A2/O工艺的固有缺欠和对策研究

分析了A2/O系统的固有缺欠硝化菌、反硝化菌和聚磷菌在有机负荷、泥龄以及碳源需求上存在着矛盾和竞争,阻碍着生物除磷脱氮技术的应用.为此各国水处理专家有针对性地进行了大量研究,新工艺层出不穷,但至今仍没有根本性的突破,营养盐去除的整体效果没有显著提高.在深入分析研究基础上,指出应以兼性厌氧反硝化除磷菌的生物特性研究为基础,开展以PHB为碳源的新工艺和硝化菌与反硝化除磷菌相分离的双污泥系统的研究,为生产实践提供理论依据和指导.     

两级SBR生物除磷脱氮工艺效果实验研究

利用SBR的工艺特点,通过合理控制泥龄,将聚磷菌与硝化茵分别控制在2个SBR反应器中优势生长,以解决聚磷菌与硝化茵等混合生长系统在除磷和脱氮过程中的矛盾.实验证明两级SBR工艺系统生物除磷脱氮是可行的.     

城市污水生物脱氮除磷新技术

概述城市污水生物脱氮除磷的基本原理,重点介绍了同时硝化反硝化、短程硝化反硝化、厌氧氨氧化、反硝化除磷几种生物脱氮除磷新技术的原理和研究现状,并认为随着生物脱氮除磷技术的发展,研究和开发经济、高效、低能耗生物脱氮除磷技术将成为发展趋势。     

城市污水生物脱氮除磷新技术

概述城市污水生物脱氮除磷的基本原理,重点介绍了同时硝化反硝化、短程硝化反硝化、厌氧氨氧化、反硝化除磷几种生物脱氮除磷新技术的原理和研究现状,并认为随着生物脱氮除磷技术的发展,研究和开发经济、高效、低能耗生物脱氯除磷技术将成为发展趋势.     

高效脱氮除磷工艺(NPR)中试研究

NPR工艺是将A2/O和BAF工艺经改进后有机结合形成的一种新型的更为高效的生物脱氮除磷技术.通过中试规模的试验,研究了该工艺处理生活污水时的脱氮除磷效果.结果表明,该工艺成功地解决了好氧段硝化菌与聚磷菌对泥龄的不同需求、厌氧段反硝化释氧与聚磷菌释磷之间矛盾的难题;NH3-N、TN和TP的去除率分别达到92.6%、68.3%和82.4%,同时CODCr和SS去除率分别达到93.4%、95.8%,且运行效果稳定.     

污水处理厂反硝化除磷研究及实践

结合苏州娄江污水处理厂生产运行实践,研究了改良型一体化交替反应池在实现良好反硝化除磷条件下的运行工况.实践表明,提高反硝化除磷的关键是要有充足的硝酸盐氮为反硝化聚磷菌(DPB)提供电子受体,当NO-2N浓度在5 mg/L以上时,可以实现较好的反硝化除磷;当SRT为12～14 d时,反硝化除磷和系统脱氮除磷效果最好,生物除磷运行成本较低.此外,进水COD/TP、好氧池DO、厌氧池MLSS以及SRT也是影响一体化反应池生物除磷的主要因素.针对雨季低负荷运行除磷效果不理想的现象,提出了相应的工况运行措施.     

低氧条件下同时硝化反硝化工艺研究

在城市污水生物脱氮工艺中 ,越来越多的研究表明硝化和反硝化可以在同一反应器内同时发生。同传统的生物脱氮工艺相比 ,同时硝化和反硝化可以减少反应设备的数量和尺寸 ;降低氧气的供给 ,从而节省能耗 ;减少甚至不需要碳源的投加 ,节省药剂费用等。本论文研究低氧条件下 (ＤＯ =0 3～ 0 8ｍｇ/Ｌ)完全混合活性污泥系统对总氮的去除和对有机物的处理效率 ,考察Ｃ/Ｎ、Ｆ/Ｍ和泥龄对同时硝化和反硝化的影响以及后续除磷的工艺。正交试验结果表明Ｃ/Ｎ对同时硝化和反硝化的影响最大 ,其次是泥龄 ,最后是Ｆ/Ｍ。同时得到低氧条件下同时硝化和…     

