检索结果-南通市图书馆

Perturbation of clopyralid on bio-denitrification and nitrite accumulation:Long-term performance and biological mechanism

在线全文

学校读者我要写书评

暂无评论

Environmental Science and Ecotechnology 2022年第1期9卷 27-39页

作者： Suyun Sun Ya-Nan Hou Wei Wei Hafiz Muhammad Adeel Sharif Cong Huang Bing-Jie Ni Haibo Li Yuanyuan Song Caicai Lu Yi Han Jianbo Guo Tianjin Key Laboratory of Aquatic Science and Technology School of Environmental and Municipal EngineeringTianjin Chengjian UniversityTianjin300384China National Technology Innovation Center of Synthetic Biology Tianjin Institute of Industrial BiotechnologyChinese Academy of SciencesTianjin300308China Centre for Technology in Water and Wastewater School of Civil and Environmental EngineeringUniversity of Technology SydneySydneyNSW2007Australia College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen518060China

The contaminant of herbicide clopyralid(3,6-dichloro-2-pyridine-carboxylic acid,CLP)poses a potential threat to the ecological ***,there is a general lack of research devoted to the perturbation of CLP to the bio-denitrification process,and its biological response mechanism remains ***,long-term exposure to CLP was systematically investigated to explore its influences on denitrification performance and dynamic microbial *** showed that low-concentration of CLP(nitrite accumulation initially,while higher concentrations(35e60 mg/L)of CLP had no further effect after long-term *** mechanistic study demonstrated that CLP reduced nitrite reductase(NIR)activity and inhibited metabolic activity(carbon metabolism and nitrogen metabolism)by causing oxidative stress and membrane damage,resulting in nitrite ***,after more than 80 days of acclimation,almost no nitrite accumulation was found at 60 mg/L *** was proposed that the secretion of extracellular polymeric substances(EPS)increased from 75.03 mg/g VSS at 15 mg/L CLP to 109.97 mg/g VSS at 60 mg/L CLP,which strengthened the protection of microbial cells and improved NIR activity and metabolic ***,the biodiversity and richness of the microbial community experienced a U-shaped *** relative abundance of denitrification-and carbon metabolism-associated microorganisms decreased initially and then recovered with the enrichment of microorganisms related to the secretion of EPS and N-acyl-homoserine lactones(AHLs).These microorganisms protected microbe from toxic substances and regulated their interactions among interand *** study revealed the biological response mechanism of denitrification after successive exposure to CLP and provided proper guidance for analyzing and treating herbicide-containing wastewater.

关键词： Denitrification nitrite accumulation Clopyralid Membrane damage Metabolism activity Microbial community

nitrite accumulation during the Denitrification Process in SBR for the Treatment of Pre-treated Landfill Leachate

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2009年第6期17卷 1027-1031页

作者：孙洪伟杨庆彭永臻时晓宁王淑莹张树军 Key Laboratory of Beijing Water Quality Science and Water Environment Recovery Engineering Beijing University of Technology Beijing 100124 China

The nitrite accumulation in the denitrification process is investigated with sequencing batch reactor （SBR） treating pre-treated landfill leachate in anoxic/anaerobic up-flow anaerobic sludge bed I（UASB）. nitrite accumulates obviously at different initial nitrate concentrations （64.9,54.8,49.3 and 29.5 mg·L^-1 ） and low temperatures, and the two break points on the oxidation-reduction potential （ORP） profile indicate the completion of nitrate and nitrite reduction. Usually, the nitrate reduction rate is used as the sole parameter to characterize the denitrification rate, and nitrite is not even measured. For accuracy, the total oxidized nitrogen （nitrate ＋ nitrite） is used as a measure, though details characterizing the process may be overlooked. Additionally, batch tests are conducted to investigate the effects of C/N ratios and types of carbon sources on the nitrite accumulation during the denitrification. It is observed that carbon source is sufficient for the reduction of nitrate to nitrite, but for further reduction of nitrite to nitrogen gas, is deficient when C/N is below the theoretical critical level of 3.75 based on the stoichiometry of denitrification. Five carbon sources used in this work, except for glucose, may cause the nitrite accumulation. From experimental results and cited literature, it is concluded that Alcaligene species may be contained in the SBR activated-sludge system.

