多点进水改良型复合A2/O处理低C/N污水

以低C/N比城市生活污水为研究对象,重点考查了改良A²/O工艺的脱氮除磷性能。原水按一定比例分配给厌氧池和缺氧池,以合理分配厌氧释磷和缺氧反硝化所需的碳源;在好氧池和缺氧池中分别投加填料,以稳定系统的硝化和反硝化效果,提高系统的脱氮性能;厌氧池和缺氧池出水都直接进入好氧池。在进水COD/TN平均为5.54,HRT为11 h,SRT为15 d,MLSS为3000～4000 mg·L^-1,污泥回流比为50%条件下,通过三种不同进水分配比以及三种混合液回流比的对比试验研究,得到系统最佳进水分配比5:5,对分配脱氮和除磷所需碳源更加合理;而混合液回流比为200%,过高会破坏缺氧池的溶解氧环境,过低又会导致缺氧池反硝化作用不能充分发挥。在最优工况下COD、NH₃-N、TN和TP出水水质分别为29.7、0.1、11.8和0.42 mg·L^-1,平均去除率分别达到87.8%、99.7%、72.4%和91.3%,出水优于国家GB 18918-2002一级A排放标准,并且在缺氧池中发生了明显的反硝化除磷现象。     

改良分段进水工艺处理低C/N城市污水流量优化控制

采用改良分段进水工艺处理低碳氮比(C/N<3.5)生活污水,研究流量分配对系统处理性能的影响。在其他条件不变的情况下,以实际处理效果以及物料衡算结果为依据来逐步提高首段进水比例以寻求最优的流量运行工况,共确定4组不同的进水流量分配。结果表明:在此碳氮比条件下,通过提高首段进水比例的方法并不能降低厌氧区氮氧化物的含量,甚至出现相反的情况;系统的同步硝化反硝化作用以及微生物同化作用强度对TN的去除起着至关重要的作用;首段进水比例的提高强化了厌氧区聚磷菌的释磷作用,提高了磷酸盐的去除率;综合考虑系统的脱氮除磷效能以及后续可优化空间,确定在进水流量分配比例为6:3:1的工况3为最优工况,系统出水COD、氨氮、总氮、磷酸盐浓度分别为45.98、0.04、17.47和2.43 mg·L^-1。     

Enhanced biological nutrient removal in modified carbon source division anaerobic anoxic oxic process with return activated sludge pre-concentration☆

A pilot-scale modified carbon source division anaerobic anoxic oxic (AAO) process with pre-concentration of returned activated sludge (RAS) was proposed in this study for the enhanced biological nutrient removal (BNR) of municipal wastewater with limited carbon source. The influent carbon source was fed in step while a novel RAS pre-concentration tank was adopted to improve BNR efficiency, and the effects of an influent carbon source distribution ratio and a RAS pre-concentration ratio were investigated. The results show that the removal efficiency of TN is mainly influenced by the carbon source distribution ratio while the TP removal relies on the RAS pre-concentration ratio. The optimum carbon source distribution ratio and RAS pre-concentration ratio are 60%and 50%, respectively, with an inner recycling ratio of 100%under the optimum steady operation of pilot test, reaching an average effluent TN concentration of 9.8 mg·L?1 with a removal efficiency of 63%and an average TP removal efficiency of 94%. The mechanism of nutrient removal is discussed and the kinetics is analyzed. The results reveal that the optimal carbon source distribution ratio provides sufficient denitrifying carbon source to each anoxic phase, reducing nitrate accumulation while the RAS pre-concentration ratio improves the condition of anaerobic zone to ensure the phosphorus release due to less nitrate in the returned sludge. Therefore, nitrifying bacteria, denitrifying bacteria and phosphorus accumulation organisms play an important role under the optimum condition, enhancing the performance of nutrient removal in this test.     

