厌氧氨氧化的生态因子研究进展

厌氧氨氧化生物脱氮技术是近年来发展起来的新型的生物脱氮技术,其实质是氨的亚硝化与亚硝化产物以氨为电子供体的还原相偶联.从生态因子的角度出发,综述了厌氧氨氧化的影响因子(生物因子及非生物因子)的研究进展.并对厌氧氨氧化的应用前景进行了展望,提出了其今后的研究方向.     

有机物对厌氧氨氧化菌活性影响研究进展

厌氧氨氧化反应(Anammax)功能菌世代时间长,生长条件苛刻,在有机物存在的条件下,反应过程和脱氮效果极易受到影响。因此,如何降低有机物对厌氧氨氧化菌(AAOB)活性的影响,是其应用的难点。近年来,研究者在有机物对Anammox反应影响方面开展了大量研究,本文主要综述了有机物的浓度和种类对AAOB活性的影响,并建议控制低浓度有机物环境下(100~200 mg/L以下),可降低有机物对AAOB活性的抑制;同时,可调控不同种类和浓度有机物的异位利用,形成Anammox-反硝化协同作用、Anammox-甲烷化-反硝化耦合作用等实现同步脱碳除氮。最后认为,在有机物对Anammox的影响方面,还可进一步开展AAOB的新陈代谢机制、与其他菌种的竞争合作机理以及耦合作用下菌种富集纯化等方面的研究。     

硫酸盐型厌氧氨氧化性能的研究

研究了自养条件下硫酸盐型厌氧氨氧化的性能．试验表明,在无氧条件下,SO4^2-和NH4^＋化学性质稳定,两者间不发生化学反应．在厌氧反应器中接种厌氧消化污泥,经过三年多的连续驯化,可使厌氧反应器发生硫酸盐型厌氧氨氧化（NH4^＋-N和SO4^2-S同时减少）．在高基质浓度下,NH4＋-N和5042-浓度平均降低71．67和56．82mg．L^-1．硫酸盐型厌氧氨氧化的标准吉布斯自由能变化较小,反应可以发生,但不易进行．高基质浓度和低氧化还原电位对该反应有促进作用．     

厌氧氨氧化颗粒污泥性质及影响因素研究进展

厌氧氨氧化(Anammox)工艺具有能耗低、无需外加有机碳源、污泥产量低等优点而成为当前研究的热点。然而,厌氧氨氧化菌(An AOB)生长缓慢,如何实现其快速富集与有效持留成为制约其工程化应用的关键。Anammox污泥颗粒化可有效控制污泥的流失,成为Anammox工艺应用的主要形式。本文在阐述Anammox颗粒污泥快速启动控制策略的基础上,分析了Anammox颗粒污泥的微观结构和基本理化性质,并讨论了有机物、盐度、温度、金属离子、抗生素、信号分子(AHLs)及氮负荷等因素对污泥颗粒形成过程及基本结构性质的影响。期望本文能对Anammox颗粒污泥的基础研究和工程化应用提供有益参考。     

NiWS/γ-Al2O3催化剂上吲哚加氢脱氮反应:H2S和喹啉的影响

在连续固定床微反装置上考察了吲哚（IND）和1,2-二氢吲哚（HIN）在NiWS/γ-Al₂O₃催化剂上加氢脱氮（HDN）的反应以及 H₂S和喹啉（Q）对其加氢脱氮反应的影响。结果表明,碱性含氮化合物HIN较吲哚对其自身的加氢脱氮反应抑制作用更为明显。H₂S能够促进HIN的C（sp³）－N断裂,但抑制了邻乙基苯胺（OEA）的 C（sp²）－N断裂;同时吲哚加氢反应途径也受到了抑制。喹啉的添加严重降低了吲哚加氢脱氮反应的转化率和脱氮率;喹啉对吲哚加氢反应和C－N键断裂反应均产生明显的抑制作用。喹啉的抑制作用主要源于喹啉及其中间产物1,2,3,4-四氢喹啉（THQ1）和5,6,7,8 -四氢喹啉（THQ5）与吲哚及其中间产物的竞争吸附。     

