进水C/P比对A2/O工艺性能的影响

我国当前面临着严重的水体富营养化问题,A²/O工艺是一种有效的同步脱氮除磷工艺,但其中进水C/P比是其运行效果的重要影响因素,为深入考察不同进水C/P比对A²/O工艺运行性能的影响,试验设计了4种进水C/P比 (55、45、34、23),研究了A²/O工艺中COD、总氮、磷和污泥特性的变化.实验结果表明,当进水C/P比小于32时,磷的去除效果随C/P比的降低而线性降低;当进水C/P比高于32时,磷的去除效果稳定在90%～98%,出水磷浓度小于0.5 mg•L^-1.但是C/P比的变化,对COD和总氮的去除率影响较小,平均去除率分别高于90%和75%.而剩余污泥中磷含量则随C/P比的下降而增加.实验发现,不同C/P比系统均存在反硝化除磷现象,可以实现“一碳两用”,有利于氮磷去除效果的提高.     

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     

碳氮比对A-O-N工艺脱氮效果的影响

研究了A-O-N生物脱氮工艺中,污水的碳氮比对脱氮的影响。试验结果表明,由于A-O-N工艺将异养菌和自养硝化菌分别置于两个反应器中,使其在各自适宜的环境中生存,两者之间不存在竞争问题,硝化率不受进水碳氮比的影响,进水碳氮质量比为5.1时脱氮效果最佳,继续增大进水碳氮比,硝化率和脱氮率均不受影响,进水碳氮质量比在2.2￣9.8变化时,TN去除率与碳氮比呈正相关性(R2为0.999)。     

Biological Nutrient Removal in a Full Scale Anoxic/Anaerobic/Aerobic/ Pre-anoxic-MBR Plant for Low C/N Ratio Municipal Wastewater Treatment

A novel full scale modified A2O （anoxic/anaerobic/aerobic/pre-anoxic）-membrane bioreactor （MBR） plant combined with the step feed strategy was operated to improve the biological nutrient removal （BNR） from low C/N ratio municipal wastewater in Southern China. Transformation of organic carbon, nitrogen and phosphorus, and membrane fouling were investigated. Experimental results for over four months demonstrated good efficiencies for chemical oxygen demand （COD） and NH4^＋-N removal, with average values higher than 84.5%and 98.1%, re-spectively. A relatively higher total nitrogen （TN） removal efficiency （52.1%） was also obtained at low C/N ratio of 3.82, contributed by the configuration modification （anoxic zone before anaerobic zone） and the step feed with a distribution ratio of 1：1. Addition of sodium acetate into the anoxic zone as the external carbon source, with a theoretical amount of 31.3 mg COD per liter in influent, enhanced denitrification and the TN removal efficiency in-creased to 74.9%. Moreover, the total phosphate （TP） removal efficiency increased by 18.0%. It is suggested that the external carbon source is needed to improve the BNR performance in treating low C/N ratio municipal waste-water in the modified A^2O-MBR process.     

污泥厌氧水解与短程硝化反硝化耦合工艺处理低碳氮比城市污水

为处理低碳氮比城市污水,在30~35℃、不调节pH值(7.01~8.33)的条件下,通过人为添加氨氮控制游离氨浓度(25mg·L-1),在SBR中6d内成功启动了短程硝化反硝化。对比实验结果表明,短程硝化反硝化在处理低C/N比城市污水时的总氮脱除效果要优于传统的全程硝化反硝化,当反应器运行稳定后,溶解氧的浓度和高游离氨不再是影响NO2--N浓度累积的主要因素,NO2--N/NOx--N始终保持在80%以上。为了进一步提高短程硝化反硝化的脱氮效率,利用污泥厌氧水解产物替代10%进水,为反硝化阶段提供附加的部分碳源,两工艺联合后处理效果良好,出水TN平均浓度和去除率分别为13.39mg·L-1和74.9%,出水水质符合排放标准的要求。     

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。     

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^-。     

进水碳氮比对连续流双污泥系统氮磷去除的影响

采用连续流双污泥系统模拟污水处理中试试验,通过改变碳源投加量实现不同C/N比,探究连续流双污泥系统C/N比对污染物去除效果的影响及作用机制。结果表明:连续流双污泥系统在不同进水C/N下,均能取得稳定的脱氮除磷效果;随C/N比升高,反硝化作用增强,TN去除率相应升高,C/N比值为5、6时,平均去除率可达86%;C/N比对氨氮去除效果影响较小;C/N比对TP去除效果影响显著,C/N比值为3时TP去除率最高,平均去除率为93%,随C/N比增高去除率逐渐下降,C/N比值为6时TP平均去除率仅为61%。可见,连续流双污泥系统对进水C/N比偏低的生活污水有着更好的处理效果。     