污泥双回流-厌氧/好氧/缺氧强化内源反硝化深度脱氮

目前,如何经济有效地实现低C/N生活污水深度脱氮仍是污水处理厂面临的一个重大挑战。理论上后置反硝化可以实现深度脱氮效果,但往往由于缺乏外碳源难以同时满足经济高效脱氮。本研究建立的新型污泥双回流-厌氧/好氧/缺氧(AOA)工艺有利于富集培养以Candidatus Competibacter为主的反硝化聚糖菌(DGAOs),能够开发与利用内碳源脱氮。该系统长期处理低C/N (3.2)实际城市生活污水,TIN去除率达91.81%,出水TIN浓度为4.36 mg·L^-1。此外,提高第二污泥回流量增加了缺氧区的MLSS同时提升了比内源反硝化速率,是深度氮去除的主要原因。随着去除效果的提升,充分的厌氧环境使得内碳源贮存量升高,脱氮效果呈现正向循环。二沉池底部产生的额外碳源随第二回流引入系统进一步强化脱氮。本研究阐明了污泥双回流-AOA系统节碳脱氮的原理与关键,为低C/N城市污水的脱氮效率提供了一种可行性。     

Nutrient removal performance of an anaerobic–anoxic–aerobic process as a function of influent C/P ratio

The laboratory scale anaerobic–anoxic–aerobic (A²O) process fed with synthetic brewage wastewater was designed to investigate the effects of changing feed C/P ratio on the performance of biological nutrient removal (BNR) processes. In the experiment, the influent chemical oxygen demand (COD) concentration was kept at approximately 300 mg L^?1 while the total phosphorus concentration was varied to obtain the desired C/P ratio. Results showed that when the C/P ratio was lower than 32, phosphorus removal efficiency increased as C/P ratio increased linearly, while when the C/P ratio was higher than 32, the P removal efficiency was maintained at 90–98%, and effluent P concentration was lower than 0.5 mg L^?1. However, regardless of the C/P ratio, excellent COD removal (90% or higher) and good total nitrogen removal (75–84%) were maintained throughout the experiments. It was also found that very good linear correlation was obtained between COD uptake per unit P released in the anaerobic zone and C/P ratio. In addition, the P content in the wasted activated sludge increased with the decrease in the C/P ratio. Based on the results, it was recommended that the wastewater C/P ratio and its effects be incorporated into BNR design and operational procedures, appropriate C/P ratios were used to achieve the effluent treatment goals. Copyright © 2005 Society of Chemical Industry     

外加碳源类型对A2/O-BCO系统脱氮除磷性能的影响

反硝化除磷系统可实现氮、磷的同步去除,但在处理实际低C/N污水时,常需补充碳源以解决碳源不足的问题。采用A²/O-BCO（anaerobic anoxic oxic-biological contact oxidation）反硝化除磷系统,通过投加两种常用的外碳源控制进水C/N在4.3左右,考察碳源类型（丙酸钠、乙酸钠）对A²/O-BCO系统长期运行效果的影响,并采用批次试验进一步探究不同外加碳源条件下活性污泥的内碳源贮存和利用特性。结果表明：碳源种类的变化会改变微生物的底物贮存和利用特性,进而影响系统的脱氮除磷效果。当采用丙酸钠为外加碳源时,PO₄^3--P去除效果稳定在94%左右,实现了磷的高效去除,但TIN的去除率仅为70.82%;而以乙酸钠为外加碳源时,系统TIN的平均去除率可以达到74%,但磷的出水浓度出现波动现象,平均去除率仅为89.90%。碳源转化分析表明,厌氧条件下,进水丙酸钠含量增多,PHV的合成比例增加,相反,乙酸钠含量增多,PHB合成比例增多;缺氧条件下,DPAOs对PHB和PHV的降解效果与其含量相关,丙酸钠作为外碳源时,PHV的降解速率高且微生物产能效率高,因此PO₄^3--P吸收速率较快。此外,本文提出了不同外加碳源条件下系统的优化运行策略。     

