SBR反应器中反硝化除磷菌的快速富集

反硝化除磷菌(DPAOs)能够在缺氧条件下同步完成脱氮除磷,是反硝化除磷工艺的主体。以武汉沙湖污水处理厂二沉池的回流污泥为种泥,采用二段式SBR工艺实现了反硝化除磷菌的快速富集。在第一阶段反应器采用厌氧/好氧(A/O)模式运行,可以实现对除磷菌(PAOs)的快速诱导和富集,运行13 d后,SBR反应器对氮、磷的去除率均达到85%以上。而后进入第二阶段,采用厌氧/好氧/缺氧(A/O/A)模式运行,以快速富集培养反硝化除磷菌,经过26 d的运行,反应器对氨氮和磷酸盐的去除率分别达到92.2%和91.2%左右,且典型周期内硝酸盐的消耗量与磷的吸收量基本呈线性关系,表明系统的反硝化除磷能力得到显著增强。     

污泥减量工艺:HA-A/A-MCO的好氧脱氮机制分析

针对污泥减量技术存在对氮、磷去除能力低的问题,开发了一种具有强化脱氮除磷功能并可实现污泥减量化的HA-A/A-MCO工艺。在该工艺取得同步脱氮除磷和污泥减量优异效果的条件下,采用其处理校园生活污水,当进水TN平均为47 mg/L时,出水TN为10.9 mg/L,系统的总脱氮率为76.8%,其中好氧脱氮量占总脱氮量的50%,缺氧脱氮量占26%;HA-A/A-MCO系统存在着在好氧条件下具有反硝化能力的菌属,对好氧脱氮有一定贡献,且DO浓度对其反硝化能力没有抑制作用;好氧池中的DO浓度梯度有利于在污泥絮体内形成缺氧环境,从而促进同步硝化反硝化(SND)的发生,但减小污泥絮体尺寸会削弱絮体内部缺氧区域比例、降低SND的脱氮效率。     

DO对A/O同步脱氮除磷工艺的影响研究

采用A/O同步脱氮除磷工艺处理模拟城市污水,考察了好氧段DO浓度对该工艺处理效果的影响.结果表明,好氧段DO浓度对系统脱氮除磷效果的影响显著,当DO控制在1.5mg/L左右时,系统的处理效果最佳,可实现同步硝化反硝化和反硝化除磷,对NH4+-N、TN、TP、COD的去除率分别为99.12%、94.61%、92.85%、96.10%,平均出水NH4+-N、TN、TP、COD分别为0.25、0.68、0.5和10 mg/L.     

A~2/O工艺的反硝化除磷特性研究

为了解传统A2/O工艺中反硝化除磷的作用及强化缺氧吸磷对系统同步脱氮除磷的贡献,以实际生活污水为处理对象,系统研究了缺氧段的反硝化除磷特性及其强化措施,并通过序批式试验考察了除磷微生物种群比例的变化.试验结果表明:稳定运行的A2/O系统中存在反硝化除磷现象,通过提高缺氧段的NO-3-N负荷,可使缺氧除磷贡献率从33.3%提高到53.3%,且系统的除磷率维持在95.4%以上;同时,好氧段的曝气量从400 L/h减少到260 L/h,节约了近35%;反硝化聚磷菌占聚磷菌的比例由35.4%提高到51.3%左右,微生物种群得到了优化.强化A2/O工艺的反硝化除磷功能,对提高低C/N值污水的脱氮除磷效率及降低运行能耗具有重要的意义.     

膜-序批式生物反应器同步脱氮除磷试验研究

研究了膜-序批式工艺处理生活污水的特性,采用厌氧(A)-好氧(O)-缺氧(A) 膜出水的运行方式,1h搅拌进水进行磷的厌氧释放,0.5h好氧吸磷和硝化,0.5h缺氧搅拌进行脱氮和反硝化除磷,在总的水力停留时间为11小时的条件下,系统对氨氮、总氮、总磷的平均去除率分别达到了95.97%,89.18%和90%。周期试验发现,好氧吸磷和反硝化除磷对磷去除贡献率分别为72.90%和17.25%,系统有较好的反硝化除磷功能,同时系统还存在同步硝化反硝化作用,对TN的去除占总去除率的16.50%。     

A／O同步脱氮除磷工艺试验研究

以模拟城市污水为研究对象,探讨了A／O同步脱氮除磷工艺的去除效果,并研究了DO、污泥龄、温度、pH值等参数对A／O同步脱氮除磷工艺的影响,得到了各工艺参数的最佳控制范围,以提高污水处理厂的运行效率。     