一株硫酸盐型厌氧氨氧化菌的分离和鉴定

以硫酸盐为电子受体、氨为电子供体的反应称为硫酸盐型厌氧氨氧化,这是一个新的生物反应.迄今为止,虽已证明硫酸盐型厌氧氨氧化的存在,但并未获得进行该反应的微生物.本课题组从长期稳定运行的厌氧脱氮除硫反应器污泥中,分离获得了一株硫酸盐型厌氧氨氧化菌.形态观察、生理试验和16SrDNA序列比对表明,该菌株可归入Bacillus benzoevorans.以Biolog板检测发现,该菌株可利用多种碳源,基质多样性明显.其最适代谢pH为8.5,最适代谢温度为30℃.研究证明,该菌株可在无氧条件下,同时去除氨氮和硫酸盐,具有硫酸盐型厌氧氨氧化活性.这一发现为硫酸盐型厌氧氨氧化的确认提供了生物学证据,为新型生物脱氮除硫工艺的研发打下了基础,为微生物学增加了新的内容,为地球氮素和硫素循环提供了新的认识.     

基于氮掺杂活性炭催化氧化合成氮甲基氧化吗啉的研究

以三聚氰胺为氮源,商用活性炭为研究对象,通过“浸渍吸附+高温热处理”的方式制得系列氮掺杂活性炭,并用于催化氧化合成氮甲基氧化吗啉（NMMO）。采用N₂吸附/脱附、Raman、XPS等对氮掺杂活性炭的孔结构和表面性质进行了表征。结果表明：随着三聚氰胺负载量的增大,氮掺杂活性炭的表面碱性含氮官能团含量增大,进而体现出更好的催化氧化合成NMMO活性。最佳催化剂（ACO850-20N）在催化剂加量为0.02 wt%,反应温度70 ℃和反应时间4 h的工艺条件下,氮甲基吗啉的转化率和NMMO收率可达99.76%和94.31%。      

理论研究8-氮杂鸟嘌呤自由基阳离子脱质子反应

由于8-氮杂鸟嘌呤（8-AG）的氧化还原电势比鸟嘌呤（G）更低,所以单电子氧化嵌有8-AG的DNA后,空穴最终会被8-AG捕获形成8-氮杂鸟嘌呤自由基阳离子（8-AG^·+）.因为酸性的急剧增强,8-AG^·+一般会发生脱质子反应.在本工作中,在M06-2X/6-31+G（d）理论水平,使用显性水分子和连续溶剂化模型模拟8-AG^·+的溶剂化效应,对其脱亚氨基质子（N（1）-H）反应进行了研究.发现位于8-AG^·+中N（1）-H、O（6）、N（2）-H附近以及在O（6）水分子附近稍微远离8-AG^·+的4个水分子会对8-AG^·+脱质子反应产生重要影响,质子从8-AG^·+传递到溶液中具有方向性;最后,通过进一步在N（2）-H、N（3）、O（6）、N（7）和N（8）等位点附近添加水分子（9H₂O）得到了更加精确的8-AG^·+脱质子反应能垒（19.5 kJ/mol）.     

HEMA与HEA辐射共聚制备固定化微生物载体的结构与性能

应用低温辐射技术辐射诱导甲基丙烯酸β-羟乙酯(HEMA)和丙烯酸羟乙酯(HEA)共聚合制备了高分子载体,用增殖细胞技术固定氨氧化细菌。利用红外光谱(FT-IR)、X射线光电子能谱(XPS)、X射线衍射(XRD)、扫描电子显微镜(SEM)以及接触角和含水率的测试对聚合物载体进行了性能表征。结果表明:经充分溶胀后的聚合物表面水接触角几乎为0,含水率为450%,润湿性能良好;聚合物表面具有极性官能团;聚合物的非晶结构有利于小分子尤其是水分子的渗透和扩散,多孔结构有利于微生物的生长和繁殖。以聚合物为载体固定化氨氧化细菌在处理含氨废水的过程中实现了短程硝化,在3种氨氮负荷(100、1502、00 mg/L)条件下,氨氮去除率和亚硝化率可分别达到95%和90%以上。     

电化学氧化和臭氧化预处理酸性化工废水的效能研究

保持一定酸度条件下对比了电化学氧化和臭氧氧化预处理酸性化工废水的效能（废水原pH 0.85）. 结果表明,在废水中添加2 g·L^-1 NaCl电化学氧化预处理效果较佳,30 mA·cm^-2条件下电解20 min后水样的CODCr（化学需氧量）去除率达43.4%,BOD₅/COD_Cr（生化需氧量与化学需氧量的比值）值从原来的0.034上升至0.14,可生化性明显提高. 单独臭氧化仅在pH 7.0才能取得一定的预处理效能. Ti(Ⅳ)/O₃/H₂O₂高级氧化体系在pH 2.85条件下亦有较好的预处理效果,16 min后水样COD_Cr去除率达22.9%,BOD₅/COD_Cr值则提高至0.072.     