木质填料床A/O系统处理低C/N比养猪废水的效能与脱氮机制

针对干清粪式养猪废水 浓度高和低C/N比的特点构建了四格室木质填料床A/O处理系统,通过调控运行探讨其除氮效能和机制。结果表明,在HRT 18.7 h、32℃、硝化液回流比200%、好氧区DO 1.5 mg·L^-1等条件下,即便进水 高达307.7 mg·L^-1,COD/TN平均为0.47,系统对COD、 和TN的去除率仍能维持在66.5%、93.6%和89.0%左右,TN去除负荷达到0.22 kg·m^-3·d^-1以上。系统对COD和TN的去除表现出一定的空间分区特征,其中前三厌氧格室是去除COD主要功能区,末端好氧格室是脱氮功能区。系统的脱氮机制以短程硝化反硝化为主,枯木填料的腐解为反硝化提供了必要的碳源。     

A2O工艺处理低C/N比生活污水的试验研究

采用52.5 L的A²O试验装置处理实际生活污水,研究了A²O工艺在处理低C/N比生活污水时的脱氮除磷特性,并探讨了如何通过强化缺氧吸磷来提高系统的脱氮除磷效率。试验结果表明：在厌氧/缺氧/好氧体积比为1/1/2、HRT为8 h、污泥回流比为70%、内回流比为300%的工况下处理C/N为7.89的生活污水,TN和SOP去除率分别能够达到85.4%和93.3%,系统中存在反硝化除磷,缺氧吸磷占总吸磷量的25.3%。同样的运行条件下处理C/N为4.20的生活污水时,SOP去除几乎不受影响,但TN去除率降低至62.2%,平均出水TN浓度也超过20 mg&#8226;L^-1。维持厌氧区体积不变,增大缺氧区体积,使得缺氧/好氧体积比为5/8时,TN去除率可上升到70.7%,缺氧吸磷占总吸磷量的55.2%。同时改变内回流比的试验表明250%的内回流比能最大程度地强化反硝化除磷的作用,此时TN去除率可提高至77.3%。强化A²O工艺中的反硝化除磷,能克服碳源不足对脱氮除磷的影响,显著提高低C/N比污水的脱氮除磷效率。     

A~2/O工艺强化反硝化除磷控制策略研究

在传统A2/O工艺的基础上,通过设立预缺氧区(即建立A-A2/O工艺)、外加碳源等手段,强化A2/O工艺处理低C/N生活污水的脱氮除磷能力。试验结果表明,经过强化后的A2/O反应器对COD、TN及TP去除效果良好,COD、TN及TP的去除率分别为92%、98%、85%。系统表现出明显的反硝化除磷现象,缺氧区除磷量占总除磷量的17.18%。反硝化除磷现象的产生降低了碳源缺乏对A2/O工艺脱氮除磷性能的影响,提高碳源的利用效率。为采用A2/O工艺处理低C/N生活污水的污水处理厂提供理论依据。     

AOA-SBR工艺用于城市污水同步脱氮除磷

以城市污水为研究对象,考察了不同COD／N／P对厌氧／好氧／兼氧（AOA）．SBR工艺脱氮除磷效果的影响。经过3个月稳定运行,当COD：N：P-800：24：11时,AOA．SBR工艺对污水中有机物、氨氮和磷的去除率分别为100％、84％和93％。实验通过提高有机物浓度削弱聚磷菌（PAOs）与聚糖菌（GAOs）竞争底物的能力,抑制了PAOs好氧放磷速率。当COD=800mg／L时,GAOs和PAOs厌氧乙酸摄取量之比为l：9。此外,实验采用兼氧／好氧吸磷速率比,对反硝化聚磷菌数量（DNPAOs）进行估算,结果表明AOA-SBR工艺比值明显高于A20和AO工艺。因此,通过调节进水有机物浓度,可使DNPAOs在AOA-SBR同步脱氮除磷过程中发挥重要作用。     

