进水碳氮比对CANON型人工湿地脱氮性能的影响

通过逐步提高进水中的有机碳源浓度,探讨进水碳氮比(C/N)对基于亚硝化的全程自养脱氮(CANON)型潮汐流人工湿地(TFCW)脱氮效能及其微生物特性的影响.结果表明: 进水C/N可显著影响CANON型TFCW中脱氮功能微生物的数量与活性,进而影响其氮素转化速率.当进水C/N由0.0增至6.0时,TFCW中反硝化功能基因的丰度随之增加,系统反硝化性能提高,TFCW中逐渐形成同步亚硝化、厌氧氨氧化与反硝化(SNAD)耦合反应体系,其脱氮效果得以强化.当进水C/N＞6.0时,好氧氨氧化菌活性受到抑制,数量逐渐减少,TFCW中的厌氧氨氧化作用与反硝化作用受阻,系统脱氮性能恶化.当进水C/N为6.0时,TFCW中的SNAD作用可得到最大限度的强化,其总氮(TN)去除率和去除负荷分别达(93.3±2.3)%和(149.30±8.00) mg·L^-1·d^-1,高于CANON系统中TN去除率的理论值.     

生物电化学耦合厌氧氨氧化强化脱氮及其微生物群落特征

为探究生物电化学强化厌氧氨氧化(anaerobic ammonia oxidation,anammox)脱氮作用过程,采用双室微生物电解池(microbial electrolysis cell,MEC)富集电活性微生物,构建耦合厌氧氨氧化阴极的生物电化学系统。具体地,在外加0.2 V电压条件下改变不同总氮进水浓度于30°C进行暗培养批次实验研究,结合循环伏安法、电化学阻抗谱、高通量测序方法等多种表征手段研究了强化脱氮机理。结果表明,在初始总氮浓度分别为200、300和400 mg/L时对应获得了96.9%±0.3%、97.3%±0.4%和99.0%±0.3%的总氮去除率,且阴极电极生物膜表现出良好的电化学活性。高通量测序结果表明外加电压富集了除厌氧氨氧化菌以外的其他脱氮功能菌群:反硝化菌(Denitratisoma)、Limnobacter和氨氧化菌SM1A02和Anaerolineaceae、亚硝化菌(Nitrosomonas europaea)和硝化螺菌属(Nitrospira)等,这些具有电化学活性的微生物构成了体系的氨氧化胞外产电菌(ammonium oxidizing exoelectrogens,AOE)和反硝化电养菌(denitrifying electrotrophs,DNE),它们连同厌氧氨氧化菌Candidatus Brocadia构成了系统的脱氮微生物群落结构。AOE和DNE的种间直接电子传递作用协同厌氧氨氧化是强化系统总氮去除的关键原因。     

溶解氧对单级自养脱氮系统功能菌数量的影响

摘要：【目的】研究溶解氧（Dissolved oxygen, DO）对单级自养脱氮系统功能菌数量的影响,为系统运行操控提出理论指导。【方法】从不同DO水平下的单级自养脱氮反应器中,分别提取活性污泥及生物膜样品基因组DNA,通过特异引物扩增系统内亚硝化菌（Ammonia oxidizing bacteria, AOB）、硝化菌（Nitrite oxidizing bacteria, NOB）及厌氧氨氧化菌（Anaerobic ammonia oxidizing bacteria, ANAMMOX）基因序列,PCR产物经回收克隆测序后,证实扩增产物为AOB、NOB及ANAMMOX 16S rDNA 保守序列,以含该序列的重组质粒作为定量PCR标准品。用荧光定量PCR技术对单级自养脱氮系统中各类功能菌进行定量分析。【结果】高DO有利于亚硝化菌AOB及硝化菌NOB生存,同时,活性污泥中AOB、NOB数量多于生物膜。DO对厌氧氨氧化菌ANAMMOX数量影响明显,高DO浓度将对ANAMMOX数量产生直接抑制,低DO浓度水平时,由于系统内缺乏厌氧氨氧化反应的电子受体NO3-或NO2-,也将间接影响ANAMMOX数量。【结论】本试验研究条件下,DO为(曝气)2.0/(停曝) 0.4 mg/L时系统运行效能最佳,ANAMMOX数量最多,AOB、NOB及ANAMMOX在此时构成一个协同代谢的稳定状态。     

