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Effect of initial ammonium concentration on a one-stage partial nitrification/anammox biofilm system:Nitrogen removal performance and the microbial community

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Journal of Environmental Sciences 2024年第9期143卷 176-188页

作者： Mengyu Zhou Yun Han Yang Zhuo Fen Yu Gaoyuan Hu Dangcong Peng School of Municipal and Environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Key Laboratory of Northwest Water Resource Environment and EcologyMOEXi’an University of Architecture and TechnologyXi’an 710055China

One-stage partial nitrification coupled with anammox(PN/A)technology effectively reduces the energy consumption of a biological nitrogen removal system.Inhibiting nitrite-oxidizing bacteria(NOB)is essential for this technology to maintain efficient nitrogen removal performance.Initial ammonium concentration(IAC)affects the degree of inhibited NOB.In this study,the effect of the IAC on a PN/A biofilm was investigated in a moving bed biofilm reactor.The results showed that nitrogen removal efficiency decreased from 82.49%±1.90%to 64.57%±3.96%after the IAC was reduced from 60 to 20 mg N/L,while the nitrate production ratio increased from 13.87%±0.90%to 26.50%±3.76%.NOB activity increased to1,133.86 mg N/m^(2)/day after the IAC decreased,approximately 4-fold,indicating that the IAC plays an important inhibitory role in NOB.The rate-limiting step in the mature biofilm of the PN/A system is the nitritation process and is not shifted by the IAC.The analysis of the microbial community structure in the biofilm indicates that the IAC was the dominant factor in changes in community structure.Ca.Brocadia and Ca.Jettenia were the main anammox bacteria,and Nitrosomonas and Nitrospira were the main AOB and NOB,respectively.IAC did not affect the difference in growth between Ca.Brocadia and Ca.Jettenia.Thus,modulating the IAC promoted the PN/A process with efficient nitrogen removal performance at medium to low ammonium concentrations.

关键词： Biological nitrogen removal partial nitrification Anammox Ammonium concentration Biofilm

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Feasibility of low-intensity ultrasound treatment with hydroxylamine to accelerate the initiation of partial nitrification and allow operation under intermittent aeration

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Journal of Environmental Sciences 2024年第5期139卷 446-459页

作者： Jianxiong Jian Xiaojian Liao Zhihua Mo Shoupeng Li Lei Li Shaojin Chen Zhenhua Huang Junhao Chen Wencan Dai Shuiyu Sun Guangzhou Key Laboratory Environmental Catalysis and Pollution Control Guangdong Key Laboratory of Environmental Catalysis and Health Risk ControlSchool of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China Guangdong Province Solid Waste Recycling and Heavy Metal Pollution Control Engineering Technology Research Center Guangdong Polytechnic of Environmental Protection EngineeringFoshan 528216China Analysis and Test Center Guangdong University of TechnologyGuangzhou 510006China

partial nitrification is a key aspect of efficient nitrogen removal,although practically it suf-fers from long start-up cycles and unstable long-term operational performance.To address these drawbacks,this study investigated the effect of low intensity ultrasound treatment combined with hydroxylamine(NH2OH)on the performance of partial nitrification.Results showthat compared with the control group,low-intensity ultrasound treatment(0.10W/mL,15 min)combined with NH2OH(5 mg/L)reduced the time required for partial nitrification initiation by 6 days,increasing the nitrite accumulation rate(NAR)and ammonia nitro-gen removal rate(NRR)by 20.4% and 6.7%,respectively,achieving 96.48% NRR.Mechanis-tic analysis showed that NH2OH enhanced ammonia oxidation,inhibited nitrite-oxidizing bacteria(NOB)activity and shortened the time required for partial nitrification initiation.Furthermore,ultrasonication combined with NH2OH dosing stimulated EPS(extracellular polymeric substances)secretion,increased carbonyl,hydroxyl and amine functional group abundances and enhanced mass transfer.In addition,16S rRNA gene sequencing results showed that ultrasonication-sensitive Nitrospira disappeared from the ultrasound+NH_(2)OH system,while Nitrosomonas gradually became the dominant group.Collectively,the results of this study provide valuable insight into the enhancement of partial nitrification start-up during the process of wastewater nitrogen removal.