关键词： landfill leachate nitrite accumulation denitrification C/N ratio carbon source sequencing batch reactor

Experimental study of nitrite accumulation in pre-denitrification biological nitrogen removal process

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2008年第2期2卷 236-240页

作者： Xuelei WU Lunqiang CHEN Yongzhen PENG Yayi WANG Pu WANG Key Laboratory of Beijing Water Environment Recovery Beijing University of TechnologyBeijing 100022China School of Architectural Engineering Zhejiang University of TechnologyHangzhou 310014China

The effect of dissolved oxygen(DO)concentration on nitrite accumulation was investigated in a pilot-scale pre-denitrification process at room temperature for 100 *** the first 10 days,due to the instability of the system,the DO concentration fluctuated between 1.0 and 2.0 mg/*** the next 14 days,the DO concentration was kept at 0.5 mg/L and nitrite accumulation occurred,with the average nitrite accumulation rate at 91%.From the 25th day,the DO concentration was increased to 2.0 mg/L to destroy the nitrite accumulation,but nitrite accumulation rate was still as high as 90%.From the 38th day the nitrite accumulation rate decreased to 15%–30%*** the 50th day,DO concentration was decreased to 0.5 mg/L to resume nitrite *** the 83rd day the nitrite accumulation rate began to increase to 80%.Dissolved oxygen was the main cause of nitrite accumulation,taking into account other factors such as pH,free ammonia concentration,temperature,and sludge retention *** of the different affinity for oxygen between nitrite oxidizing bacteria and ammonia oxidizing bacteria when DO concentration was kept at 0.5 mg/L,nitrite accumulation occurred.

关键词： pre-denitrification biological nitrogen removal nitrite accumulation dissolved oxygen

Effect of Sludge Retention Time on nitrite accumulation in Real-time Control Biological Nitrogen Removal Sequencing Batch Reactor

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2011年第3期19卷 512-517页

作者：吴昌永彭永臻王淑莹李晓玲王然登 Research Center of Water Pollution Control Technology Chinese Research Academy of Environmental Sciences School of Municipal and Environmental Engineering Harbin Institute of Technology Key Laboratory of Beijing for Water Environmental Recovery Engineering Beijing University of Technology

In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was *** real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of *** addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day *** the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after *** the SRT was 40 d,the nitrification process was significantly *** of 10 to 20 d was more suitable in this *** real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.

关键词： biological nitrogen removal nitrite accumulation real time control sludge retention time sequencing batch reactors

Effect of self-alkalization on nitrite accumulation in a high-rate denitrification system:performance,microflora and enzymatic activities

在线全文

学校读者我要写书评

暂无评论

Effect of self-alkalization on nitrite accumulation in a hig...

DMPP mitigates N_(2)O and NO productions by inhibiting ammonia-oxidizing bacteria in an intensified vegetable field under different temperature and moisture regimes

中国生物工程学会第六次全国会员代表大会暨第九届学术年会

作者： Wei Li Ping Zheng Department of Environmental Engineering College of Environmental and Resource ScienceZhejiang University

The self-alkalization of denitrifying automatic circulation(DAC) reactor resulted in a large increase of pH up to 9.20 and caused a tremendous accumulation of nitrite up to 451.1±49.0 mgN·L at nitrate loading rate(NLR) from 35 kgN·m·d to 55 kgN·m·*** nitrite accumulation was greatly relieved even at the same NLR once the pH was maintained at 7.6±0.2 in the *** assays indicated that the long-term bacterial exposure to high pH significantly inhibited the activity of copper type nitrite reductase(NirK) rather than the cytochrome cd1 type nitrite reductase(NirS).The terminal restriction fragment length polymorphism(T-RFLP) analysis revealed that the dominant denitrifying bacteria shifted from the NirS-containing Thauear sp.27 to the NirK-containing Hyphomicrobium nitrativorans strain NL23 during the *** significant nitrite accumulation in the high-rate denitrification system could be therefore,due to the inhibition of Cu-containing NirK by high pH from the *** results suggest that the NirK-containing *** strain NL23 could be an ideal functional bacterium for the conversion of nitrate to nitrite,***,which could be combined with anaerobic ammonium oxidation(Anammox) to develop a new process for nitrogen removal from wastewater.