溶解氧对低碳源污水一体化处理工艺脱氮除磷的影响

通过试验对比,研究了溶解氧对低碳源污水一体化工艺脱氮除磷效果的影响。结果表明,平均溶解氧为0.18mg/L时,系统出水可以稳定达到GB 18918—2002一级A标准,溶解氧过高或过低都会降低系统脱氮除磷效果。在平均溶解氧为0.18mg/L的工况下,系统存在反硝化吸磷、同时硝化反硝化及全程反硝化3种脱氮方式,且反硝化吸磷和同时硝化反硝化脱氮量占氮总去除量的66.7%,可以较大程度降低脱氮除磷过程所需碳源量并节省耗氧量,提高低碳源污水脱氮除磷效果。     

生物除磷脱氮系统工程设计中值得探讨的几个问题

针对目前生物除磷脱氮系统工程设计中几个热点问题进行了分析探讨,以引起设计人员的重视。首先分析了系统总污泥龄与好氧污泥龄的区别,强调好氧污泥龄不宜盲目取大,可用满足硝化功能的最小污泥龄乘以适宜的安全系数求得;其次,指出仍沿用设置初沉池时的f值进行无初沉池A2/O系统的工程设计会带来约40%～60%的误差,对系统产率系数的性质进行了探讨,建议不设初沉池的生物除磷脱氮系统采用反映系统综合性能的净过程产率系数Yn或总产率系数yBOD进行设计计算;最后强调了活性污泥总量的重要性,同时给出了设计程序。     

NO-2-N、MLSS对反硝化脱氮除磷的影响

通过对实验室培养的富集反硝化聚磷菌活性污泥在不同电子受体条件、不同MLSS条件下进行缺氧批式试验,研究了NO-2-N作为电子受体时对反硝化脱氮除磷的影响,并与NO-3-N作为电子受体时进行比较。同时分析了MLSS对反硝化脱氮除磷的影响。结果表明:NO-2-N可作为电子受体被DPAOs利用,但是过量的NO-2-N会对吸磷产生抑制作用;NO-2-N作为电子受体可能同时参与了反硝化除磷和常规的内源反硝化。此外,增加活性污泥浓度(MLSS)可提高缺氧吸磷速率,但过高的污泥浓度会导致单位污泥的吸磷速率降低,因此需合理控制反硝化除磷中的MLSS。     

不同电子受体的反硝化除磷效果对比研究

反硝化除磷作用可以明显节省脱氮除磷过程的碳源需求和能耗。为研究不同电子受体下的反硝化除磷效果,利用一体化活性污泥工艺中污泥经过厌氧释磷后在不同电子受体下进行反硝化除磷试验,结果表明NO3-—N和NO2-—N均能参与反硝化除磷过程,在NO2-—N初始浓度高达30mg/L的条件下,除磷率仍在93%以上,未对反硝化除磷过程产生毒害作用。在工程应用中应加强短程硝化反硝化与反硝化除磷作用的耦合,在提高脱氮除磷效率的同时,取得明显的节能效果。     

A two-sludge system for simultaneous biological C, N and P removal via the nitrite pathway

Nitrogen removal via the nitrite pathway results in significant savings in both aeration costs and COD requirements for denitrification when compared to the conventional biological nitrogen removal process. Implementation of the nitrite pathway for simultaneous C/N/P removal in a single sludge system has a major drawback: the aeration phase disfavours denitrifying phosphorus removal. A possible configuration to overcome this issue is the utilisation of a two-sludge system where autotrophic and heterotrophic populations are physically separated. This paper experimentally demonstrates the feasibility of a nitrite-based two-sludge system with sequencing batch reactors (SBR) for the treatment of urban wastewater: a heterotrophic SBR with denitrifying PAOs for P removal and an aerobic SBR for N removal. Partial nitrification was attained in the autotrophic SBR so that shortcut biological nitrogen removal was achieved by using the anoxic dephosphatation activity of DPAOs. Finally, the effect of operating this system without pH control was studied using different influent pH values (pH = 6.8, 7.5 and 8.2) and, despite some efficiency lost due to the pH fluctuations, the system was able to remove most of the C, N and P present in the wastewater.     