Influence of Free Ammonia on Completely Autotrophic Nitrogen Removal over Nitrite (CANON) Process

Free ammonia (FA) plays a significant role in the stable, long-term, completely autotrophic nitrogen removal over nitrite (CANON) system operation. The influence of FA on the CANON process in a sequencing batch biofilm reactor was explored. Under controlled FA concentrations of 5.0?mg L^?1 to 10.0?mg L^?1, nitrite-oxidizing bacteria (NOB) was inhibited and achieved partial nitrification, which was important for a successful and quick start-up of the CANON process from activated sludge. However, NOB was acclimated to the condition after the process start-up. Ammonia-oxidizing bacteria (AOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) activities were unaffected when FA concentration was increased from 10?mg L^?1 to 17?mg L^?1, but NOB was completely inhibited only for a short time. The AOB and AnAOB activities were inhibited and the CANON system was deteriorated when FA concentration reached 30?mg L^?1 to 32.5?mg L^?1 at pH?8.5, whereas NOB activity was unaffected. Correlation analysis showed that FA concentration higher than 20?mg L^?1 resulted in the deterioration of the system.     

Stable partial nitritation of mature landfill leachate in a continuous flow bioreactor: Long-term performance,microbial community evolution,and mechanisms

A continuous flow bioreactor was operated for 300 days to investigate partial nitritation (PN) of mature landfill leachate, establishing the long-term performance of the system in terms of the microbial community composition, evolution, and interactions. The stable operation phase (31–300 d) began after a 30 days of start-up period, reaching an average nitrite accumulation ratio (NAR) of 94.43% and a ratio of nitrite nitrogen to ammonia nitrogen (NO₂⁻-N/NH₄⁺-N) of 1.16. Some fulvic-like and humic-like compounds and proteins were effectively degraded in anaerobic and anoxic tanks, which was consistent with the corresponding abundance of methanogens and syntrophic bacteria in the anaerobic tank, and organic matter degrading bacteria in the anoxic tank. The ammonia-oxidizing bacteria (AOB) Nitrosomonas was found to be the key functional bacteria, exhibiting an increase in abundance from 0.27% to 6.38%, due to its collaborative interactions with organic matter degrading bacteria. In-situ inhibition of nitrite-oxidizing bacteria (NOB) was achieved using a combination of free ammonia (FA) and free nitrous acid (FNA), low dissolved oxygen (DO) with fewer bioavailable organics conditions were employed to maintain stable PN and a specific ratio of NO₂⁻-N/NH₄⁺-N, without an adverse impact on AOB. The synergistic relationships between AOB and both denitrifying bacteria and organic matter degrading bacteria, were found to contribute to the enhanced PN performance and microbial community structure stability. These findings provide a theoretical guidance for the effective application of PN-Anammox for mature landfill leachate treatment.     

Evaluation of the stability of shortcut nitrification-denitrification process based on online specific oxygen uptake rate monitoring

Shortcut nitrification-denitrification (SCND) is widely concerned because of its low energy consumption and high nitrogen removal efficiency. However, the current difficulty lies in the stable maintenance of SCND performance, which leads to the challenge of large-scale application of this new denitrification technology. In this study, the nitrogen removal pathway from complete nitrification-denitrification (CND) to SCND was rapidly realized under high free ammonia (FA), high pH and low dissolved oxygen (DO) conditions. The variations of specific oxygen uptake rate (SOUR) of activated sludge in both processes were investigated by an online SOUR monitoring device. Different curves of SOUR from CND to SCND process were observed, and the ammonia peak obtained based on SOUR monitoring could be used to control aeration time accurately in SCND process. Accordingly, the SOUR ratio of ammonia oxidizing bacteria (AOB) to nitrite oxidizing bacteria (NOB) (SOUR_AOB/SOUR_NOB) was increased from 1.40 to 2.93. 16S rRNA Miseq high throughput sequencing revealed the dynamics of AOB and NOB, and the ratio of relative abundance (AOB/NOB) was increased from 1.03 to 3.12. Besides, SOUR_AOB/SOUR_NOB displayed significant correlations to ammonia removal rate (P<0.05), ammonia oxidation rate / nitrite oxidation rate (P < 0.05), nitrite accumulation rate (P < 0.05) and the relative abundance of AOB/NOB (P < 0.05). Thus, a strategy for evaluation the SCND process stability based on online SOUR monitoring is proposed, which provides a theoretical basis for optimizing the SCND performance.     

