厌氧氨氧化生物脱氮技术的研究进展

厌氧氨氧化是指在厌氧条件下,厌氧氨氧化混合菌直接以NH4 为电子供体,以NO3-或NO2-为电子受体,将NH4^ 、NO3-或NO2-转变成N2的过程。厌氧氨氧化作为一种新型的污水处理工艺具有较高的理论意义和良好的应用前景。本文主要阐述了厌氧氨氧化生物脱氮技术原理、厌氧氨氧化的可能途径、方法及其应用现状,并且讨论了厌氧氨氧化反应的微生物学机理和厌氧氨氧化工艺的开发,提出了今后研究的主要方向。     

Candidatus 'Brocadia fulgida': an autofluorescent anaerobic ammonium oxidizing bacterium

Anaerobic ammonium oxidizing (anammox) bacteria are detected in many natural ecosystems and wastewater treatment plants worldwide. This study describes the enrichment of anammox bacteria in the presence of acetate. The results obtained extend the concept that the anammox bacteria can be enriched to high densities in the presence of substrates for heterotrophic growth. Batch experiments showed that among the tested biomass, the biomass from the Candidatus 'Brocadia fulgida' enrichment culture oxidizes acetate at the highest rate. Continuous cultivation experiments showed that in the presence of acetate, ammonium, nitrite and nitrate, Candidatus 'Brocadia fulgida' out-competed other anammox bacteria. The results indicated that Candidatus 'Brocadia fulgida' did not incorporate acetate directly into their biomass. Candidatus 'Brocadia fulgida' exhibited the common characteristics of anammox bacteria: the presence of an anammoxosome and ladderane lipids and the production of hydrazine in the presence of hydroxylamine. Interestingly, the biofilm aggregates of this species showed strong autofluorescence. It is the only known anammox species exhibiting this feature. The autofluorescent extracellular polymeric substance had two excitation (352 and 442 nm) and two emission (464 and 521 nm) maxima.     

废水中的脱氮除硫研究

随着氮、硫污染物对江河湖泊污染的扩大,同步脱氮除硫已成为净化水体的一个重要课题。试验中采用UASB反应器,接种含有厌氧氨氧化菌的污泥处理含有氮硫的废水。通过硫酸盐取代亚硝酸作为电子受体,驯化同步脱氮除硫。进水浓氨氮和硫酸盐浓度分别控制在50～60mg·L^-1和210～240mg·L^-1的情况下,60天后得到一定的稳定处理效果,出水氨氮和硫酸盐浓度为30mg·L和160mg·L^-1。这种新型的脱氮除硫现象有助于为氮硫循环开辟新的途径。     

Nitrogen removal with the anaerobic ammonium oxidation process

Anaerobic ammonium-oxidizing (anammox) bacteria convert ammonium to N₂ with nitrite as the terminal electron acceptor in the absence of O₂. Nitritation–anammox bioreactors provide a cost-effective and environment-friendly alternative to conventional nitrification/denitrification nitrogen removal systems. Currently, this process is only applied for ammonium removal from wastewater with high ammonium load and temperature. Nevertheless, recent results obtained with laboratory-scale bioreactors suggest new possible routes of application of the Nitritation–anammox technology including (1) municipal wastewater treatment, removal of (2) methane in combination with nitrite-reducing methane-oxidizing bacteria, (3) nitrate coupled to organic acid oxidation and (4) nitrogen oxides. The current review summarizes the state-of-the-art of the application of Nitritation–anammox systems and discusses the possibilities of utilizing these recent results for wastewater treatment.     

厌氧氨氧化菌群体感应系统研究

厌氧氨氧化(Anammox)是以铵为电子供体将亚硝酸盐转化为氮气的生物过程。厌氧氨氧化菌(AAOB)生理代谢和细胞结构均十分特殊,且在氮素循环中起着十分重要的作用。厌氧氨氧化已成为环境学、微生物学、海洋学等领域的研究热点。但是,至今人们未能对厌氧氨氧化菌进行纯培养,这严重限制了对厌氧氨氧化菌的深入研究。群体感应是一种普遍存在于微生物细胞之间的通讯机制,它具有根据菌群密度和周围环境变化调节基因表达,以控制细菌群体行为的功能。厌氧氨氧化菌活性的细胞密度效应和生物团聚行为与细菌中普遍存在的群体感应现象相符。探讨了厌氧氨氧化菌群体感应系统存在的可能性、工作机制及其生态学意义,以期为厌氧氨氧化菌的分离培养、团聚体培育等提供理论指导。     

厌氧氨氧化细菌的研究进展

厌氧氨氧化是指微生物在无氧条件下,以NO2-为电子受体,将NH4+氧化成N2的过程,该过程主要由浮霉菌门下的厌氧氨氧化细菌参与.厌氧氨氧化细菌广泛存在于海洋生态系统、淡水生态系统、陆地生态系统及其他一些特殊生境中,其在废水生物脱氮和地球氮循环中扮演着重要角色.本文从厌氧氨氧化细菌的发现历程、种类、特性、代谢途径、分布、...     

