高浓度氨氮废水同步硝化反硝化性能研究

利用序批式反应器研究了溶解氧浓度和进水碳氮比对高浓度氨氮废水脱氮性能的影响.结果表明,溶解氧浓度降低实现了短程同步硝化反硝化,并提高了反应器脱氮效率.反应器运行经历了外部碳源的摄取、PHB储存、PHB有氧氧化和同步硝化反硝化作用,PHB作为同步硝化反硝化过程中反硝化的电子供体.     

植物作为反硝化碳源

研究得到一种新型的筛选反硝化碳源的方法:可以通过比较材料浸出液的C/N值,筛选出有效的反硝化碳源;对芦苇秸秆、梧桐黄叶、梧桐绿叶、橘树叶、玉米秸秆和玉米芯6种材料浸出液的C/N值进行了研究,其中当以叶片作为反硝化固相碳源时,应该选取新鲜叶片作为研究对象。橘树叶和玉米芯均属于良好的反硝化碳源。以驯化后的河泥作为反硝化污泥,可以利用橘树叶或者玉米芯作为反硝化固相碳源,进行持续脱氮除磷反应,其中橘树叶脱氮效果强于玉米芯,而玉米芯除磷能力强于橘树叶。扫描电镜实验表明,橘树叶和玉米芯均适合作为生物膜载体。     

高氨氮污泥脱水液短程硝化反硝化的启动及稳定

采用A/O-CSTR工艺处理高氨氮污泥脱水液。进水氨氮浓度浓度约为375 mg/L,C/N比小于1.0,反硝化碳源明显不足。A/O反应器完成短程硝化反应,CSTR定期投加初沉污泥作为碳源进行反硝化。两者联合达到总氮去除的目的。实验研究短程硝化反应的启动过程,以及CSTR出水回流对短程硝化和系统脱氮效果的影响。实验结果表明系统具有良好的硝化反硝化效果。A/O反应器亚硝酸盐积累率迅速提高并稳定在90%以上。CSTR有效利用初沉污泥实现了稳定的反硝化。出水回流有利于提高总氮去除率,在回流比为200%时,系统平均总氮去除率达到85%以上。     

一种高速反硝化颗粒污泥的培养

以葡萄糖为碳源,在USB反应器内接种好氧活性污泥在40 d内培养出良好的反硝化颗粒污泥.颗粒污泥形成经历了2个阶段:起始阶段,接种的好氧活性污泥中非反硝化菌逐渐衰亡演变为"惰性固体",与原有的固体一起,成为反硝化菌附着生长的载体,与此同时,反硝化菌在载体表面渐渐繁殖,形成细颗粒污泥;随后,反硝化菌在细颗粒污泥表面不断增殖,颗粒长大,发育成为成熟的颗粒污泥.成熟的颗粒污泥密实,表面均为杆状菌,且排列紧密,当污泥床容积负荷为19.1 g N/L·d时,去除率高达98.4%(N).     

不同分子量聚乳酸的异养反硝化脱氮性能及脱氮反应机制

聚乳酸(PLA)是一种发展潜力巨大的反硝化固体碳源。为探究不同分子量PLA反硝化脱氮路径及机制,以不同分子量PLA为固体碳源研究了PLA的静态释碳性能和反硝化脱氮效果,考察了反硝化出水溶解性有机质(DOM)组分和微生物群落结构。结果表明：PLA释碳稳定,在清水和脱氮反应器中出水COD均能稳定在20 mg·L^-1;PLA分子量越低,脱氮效果越好,5 000 g·mol^-1分子量PLA的NO₃^--N去除率和反硝化速率达到100%和1.29 mg·L^-1·h^-1。PLA脱氮路径有2条：一是反硝化功能菌群利用水解微生物分解PLA释放的小分子碳源作为电子供体进行异养反硝化作用;一是微生物利用溶解性微生物代谢产物等有机物进行反硝化脱氮。该研究结果可为PLA固体碳源在反硝化脱氮工艺中的高效应用提供参考。     