关键词： partial nitrification Low-intensity ultrasound Hydroxylamine Ammonia oxidizing bacteria Nitrite oxidizing bacteria

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Removal of pathogenic indicator microorganisms during partial nitrification:the role of free nitrous acid

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 93-102页

作者： Jiaojiao Xu Xiaotian Chen Rui Tang Jingwei Feng Shoujun Yuan Wei Wang Zhen-Hu Hu Anhui Engineering Laboratory of Rural Water Environment and Resource School of Civil EngineeringHefei University of TechnologyHefei 230009China Hefei 168 High School Hefei 230025China Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power Shanghai University of Electric PowerShanghai 200090China

Digested wastewater contains pathogenic microorganisms and high ammonia concentrations,which can pose a potential risk to public health.Effective removal of pathogens and nitrogen is crucial for the post-treatment of digested wastewater.partial nitrification-anammox is an energy-saving nitrogen removal process.Free nitrous acid(FNA),an intermediate product of partial nitrification,has the potential to inactivate microorganisms.However,the efficiency and mechanisms of FNA-related inactivation in pathogens during partial nitrification remains unclear.In this study,Enterococcus and Escherichia coli(E.coli)were selected to investigate the efficiency and mechanisms of FNA-related inactivation in partial nitrification process.The results revealed that 83%±13%and 59%±27%of E.coli and Enterococcus were removed,respectively,in partial nitrification process at FNA concentrations of 0.023−0.028 mg/L.When the concentration of FNA increased from 0 to 0.5 mg/L,the inactivation efficiencies of E.coli and Enterococcus increased from 0 to 99.9%and 89.9%,respectively.Enterococcus exhibited a higher resistance to FNA attack compared to E.coli.3D-laser scanning microscopy(3D-LSM)and scanning electron microscopy(SEM)revealed that FNA exposure caused the surface collapse of E.coli and Enterococcus,as well as visible pore formation on the surface of E.coli cells.4',6-Diamidino-2-phenylindole dihydrochloride n-hydrate(DAPI)/propidium iodide(PI)and biomolecule leakage confirmed that inactivation of E.coli and Enterococcus occurred due to breakdown of cell walls and cell membranes.These findings indicate that partial nitrification process can be used for the removal of residual pathogenic microorganisms.

关键词： partial nitrification Free nitrous acid Pathogenic indicator microorganism Inactivation Cell structure

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The effect of dissolved oxygen concentration on long-term stability of partial nitrification process

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Journal of Environmental Sciences 2020年第4期32卷 343-351页

作者： Bin Cui Qing Yang Xiuhong Liu Siting Huang Yubing Yang Zhibin Liu National Engineering Laboratory for Aduanced Municipal Wastewater Treatment and Reuse Technology Beijing University of TechnologyBeijing 100124China

Dissolved oxygen(DO)concentration is regarded as one of the crucial factors to influence partial nitrification process.However,achieving and keeping stable partial nitrification under different DO concentrations were widely reported.The mechanism of DO concentration influencing partial nitrification is still unclear.Therefore,in this study two same sequencing batch reactors(SBRs)cultivated same seeding sludge were built up with realtime control strategy.Different DO concentrations were controlled in SBRs to explore the effect of DO concentration on the long-term stability of partial nitrification process at room temperature.It was discovered that ammonium oxidation rate(AOR)was inhibited when DO concentration decreased from 2.5 to 0.5 mg/L.The abundance of Nitrospira increased from 1011.5 to 1013.7 copies/g DNA,and its relative percentage increased from 0.056%to 3.2%during 190 operational cycles,causing partial nitrification gradually turning into complete nitrification process.However,when DO was 2.5 mg/L the abundance of Nitrospira was stable and AOB was always kept at 1010.7 copies/g DNA.High AOR was maintained,and stable partial nitrification process was kept.Ammonia oxidizing bacteria(AOB)activity was significantly higher than nitrite oxidizing bacteria(NOB)activity at DO of 2.5 mg/L,which was crucial to maintain excellent nitrite accumulation performance.