A2/O-曝气生物滤池深度生物脱氮除磷工艺分析

重点介绍了A<'2>/O-曝气生物滤池工艺的工作原理、运行方式及工艺特征.通过缩短A<'2>/O单元的泥龄,将硝化过程分离出去,使曝气生物滤池实现硝化.A<'2>/O单元在短泥龄条件下运行,有利于除磷及反硝化;曝气生物滤池在长泥龄条件下运行,有利于硝化效果的稳定和高效;从曝气生物滤池回流来的硝酸盐氮为A<'2>/O的缺氧段提供了充足的电子受体,为反硝化除磷提供了必要条件,最大限度地缓解了低C/N值污水在脱氮除磷过程中碳源不足的难题.小试结果表明,该工艺可以实现有机物、氮、磷的同步深度去除,出水水质满足<城镇污水处理厂污染物排放标准>(GB 18918-2002)的一级A排放标准.     

缺氧区、好氧区容积比对A2/O工艺反硝化除磷的影响

反硝化除磷菌可以在碳源不足的条件下,通过"一碳两用"的方式同时实现反硝化脱氮和吸磷过程,有研究表明,A2/O工艺中存在反硝化除磷现象.为此以啤酒废水为处理对象,研究了缺氧区与好氧区容积比对A2/O工艺反硝化除磷的影响.试验结果表明,在缺氧区与好氧区容积比分别为0.33、0.48、0.60的条件下,A2/O系统对总氮的平均去除率分别为68.04%、79.64%和85.70%,对总磷的平均去除率分别为85.38%、90.80%和96.84%,对COD的去除率均在90%以上.此外,如果继续增大缺氧区与好氧区容积比,应适当调整内循环比,否则会由于缺氧区硝酸盐浓度不够而发生二次释磷现象.     

双污泥反硝化除磷工艺处理生活污水的中试研究

为了探索双污泥反硝化除磷工艺(A2N工艺)的实际运行效果,采用好氧段为活性污泥法的A2N工艺处理无锡某污水处理厂的曝气沉砂池出水.中试结果表明:A2N工艺对COD、TP、磷酸盐、氨氮具有较好的去除效果,出水平均浓度分别为21.6、0.19、0.04和2.73 mg/L,对COD、TP和氨氮的平均去除率分别为80.8%、89.9%和89.3%;进水TN平均为28.8 mg/L,出水平均浓度为12.6 mg/L,平均去除率为55.95%;设置后曝气池确保了出水磷酸盐和氨氮的达标排放,而且通过吹脱氮气,还提高了反硝化聚磷污泥的沉降性能.     

不同城市污水处理厂反硝化除磷性能的比较研究

对采用不同工艺的3个城市污水处理厂的活性污泥进行了厌氧释磷、好氧聚磷及反硝化聚磷试验研究,以确定其反硝化除磷能力及差异性。3个污水处理厂采用的工艺分别为内设厌氧段的Carrousel氧化沟(A/O)、外设厌氧池的Carrousel氧化沟(A/C)和具有独立厌氧、缺氧及曝气池的A2/O工艺。结果表明,A/O工艺中活性污泥的释磷能力相对较强,A/C与A2/O工艺中活性污泥的释磷能力相当;A/C工艺中活性污泥的好氧聚磷和反硝化聚磷能力均优于其他两种工艺,好氧聚磷量和反硝化聚磷量分别为15.39和8.09 mgP/gVSS,活性污泥中存在数量可观的反硝化聚磷菌(DPB),反硝化聚磷菌与好氧聚磷菌的比例(DPB/PAO)为57.7%;A/O和A2/O工艺的活性污泥中同样存在DPB,但DPB/PAO值较低,分别为32%和27%。     

缺氧区、好氧区容积比对A^2／O工艺反硝化除磷的影响

反硝化除磷茵可以在碳源不足的条件下，通过“一碳两用”的方式同时实现反硝化脱氮和吸磷过程，有研究表明，A^2／O工艺中存在反硝化除磷现象。为此以啤酒废水为处理对象，研究了缺氧区与好氧区容积比对A^2／O工艺反硝化除磷的影响。试验结果表明，在缺氧区与好氧区容积比分别为0．33、0．48、0．60的条件下，A^2／O系统对总氮的平均去除率分别为68．04％、79．64％和85．70％，对总磷的平均去除率分别为85．38％、90．80％和96．84％，对COD的去除率均在90％以上。此外，如果继续增大缺氧区与好氧区容积比，应适当调整内循环比，否则会由于缺氧区硝酸盐浓度不够而发生二次释磷现象。     

Calibration of denitrifying activity of polyphosphate accumulating organisms in an extended ASM2d model