厌氧氨氧化组合脱氮工艺研究进展

厌氧氨氧化工艺是一项高效、低耗的生物脱氮工艺,但受限于底物类型、硝氮积累等问题,其在主流应用中仍然面临一些挑战。近些年来,针对上述问题,厌氧氨氧化组合工艺得到了广泛关注。通过对近年来所开发的厌氧氨氧化组合工艺,从工艺原理、优缺点、影响因素、工艺拓展性及其在推广应用中存在的关键瓶颈等角度进行探讨,并结合课题组相关工作,展望了厌氧氨氧化组合工艺在城市生活污水处理中的发展前景。     

Enhancing mainstream nitrogen removal by employing nitrate/nitrite-dependent anaerobic methane oxidation processes

Due to serious eutrophication in water bodies, nitrogen removal has become a critical stage for wastewater treatment plants (WWTPs) over past decades. Conventional biological nitrogen removal processes are based on nitrification and denitrification (N/DN), and are suffering from several major drawbacks, including substantial aeration consumption, high fugitive greenhouse gas emissions, a requirement for external carbon sources, excessive sludge production and low energy recovery efficiency, and thus unable to satisfy the escalating public needs. Recently, the discovery of anaerobic ammonium oxidation (anammox) bacteria has promoted an update of conventional N/DN-based processes to autotrophic nitrogen removal. However, the application of anammox to treat domestic wastewater has been hindered mainly by unsatisfactory effluent quality with nitrogen removal efficiency below 80%. The discovery of nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) during the last decade has provided new opportunities to remove this barrier and to achieve a robust system with high-level nitrogen removal from municipal wastewater, by utilizing methane as an alternative carbon source. In the present review, opportunities and challenges for nitrate/nitrite-dependent anaerobic methane oxidation are discussed. Particularly, the prospective technologies driven by the cooperation of anammox and n-DAMO microorganisms are put forward based on previous experimental and modeling studies. Finally, a novel WWTP system acting as an energy exporter is delineated.     

Identification of a denitrifying bacterium and verification of its anaerobic ammonium oxidation ability

A strain D₃ of denitrifying bacterium was isolated from an anammox reactor, and identified as Pseudomonas mendocina based on the morphological and physiological assay, Vitek test, Biolog test, (G+C) mol% content, and 16S rDNA phylogenetic analysis. As a typical denitrifying bacterium, strain D₃ achieved the maximal nitrate reduction rate of 26.2 mg/(L·d) at the nitrate concentration of 88.5 mg N/L. The optimal pH and growth temperature were 7.84 and 34.9°C, respectively. Strain D₃ was able to oxidize ammonia under anaerobic condition. The maximum nitrate and ammonium utilization rates were 6.37 mg/(L·d) and 3.34 mg/(L·d), respectively, and the consumption ratio of ammonia to nitrate was 1:1.91. Electron microscopic observation revealed peculiar cell in clusions in strain D₃. Because of its relation to anammox activity, strain D₃ was presumed to be anammoxosome. The present investigation proved that denitrifying bacteria have the anammox ability, and the results have engorged the range of anammox populations.     

Identification of a denitrifying bacterium and verification of its anaerobic ammonium oxidation ability

A strain D3 of denitrifying bacterium was isolated from an anammox reactor,and identi-fied as Pseudomonas mendocina based on the morphological and physiological assay,Vitek test,Biolog test,(G C) mol% content,and 16S rDNA phylogenetic analysis.As a typical denitrifying bac-terium,strain D3 achieved the maximal nitrate reduction rate of 26.2 mg/(L·d) at the nitrate concen-tration of 88.5 mg N/L.The optimal pH and growth temperature were 7.84 and 34.9℃,respectively.Strain D3 was able to oxidize ammonia under anaerobic condition.The maximum nitrate and ammo-nium utilization rates were 6.37 mg/(L·d) and 3.34 mg/(L·d) ,respectively,and the consumption ratio of ammonia to nitrate was 1:1.91.Electron microscopic observation revealed peculiar cell inclusions in strain D3.Because of its relation to anammox activity,strain D3 was presumed to be anammoxosome.The present investigation proved that denitrifying bacteria have the anammox ability,and the results have engorged the range of anammox populations.     