以聚丁酸丁二醇酯为碳源去除含盐水体硝酸盐的研究

以可生物降解聚合物为碳源和生物膜载体可以解决异养反硝化有机碳源的添加不足或过量的问题.在序批式反应条件下,以聚丁酸丁二醇酯(PBS)为碳源和生物膜载体,对含盐水体异养反硝化过程中的细菌群落特征进行了研究.结果表明,试验条件下硝酸盐可以得到很好的去除,虽然有亚硝酸盐的明显积累,但最终被降低.硝酸盐的存在会降低含PBS水体中溶解性有机物的含量.应用变性梯度凝胶电泳和16S rDNA的方法鉴别到的细菌包括:Pseudomonas stutzeri,Pseudomonas sp.,Alteromonas sp.,Marinobacter salsuginis,Thalassospira xianheensis,Itellibacter vladivostokensis,Euplotopsis encysticus,Alcanivorax venustensis,Halomonas sp.,Agrobacterium tume aciens,Pannonibacter phragmitetus,Vitellibacter vladivostokensis.试验结果表明,反硝化条件下PBS具有较好的可生物降解性和明显的NO3--N去除能力,是比较理想的低C/N含盐水体异养反硝化碳源.     

可生物降解塑料与沸石载体体系对硝酸盐氮污染地下水的生物修复研究

生物反硝化是修复地下水硝酸盐氮污染的一种有效途径。为进一步确定异养反硝化碳源与载体投加量的配比,取用污水处理厂活性污泥为微生物来源,以可生物降解塑料为新型固相碳源,沸石为微生物载体,设计了9组固相碳源与载体不同配比的柱实验,旨在遴选出可生物降解塑料和沸石的最优配比。同时考察在最优配比时,不同进水硝酸盐氮浓度下的硝酸盐氮去除率、填料降解率、生物膜附着量、生物膜附着效率、反硝化效率等反应特性。结果表明,可生物降解塑料∶沸石(质量比)=2∶1为最优配比。在最优配比下,进水硝酸盐氮质量浓度为40~100mg/L时,异养反硝化对硝酸盐氮具有很好的去除效果(最终去除率均在99%以上),且能够保持较高的反硝化效率,同时载体负载微生物的性能稳定。     

以聚己内酯作为生物反硝化固体碳源的研究

为解决水体因低碳氮比而导致脱氮效率差的问题,将颗粒聚己内酯(PCL)重新塑形为阶梯环状,研究其作为反硝化过程的生物膜载体与固相碳源的反硝化性能。结果表明,在静态实验中,平均反硝化速率为8.57 mg NO3-N/(L·h);反硝化过程为零级反应。连续填充床实验中,超过90%的硝酸盐可被去除,出水NO2-N质量浓度低于0.20 mg/L;出水NH3-N质量浓度略有上升;出水溶解性有机碳(DOC)先上升后降低至1 mg/L左右。电子扫描显微镜扫描显示,PCL阶梯环反应表面空隙率较高,表面生物膜以杆菌为主,反应后被明显腐蚀;液相色谱检测显示PCL阶梯环分子量反应前后略有下降,其结构未受到破坏;表明该材料适合作为反硝化反应的碳源的同时,又可以作为载体供微生物附着生长。     

碳源投加方式对SBR工艺脱氮速率的影响

为了提高生物反应器的脱氮效率,研究采用SBR处理模拟生活污水,利用醋酸钠作为碳源,考察碳源投加方式对脱氮速率的影响。结果表明,当温度为10~15℃,进水COD为330~550 mg/L时,采用不同的碳源投加方式,COD去除率均高于95%。进水一次投加2.4 g碳源,COD平均反应速率为5.3 mg/(g·h),平均反硝化速率为0.28 mg/(g·h)。进水、反应器运行3 h时分别投加1.2 g碳源,COD平均反应速率为6.89 mg/(g·h),平均反硝化速率为0.37 mg/(g·h)。进水、反应6 h时分别投加1.2 g碳源,COD平均反应速率为6.50 mg/(g·h),平均反硝化速率为0.52 mg/(g·h)。进水投加1.2 g碳源、反应器运行3 h和6 h时分别投加0.6 g醋酸钠碳源,COD平均反应速率为6.2 mg/(g·h),平均反硝化速率为0.39 mg/(g·h)。分次投加碳源能够提高COD反应速率和TN去除率,同时保持较高的硝化反硝化速率。     