UV-C Peroxymonosulfate Activation for Wastewater Regeneration: Simultaneous Inactivation of Pathogens and Degradation of Contaminants of Emerging Concern

This study explores the capability of Sulfate Radical-based Advanced Oxidation Processes (SR-AOPs) for the simultaneous disinfection and decontamination of urban wastewater. Sulfate and hydroxyl radicals in solution were generated activating peroxymonosulfate (PMS) under UV-C irradiation at pilot plant scale. The efficiency of the process was assessed toward the removal of three CECs (Trimethoprim (TMP), Sulfamethoxazole (SMX), and Diclofenac (DCF)) and three bacteria (Escherichia coli, Enterococcus spp., and Pseudomonas spp.) in actual urban wastewater (UWW), obtaining the optimal value of PMS at 0.5 mmol/L. Under such experimental conditions, bacterial concentration ≤ 10 CFU/100 mL was reached after 15 min of UV-C treatment (0.03 kJ/L of accumulative UV-C radiation) for natural occurring bacteria, no bacterial regrowth was observed after 24 and 48 h, and 80% removal of total CECs was achieved after 12 min (0.03 kJ/L), with a release of sulfate ions far from the limit established in wastewater discharge. Moreover, the inactivation of Ampicillin (AMP), Ciprofloxacin (CPX), and Trimethoprim (TMP) antibiotic-resistant bacteria (ARB) and reduction of target genes (ARGs) were successfully achieved. Finally, a harmful effect toward the receiving aquatic environment was not observed according to Aliivibrio fischeri toxicity tests, while a slightly toxic effect toward plant growth (phytotoxicity tests) was detected. As a conclusion, a cost analysis demonstrated that the process could be feasible and a promising alternative to successfully address wastewater reuse challenges.     

N2O emission in partial nitritation-anammox process

Nitrous oxide(N2O)is one of the significant greenhouse gases,and partial nitritation-anammox(PNA)process emits higher N2O than traditional nitrogen removal processes.N2O production in PNA mainly occurs in three different pathways,i.e.,the ammonia oxidizing bacteria(AOB)denitrification,the hydroxylamine(NH2 OH)oxidation and heterotrophic denitrifiers denitrification.N2O emission data vary significantly because of the different operational conditions,bioreactor configurations,monitoring systems and quantitative methods.Under the common operational parameter scopes of PNA,N2O emission via NH2 OH oxidation dominates at relatively low dissolved oxygen(DO),low inorganic carbon(IC),high pH or low N02-concentration,while N2O emission via AOB denitrification dominates at relative higher DO,higher IC.lower pH or higher N2O-concentration.AOB are highly enriched while nitriteoxidizing bacteria(NOB)are rarely found in partial nitritation process,and the order Nitrosomonadales of AOB is the dominant group and N2O producer.Anammox bacteria,AOB and certain amount of heterotrophic denitrifying bacteria are observed in the anammox process,the genus Denitratisoma and the heterotrophic denitrifying bacteria in the deep layer of anammox granules are the dominant N2O generation bacteria.In one-stage PNA reactors,anammox bacteria account for a large fraction of the biomass,AOB account for small portion,and NOB account for even less.The microbial community,diversity and N2O producers in one-stage PNA reactors are similar with those in two-stage PNA reactors.The dominant anammox bacteria,AOB and NOB in PNA are the species Candidatus Brocadia,the genera of Nitrotoga,Nitrospira and Nitrobacter,and the genus Nitrosomonas,respectively.The relations between N2O emission pathways and microbial communities need further study in the future.     