This paper presents the results of an experimental study for the modelling and calibration of denitrifying activity of polyphosphate accumulating organisms (PAOs) in full-scale WWTPs that incorporate simultaneous nitrogen and phosphorus removal. The convenience of using different yields under aerobic and anoxic conditions for modelling biological phosphorus removal processes with the ASM2d has been demonstrated. Thus, parameter η_PAO in the model is given a physical meaning and represents the fraction of PAOs that are able to follow the DPAO metabolism. Using stoichiometric relationships, which are based on assumed biochemical pathways, the anoxic yields considered in the extended ASM2d can be obtained as a function of their respective aerobic yields. Thus, this modification does not mean an extra calibration effort to obtain the new parameters. In this work, an off-line calibration methodology has been applied to validate the model, where general relationships among stoichiometric parameters are proposed to avoid increasing the number of parameters to calibrate. The results have been validated through a UCT scheme pilot plant that is fed with municipal wastewater. The good concordance obtained between experimental and simulated values validates the use of anoxic yields as well as the calibration methodology. Deterministic modelling approaches, together with off-line calibration methodologies, are proposed to assist in decision-making about further process optimization in biological phosphate removal, since parameter values obtained by off-line calibration give valuable information about the activated sludge process such as the amount of DPAOs in the system.     

(AO)2-SBBR反硝化除磷工艺处理低碳城市污水

低碳源浓度城市污水的脱氮除磷一直是个难题，为此在AO-SBBR工艺中引入一个缺氧段而形成（AO）2-SBBR工艺，研究了AO-SBBR和（AO）2-SBBR对低碳源浓度城市污水中氮、磷的去除效果。试验结果表明：在进水BOD5／TN=3、BOD5／TP=17的情况下，（AO）2-SB．BR工艺比AO-SBBR工艺具有更好的同步脱氮除磷效果，对总磷的去除率达到了79．8％，对总氮的去除率从25．83％提高到51．26％，出水水质达到了《城镇污水处理厂污染物排放标准》的一级标准。该工艺有效解决了低碳源浓度城市污水在同步脱氮除磷过程中有机物不足的问题，并在单一反应器中实现了反硝化除磷菌的增殖过程，反硝化除磷菌占聚磷菌的比例从14．82％增长到63．04％；反硝化除磷菌能够以低浓度的亚硝酸盐氮作为电子受体进行缺氧吸磷，如亚硝酸盐氮〉10mg／L则会抑制反硝化除磷菌的活性，而且这种抑制作用并不是瞬时的，至少要持续一段时间其活性才能恢复。     

Anoxic growth of phosphate-accumulating organisms (PAOs) in biological nutrient removal activated sludge systems

In this paper, research on the growth performance of phosphate-accumulating organisms (PAOs) was conducted based on literature and experimental investigations on biological nutrient removal (BNR) activated sludge (BNRAS) systems. The research aims at presenting the occurrence of denitrifying PAOs (DPAOs), abstracting information on the kinetics and stoichiometry of PAOs under anoxic conditions and determining the conditions that stimulate the PAO growth under anoxic conditions. The research results indicate that the PAOs are capable of utilizing nitrate as electron acceptor instead of oxygen in BNRAS systems, particularly in external nitrification BNRAS (ENBNRAS) systems. However, the growth yield of PAOs under anoxic conditions should be reduced to about 70% of that under aerobic conditions, and further the stoichiometric coefficient for anoxic P uptake per PHB COD utilized should be reduced to about 80% of that under aerobic conditions as the DPAOs show a significantly lower BEPR performance and use the influent RBCOD less "efficiently" compared with aerobic PAOs (APAOs). The research results also indicate that the major factor influencing the occurrence of DPAOs and associated anoxic P uptake is the nitrate load into the anoxic reactor, i.e. the nitrate load should be large enough or exceeds the denitrification potential of ordinary heterotrophic organisms (OHOs), i.e. non-PAO organisms in the anoxic reactor to stimulate DPAOs in the system as the specific denitrification rate of OHOs (K'2 OHO) is significantly larger than that of PAOs (K'2 PAO). In terms of this competition, if the nitrate load into the main anoxic reactor is less than the denitrification potential of OHOs, then the OHOs will outcompete PAOs for using the limited nitrate, while if the nitrate load in the main anoxic reactor exceeds the denitrification potential of OHOs, then the PAOs would have opportunities to use the "excess" nitrate and so develop in the system. The other factors that influence DPAOs include the system aerobic mass fraction, sequence of reactors and frequency of sludge alternation between the aerobic and anoxic states. Although it does appear that these factors above may significantly influence the fraction of DPAOs (etaG), the quantitative relationship between these factors and etaG is not known, and the experimental observations indicate that this will be system-specific, and require calibration for each situation.     