碳氮比对SBR系统硝化过程及EPS三维荧光光谱特性的影响

以人工模拟废水为研究对象，采用4组间歇式活性污泥（SBR）反应器（R₀、R₅、R₁₀和R₁₅），探究了硝化过程中碳氮比（C/N）对NH{}_{\mathrm{4}}^{+}-N去除和胞外聚合物（EPS）含量的影响。同时采用三维荧光光谱技术（3D-EEM）结合积分区域法（FRI），分析进出水时EPS各组分所占比例及变化情况。结果表明，4种C/N系统均获得了较高的NH{}_{\mathrm{4}}^{+}-N去除率，且氨氧化速率与C/N呈负相关；C/N升高（0→15），进出水时的EPS及其组分含量随之增大，其中C/N对PS含量影响尤为显著，且硝化过程中多糖（PS）积累。根据荧光区域积分法（FRI）分析，不同C/N条件下EPS各荧光区域强度百分比存在显著差异，其中荧光区域V（腐殖酸类物质，46%~57%）的强度百分比值（P_i,n）最高。此外，蛋白质类物质酪氨酸和色氨酸以及溶解性微生物代谢产物在硝化过程中均被微生物所利用。     

改良型多级A/O-MBR组合工艺对低C/N比生活污水的强化除磷

采用多级厌氧/耗氧膜生物反应器（A/O-MBR）组合工艺对低C/N比生活污水进行处理时,存在总磷（TP）处理不达标的问题。通过改变污泥回流位置并增加内回流的改良型多级A/O-MBR组合工艺强化除磷,探究该工艺对低C/N比生活污水中TP的去除效果,并通过污泥静态分析研究其污泥反硝化除磷机理。结果表明,改良型多级A/O-MBR组合工艺对TP去除效果良好,平均去除率达到了86.36%,同时对化学需氧量（COD）、总氮（TN）及氨氮去除效果良好,均达到一级A排放标准。该工艺提高了聚磷菌及反硝化聚磷菌的比例,有效强化了对TP的去除。     

流量分配比对改良多级A/O污染物的去除影响

针对传统多级A/O工艺处理低碳氮比生活污水除磷效果差的问题，本文通过增设前置厌氧段改良多级A/O工艺，重点研究了流量分配比对低碳氮比生活污水脱氮除磷的影响。系统在温度为(22±4)℃、水力停留时间为8h、污泥龄为14d、活性污泥浓度为2～3g/L、污泥回流比为75%时，系统依次在100%∶0∶0、45%∶30%∶25%、60%∶30%∶10%三种流量分配比下连续运行47d。结果表明，在45%∶30%∶25%的进水比下，COD、氨氮去除效果最佳，去除率分别达到90.24%和96.66%，出水浓度分别为30.97mg/L、2.11mg/L，均优于GB18918—2002《城镇污水处理厂污染物排放标准》一级A排放标准。三种流量分配比下系统对TN、TP总体去除效果一般，平均去除率为47.31%、49.33%，可通过外加碳源增强反硝化作用及化学除磷进一步降低氮磷出水浓度，出水有望达到一级B标准。改良工艺在保证有机物去除效果的基础上基本实现了脱氮除磷，可为实际生活中处理低C/N生活污水提供参考。     

改进型分段进水厌氧/缺氧/好氧工艺强化营养物去除

In order to enhance phosphorus removal in traditional step-feed anoxic/oxic nitrogen removal process,a modified pilot-scale step-feed anaerobic/anoxic/oxic (SFA²/O) system was developed,which combined a reactor similar to UCT-type configuration and two-stage anoxic/oxic process.The simultaneous nitrogen and phosphorus removal capacities and the potential of denitrifying phosphorus removal,in particular,were investigated with four different feeding patterns using real municipal wastewater.The results showed that the feeding ratios(Q₁)in the first stage determined the nutrient removal performance in the SFA²/O system.The average phosphorus removal efficiency increased from 19.17% to 96.25% as Q₁ was gradually increased from run 1 to run 4,but the nitrogen removal efficiency exhibited a different tendency,which attained a maximum 73.61% in run 3 and then decreased to 59.62% in run 4.As a compromise between nitrogen and phosphorus removal,run 3 (Q₁=0.45Q_total) was identified as the optimal and stable case with the maximum anoxic phosphorus uptake rate of 1.58mg·(g MLSS)^-1·h^-1.The results of batch tests showed that ratio of the anoxic phosphate uptake capacity to the aerobic phosphate uptake capacity increased from 11.96% to 36.85% with the optimal influent feeding ratio to the system in run 3,which demonstrated that the denitrifying polyP accumulating organisms could be accumulated and contributed more to the total phosphorus removal by optimizing the inflow ratio distribution.However,the nitrate recirculation to anoxic zone and influent feeding ratios should be carefully controlled for carbon source saving.     