有机碳源下废水厌氧氨氧化同步脱氮除碳

为明确有机碳源胁迫下,厌氧氨氧化反应器的同步脱氮除碳规律及功能微生物群落结构的动态变化,采用成功启动的厌氧氨氧化UASB反应器,通过逐步提升进水有机负荷,探究有机碳源下废水厌氧氨氧化同步脱氮除碳。研究表明,当进水化学需氧量(Chemical oxygen demand,COD)浓度从172 mg/L升至620 mg/L,反应器维持较高的脱氮效率,氨氮和总氮去除率均在85%以上,并对COD具有平均56.6%的去除率,高浓度COD未对Anammox菌活性构成显著抑制作用。聚合酶链式反应和变性梯度凝胶电泳(PCR-DGGE)图谱和割胶测序结果表明,变形菌门Proteobacteria、浮霉菌门Planctomycetes、绿曲挠菌门Chloroflexi以及绿菌门Chlorobi等微生物共存于同一反应体系中,推测反应器内存在复杂的脱氮除碳途径。而且,代表厌氧氨氧化的部分浮霉菌门微生物能耐受高浓度有机碳源,在高有机负荷下依旧发挥着高效的脱氮作用,为反应器高效脱氮提供了保障。     

OLAND生物脱氮系统中硝化菌群16S rDNA的DGGE分析

为了考察生物脱氮系统中硝化菌群（氨氧化菌和亚硝酸氧化菌）的种群多样性及硝化菌群随溶解氧降低的种群变化规律,并建立一套行之有效的用于自养生物脱氮系统中功能微生物菌群的快速分子检测技术,采用DGGE（变性梯度凝胶电泳）分子检测技术对硝化菌群的16SrDNA的特异性PCR扩增产物进行了分析,结果表明：OLAND生物脱氮系统中氨氧化菌和亚硝酸氧化菌随溶解氧的降低表现出了不同的种群变化规律,氨氧化菌种群多样性受溶解氧的影响非常大,而非亚硝酸氧化菌的种群多样性比较单一,且不受溶解氧的影响。结合FISH（全细胞荧光原位杂交）分析结果表明,在OLAND限氧稳定运行后期,亚硝化单胞菌属（Nitrosomonas）是主要的氨氧化菌,占OLAND限氧亚硝化阶段反应器中总细菌数的72.5%左右。     

铁矿物强化厌氧氨氧化效能及其微生物机制研究进展

自然界中的氮循环与铁循环相互交联,参与氮循环的厌氧氨氧化（anaerobic ammonium oxidation,anammox）菌的生长代谢及活性发挥也与铁元素紧密关联。自然界广泛存在的铁矿物因具有运行成本低廉、稳定性好、二次污染小等优势,在污水处理领域得到广泛应用。在厌氧氨氧化脱氮系统中引入适量铁矿物,不仅有助于促进anammox菌和铁还原菌的富集,提高功能基因丰度和相关酶活性,还可能通过影响污泥浓度、血红素c含量、胞外聚合物含量和颗粒化程度,改善污泥性能和提高厌氧氨氧化系统的稳定性。同时,铁矿物具有促进体系多种氮素转化途径（如anammox、铁自养反硝化、铁氨氧化、异化硝酸盐还原成铵和反硝化）相耦合的潜能,可以提高anammox污水处理系统的总氮去除率。本文基于铁矿物在促进污水生物脱氮方面的良好性能及其在anammox系统中的变化,从脱氮效能、污泥特性、微生物特征及酶活性等方面,系统综述了铁矿物对厌氧氨氧化系统的强化作用机制,并从anammox菌对铁矿物的利用及铁元素的摄取角度展望了后续的研究方向,以期为铁矿物强化厌氧氨氧化系统的实际应用提供理论和技术指导。     