新型双泥生物反硝化除磷脱氮工艺

在对生物脱氮与除磷机理进行深入研究后发现，生物脱氮与除磷是两个相对独立而又相互交叉的生理过程，其交叉点是部分聚磷菌在缺氧状态下的反硝化吸磷脱氮。在此基础上提出的新型双泥生物反硝化除磷脱氮工艺（由两个不同功能的SBR反应器组成）成功地解决了硝化菌与聚磷菌的泥龄之争。反硝化与聚磷菌厌氧释磷的矛盾等难题，该工艺运行稳定且处理效果良好，特别适合于处理BOD5/TP值低的污水。     

倒置A~2/O工艺的原理与特点研究

通过短时厌氧环境的生化特性、厌氧 /缺氧环境倒置效应和小型系统平行对比试验 ,较系统地研究了倒置A2 /O工艺的原理和工艺特点。指出 :①聚磷菌厌氧有效释磷水平的充分与否 ,并不是决定其在后续曝气条件下过度吸磷能力的充分必要条件。推进聚磷菌过度吸磷的本质动力与厌氧区HRT和厌氧环境的厌氧程度有关。在一定范围内 ,厌氧环境的HRT越长 ,厌氧程度越充分 ,聚磷菌的吸磷动力越强。②把常规生物脱氮除磷系统的厌氧、缺氧环境倒置过来 ,可以得到更好的脱氮除磷效果。小型系统平行对比试验表明 ,倒置A2 /O工艺的氮磷脱除功能明显优于常规A2 /O工艺 ,其COD去除能力则与常规A2 /O工艺相当。     

Development of a 2-sludge, 3-stage system for nitrogen and phosphorous removal from nutrient-rich wastewater using granular sludge and biofilms

A novel 2-sludge 3-stage process using a combination of granular sludge and biofilm was developed to achieve biological removal of nitrogen and phosphorus from nutrient-rich wastewater. The system consists of a granular sequencing batch reactor (SBR) working under alternating anaerobic/anoxic conditions supplemented with a short aerobic phase and an aerobic biofilm SBR. The wastewater is first fed to the granular SBR reactor, where easily biodegradable carbon sources are taken up primarily by polyphosphate accumulating organisms (PAOs). The supernatant resulting from quick settling of the granular sludge is then fed to the biofilm SBR for nitrification, which produces oxidized nitrogen that is returned to the granular reactor for simultaneous denitrification and phosphorus removal. While maximizing the utilization of organic substrates and reducing operational costs, as do other 2-sludge processes previously reported in literature, the proposed system solves the bottleneck problem of traditional 2-sludge systems, namely high effluent ammonia concentration, due to its high-volume exchange ratios. An ammonia oxidation rate of 32 mg N/Lh was achieved in the biofilm SBR, which produced nitrite as the final product. This nitrite stream was found to cause major inhibition on the anoxic P uptake and also to result in the accumulation of N(2)O. These problems were solved by feeding the nitrite-containing stream continuously to the granular reactor in the anoxic phase. With a nitrogen and phosphorus removal efficiency of 81% and 94%, respectively, the system produces an effluent that is suitable for land irrigation from a wastewater stream containing 270 mg N/L of total nitrogen and 40 mg P/L of total phosphorus.     

Advancing post-anoxic denitrification for biological nutrient removal

The objective of this research was to advance a fundamental understanding of a unique post-anoxic denitrification process for achieving biological nutrient removal (BNR), with an emphasis on elucidating the impacts of surface oxygen transfer (SOT), variable process loadings, and bioreactor operational conditions on nitrogen and phosphorus removal. Two sequencing batch reactors (SBRs) were operated in an anaerobic/aerobic/anoxic mode for over 250 days and fed real municipal wastewater. One SBR was operated with a headspace open to the atmosphere, while the other had a covered liquid surface to prevent surface oxygen transfer. Process performance was assessed for mixed volatile fatty acid (VFA) and acetate-dominated substrate, as well as daily/seasonal variance in influent phosphorus and ammonia loadings. Results demonstrated that post-anoxic BNR can achieve near-complete (>99%) inorganic nitrogen and phosphorus removal, with soluble effluent concentrations less than 1.0 mgN L⁻¹ and 0.14 mgP L⁻¹. Observed specific denitrification rates were in excess of typical endogenous values and exhibited a linear dependence on the glycogen concentration in the biomass. Preventing SOT improved nitrogen removal but had little impact on phosphorus removal under normal loading conditions. However, during periods of low influent ammonia, the covered reactor maintained phosphorus removal performance and showed a greater relative abundance of polyphosphate accumulating organisms (PAOs) as evidenced by quantitative real-time PCR (qPCR). While GAOs were detected in both reactors under all operational conditions, BNR performance was not adversely impacted. Finally, secondary phosphorus release during the post-anoxic period was minimal and only occurred if nitrate/nitrite were depleted post-anoxically.