SBR工艺对低碳量城市污水的反硝化除磷研究

广州地区的城市污水含碳量低，碳、氮、磷浓度比例失调，采用传统工艺处理很难达到理想的脱氮除磷效果，为此采用SBR工艺对其进行处理，考察了该工艺的反硝化除磷效果。结果表明，在厌氧／缺氧／好氧的运行模式下，采用逐步增加缺氧段运行时间的方法可有效提高污泥的反硝化除磷性能；在试验进水水质条件下，反应器厌氧运行30min、缺氧运行3h、好氧运行1h可保证对磷的稳定高效去除，出水TP〈1mg／L；ORP值无法指示缺氧反硝化与吸磷过程，pH值可作为缺氧吸磷结束的指示参数，而ORP和pH值均可作为好氧吸磷结束的控制参数。     

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。     

同时硝化/反硝化除磷过程的控制策略研究

为实现同时硝化/反硝化除磷(SNDPR)过程,在SBR反应器内,采用模拟低碳源污水和厌氧-交替好氧/缺氧的运行方式对污泥进行培养驯化,成功实现了反硝化聚磷茵和硝化茵的良好共存.在此基础上,考察了厌氧/间歇曝气和厌氧/连续曝气两种模式下SNDPR工艺对污水的处理效果.结果表明,在上述两种模式下,系统对TP的去除率分别为92%和90%,对TN的去除率分别为83%和72%;厌氧/间歇曝气模式更有利于SNDPR工艺对低碳源污水的处理.另外,对电化学参数的研究表明,pH曲线上的"膝点"可近似预示SNDPR过程的结束,而ORP的变化范围及稳定性可预示SNDPR过程中硝化和反硝化除磷同时发生的平衡程度.     

五箱一体化工艺活性污泥反硝化除磷能力研究

在五箱一体化活性污泥工艺试验中发现,在从较高负荷转入较低负荷运行时出现反硝化除磷现象.为进一步研究该工艺的反硝化除磷能力,取反应器污泥加入一定量COD厌氧搅拌以释放磷,富磷污泥分别置于好氧和缺氧环境中,比较好氧吸磷和反硝化吸磷的差异,同时取按A2/O运行的氧化沟污泥进行对比试验.结果表明,五箱一体化工艺活性污泥具有较高的反硝化除磷能力,缺氧初期反硝化吸磷速度远远高于好氧吸磷速度,反硝化聚磷菌占全部聚磷菌的99.25%,高于按A2/O运行的氧化沟的88.2%.     

交替曝气时间对两级生物滤池除磷的影响

交替曝气时间是影响新型两级生物滤池工艺除磷效果的关键因素。在四种不同的厌氧／好氧交替曝气时间下,考察了该工艺对TP的去除效果。试验结果表明：交替曝气时间为12h时除磷效果最好,对TP的平均去除率为80．18％,平均出水TP为0．94mg／L,达到了《城镇污水处理厂污染物排放标准》（GB18918-2002）的一级B标准;厌氧释磷的最佳反应时间是9h,好氧吸磷的最佳反应时间是6h,除磷率最高可达87．65％。     

颗粒污泥的反硝化除磷研究

借助SBR反应器,采用厌氧/好氧/缺氧的运行方式,对富集的以反硝化聚磷菌（DNPAOs）为优势菌的活性污泥进行颗粒化培养,约35 d后得到了较成熟的颗粒污泥.考察了该颗粒污泥的脱氮除磷性能,结果表明：当以厌氧/缺氧方式运行时系统具有良好的反硝化除磷性能,缺氧结束时除磷率＞96%,对氨氮的去除率为95%左右;外加NO3^- -N的浓度对缺氧段的反硝化吸磷速率有一定影响;颗粒污泥中的DNPAOs可以利用内碳源进行反硝化吸磷,从而实现了同步脱氮除磷.     

分置式重力流MSBR的反硝化除磷脱氮研究

采用新型分置式重力流MSBR处理校园生活污水,在厌氧-好氧-缺氧-膜重力流出水的运行方式下,对TP、TN、COD和NH3-N的平均去除率分别达到了89.51%、64.25%、87.27%和95.88%;缺氧段发生了反硝化吸磷,其吸磷量为好氧段吸磷量的7.12%,在没有外加碳源的条件下,缺氧段的TOC/TN＞12时反硝化脱氮率＞75%.分置式重力流MSBR经膜组件曝气可以有效减轻膜污染,是一种值得推广的工艺手段.     

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%。     

溶解氧对反硝化聚磷菌的影响研究

为考察在有氧条件下好氧聚磷菌与反硝化聚磷菌（DPB）可否共存,以模拟低碳城市污水为原水,在厌氧／缺氧运行的SBR内引入不同时长的好氧段以及在厌氧／好氧运行的SBR内采用相同时长的好氧段和不同的溶解氧浓度,考察了DO对DPB的存活及其除磷脱氮功能的影响。结果表明,聚磷菌（PAOs）以氧或硝酸盐氮为电子受体时的吸磷能力基本相同,且其在缺氧和好氧条件下的活性也基本相同;在有氧条件下,维持低氧环境有利于DPB反硝化除磷的实现,而高DO浓度则利于好氧吸磷。因此,DO对DPB的存活没有决定性影响,DPB和好氧PAOs可以共存,而对DO浓度的合理控制是实现反硝化除磷的关键。     