关键词： Denitrification High-load Self-alkalization nitrite accumulation Microbial mechanism

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Pedosphere 2024年第3期34卷 652-663页

作者： Xi ZHANG Xintong XU Chenyuan WANG Qianqian ZHANG Yubing DONG Zhengqin XIONG Jiangsu Key Laboratory of Low Carbon Agriculture and GHGs Mitigation College of Resources and Environmental SciencesNanjing Agricultural UniversityNanjing 210095(China) Department of Soil Science of Temperate Ecosystems Department of Agricultural Soil ScienceGeorg-August University of GottingenGottingen 37077(Germany) State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityHangzhou 311300(China) Huaiyin Institute of Agricultural Sciences of Xuhuai Region in Jiangsu Jiangsu Academy of Agricultural SciencesHuai’an 223001(China)

Vegetable soils with high nitrogen input are major sources of nitrous oxide(N_(2)O)and nitric oxide(NO),and incorporation of the nitrification inhibitor 3,4-dimethylpyrazole phosphate(DMPP)into soils has been documented to effectively reduce ***,the efficiency of DMPP in terms of soil N_(2)O and NO mitigations varies greatly depending on soil temperature and moisture ***,further evaluations of DMPP efficiency in diverse environments are required to encourage widespread application.A laboratory incubation study(28 d)was established to investigate the interactive effects of DMPP,temperature(15,25,and 35?C),and soil moisture(55% and 80% of water-holding capacity(WHC))on net nitrification rate,N_(2)O and NO productions,and gene abundances of nitrifiers and denitrifiers in an intensive vegetable *** showed that incubating soil with 1%DMPP led to partial inhibition of the net nitrification rate and N_(2)O and NO productions,and the reduction percentage of N_(2)O production was higher than that of NO production(69.3%vs.38.2%)regardless of temperature and soil moisture *** increased temperatures promoted the net nitrification rate but decreased soil N_(2)O and NO *** moisture influenced NO production more than N_(2)O production,decreasing with the increased moisture level(80%).The inhibitory effect of DMPP on cumulative N_(2)O and NO productions decreased with increased temperatures at 55%***,the inhibitory effect of DMPP on cumulative N_(2)O production increased with increased temperatures at 80%*** on the correlation analyses and automatic linear modeling,the mitigation of both N_(2)O and NO productions from the soil induced by DMPP was attributed to the decreases in ammonia-oxidizing bacteria(AOB)amoA gene abundance and NO_(2)^(-)-N ***,our study indicated that DMPP reduced both N_(2)O and NO productions by regulating the associated AOB amoA gene abundance and NO_(2)^(-)-N concentra

关键词： 3,4-dimethylpyrazole phosphate environment condition gene abundance nitrification inhibitor nitrite accumulation soil water content

Community analysis of ammonia and nitrite oxidizers in start-up of aerobic granular sludge reactor

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2007年第8期19卷 996-1002页

作者： WANG Feng XIA Si-qing LIU Yi CHEN Xue-song ZHANG Jun State Key Laboratory of PoUution Control and Resource Reuse School of Environmental Science and Engineering Tongji University Shanghai 200092 China. College of Biology and Environment Engineering Zhejiang Shuren University Hangzhou 310015 China Medical School Tongji University Shanghai 200092 China

A lab-scale sequencing batch reactor （SBR） was set-up and the aerobic granular sludge was successfully incubated using anaerobic granular sludge as seed sludge. Nitrogen was partially removed by simultaneous nitrification and denitrification （SND） via nitrite with free ammonia （FA） of about 10 mg/L. The denaturing gradient gel electrophoresis （DGGE） method was used to investigate community structure of α-Proteobacteria, β-Proteobacteria, ammonia oxidizing bacteria （AOB）, and Nitrospira populations during start-up. The population sizes of bacteria, AOB and Nitrospira were examined using real-time PCR method. The analysis of community structure and Shannon index showed that stable structure of AOB population was obtained at day 35, while the communities of α- Proteobacteria, β-Proteobacteria, and Nitrospira became stable after day 45. At stable stage, the average cell densities were 1.1× 10^12, 2.2×10^10 and 1.0×10^10 cells/L for bacteria, AOB and Nitrospira, respectively. The relationship between characteristics of nitrifying bacteria community and nitrogenous substrate utilization constant was discussed by calculating Pearson correlation. Certain correlation seemed to exist between population size, biodiversity, and degradation constant. And the influence of population size might be greater than that of biodiversity.