碳源强化下的硫自养/异养反硝化协同作用

为强化硫自养反硝化过程,通过向连续稳定运行的硫自养反硝化反应器内投加少量碳源以进行强化,乙酸钠投加量分别为5.99、11.98、23.96 mg·L~(-1)。分析投加前后反应器内硝氮、COD、硫酸根和耗碱量的变化;研究了碳源强化下硫自养反硝化运行效能及反应机理。结果表明,投加少量碳源可增强自养反硝化过程硝氮的去除效果;在3种碳源投加量条件下,COD的利用率均大于85%,但硫酸盐生成量并未减少;在5.99 mg·L~(-1)碳源投加量下,系统实际耗碱量大于以硫酸根和COD计的理论耗碱量,而在11.98 mg·L~(-1)和23.96 mg·L~(-1)投加量下,实际耗碱量均介于2种理论值之间。在投加少量碳源后,自养反硝化脱氮效果明显提高,异养反硝化趋势随着碳源投加量的增加而增加。     

Denitrification using PBS as carbon source and biofilm support in a packed-bed bioreactor

Biodegradable polymer was used as carbon source and biofilm support for nitrate removal from aqueous solution as an attractive alternative for biological denitrification. The objective of this paper was to investigate the denitrification performance and microbial community of a packed-bed bioreactor using poly (butanediol succinate) (PBS), a biodegradable polymer, as carbon source and biofilm support. NO₃–N concentration was determined by UV spectrophotometer. NO₂–N concentration was assayed by hydrochloric acid naphthyl ethylenediamine spectrophotometry method. Total organic carbon (TOC) was measured using a TOC analyzer. The morphology of the samples was observed using an environmental scanning electron microscope (ESEM). The microbial community was analyzed by pyrosequencing method. The experimental results showed that an average removal efficiency of nitrate was 95 %. ESEM observation and FTIR analysis indicated the changes of PBS granules before and after microbial utilization. Pyrosequencing results showed that Betaproteobacteria predominated, and most of PBS-degrading denitrifying bacteria were assigned to the family Comamonadaceae. Denitrifying bacteria accounted for 13.02 % in total population. The PBS granules were suitable support and carbon source for denitrifying bacteria.     

有机碳源条件下厌氧氨氧化SBBR中的微生物多样性

研究有机碳源对SBBR厌氧氨氧化菌群等微生物的影响。采用16S rDNA序列与PCR-DGGE分析技术相结合的方法,对稳定运行的反应器内的活性污泥和生物膜样品,进行细菌多样性图谱分析,同时采用巢式PCR-DGGE技术对浮霉状菌属(Planctomycetes)细菌进行分析。结果表明,在有机碳源反应系统细菌条带数和多样性指数均高于无机系统,与活性污泥相比,生物膜表尤为明显。当进水不含有机碳源时,氨氧化细菌(ammonia oxidizing bacteria,AOB),厌氧氨氧化菌(anaerobic ammonia oxidizing bacteria,ANAMMOX)为优势功能菌;当进水含有机碳源时,系统中存在的AOB以亚硝化单胞菌(Nitrosomonas sp.)为优势菌群,同时存在反硝化菌,如索氏菌(Thauera sp.)以及厌氧氨氧化菌,它们共同作用完成N的去除。此外,与无机碳源系统相比,有机碳源的存在,有利于浮霉状菌的积累,但压缩了ANAMMOX的生存空间。本研究可为厌氧氨氧化工艺处理低C/N比有机废水提供了理论依据。     