Biological nutrient removal in membrane bioreactors: denitrification and phosphorus removal kinetics.

The impact of including membranes for solid liquid separation on the kinetics of nitrogen and phosphorus removal was investigated. To achieve this, a membrane bioreactor (MBR) biological nutrient removal (BNR) activated sludge system was operated. From batch tests on mixed liquor drawn from the MBR BNR system, denitrification and phosphorus removal rates were delineated. Additionally the influence of the high total suspended solids concentrations present in the MBR BNR system and of the limitation of substrate concentrations on the kinetics was investigated. Moreover the ability of activated sludge in this kind of system to denitrify under anoxic conditions with simultaneous phosphate uptake was verified and quantified.The denitrification rates obtained for different mixed liquor (ML) concentrations indicate no effect of ML concentration on the specific denitrification rate. The denitrification took place at a single specific rate (K(2)) with respect to the ordinary heterotrophic organisms (OHOs, i.e. non-PAOs) active mass. Similarly, results have been obtained for the P removal process kinetics: no differences in specific rates were observed for different ML or substrate concentrations. From the P removal batch tests results it seems that the biological phosphorus removal population (PAO) consists of 2 different sets of organisms denitrifying PAO and aerobic PAO.     

Alternate anoxic/aerobic operation for nitrogen removal in a membrane bioreactor for municipal wastewater treatment

A large pilot-scale membrane bioreactor (MBR) with a conventional denitrification/nitrification scheme for municipal wastewater treatment has been run for one year under two different aeration strategies in the oxidation/nitrification compartment. During the first five months air supply was provided according to the dissolved-oxygen set-point and the system run as a conventional predenitrification MBR; then, an intermittent aeration strategy based on effluent ammonia nitrogen was adopted in the aerobic compartment in order to assess the impact on process performances in terms of N and P removal, energy consumption and sludge reduction. The experimental inferences show a significant improvement of the effluent quality as COD and total nitrogen, both due to a better utilization of the denitrification potential which is a function of the available electron donor (biodegradable COD) and electron acceptor (nitric nitrogen); particularly, nitrogen removal increased from 67% to 75%. At the same time, a more effective biological phosphorus removal was observed as a consequence of better selection of denitrifying phosphorus accumulating organisms (dPAO). The longer duration of anoxic phases also reflected in a lower excess sludge production (12% decrease) compared with the standard pre-denitrification operation and in a decrease of energy consumption for oxygen supply (about 50%).     

Evaluation of sludge reduction and phosphorus recovery efficiencies in a new advanced wastewater treatment system using denitrifying polyphosphate accumulating organisms.

A new biological nutrient removal process, anaerobic-oxic-anoxic (A/O/A) system using denitrifying polyphosphate-accumulating organisms (DNPAOs), was proposed. To attain excess sludge reduction and phosphorus recovery, the A/O/A system equipped with ozonation tank and phosphorus adsorption column was operated for 92 days, and water quality of the effluent, sludge reduction efficiency, and phosphorus recovery efficiency were evaluated. As a result, TOC, T-N and T-P removal efficiency were 85%, 70% and 85%, respectively, throughout the operating period. These slightly lower removal efficiencies than conventional anaerobic-anoxic-oxic (A/A/O) processes were due to the unexpected microbial population in this system where DNPAOs were not the dominant group but normal polyphosphate-accumulating organisms (PAOs) that could not utilize nitrate and nitrite as electron acceptor became dominant. However, it was successfully demonstrated that 34-127% of sludge reduction and around 80% of phosphorus recovery were attained. In conclusion, the A/O/A system equipped with ozonation and phosphorus adsorption systems is useful as a new advanced wastewater treatment plant (WWTP) to resolve the problems of increasing excess sludge and depleted phosphorus.     

Outcomes of a 2-year investigation on enhanced biological nutrients removal and trace organics elimination in membrane bioreactor (MBR).