Nutrient Removal and Biomass Production in an Outdoor Pilot-Scale Phototrophic Biofilm Reactor for Effluent Polishing

An innovative pilot-scale phototrophic biofilm reactor was evaluated over a 5-month period to determine its capacity to remove nitrogen and phosphorus from Dutch municipal wastewater effluents. The areal biomass production rate ranged between 2.7 and 4.5 g dry weight/m²/day. The areal nitrogen and phosphorus removal rates averaged 0.13 g N/m²/day and 0.023 g P/m²/day, which are low compared to removal rates achieved in laboratory biofilm reactors. Nutrient removal increased during the day, decreased with decreasing light intensity and no removal occurred during the night. Additional carbon dioxide supply was not requisite as the wastewater was comprised of enough inorganic carbon to sustain microalgal growth. The study was not conclusive for the limiting factor that caused the low nutrient removal rate, possibly the process was limited by light and temperature, in combination with pH increases above pH 9 during the daytime. This pilot-scale study demonstrated that the proposed phototrophic biofilm reactor is not a viable post-treatment of municipal wastewater effluents under Dutch climate conditions. However, the reactor performance may be improved when controlling the pH and the temperatures in the morning. With these adaptations, a phototrophic biofilm reactor could be feasible at lower latitudes with higher irradiance levels.     

Advances and challenges of sulfur-driven autotrophic denitrification (SDAD) for nitrogen removal

Sulfur-driven autotrophic denitrification (SDAD), a process suited for the treatment of nitrogen and sulfur-polluted wastewater without extra supplement of organic carbon, is a promising biological nitrogen removal process. However, the SDAD process was affected by many factors such as various electron donors, organic carbon and exogenous substances (e.g., antibiotics and heavy metal), which prevent further application. Thus, we conducted a detailed review of previous studies on such influence factors and its current application. Besides, a comparative analysis was adopted to recognize the current challenges and future needs for feasible application, so as to ultimately perfect the SDAD process and extend its application scope.     

Isolation and Nitrogen Removal Characteristics of an Aerobic Heterotrophic Nitrifying-Denitrifying Bacterium,Klebsiella sp. TN-10

Nitrogen removal by microorganisms has attracted increasing attention in wastewater treatment. In the present study, a heterotrophic nitrification bacterium was isolated from tannery wastewater and identified as Klebsiella sp. TN-10 based on phenotypic and phylogenetic characteristics. The optimal conditions for cell growth and nitrogen removal were investigated, and the results showed that the greatest ammonium removal rate and maximum biomass were achieved by using sodium pyruvate (7 g/L) as carbon source, C/N 12, pH 7, and temperature 30 °C. Under optimal conditions, the removal rate of ammonia nitrogen reached 96%. Besides, the growth characteristic and the ability of utilizing nitrate and nitrite were investigated. The results demonstrated that strain TN-10 exhibited excellent characteristics to remove both nitrate and nitrite, with the removal rate of 95.44% and 99.87%, respectively. In addition, the nitrite reductase (NiR) and nitrate reductase (NR) involved in denitrification were both active, with the activities of 0.0815 and 0.0283 U/mg proteins, respectively. Furthermore, the aggregation ability, auto-aggregation kinetics, and the relationship between zeta potentials and flocculating efficiency were determined. These results indicated that the strain Klebsiella sp. TN-10, with efficient heterotrophic nitrification-aerobic denitrification ability, has potential application in wastewater treatment.

     

游离氨抑制协同过程控制实现渗滤液短程硝化

采用UASB-SBR生化系统处理高氮晚期渗滤液为研究对象,在获得稳定有机物和氮去除的前提下,考察了采用游离氨(FA)协同过程控制对实现渗滤液长期稳定短程硝化的可行性,建立实现与维持SBR系统内稳定短程硝化的途径及方法.试验结果表明:经过36d的运行,SBR系统的亚硝积累率始终稳定在90%以上,获得了稳定的短程硝化.游离氨和过程控制的协同作用是实现与维持SBR反应器稳定短程硝化的决定因素,以DO,ORP和pH作为渗滤液短程硝化反硝化的过程控制参数是可行的,在充分利用较高FA抑制亚硝酸盐氧化菌活性的前提下,过程控制能够准确判断硝化终点,避免过度曝气破坏短程硝化,从而为氨氧化菌(AOB)的生长创造有利条件,有效抑制亚硝酸盐氧化菌(NOB)的生长并逐渐从系统中淘洗出去,实现了硝化菌种群的优化,荧光原位杂交技术(FISH)检测也证明这一点.在此基础上,通过批次实验考察了微生物种群的反硝化动力学特性,符合Monod动力学方程,NO2--N基质最大比利用速率和半饱和常数分别为0.44gNO2--NgVSS-1d-1和15.8mgL-1.