厌氧氨氧化菌驱动脱氮途径的研究进展

厌氧氨氧化菌(anaerobic ammonia-oxidizing bacteria, AnAOB)的代谢多样性,使得该菌群能够在海洋、湿地和陆地等不同的自然生态系统中广泛分布,甚至在一些极热和极寒环境中也检测到了该菌群的存在。本文回顾并总结了厌氧氨氧化菌在不同生态系统中的发现、分布及脱氮贡献等方面的研究,分析了厌氧氨氧化菌分布的主要环境影响因素。该综述将帮助我们更好地理解全球氮循环中厌氧氨氧化菌的实际角色和功能,并基于厌氧氨氧化(anaerobicammoniaoxidation,anammox)过程,探究能与其进行协作的新型生物脱氮工艺,以期为这些工艺的研发和推广提供生态学基础和新的思考,从而实现脱氮工艺的技术变革。     

好氧甲烷氧化耦合反硝化极限脱氮系统的效能及应用

【目的】探究甲烷浓度、温度和氮浓度对好氧甲烷氧化耦合反硝化(AME-D)极限脱氮系统的影响,分析该系统微生物群落结构,并对贵阳某污水处理厂尾水进行应用研究。【方法】采用阶段性实验研究甲烷浓度、温度和氮浓度对系统脱氮效能的影响,通过16SrRNA基因测序技术分析系统中微生物群落结构,利用共焦显微拉曼光谱仪分析实际废水水质变化特征。【结果】甲烷进气比为3%、温度为30°C、氮浓度为20 mg/L时脱氮效果最好,系统的总氮、氨氮和硝酸盐氮平均去除率分别为93.66%、96.13%和92.25%;系统中的主要甲烷氧化菌分别为Methylosarcina(1.84%)、Methylovulum(0.01%)和Crenothrix(0.14%),以及兼性甲烷氧化菌属Methylocystis(1.9%),主要的亚硝化菌为Nitrosomonas(0.008%),硝化菌为Nitrospira (0.42%),反硝化菌为Hyphomicrobium (1.19%)和Pseudomonas (0.61%);采用该系统处理贵阳某污水处理厂尾水时,出水总氮平均浓度达到0.96mg/L,能达到极限脱氮的目的,拉曼光谱分析显示系统对硝酸盐氮和亚硝酸盐氮有较高的去除,甲烷被氧化形成的中间产物可能为醇类或醛类物质,为反硝化菌提供所需碳源。【结论】AME-D极限脱氮由多种微生物协同实现,其功能微生物为甲烷氧化菌、亚硝化菌、硝化菌和反硝化菌,应用研究显示该系统在城镇污水处理系统中具有较大的应用潜力。     

湖泊氮素氧化及脱氮过程研究进展

自然界中氮的生物地球化学循环主要由微生物驱动,由固氮作用、硝化作用、反硝化作用和氨化作用来完成。过去数十年间,随着异养硝化、厌氧氨氧化和古菌氨氧化作用的发现,人们对环境中氮素循环认识逐步深入,提出了多种脱氮途径新假说。对湖泊生态系统中氮素的输入、输出及其在水体、沉积物和水土界面的迁移转化过程进行了概括,对湖泊生态系统中反硝化和厌氧氨氧化脱氮机理及脱氮效率的最新研究进展进行了探讨,并对以后的氮素循环研究进行了展望。     

污水短程硝化体系氨氧化菌与亚硝酸盐氧化菌的生态学研究进展

短程硝化(partial nitrification, PN)是一种绿色低碳的生物脱氮创新技术,伴随厌氧氨氧化(anaerobic ammonia oxidation, Anammox)污水脱氮技术的进一步推广,短程硝化作为提供其电子受体的重要环节,已成为了污水脱氮领域的研究热点。氨氧化菌(ammonia-oxidizing bacteria,AOB)和亚硝酸盐氧化菌(nitrite-oxidizing bacteria, NOB)是该技术的核心竞争微生物,掌握这两类微生物的生态学特征,借助生态学理论和手段调控AOB淘汰NOB,提高种群的可预测性,对于实现稳定高效的短程硝化具有重要意义。本文基于生态学角度介绍了AOB和NOB基础分类、生理性能及生态位分离,重点综述了短程硝化系统中AOB和NOB的生长动力学、群落构建、环境因素和相互作用,最后对这两类微生物的未来研究重点和研究方法进行了展望,为短程硝化工艺的快速启动和稳定运行提供理论指导。     