改变缺氧池容积强化A^2/O工艺脱氮除磷效率

采用实验室规模连续流厌氧-缺氧-好氧(A/A/O)工艺处理人工模拟生活污水,考察了不同碳氮比(C/N)和溶解氧(DO)工况下改变缺氧池容积对A^2/O工艺脱氮除磷效果的影响。结果表明,在低C/N和好氧阶段DO含量较低时,增大缺氧池容积有利于提高TN的去除率和除磷效率,在COD/ρ(TN)(ρ(TN)≈40 mg/L)约为7,DO的质量浓度在0.9~1.2 mg/L的条件下,缺氧池容积增加1倍,TN去除率可达71.1%,PO4^3--P去除率可达94.0%;在高C/N和好氧阶段DO含量较高时,增大缺氧池容积在提高TN去除率和改善出水水质方面效果不显著。     

碳氮比对AAO泥水回流工艺处理焦化废水的影响

采用AAO泥水回流工艺处理焦化废水,研究了进水碳氮比（C／N）对COD、氨氮及TN去除率的影响。研究表明,进水碳氮比（C/N）在12—25范围内,厌氧滤池COD去除率和氨化率分别达到37％和30％;缺氧进水碳氮比（C／N）控制在5．3-11．9范围内,MO泥水回流系统去除COD与氨氮效果的影响不明显,平均去除率分别为89．6％和95．2％;缺氧进水碳氮比（C/N）控制在7．5～8．6范围内,系统具有较好的TN去除率,平均值为72．2％。出水COD和NH3-N均能够达到污水综合排放标准中的二级标准。     

流量分配比对改良A/O分段进水脱氮除磷特性的影响

采用改良A/O分段进水工艺处理我国南方低浓度、低碳氮比城市生活污水。在进水COD/TN为5.16,HRT为8.7 h,SRT为15 d,MLSS为5.66 g·L^-1,污泥回流比为75%,厌氧/缺氧/好氧体积比为4∶8∶10条件下,通过设置6种不同进水流量分配比,控制各好氧段DO为1～1.5 mg·L^-1,经过150 d的连续运行,得到系统最佳流量分配比为20%∶35%∶35%∶10%;在此工况下COD、氨氮、总氮、总磷出水水质分别为33.05 mg·L-1、0.58 mg·L^-1、9.26 mg·L^-1、0.46 mg·L^-1,出水优于国家GB 18918-2002一级A排放标准。原水COD绝大部分作为厌氧释磷和反硝化脱氮所需碳源,系统对碳源有效利用率达74%;DO和ORP 的协同控制可以作为系统厌氧放磷段的控制参数;同时亦可作为缺氧段反硝化完成和好氧段硝化完成的指示性参数。     

N-SBR单元硝化时间分配比对A2N2系统运行性能的影响

以低C/N实际生活污水为处理对象,重点考察了N-SBR单元硝化时间分配比对A₂N₂系统运行性能的影响。在A²/O-SBR单元厌氧1.5 h,缺氧2 h,好氧0.5 h,A²/O-SBR和N-SBR单元的曝气量分别恒定在100、120 L·h^-1的条件下,将硝化时间分配比分别设定为5：1、4：1、3.5：1、3：1、7：1、8：1进行试验。结果表明,系统在A²/O-SBR单元可实现碳源的高效利用,有机物的去除受硝化时间分配比影响不大;为保证系统良好的硝化和反硝化除磷性能,一次硝化时间必须≥3.5 h;在总曝气时间一定的条件下,适当增加一次硝化时间,更有利于提高系统TN去除率;适当增加二次硝化时间,可以降低出水浓度,使出水达标排放。当硝化时间分配比为4：1时,系统脱氮除磷效果最好。TN、PO₄^3--P平均出水浓度分别为11.5、0 mg·L^-1,平均去除率分别为75%、100%。     

