Overall,this study provides a novel strategy to enrich anammox biomass driven by rapid achievement of partial denitrification through the addition of bio-carriers,which will improve large-scale application of anammox processes in mainstream wastewater treatment.
文摘In order to realize the simultaneous treatment of low C/N municipal and nitrate( NO3^--N) wastewaters,a sequencing batch reactor( SBR) was used to optimize the partial denitrification( PD),which the influent substrate and the anoxic reaction time were appropriately controlled. The carbon and nitrogen removal and the characteristic parameters of PD during long-term operation were studied. Experimental results showed that the PD showed stable characteristics of nitrogen and carbon removal and NO2^--N accumulation after an adaptation of 20 d with municipal wastewater used. The anoxic reaction time was extended from 50 to 70 min with the initial COD/NO3^--N decreased from 3. 0 to about 2. 5. When the influent NO3^--N was 117. 93 mg/L,the effluent NO2^--N and NAR were 23. 10 mg/L and 82. 26%,respectively,and the nitrogen and carbon removal rate reached 91. 76% and 65. 70%,respectively. The effluent NO2^--N/NH4^+ -N meantime reached 1.17-1. 22. Moreover,the cumulative concentration of NO2^--N and the system NAR increased linearly with the consumption of NO3^--N and COD,and the change trend was highly significant within 0-20 min,and gradually flattened.
文摘The effects of aeration rates and aeration patterns on the oxidation of ammonia-nitrogen into nitrite were investigated. The influent high ammonia-nitrogen synthetic wastewater resembled to those of the catalytic process of the petrochemical refinery. The method involved the biological shortcut nitrification and denitrification lab-scale’s sequencing batch reactor (SBR) process based on intermittent aerations and aeration patterns. All the operations were carried out in a 20 L working volume SBR bioreactor, and the influent synthetic wastewater’s concentration was always 1000 mg/L ammonia-nitrogen NH<sub>4</sub>-N concentration at a C/N (carbon/nitrogen) ratio of 2.5:1. Effective shortcut nitrification to nitrite was registered at 1.1 mg-O<sub>2</sub>/L (i.e. 9 L-air/min) with 99.1% nitrification efficiency, 99.0% nitritation rate and 2.6 mg-NO<sub>3</sub>-</sup>-N/L nitrate concentration. The best results with 99.3% nitrification efficiency were recorded when operating at 1.4 mg-O<sub>2</sub>/L (i.e. 12 L-air/min). According to these experiments, it results that the nitrite accumulation rate was related to aeration rate and cycle’s duration. However, at 1.7 mg-O<sub>2</sub>/L (i.e. 15 L-air/min), the system was limited by an increase in nitrate concentration with more than 5 mg/L which could be a point of reverse to conventional nitrification. The best total nitrogen (TN) removal was about 71.5%.
基金supported by the National Science Foundation of China (Nos. 51978487 and 51678424)National Key Research and Development Program of China (No. 2019YFC1906402)the National Science Centre (No. 2017/26/D/ST8/00967)
文摘In this study,the effects of soluble readily biodegradable COD(sCOD)and particulate slowly biodegradable COD(pCOD)on anammox process were investigated.The results of the longterm experiment indicated that a low sCOD/N ratio of 0.5 could accelerate the anammox and denitrification activity,to reach as high as 84.9%±2.8%TN removal efficiency.Partial denitrification-anammox(PDN/anammox)and denitrification were proposed as the major pathways for nitrogen removal,accounting for 91.3% and 8.7% of the TN removal,respectively.Anammox bacteria could remain active with high abundance of anammox genes to maintain its dominance.Candidatus Kuenenia and Thauera were the predominant genera in the presence of organic matter.Compared with sCOD,batch experiments showed that the introduction of pCOD had a negative effect on nitrogen removal.The contribution of denitrification to nitrogen removal decreased from approximately 14%to 3% with increasing percentage of pCOD.In addition,the analysis result of the process data using an optimized ASM1 model indicated that high percentage of pCOD resulted in serious N_(2)O emission(the peak value up to 0.25mg N/L),whichwas likely due to limited mass diffusion and insufficient available carbon sources for denitrification.However,a high sCOD/N ratio was beneficial for alleviating N_(2)O accumulation.