Assessment of the positive effect of salinity on the nitrogen removal performance and microbial composition during the start-up of CANON process

In this study, a non-woven rotating biological contactor reactor was operated for the start-up of completely autotrophic nitrogen removal over nitrite (CANON) process. In this perfectly attached growth system, nitrite oxidizing was identified, which interfered with the nitrogen removal performance. Batch tests indicated that 10 g NaCl per liter salinity was a preferable definite level to stand out ammonium-oxidizing activity and anammox activity, and selectively suppress nitrite-oxidizing activity under oxygen-limited conditions. Reactor operation showed that the maximum TN removal rate was increased from 425 mg N l(-1) day(-1) to 637 mg N l(-1) day(-1) after the addition of 10 g NaCl per liter salinity on analogous technological parameters. Microbiological community analysis revealed that bacteria strains similar to the genus Nitrospira sp. were specialized nitrite oxidizers existing in CANON reactor, which were then eliminated under salinity exposure for their no salinity-tolerant relative. However, anammox bacteria belonging to Planctomycetes and some aerobic ammonium oxidizers belonging to Nitrosomonas could be highly enriched under this oxygen-limited salinity conditions. Salinity-contained high ammonium wastewater will be so considered as suitable influent for CANON process in further industrial application.     

三级串联垂直潜流人工湿地的脱氮性能及微生物学特征

探究了3种水力负荷(HLR)下三级串联垂直潜流人工湿地(T-VFCWs)对农村生活污水的处理效果,并解析了系统中的氮素转化机制。结果表明: 当系统HLR由0.10增至0.20 m³·m^-2·d^-1时,T-VFCWs始终保持着对农村生活污水高效的处理效果,系统出水水质满足《城镇污水处理厂污染物排放标准》(GB 18918—2002)一级A标准。T-VFCWs中顺次连接的3个VFCW单元(标记为V-1、V-2和V-3)在限氧环境下因其进水水质的差异可形成各自不同的氮素转化途径,并通过协同作用实现系统的高效脱氮。当T-VFCWs在试验期间连续运行时,V-1、V-2和V-3中主要的脱氮途径分别为短程硝化/反硝化作用、基于亚硝化的全程自养脱氮(CANON)作用和反硝化作用,上述3单元对进水中总氮(TN)和NH₄⁺-N去除的贡献率分别为(51.3±4.4)%和(63.7±2.6)%、(30.9±4.8)%和(35.5±4.5)%、(17.8±5.0)%和(0.8±0.1)%。该研究可为组合式人工湿地的研发及工程化应用提供科学依据和技术支撑。     

Potential coupling effects of ammonia-oxidizing and anaerobic ammonium-oxidizing bacteria on completely autotrophic nitrogen removal over nitrite biofilm formation induced by the second messenger cyclic diguanylate

The objective of this study was to investigate the influence of extracellular polymeric substance (EPS) on the coupling effects between ammonia-oxidizing bacteria (AOB) and anaerobic ammonium-oxidizing (anammox) bacteria for the completely autotrophic nitrogen removal over nitrite (CANON) biofilm formation in a moving bed biofilm reactor (MBBR). Analysis of the quantity of EPS and cyclic diguanylate (c-di-GMP) confirmed that the contents of polysaccharides and c-di-GMP were correlated in the AOB sludge, anammox sludge, and CANON biofilm. The anammox sludge secreted more EPS (especially polysaccharides) than AOB with a markedly higher c-di-GMP content, which could be used by the bacteria to regulate the synthesis of exopolysaccharides that are ultimately used as a fixation matrix, for the adhesion of biomass. Indeed, increased intracellular c-di-GMP concentrations in the anammox sludge enhanced the regulation of polysaccharides to promote the adhesion of AOB and formation of the CANON biofilm. Overall, the results of this study provide new comprehensive information regarding the coupling effects of AOB and anammox bacteria for the nitrogen removal process.