关键词： partial nitrification Dissolved oxygen Ammonium oxidation rate Nitrospira Nitrogen removal

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Nitrifiers activity and community characteristics under stress conditions in partial nitrification systems treating ammonium-rich wastewater

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Journal of Environmental Sciences 2018年第11期30卷 1-8页

作者： Jia Miao Qidong Yin Tomoyuki Hori Tomo Aoyagi Hiroshi Habe Guangxue Wu Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety Graduate School at ShenzhenTsinghua University Environmental Management Research Institute National Institute of Advanced Industrial Science and Technology(AIST)

Long-term exposure of nitrifiers to high concentrations of free ammonia （FA） and free nitrous add （FNA） may affect nitrifiers activity and nitrous oxide （N2O） emission. Two sequencing batch reactors （SBRs） were operated at influent ammonium nitrogen （NH4-N） concentrations of 800 mg/L （SBRH） and 33S mg/L （SBRL）, respectively. The NH4-N removal rates in SBRH and SBRL were around 2.4 and 1.0 g/L/day with the nitritation efficiencies of 99.3% and 95.7%, respectively. In the simulated SBR cycle, the N20 emission factors were 1.61% in SBRH and 2.30% in SBRL. N2O emission was affected slightly by FA with the emission factor of 0.22%-0.65%, while N2O emission increased with increasing FNA concentrations with the emission factor of 0.22%～3.96%. The dominant ammonia oxidizing bacteria （AOB） were Nitrosomonas spp. in both reactors, and their relative proportions were 38.89% in SBRH and 13.36% in SBRL. Within the AOB genus, a species （i.e., operational taxonomic unit [OTU] 76） that was phylogenetically identical to Nitrosomonas europaea accounted for 99.07% and 82.04% in SBRH and SBRL, respectively. Additionally, OTU 215, which was related to Nitrosomonas stercoris, accounted for 16.77% of the AOB in SBRL.

关键词： Ammonium-rich wastewater Free ammonia Free nitrous acid N2O emission partial nitrification

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Effects of Different Concentrations of Ammonia Nitrogen on N_2O Emission in the Process of partial nitrification

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Meteorological and Environmental Research 2012年第12期3卷 68-70,76页

作者： TIAN Lin KONG Qiang ZHANG Jian MIAO Ming-sheng College of Life Sciences Shandong Normal University School of Environmental Science and Engineering Shandong University

[Objective] The study aimed to discuss the effects of different concentrations of ammonia nitrogen on N2O emission in the process of partial nitrification. [Method] By using a sequencing batch biofilm reactor (SBBR) under intermittent aeration, the influences of various concentrations of influent ammonia nitrogen on nitrous oxide (N2O) emission from partial nitrification were analyzed. [Result] When the concentration of influent ammonia nitrogen varied from 200 to 400 mg/L, the changing trends of DO and ORP value were consistent during the process of partial nitrification, and the concentration ratio of NO-2-N to NH+4-N in effluent water reached 1∶1, with lower NO-3-N level. In addition, ammonia nitrogen concentration in the influent had significant effects on N2O emission in the process of partial nitrification, that is, the higher the ammonia nitrogen concentration, the more the N2O emission. When ammonia nitrogen concentration was 400 mg/L, N2O emission was up to about 37 mg. [Conclusion] N2O emission in the process of partial nitrification might be related to the concentrations of NH+4 and NO-2.

关键词： Ammonia nitrogen partial nitrification SBBR N2O China

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Responses of nitrification performance,triclosan resistome and diversity of microbes to continuous triclosan stress in activated sludge system

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Journal of Environmental Sciences 2020年第6期32卷 211-223页

作者： Da Zhang Jingfeng Gao Lifang Zhang Wenzhi Zhang Jingxin Jia Huihui Dai Zhiqi Wang National Engineering Laboratory for Aduanced Municipal Wastewater Treatment and Reuse Technology College of Environmental and Energy EngineeringBeijing University of TechnologyBeijing 100124China