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。     

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。     

短好氧泥龄下A2/O和BAF联合工艺的脱氮除磷特性

采用小试装置,研究了短好氧污泥龄下A2/O和BAF联合工艺处理低C/N和C/P污水时的脱氮除磷特性.结果表明,通过提高A2/O工艺段的厌氧区有机负荷和缺氧区硝酸盐负荷对反硝化聚磷菌（DPAOs）进行选择和强化后,其在聚磷菌（PAOs）中的比例维持在28%左右,工艺具有部分反硝化除磷能力,能够减少脱氮除磷过程中对碳源的总需求量.但在联合工艺中,好氧除磷仍是主要的除磷方式.在A2/O工艺段内,好氧污泥龄在满足好氧PAOs存活的同时,还必须满足抑制硝化细菌生长的要求,且为了保证工艺对磷的整体去除效果,混合液在好氧区的接触时间须大于30 min.此外,以保证缺氧区出水中含有1～4 mg/L的硝态氮为原则来控制BAF出水的回流量,可达到较好的脱氮除磷效果.该联合工艺结合了活性污泥工艺和生物膜工艺的优点,运行稳定,出水水质优良,不仅适合于新建污水处理厂,也特别适合于不能脱氮除磷污水处理厂的技术改造.     

(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。     

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.     

温度对A/O工艺反硝化除磷效果的影响

以A／O工艺中充分释磷的厌氧污泥为研究对象,分别投加NO3^- -N和NO2^- -N,考察了温度对反硝化除磷效果的影响。结果表明,在一定范围内,随着温度的升高,NO3^- -N型反硝化除磷和脱氮速率均加快,但消耗单位氮的吸磷量却下降,若要取得良好的氮、磷去除效果,需适当提高缺氧段的NO3^- -N浓度;NO2^- -N对聚磷菌的抑制浓度并非为定值,而是随温度的升高而上升;随温度的升高,NO2^- -N型反硝化脱氮速率加快,而吸磷速率却未表现出明显的上升趋势。     

Development of an innovative vertical submerged membrane bioreactor (VSMBR) for simultaneous removal of organic matter and nutrients

A novel vertical submerged membrane bioreactor (VSMBR) composed of anoxic and oxic zones in one reactor was developed in an attempt to reduce the problems concerning effective removal of pollutants from synthetic wastewater including glucose as a sole carbon source as well as membrane fouling. The optimal volume ratio of anoxic zone/oxic zone was found as 0.6. The desirable internal recycle rate and hydraulic retention time (HRT) for effective nutrient removal were 400% and 8h, respectively. Under these conditions, the average removal efficiencies of total nitrogen (T-N) and total phosphorus (T-P) were 75% and 71%, respectively, at the total chemical oxygen demand (T-COD)/T-N ratio of 10. In addition, the VSMBR showed high specific removal rates of nitrogen and phosphorus while the biomass growth yield from the reactor was about 20% of the conventional activated sludge process.     

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.     

Biochemical model for enhanced biological phosphorus removal

Enhanced biological phosphorus (bio-P) removal from wastewater is a promising technology for which the fundamental mechanisms are still unclear. The purpose of this paper is to present a biochemical model that explains bio-P removal mechanisms occurring under anaerobic, aerobic and anoxic conditions of the process. A bio-P bacterium is referred to as one that can store both polyphosphate and carbon (as poly-β-hydroxybutyrate for example). In this communication, observations from the literature are first reviewed and mechanisms of bacterial bioenergetics and membrane transport are summarized. The model for bio-P metabolism under anaerobic, aerobic and anoxic conditions is then presented. The role of polyphosphate under anaerobic conditions is suggested to be as a source of energy both for the reestablishment of the proton motive force, which would be consumed by substrate transport and for substrate storage. The role of the anaerobic zone is to maximize the storage of organic substrates in bio-P bacteria. For this purpose the supply of readily available substrates should be maximized and the presence of electron acceptors (molecular oxygen or oxidized nitrogen) minimized. Under subsequent aerobic or anoxic conditions, bio-P bacteria will accumulate polyphosphates in response to the availability of electron acceptors (oxygen or oxidized nitrogen) for energy production. Carbon reserves in bio-P bacteria should provide energy for growth and for soluble phosphate accumulation as polyphosphate reserves.     

Biological nitrogen removal with enhanced phosphate uptake in a sequencing batch reactor using single sludge system

Simultaneous biological phosphorus and nitrogen removal with enhanced anoxic phosphate uptake was investigated in an anaerobic-aerobic-anoxic-aerobic sequencing batch reactor ((AO)2 SBR). Significant amounts of phosphorus-accumulation organisms (PAOs) capable of denitrification could be accumulated in a single sludge system coexisting with nitrifiers. The ratio of the anoxic phosphate uptake to the aerobic phosphate uptake capacity was increased from 11% to 64% by introducing an anoxic phase in an anaerobic aerobic SBR. The (AO)2 SBR system showed stable phosphorus and nitrogen removal performance. Average removal efficiencies of TOC, total nitrogen, and phosphorus were 92%, 88%, and 100%, respectively. It was found that nitrite (up to 10 mg NO2(-)-N/l) was not detrimental to the anoxic phosphate uptake and could serve as an electron acceptor like nitrate. In fact, the phosphate uptake rate was even faster in the presence of nitrite as an electron acceptor compared to the presence of nitrate. It was found that on-line sensor values of pH, ORP, and DO were somehow related with the dynamic behaviours of nutrient concentrations (NH4+, NO3-, and PO4(3-)) in the SBR. These on-line sensor values were used as real-time control parameters to adjust the duration of each operational phase in the (AO)2 SBR. The real-time controlled SBR exhibited better performance in the removal of phosphorus and nitrogen than the SBR with fixed-time operation.