Two configurations of membrane bioreactors were identified to achieve enhanced biological phosphorus and nitrogen removal, and assessed over more than two years with two parallel pilot plants of 2m3 each. Both configurations included an anaerobic zone ahead of the biological reactor, and differed by the position of the anoxic zone: standard pre-denitrification, or post-denitrification without dosing of carbon source. Both configurations achieved improved phosphorus removal. The goal of 50 microgP/L in the effluent could be consistently achieved with two types of municipal wastewater, the second site requiring a low dose of ferric salt ferric salt < 3 mgFe/L. The full potential of biological phosphorus removal could be demonstrated during phosphate spiking trials, where up to 1 mg of phosphorus was biologically eliminated for 10 mg BOD5 in the influent. The post-denitrification configuration enabled a very good elimination of nitrogen. Daily nitrate concentration as low as 1 mgN/L could be monitored in the effluent in some periods. The denitrification rates, greater than those expected for endogenous denitrification, could be accounted for by the use of the glycogene pool, internally stored by the denitrifying microorganisms in the anaerobic zone. Pharmaceuticals residues and steroids were regularly monitored on the two parallel MBR pilot plants during the length of the trials, and compared with the performance of the Berlin-Ruhleben WWTP. Although some compounds such as carbamazepine were persistent through all the systems, most of the compounds could be better removed by the MBR plants. The influence of temperature, sludge age and compound concentration could be shown, as well as the significance of biological mechanisms in the removal of trace organic compounds.     

污泥碱解发酵液用于生活污水脱氮 除磷的效果研究

为了减轻水体富营养化程度,提高污水的脱氮除磷效果,并解决污泥减量化和资源化问题,本研究将碱预处理的污泥进行厌氧发酵产酸,并将发酵液作为污水脱氮除磷的外加碳源。研究结果表明：投加污泥发酵液后,出水氨氮浓度为0.3~0.5 mg/L,总磷浓度为0.5 mg/L,与未投加污泥发酵液相比分别降低了1.7~2.3 mg/L和3~4 mg/L。     

影响反硝化除磷与厌氧氨氧化耦合的因素

氧对厌氧氨氧化菌有毒,但在颗粒污泥和生物膜中的厌氧氨氧化菌对氧有较高的耐受能力,并且聚磷菌能消耗影响氧氨氧化菌生长的氧。厌氧氨氧化菌的生长无需有机物的参与,聚磷菌释磷需要吸收有机物,少量有机物的加入对厌氧氨氧化菌的活性影响不大。亚硝酸盐是厌氧氨氧化菌氧化氨的电子受体,较高浓度的亚硝酸盐对反硝化聚磷有抑制作用,但合适浓度的亚硝酸盐(该浓度可以通过驯化来提高)可以作为反硝化聚磷菌吸磷的电子受体。厌氧氨氧化过程中有硝酸盐生成,反硝化聚磷菌能利用这部分硝酸盐。另外,两类菌都适宜于中温略偏碱性的环境。因此,通过创造同时对厌氧氨氧化菌和反硝化聚磷菌有利的微生态环境,发挥两者在脱氮除磷方面的协同耦合作用,达到高度脱氮除磷,是极有前景的废水厌氧(缺氧)处理研究方向。     

活性污泥法脱氮除磷工艺设计方法探讨

对活性污泥法脱氮除磷工艺的设计方法进行探讨,提出以泥龄为主进行控制,采用活性污泥数学模型与经验方法相结合,并以COD为计量单位,对不同种类有机物进行分类.简述了不同有机物测定方法和设计过程.     

Biological phosphorus removal with nitrite as election acceptor.

Biological phosphorus removal was studied in a sequencing batch reactor (SBR). The results showed that nitrite could be used as electron acceptor in denitrifying phosphorus removal. Feed mode of nitrite had significant influence on denitrifying phosphorus removal. Anoxic phosphorus assimilation rate could reach 10.44 mgP/gSS.h and the percentage of anoxic phosphorus assimilation amount was more than 97% with continuous feed mode. Granular sludge with denitrifying phosphorus removal activity was found in the SBR. The effects of different operational conditions, such as COD loading, settling time, HRT etc., on the formation of granules were also studied.