     

The ammonium nitrogen oxidation process in horizontal subsurface flow constructed wetlands

The ammonium nitrogen oxidation process (ANOP) is the first and most important step for nitrogen removal in constructed wetlands (CWs). The process was investigated by observing the products generated from the ANOP in on-site aerobic systems with selective inhibition of nitrite-oxidizing bacteria (NOB) through appropriate regulation of the pH, temperature and dissolved oxygen concentrations. The effects of season, plant type and density on ANOP were also studied to determine the optimal conditions for the ANOP. Nitrite accumulation was found in the aerobic experiments and greater ammonia-oxidizing bacteria than NOB numbers, showing that partial nitrification to nitrite was occurring in the studied CWs. The nitrogen removal rate was positively linearly correlated with the nitrite accumulation rate, and so the more NH₃-N removed by ANOP, the greater the resulting nitrogen removal. Season and plant density had a significant effect on the ANOP. However, there were no significant differences between the units planted with common reed and cattail.     

Application, eco-physiology and biodiversity of anaerobic ammonium-oxidizing bacteria

The demand for new and sustainable systems for nitrogen removal has increased dramatically in the last decade. It is clear that the conventional systems cannot deal with the increasing nitrogen loads in a cost effective way. As an alternative, the implementation of the anammox (anaerobic ammonium oxidation) process in the treatment of wastewater with high ammonium concentrations has been started. The compact anammox reactors can sustain high nitrogen loads without any problems. The highest observed anammox capacity is 8.9 kg N removed m^-3 reactor day^-1. The first 75 m³ anammox reactor is operating in Rotterdam, the Netherlands, combined with the partial nitrification process Single reaction system for High Ammonium Removal Over Nitrite (SHARON). Partial nitrification and anammox can also be combined in one reactor systems like Completely Autotrophic Nitrogen removal Over Nitrite (CANON) or Oxygen Limited Ammonium removal via Nitrification Denitrification (OLAND) where aerobic ammonium-oxidizing bacteria (AOB) and anammox bacteria cooperate under oxygen-limitation. These systems remove about 1.5 kg N m^-3 reactor day^-1. In addition to ammonium, urea can also be converted in the CANON system after a two-week adaptation period. The ecophysiological properties of the anammox bacteria make them very well suited to convert ammonium and nitrite. The K_s values for ammonium and nitrite are below 5 M. However, nitrite above 10 mM is detrimental for the anammox process, and oxygen reversibly inhibits the process at concentrations as low as 1 M. Acetate and propionate can be used by the anammox bacteria to convert nitrite and nitrate, whereas methanol and ethanol severely inhibit the anammox reaction. The enzyme hydroxylamine/hydrazine oxidoreductase (HAO), one of the key enzymes, is located in the anammoxosome, which is a membrane bound organelle. The membranes of the anammox bacteria contain unique ladderane lipids and hopanoids. The bacteria responsible for the anammox reaction are related to the Planctomycetes. The first anammox bacteria were isolated via Percoll centrifugation and characterized as Candidatus Brocadia anammoxidans. Survey of different wastewater treatment plants using anammox specific 16S rRNA gene primers and anammox specific oligonucleotide probes has revealed the presence of at least three other anammox bacteria, which have been tentatively named Candidatus Kuenenia stuttgartiensis, Candidatus Scalindua wagneri and Candidatus Scalindua brodae. A close relative of the latter, Candidatus Scalindua sorokinii was found to be responsible for about 50% of the nitrogen conversion in the anoxic zone of the Black Sea, making the anammox bacteria an important player in the oceanic nitrogen cycle.     