Triclosan(TCS)is commonly found in wastewater treatment plants,which often affects biological treatment processes.The responses of nitrification,antibiotic resistome and microbial community under different TCS concentrations in activated sludge system were evaluated in this study.The experiment was conducted in a sequencing batch reactor(SBR)for 240 days.Quantitative PCR results demonstrated that the abundance of ammonium oxidizing bacteria could be temporarily inhibited by 1 mg/L TCS and then gradually recovered.And the abundances of nitrite oxidizing bacteria(NOB)under 2.5 and 4 mg/L TCS were three orders of magnitude lower than that of seed sludge,which accounted for partial nitrification.When the addition of TCS was stopped,the abundance of NOB increased.The mass balance experiments of TCS demonstrated that the primary removal pathway of TCS changed from adsorption to biodegradation as TCS was continuously added into the SBR system.Moreover,TCS increased the abundance of mexB,indicating the efflux pump might be the main TCS-resistance mechanism.As a response to TCS,bacteria could secrete more protein(PN)than polysaccharide.Three-dimensional excitation-emission matrix revealed that tryptophan PN-like substances might be the main component in PN to resist TCS.High-throughput sequencing found that the relative abundances of Paracoccus,Pseudoxanthomonas and Thauera increased,which could secrete extracellular polymeric substances(EPS).And Sphingopyxis might be the main TCS-degrading bacteria.Overall,TCS could cause partial nitrification and increase the relative abundances of EPS-secreting bacteria and TCS-degrading bacteria.

关键词： Triclosan partial nitrification Nitrite oxidizing bacteria Triclosan resistome Microbial community

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Mechanism studies on nitrogen removal when treating ammonium-rich leachate by sequencing batch biofilm reactor

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Frontiers of Environmental Science & Engineering 2007年第1期1卷 43-48页

作者： XU Zhengyong YANG Zhaohui ZENG Guangming XIAO Yong DENG Jiuhua College of Environmental Science and Engineering Hunan UniversityChangsha 410082China

The nitrogen removal mechanism was studied and analyzed when treating the ammonium-rich landfill leachate by a set of sequencing batch biofilm reactors(SBBRs),which was designed independently.At the liquid temperature of(32P0.4)°C,and after a 58-days domestica-tion period and a 33-days stabilization period,the efficiency of ammonium removal in the SBBR went up to 95%.Highly frequent intermittent aeration suppressed the activity of nitratebacteria,and also eliminated the influence on the activity of anaerobic ammonium oxidation(ANAMMOX)bacteria and nitritebacteria.This influence was caused by the accumulation of nitrous acid and the undulation of pH.During the aeration stage,the concentration of dissolved oxygen was controlled at 1.2-1.4 mg/L.The nitritebacteria became dominant and nitrite accumulated gradually.During the anoxic stage,along with the concentration debasement of the dissolved oxygen,ANAMMOX bacteria became domi-nant;then,the nitrite that was accumulated in the aeration stage was wiped off with ammonium simultaneously.

关键词： landfill leachate sequencing batch biofilm reactor(SBBR) partial nitrification anaerobic ammonium oxidation

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Analysis of the nitrification and Ammonia and Nitrite oxidizing Bacteria Stratification in a Filter Reactor

Analysis of the nitrification and Ammonia and Nitrite oxidiz...

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2011 World Congress on Engineering and Technology(CET 2011)

作者： Jack E.Behar Marlene Roeckel Estrella Aspé Víctor Campos Department of Chemical Engineering Engineering Faculty University of Concepción Department of Microbiology Faculty of Biological SciencesUniversity of Concepción

The effects of the feed dilution and the increase of the inlet flow corresponding to a recycle from the nitrificant zone to the denitrificant zone in a filter reactor on the nitrification and on the stratification of the ammonia （AOB） and nitrite oxidizing bacteria were studied.A synthetic substrate,and recycle ratios of 0 and 2 were used.A total ammonia nitrogen （TAN） removal efficiency of 81% and 88%,and a NO2-N accumulation of 0.4% and 0.45% for conditions that mimic recycle ratios of 0 and 2,respectively were accomplished.When the recycle ratio increased from 0 to 2,DGGE analysis focusing to gen 16S rDNA indicated an increase in nitrifying bacteria identified as Nitrosomonas europea （AOB） mainly in the two thirds of the reactor;in the first third their relative abundance increased from 8.8 to 63%.

关键词： component partial nitrification biological aerated filter hydraulic retention time bacterial estratification

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