PVA-alginate immobilized cells for anaerobic ammonium oxidation (anammox) process

The feasibility of an anaerobic ammonium oxidation (anammox) process combined with a cell-immobilization technique for autotrophic nitrogen removal was investigated. Anammox biomass was cultivated from local activated sludge and achieved significant anammox activity in 6 months. The development of a mature anammox biomass was confirmed by fluorescence in situ hybridization (FISH) analysis and off-line activity measurements. The abundance fraction of the anammox bacteria determined by FISH analysis was estimated by software. The anaerobic ammonia oxidizers occupied almost half of the total cells. Additionally, the anammox biomass was granulated as spherical gel beads of 3-4 mm in diameter by using a cell-immobilization technique. The nitrogen removal activity was proved to be successfully retained in the beads, with about 80% of nitrogenous compounds (NH(4) (+), NO(2) (- )and total nitrogen) removed after 48 h. These results offer a promising technique for the preservation of anammox microorganisms, the protection of them against the unfavorable surroundings, and the prevention of biomass washout towards the implementation of sustainable nitrogen elimination biotechnology. This is the first report on the immobilization of anammox biomass as gel beads.     

自然生态系统中的厌氧氨氧化

厌氧氨氧化（anaerobic ammonium oxidation,anammox）是由anammox菌在缺氧条件下以氨为电子供体、以亚硝酸为电子受体的生物反应,反应产物为氮气,该反应的发现为全球氮素循环增添了新的内容。参与anammox反应的微生物是anammox菌,anammox菌是一群分支很深的浮霉状菌,目前已发现的anammox菌有5个属8个种。催化anammox反应的是一特殊的细胞结构-厌氧氨氧化体,每种已发现的anammox菌中都存在该特殊结构。有关anammox反应的生化机理目前普遍认为,NO和联氨（N2H4）是anammox反应的重要中间体,NO可将NH4 直接氧化,形成N2H4,N2H4在联氨氧化酶的作用下最终转化为氮气。Anammox最初发现于人工脱氮系统,已发现的8种anammox菌中7种来自于人工系统。但越来越多的证据表明,anammox菌广泛分布于自然界的海洋、淡水和陆地生态系统中,在区域氮素循环中起着不同程度的作用。影响自然生态系统中anammox反应的主要环境因子包括有机质含量、NO3-浓度和盐度等,但在不同的生态系统,anammox反应的主导影响因子存在较明显差异。本文综述了anammox菌的类群和生化反应机理,总结了anammox菌在各种自然生态系统中的分布与生态多样性,并论述了anammox反应在全球氮素循环中的重要性以及影响此过程发挥的主要环境因子。     

Immobilization of anaerobic sludge using chitosan crosslinked with lignosulfonate

A new method for immobilization of anaerobic sludge in chitosan is described. It is based on the reaction of basic NH₂ groups of chitosan with the acidic sulfonic-groups of lignosulfonate to form sulfonilamide linkages. The new procedure features simplicity, low-cost and mild immobilization conditions. Batch tests of acetate consumption along with a continuous reactor operation confirmed the effectiveness of the immobilization technique for maintenance of long-term stability of the polymer. Received 27 March 1997/ Accepted in revised form 01 October 1997     

Nitrogen removal performance of anaerobic ammonia oxidation (ANAMMOX) in presence of organic matter

A sequencing batch reactor (SBR) was used to test the nitrogen removal performance of anaerobic ammonium oxidation (ANAMMOX) in presence of organic matter. Mesophilic operation (30 ± 0.5 °C) was performed with influent pH 7.5. The results showed, independent of organic matter species, ANAMMOX reaction was promoted when COD was lower than 80 mg/L. However, specific ANAMMOX activity decreased with increasing organic matter content. Ammonium removal efficiency decreased to 80% when COD of sodium succinate, sodium potassium tartrate, peptone and lactose were 192.5, 210, 225 and 325 mg/L, respectively. The stoichiometry ratio resulting from different OM differed largely and R₁ could be as an indicator for OM inhibition. When COD concentration was 240 mg/L, the loss of SAA resulting from lactose, peptone, sodium potassium tartrate and sodium succinate were 28, 36, 50 and 55%, respectively. Sodium succinate had the highest inhibitory effect on SAA. When ANAMMOX process was used to treat wastewater containing OM, the modified Logistic model could be employed to predict the NRE_max.     