Identification of bacteria coexisting with anammox bacteria in an upflow column type reactor

Anammox process has attracted considerable attention in the recent years as an alternative to conventional nitrogen removal technologies. In this study, a column type reactor using a novel net type acrylic fiber (Biofix) support material was used for anammox treatment. The Biofix reactor was operated at a temperature of 25°C (peak summer temperature, 31.5°C). During more than 340 days of operation for synthetic wastewater treatment, the nitrogen loading rates of the reactor were increased to 3.6 kg-N/m³/d with TN removal efficiencies reaching 81.3%. When the reactor was used for raw anaerobic sludge digester liquor treatment, an average TN removal efficiency of 72% was obtained with highest removal efficiency of 81.6% at a nitrogen loading rate of 2.2 kg-N/m³/d. Results of extracellular polymeric substances (EPS) quantification revealed that protein was the most abundant component in the granular sludge and was found to be almost twice than that in the sludge attached to the biomass carriers. The anammox granules in the Biofix reactor illustrated a dense morphology substantiated by scanning electron microscopy and EPS results. The results of DNA analyses indicated that the anammox strain KSU-1 might prefer relatively low nutrient levels, while the anammox strain KU2 strain might be better suited at high nutrient concentration. Other types of bacteria were also identified with the potential of consuming dissolved oxygen in the influent and facilitating survival of anammox bacteria under aerobic conditions.     

The CANON system (Completely Autotrophic Nitrogen-removal Over Nitrite) under ammonium limitation: interaction and competition between three groups of bacteria

The CANON system (Completely Autotrophic Nitrogen Removal Over Nitrite) can potentially remove ammonium from wastewater in a single, oxygen-limited treatment step. The usefulness of CANON as an industrial process will be determined by the ability of the system to recover from major disturbances in feed composition. The CANON process relies on the stable interaction between only two bacterial populations: Nitrosomonas-like aerobic and Planctomycete-like anaerobic ammonium oxidising bacteria. The effect of extended periods of ammonium limitation was investigated at the laboratory scale in two different reactor types (sequencing batch reactor and chemostat). The lower limit of effective and stable nitrogen removal to dinitrogen gas in the CANON system was 0.1 kg N m(-3) day(-1). At this loading rate, 92% of the total nitrogen was removed. After prolonged exposure (> 1 month) to influxes lower than this critical NH4+-influx, a third population of bacteria developed in the system and affected the CANON reaction stoichiometry, resulting in a temporary decrease in nitrogen removal from 92% to 57%. The third group of bacteria were identified by activity tests and qualititative FISH (Fluorescence In Situ Hybridisation) analysis to be nitrite-oxidising Nitrobacter and Nitrospira species. The changes caused by the NH4+-limitation were completely reversible, and the system re-established itself as soon as the ammonium limitation was removed. This study showed that CANON is a robust system for ammonium removal, enduring periods of up to one month of ammonium limitation without irreversible damage.     

反硝化基因工程菌株YP4S的构建及对污水除氮特性研究

从养殖场污泥中筛选出菌株YP4,经16S rDNA分子发育树的同源序列比对,确定为克雷伯什菌属(Klebsiella sp.)。由NCBI数据库查编码亚硝酸还原酶(Nir)的基因nirS序列,设计引物,以铜绿假单胞菌PAOI基因组DNA为模板,应用PCR技术扩增目的片段nirS,经过双酶切、克隆和转化,得到重组质粒pYP4S,然后转化野生菌株YP4,构建反硝化基因工程菌YP4S。菌株生长曲线测定表明,工程菌株YP4S与YP4的生长特性基本一致。工程菌株YP4S对模拟污水COD、TN、NH_4^+-N和NO_3^--N具有较高的去除率,YP4S与YP4相比,对NO_2^--N积累的减少量为(32.44±3.96)%,明显减少了NO_2^--N的积累。通过正交试验获得工程菌株YP4S在C/N=10、T=30℃、r=200 r/min和pH=7.0的最佳组合条件下,对模拟污水TN去除率较高。应用工程菌株YP4S处理猪场沉淀池的实际污水,COD、TN、TP、NH_4^+-N和NO_3^--N去除率分别为(95.87±0.82)%、(76.38±3.84)%、(97.13±0.54)%和(75.35±2.57)%,NO_2^--N积累量为(3.31±1.24) mg/L,表明工程菌株YP4S具有较好反硝化作用,对含氮量高的实际污水修复具有潜在的应用前景。