碳氮比对AAO-BAF工艺运行性能的影响

AAO-BAF工艺由厌氧-缺氧-好氧反应器和曝气生物滤池组成,属于外硝化反硝化除磷工艺。以实际生活污水为处理对象,通过调节进水COD浓度(从211 mg·L^-1增加到675 mg·L^-1),研究了进水COD和TN的比(C/N)对AAO-BAF工艺运行性能的影响。结果表明,进水有机物浓度低或高,可以通过限制厌氧释磷量或竞争AAO反应器缺氧区的NO₃^-,从而影响工艺的反硝化除磷效果。当进水C/N大于4,小于7时,AAO-BAF工艺对COD、TN和PO₄^3-的去除率分别可达86%、78%和90%以上。很高的C/N(如9.5)会使缺氧区内存在大量挥发性脂肪酸(VFA),导致普通反硝化菌迅速消耗反硝化聚磷菌(DPAOs)的电子受体NO₃^-。     

Removal of nitrogen and phosphorus using a new biofilm process-INRS (Innovative Nutrient Removal System)

Adopting various process configurations may perform biological nutrient removal (BNR) from sewage. To get a compact BNR process, biofilm reactors were chosen for nitrification and denitrification. Enhanced biological nitrogen and phosphorus removal in a new fixed biofilm reactor was investigated in operation strategies with two reaction phases: anaerobic/anoxic/aerobic process with post-anoxic/aerobic biofilm process (Run 2A) and Run 2A with exogenous carbon sources for denitrifying and removing phosphorus (Run 2B). The influent used was “J” WWTP influent that consisted of wastewater from nearby a factory district area, leachate, and sewage. Therefore, the influent contained a great deal of refractory organic compound. The mean concentrations of COD, NH ₄ ⁺ -N and T-P in the influent were about 297.0 mg/L, 64.92 mg/L and 2.63 mg/L, respectively. The C: N: P ratio of influent was 113: 25: 1 and it was not suitable for growth of microorganism compared with 100: 5: 1 of proper growth C:N:P ratio. But, at a total HRT of the system of 16 hours in Run 2, the system worked successfully obtaining removal of COD, T-N and T-P of the case of Run 2A, 80.1 %, 74.9 %, and 50.8 %, respectively, and Run 2B(c) with exogenous carbon source (Na-acetate) obtained 86.2 % T-N removal efficiency. The results of this research showed that an innovative nutrient removal system (INRS) process packed with SAC media could be applicable for treatment of nutrients from municipal wastewater.     

A2N2双污泥系统反硝化除磷工艺的启动与稳定

采用低C/N比实际生活污水,以A₂N₂-SBR（厌氧/硝化/缺氧/硝化）双污泥系统为研究对象,重点考察了A₂N₂系统启动过程中的脱氮除磷特性。试验结果表明：采用在A²/O-SBR和N-SBR单元分别接种种泥,分开培养驯化聚磷菌污泥和硝化菌生物膜,并利用A²/O-SBR单元的出水作为N-SBR单元的进水,25 d好氧硝化菌生物膜挂膜成功,氨氮去除率稳定在93%以上;A²/O-SBR单元采用先厌氧/好氧（A/O）后厌氧/缺氧（A/A）的运行方式,43 d成功培养富集了反硝化聚磷菌（DPAOs）,DPAOs占PAOs的67.81%,反硝化除磷率在77.9%以上;启动成功后原水中约73%和13%的COD分别在A²/O-SBR单元的厌氧段和N-SBR单元曝气过程中被去除,系统出水COD、NH⁺₄-N、PO₄^3--P、TN浓度分别为40.6、0、0.4、13.5 mg·L^-1,达到国家《城镇污水处理厂污染物排放标准》（GB 18918-2002）一级A排放标准。     