Cold shocks of Anammox biofilm stimulate nitrogen removal at low temperatures

The adaptation of Anammox (ANaerobic AMMonium OXidation) to low temperatures (10–15°C) is crucial for sustaining energy‐efficient nitrogen removal from the mainstream of municipal wastewater. But, current adaptation methods take months or even years. To speed up the adaption of Anammox to low temperatures, this study describes a new approach: exposing Anammox microorganisms to an abrupt temporary reduction of temperature, i.e., cold shock. Anammox biomass in a moving bed biofilm reactor was subjected to three consecutive cold shocks (reduction from 24 ± 2 to 5.0 ± 0.2°C), each taking eight hours. Before the cold shocks, Anammox activity determined in ex situ tests using the temperature range of 12.5–19.5°C was 0.005–0.015 kg‐N kg‐VSS^?1 day^?1. Cold shocks increased the activity of Anammox at 10°C to 0.054 kg‐N kg‐VSS^?1 day^?1 after the third shock, which is similar to the highest activities obtained for cold‐enriched or adapted Anammox reported in the literature (0.080 kg‐N kg‐VSS^?1 day^?1). Fluorescence in situ hybridization analysis showed that Ca. Brocadia fulgida was the dominant species. Thus, cold shocks are an intriguing new strategy for the adaptation of Anammox to low temperature. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 34:277–281, 2018     

Anammox bacteria enrichment in upflow anaerobic sludge blanket (UASB) reactor

We investigated the anaerobic ammonium oxidation (anammox) reaction in a labscale upflow anaerobic sludge blanket (UASB) reactor. Our aim was to detect and enrich the organisms responsible for the anammox reaction using a synthetic medium that contained low concentrations of substrates (ammonium and nitrite). The reactor was inoculated with granular sludge collected from a full-scale anaerobic digestor used for treating brewery wastewater. The experiment was performed during 260 days under conditions of constant ammonium concentration (50 mg NH₄/⁺-N/L) and different nitrite concentrations (50∼150 mg NO₂-N/L). After 200 days, anammox activity was observed in the system. The microorganisms involved in this anammox reaction were identified as CandidatusB. Anammoxidans andK. Stuttgartiensis using fluorescencein situ hybridization (FISH) method.     

Iron-mediated anaerobic ammonium oxidation recorded in the early Archean ferruginous ocean

The nitrogen isotopic composition of organic matter is controlled by metabolic activity and redox speciation and has therefore largely been used to uncover the early evolution of life and ocean oxygenation. Specifically, positive δ¹⁵N values found in well-preserved sedimentary rocks are often interpreted as reflecting the stability of a nitrate pool sustained by water column partial oxygenation. This study adds much-needed data to the sparse Paleoarchean record, providing carbon and nitrogen concentrations and isotopic compositions for more than fifty samples from the 3.4 Ga Buck Reef Chert sedimentary deposit (BRC, Barberton Greenstone Belt). In the overall anoxic and ferruginous conditions of the BRC depositional environment, these samples yield positive δ¹⁵N values up to +6.1‰. We argue that without a stable pool of nitrates, these values are best explained by non-quantitative oxidation of ammonium via the Feammox pathway, a metabolic co-cycling between iron and nitrogen through the oxidation of ammonium in the presence of iron oxides. Our data contribute to the understanding of how the nitrogen cycle operated under reducing, anoxic, and ferruginous conditions, which are relevant to most of the Archean. Most importantly, they invite to carefully consider the meaning of positive δ¹⁵N signatures in Archean sediments.     

Modeling a granule‐based anaerobic ammonium oxidizing (ANAMMOX) process

A mathematical model was developed to describe the anaerobic ammonium oxidation (ANAMMOX) process in a granular upflow anaerobic sludge blanket (UASB) reactor. ANAMMOX granules were cultivated in the UASB reactor by seeding aerobic granules. The granule‐based reactor had a great N‐loading resistant capacity. The model simulation results on the 1‐year reactor performance matched the experimental data well. The yield coefficient for the growth and the decay rate coefficient of the ANAMMOX granules were estimated to be 0.164 g COD g^?1 N and 0.00016 h^?1, respectively. With this model, the effects of process parameters on the reactor performance were evaluated. Results showed that the optimum granule diameter for the maximum N‐removal should be between 1.0 and 1.3 mm and that the optimum N loading rate should be 0.8 kg N m^?3 d^?1. In addition, the substrate micro‐profiles in the ANAMMOX granules were measured with a microelectrode to explore the diffusion dynamics within the granules, and the measured profiles matched the predicted results well. Biotechnol. Bioeng. 2009;103: 490–499. © 2009 Wiley Periodicals, Inc.     

舟山群岛海域沉积物厌氧氨氧化细菌多样性

通过构建16S rRNA基因文库和克隆测序研究了舟山海域沉积物中厌氧氨氧化细菌(AAOB)的多样性。从5个克隆文库中共获得297条16S rRNA基因序列,包含16个操作分类单元(OTUs)。离岸距离较近的3个站具有相似的群落结构,且与离岸较远的2个站具有明显差异。系统发育结果显示,Scalindua属是该海域AAOB的优势类群,95.3%的序列与Scalindua属AAOB具有较近的亲缘关系;1条序列与Kuenenia属具有较近的亲缘关系;此外还有15条序列与已知的AAOB相似性较低。相关性分析表明沉积物有机碳含量与多样性指数具有显著正相关,可能是该海域AAOB多样性变化的重要影响因子。