Nitrate removal from groundwater using biodegradable polymers as carbon source and biofilm support

A new kind of biodegradable polymer, PBS, was used as both carbon source and biofilm support in a fixed-bed reactor to remove nitrate from groundwater. The experimental results showed that the denitrifying bacteria can easily attach to the surface of PBS granules and adapt to use PBS as carbon source. The SEM observation indicated that the fine biofilm can develop on the surface of PBS granules within 15 days. The denitrification rate increased with temperature increase in the range of 10-35°C, the maximum denitrification rate reached 1.00 mg/g.d at 35°C. Continuous experiment results showed that nitrate (50 mg/l) can be removed effectively and nitrite did not accumulate in the effluent.     

An anaerobic continuous-flow fixed-bed reactor sustaining a 3-chlorobenzoate-degrading denitrifying population utilizing versatile electron donors and acceptors

An anaerobic continuous-flow fixed-bed column reactor capable of degrading 3-chlorobenzoate (3-CBA) under denitrifying conditions was established, and its rate reached 2.26 mM d(-1). The denitrifying population completely degraded 3-CBA when supplied at 0.1-0.54 mM, but its activity was partly suppressed when 3-CBA was supplied at 0.89 mM. Nitrate was concomitantly consumed throughout the operation of the reactor, the amount of which was similar to or up to 35% higher than the theoretical stoichiometric value that was calculated by assuming that 3-CBA degradation is coupled with denitrification. Batch incubation experiments proved that nitrate is strictly required for 3-CBA degradation in the absence of molecular oxygen. The population also degraded 3-CBA aerobically. Benzoate and 4-CBA were degraded under denitrifying conditions as well as 3-CBA, but 2-CBA was not. Considering that the previously reported denitrifying 3-CBA-degrading cultures do not exhibit 4-CBA degradation under denitrifying conditions, nor aerobic 3-CBA degradation [FEMS Microbiol. Lett. 144 (1996) 213, Appl. Environ. Microbiol. 66 (2000) 3446], the microbial population developed in this experiment was physiologically versatile with respect to the utilization of both electron donors and electron acceptors.     

气升式环流生物膜反应器硝化反硝化除磷过程的研究

针对反硝化聚磷菌的生物学特性,设计并制作了硝化反硝化除磷气升式环流生物膜反应器,并就其对生活污水的脱氮、脱碳和除磷过程进行了试验.试验结果表明,当进水COD为309.8 mg/L、NH4 -N为116.0 mg/L、PO34-P为10.5 mg/L时,它们的去除率分别为95.3%、94.6%和73.1%.通过间歇试验表明该反应器可以实现反硝化除磷.     

电化学强化脱氮中反硝化菌对活性炭纤维电极电化学反应影响初步研究

研究固定反硝化菌活性炭纤维电极的阴极极化行为及其硝酸盐氮脱除率,考察了活性炭纤维电极电化学强化脱氮系统中生物过程对电化学过程的影响。实验表明,反硝化过程影响电极电化学反应,参数表观交换电流密度可用来表征体系反硝化菌的反硝化能力,新定义了生物效益量,其变化率与硝酸盐氮脱除率相关性良好。     

Effects of different quinoid redox mediators on the removal of sulphide and nitrate via denitrification

The impact of different quinoid redox mediators on the simultaneous conversion of sulphide and nitrate in a denitrifying culture was evaluated. All quinones evaluated, including anthraquinone-2,6-disulphonate (AQDS), 2-hydroxy-1,4-naphthoquinone and 1,2-naphthoquinone-4-sulphonate (NQS) were reduced by sulphide under abiotic conditions. NQS showed the highest reduction rate by sulphide (132 μmol h⁻¹) and promoted the maximum rate of sulphide oxidation (87 μmol h⁻¹) by denitrifying sludge, which represents an increase of 44% compared to the control lacking quinones. The reduced form of AQDS (AH₂QDS) served as an electron donor for the microbial reduction of nitrite and N₂O, which represents the first demonstration of hydroquinones supporting the microbial reduction of denitrifying intermediates. The results taken as a whole suggest that some quinones may significantly increase the rate of removal of S and N under denitrifying conditions.     