关键词： aerobic granular sludge simultaneous nitrification and denitrification nitrite accumulation denaturing gradient gel electrophoresis real-time PCR

An innovative membrane bioreactor and packed-bed biofilm reactor combined system for shortcut nitrification-denitrification

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2009年第5期21卷 568-574页

作者： ZHANG Yunxia, ZHOU Jiti, ZHANG Jinsong, YUAN Shouzhi School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024, China. School of Environmental and Biological Science and Technology Dalian University of Technology

An innovative shortcut biological nitrogen removal system, consisting of an aerobic submerged membrane bioreactor （MBR） and an anaerobic packed-bed biofilm reactor （PBBR）, was evaluated for treating high strength ammonium-bearing wastewater. The system was seeded with enriched ammonia-oxidizing bacteria （AOB） and operated without sludge purge with a decreased hydraulic retention time （HRT） through three phases. MBR was successful in both maintaining nitrite ratio over 0.95 and nitrification efficiency higher than 98% at HRT of 24 h, and PBBR showed satisfactory denitrification efficiency with very low effluent nitrite and nitrate concentration （both below 3 mg/L）. By examining the nitrification activity of microorganism, it was found that the specifc ammonium oxidization rate （SAOR） increased from 0.17 to 0.51 g N/（g VSS.d） and then decreased to 0.22 g N/（g VSS.d） at the last phase, which resulted from the accumulation of extracellular polymers substances （EPS） and inert matters enwrapping around the zoogloea. In contrast, the average specific nitrite oxidization rate （SNOR） is 0.002 g N/（g VSS.d）, only 1% of SAOR. Because very little Nitrobactor has been detected by fluorescence in situ hybridization （FISH）, it is confirmed that the stability of high nitrite accumulation in MBR is caused by a large amount of AOB.

关键词： shortcut nitrification-denitrification ammonia-oxidizing bacteria nitrite accumulation FISH

Model-based evaluation on the conversion ratio of ammonium to nitrite in a nitritation process for ammonium-rich wastewater treatment

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2004年第6期16卷 1005-1010页

作者： LIXiao-ming YANGQi ZENGGuang-ming A.Cornelius K.H.Rosenwinkel S.Kunst D.Weichgrebe DepartmentofEnvironmentalScienceandEngineering HunanUniversityChangsha410082China InstituteofWaterQualityandWasteManagement HannoverUniversityWelfengartenD-130167HannoverGermany

Modeling for nitritation process was discussed and analyzed quantitatively for the factors that influence nitrite accumulation. The results indicated that pH, inorganic carbon source and Hydraulic Retention Time(HRT) as well as biomass concentration are the main factors that influenced the conversion ratio of ammonium to nitrite. A constant high pH can lead to a high nitritation rate and results in high conversion ratio on condition that free ammonia inhibition do not happen. In a CSTR system, without pH control, this conversion ratio can be monitored by pH variation in the reactor. The pH goes down far from the inlet level means a strongly nitrite accumulation. High concentration of alkalinity can promoted the conversion ratio by means of accelerating the nitritation rate through providing sufficient inorganic carbon source(carbon dioxide). When inorganic carbon source was depleted, the nitritation process stopped. HRT adjustment could be an efficient way to make the nitritation system run more flexible, which to some extent can meet the requirements of the fluctuant of inlet parameters such as ammonium concentration, pH, and temperature and so on. Biomass concentration is the key point, especially for a CSTR system in steady state, which was normally circumscribed by the characteristics of bacteria and may also affected by aeration mode and can be increased by prolonging the HRT on the condition of no nitrate accumulation when no recirculation available. The higher the biomass concentration is, the better the nitrite accumulation can be obtained.

关键词： conversion ratio modeling analysis nitritation process nitrite accumulation