长泥龄改良A2/O工艺的短程硝化反硝化除磷

为解决传统A²/O工艺硝化与除磷泥龄(SRT)之间的矛盾,进一步提高低C/N(P)比生活污水同步脱氮除磷效率,采用一种改良A²/O工艺在长SRT条件下处理生活污水.试验结果表明,该工艺可有效筛选和强化反应器内活性污泥,并大量富集长SRT的反硝化除磷菌(DPAO).通过亚硝酸盐氧化菌(NOB)淘洗阶段后,反应器在SRT=19.6d、A²O段污泥浓度(MLSS)=5.5 g·L^-1、水力停留时间(HRT)=8.2 h、污泥回流比(R)=90%、硝化液回流比(r)=250%、溶解氧(DO)=1.5～0.3 mg·L^-1,间歇曝气段HRT=4 h、曝气周期1 h曝气1 min(DO=0.3～0.5 mg·L^-1)、沉淀59 min条件下长期运行,COD、NH₄⁺-N、TP和TN的平均去除率分别为88.71%、99.2%、93.77%和89.52%,出水亚硝化率(NO₂^--N/NO_x^--N)可达97.2%,DPAO占聚磷菌(PAO)比为95.5%.污水中约72.96%的COD被DPAO合成PHA除磷,15.75%的COD由异养反硝化消耗,约41.96%和31.31%的N分别通过反硝化除磷和异养反硝化去除.剩余污泥主要由DPAO和反硝化菌增殖产生,分别占82.74%和17.24%,较传统脱氮除磷途径减少了58.76%的碳源消耗和44.6%的污泥排放.     

基于MABR的市政污水处理强化脱氮中试研究

建立了A²/O-MABR耦合的中试系统,在不改变污水处理厂原有A²/O工艺以及不外加碳源的条件下,利用MABR丰富的微生物群落强化碳和氮的去除。该系统在最适宜参数下运行,COD、NH₄⁺-N和TN的出水水质满足市政污水处理厂一级A排放标准。微生物分析表明MABR生物膜上富集了丰富的脱氮功能菌群,例如Proteobacteria和Bacteroidetes等常规反硝化菌群,以及Thauera和Paracoccus等好氧反硝化菌群。MABR生物膜上丰富的脱氮功能菌群强化了系统对TN的去除。实验结果表明MABR在市政污水处理厂提标改造和强化脱氮方面拥有很大的应用潜力。     

Performance and microbial population variation in a plug‐flow A2O process treating domestic wastewater with low C/N ratio

BACKGROUND: In this study, a plug‐flow A²O (anaerobic/anoxic/oxic) reactor, with a working volume of 52.5 L, was employed to investigate the performance of biological nutrients removal and microbial population variations when treating low C/N ratio domestic wastewater. RESULTS: Results showed that TN removal was significantly affected by the shortage of carbon source while phosphorus removal was only slightly affected. The effluent soluble orthophosphate‐phosphorus (SOP) concentration was lower than 0.50 mg L^?1 but the TN concentration was over 20 mg L^?1 when the C/N ratio was 4.43. There was denitrifying phosphorus removal in the anoxic reactor and this was enhanced by increasing the volume ratio of anoxic reactor and maintaining appropriate mixed liquor recycle rate. More than 60% of the SOP were removed in anoxic reactors by denitrifying phosphorus removal when the volume ratio of anaerobic/anoxic/oxic was 1/1.4/1.6 and the mixed liquor recycle rate was 250%. The TN concentration of effluent decreased to 11.34 mg L^?1 and SOP concentration was still lower than 0.5 mg L^?1 in this condition. The main microorganisms found in the process by polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR‐DGGE) and the functional biodiversity are discussed. CONCLUSION: Traditional design and operating parameters of A²O are not appropriate for treating low C/N wastewater. Enhancing the denitrifying phosphorus removal ratio in an A²O process is an effective way to increase the removal rate of N and P from low C/N wastewater. Copyright © 2010 Society of Chemical Industry