Effects of different quinoid redox mediators on the removal of sulphide and nitrate via denitrification

The impact of different quinoid redox mediators on the simultaneous conversion of sulphide and nitrate in a denitrifying culture was evaluated. All quinones evaluated, including anthraquinone-2,6-disulphonate (AQDS), 2-hydroxy-1,4-naphthoquinone and 1,2-naphthoquinone-4-sulphonate (NQS) were reduced by sulphide under abiotic conditions. NQS showed the highest reduction rate by sulphide (132 μmol h⁻¹) and promoted the maximum rate of sulphide oxidation (87 μmol h⁻¹) by denitrifying sludge, which represents an increase of 44% compared to the control lacking quinones. The reduced form of AQDS (AH₂QDS) served as an electron donor for the microbial reduction of nitrite and N₂O, which represents the first demonstration of hydroquinones supporting the microbial reduction of denitrifying intermediates. The results taken as a whole suggest that some quinones may significantly increase the rate of removal of S and N under denitrifying conditions.     

Illumina sequencing-based analysis of a microbial community enriched under anaerobic methane oxidation condition coupled to denitrification revealed coexistence of aerobic and anaerobic methanotrophs

Methane is produced in anaerobic environments, such as reactors used to treat wastewaters, and can be consumed by methanotrophs. The composition and structure of a microbial community enriched from anaerobic sewage sludge under methane-oxidation condition coupled to denitrification were investigated. Denaturing gradient gel electrophoresis (DGGE) analysis retrieved sequences of Methylocaldum and Chloroflexi. Deep sequencing analysis revealed a complex community that changed over time and was affected by methane concentration. Methylocaldum (8.2%), Methylosinus (2.3%), Methylomonas (0.02%), Methylacidiphilales (0.45%), Nitrospirales (0.18%), and Methanosarcinales (0.3%) were detected. Despite denitrifying conditions provided, Nitrospirales and Methanosarcinales, known to perform anaerobic methane oxidation coupled to denitrification (DAMO) process, were in very low abundance. Results demonstrated that aerobic and anaerobic methanotrophs coexisted in the reactor together with heterotrophic microorganisms, suggesting that a diverse microbial community was important to sustain methanotrophic activity. The methanogenic sludge was a good inoculum to enrich methanotrophs, and cultivation conditions play a selective role in determining community composition.     

Accumulation of nitrite in denitrifying barriers when phosphate is limiting

Permeable in situ denitrifying barriers can remove nitrate from groundwater. Barriers may be constructed by filling an excavated area with a porous mixture of sand, fine gravel, and substrate or by the injection of a nonaqueous phase substrate into an aquifer. The substrate stimulates the development of a denitrifying microbial community by providing an electron donor. The objective of this study was to determine the ability of denitrifying barriers to function under low-phosphate conditions. Sand columns injected with a soybean oil emulsion were used as laboratory models of denitrifying barriers. When a natural groundwater containing 17 mg l(-1) nitrate-N and 0.009 mg l(-1) phosphate-P was pumped through the columns, only a small amount of nitrate was removed from the water and, in some effluent fractions, 52% to 88% of the influent nitrate had converted to nitrite. Nitrite also accumulated when the phosphate concentration of the groundwater was increased to 0.040 or 0.080 mg l(-1) phosphate-P. Only when a 0.160 mg l(-1) phosphate-P supplement was added to the groundwater was there a loss of nitrate without a large accumulation of nitrite. The addition of solid calcium phosphate or rock phosphate to the sand columns was found to provide adequate phosphate for denitrification in short-term studies. These studies point out the need to ensure that adequate phosphate is present in denitrifying barriers especially when such barriers are used beneath phosphate-binding soils.