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。     

低C/N比生活污水对脱氮除磷影响对比试验研究

利用长春市南郊污水处理城市污水为对象,分别采用填料A/A/O和SBR反应器进行低C/N比条件下的脱氮除磷的试验研究。结果表明,相同水力停留时间下,填料A/A/O反应器和SBR反应器的脱氮除磷效果较好,建议水力停留时间为6 h;污泥龄和C/N比对填料A/A/O反应器和SBR反应器的COD去除效果影响不大,各种条件下COD去除率在80%左右;推荐填料A/A/O反应器的最适SRT为15 d,而SBR反应器的最适SRT为20 d;SBR反应器更适合处理低温污水;C/N比值越大,填料A/A/O反应器和SBR反应器的TN去除率越高,最佳范围在4~6之间,其中填料A/A/O反应器的去除效果最好。     

Characteristics of nitrogen and phosphorus removal in SBR and SBBR with different ammonium loading rates

Laboratory scale experiments were conducted to study the deterioration of enhanced biological phosphorus removal (EBPR) due to influent ammonium concentration, and to compare the performance of two types of sequencing batch reactor (SBR) systems, a conventional SBR and sequencing batch biofilm reactor (SBBR). Both in SBR and SBBR, the total nitrogen removal efficiency decreased from 100% to 53% and from 87.5% to 54.4%, respectively, with the increase of influent ammonium concentration from 20 mg/l to 80 mg/l. When the influent ammonium concentration was as low as 20 mg/l (C: N: P=200: 20: 15), denitrifying glycogen-accumulating organisms (DGAOs) were successfully grown and activated by using glucose as a sole carbon source in a lab-scale anaerobic-oxic-anoxic (A₂O) SBR. In the SBR, due to the effect of incomplete denitrification and pH drop, the nitrogen and phosphorus removal efficiency decreased from 77% to 33.3% when the influent ammonium concentration increased from 20 mg/l to 80 mg/l. However, in the SBBR, simultaneous nitrification/denitrification (SND) occurred, and the nitrification rate in the aerobic phase did not change remarkably in spite of the increase in influent ammonium concentration. Phosphorus removal was not affected by the increase of influent ammonium concentration.     

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。     

厌氧-限氧SBR处理低C/N生活污水SNDPR启动及N2O释放

以厌氧-限氧方式运行序批式生物反应器（SBR）,采用逐步降低进水碳氮比（C/N）方式驯化聚磷菌（PAOs）和聚糖菌（GAOs）,启动了低C/N生活污水同步脱氮除磷过程（SNDPR）,并考察了SNDPR内PAOs、GAOs间竞争关系及系统脱氮除磷性能过程N₂O释放特性。结果表明,C/N=7.0,SBR限氧段脱氮和除磷效率分别为83.5%和90%以上,N₂O产量为0.54 mg/L;C/N=3.0~3.5,脱氮和除磷效率分别降至60.1%和80.5%,N₂O产量达1.09 mg/L。SBR内不同反应阶段内源物质变化均表现出PAOs-GAOs共存特性。高C/N有利于微生物合成聚-β-羟基烷酸酯（PHA）并促进N₂O还原。C/N降低,SBR内污泥内源物质转化倾向于富集GAOs的降解特性。氨氧化菌（AOB）好氧反硝化过程及GAOs以PHA作为电子供体的内源反硝化过程促进了N₂O的释放。随C/N降低,SBR内污泥平均胞外聚合物（EPS）由43.4 mg/g VSS增至50.5 mg/g VSS,污泥容积指数（SVI）由99 ml/g增至127 ml/g。疏松型EPS（LB-EPS）内,蛋白质（PN）与多糖（PS）之比（PN/PS）随C/N增加而降低,污泥亲水性增加,不利于污泥脱水。     

Optimisation of anaerobic/anoxic/oxic process to improve performance and reduce operating costs

A laboratory‐scale anaerobic/anoxic/oxic reactor system was used to treat synthetic brewery wastewater for 1 year. The objectives were to enhance denitrifying phosphorus removal, improve biological nutrient removal and reduce operating costs. Three operational strategies were tested: (1) controlling nitrate recirculation to stimulate the growth of denitrifying phosphate‐accumulating organisms; (2) adjusting the volume ratio of the anaerobic/anoxic/oxic zones to enhance anoxic P uptake; (3) bypassing a part of the influent flow into the anoxic zone to maximise anoxic P uptake and denitrification. The results showed that not only was anoxic P uptake enhanced but also energy consumption for aeration could be reduced when the anoxic effluent NO₃^?‐N concentration was controlled between 1 and 3 mg L^?1. The optimal volume ratio of the anaerobic/anoxic/aerobic zones in this system was found to be 1:1:2. The optimal bypass flow ratio was 0.32. The results indicated that the optimal strategies could improve treatment performance and reduce operational costs, but there was still a challenge to treat wastewater with low C/N ratio. Copyright © 2006 Society of Chemical Industry     

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.