城市污水的低氧短程脱氮中试研究

采用中试A<'2>/O系统处理实际城市污水,考察了在低氧条件下实现短程脱氮的可行性.结果表明,当缺氧池D0从1.0 mg/L降到0.2 mg/L,好氧池DO从2.5 mg/L降到1.0 mg/L时,系统的脱氮效果显著提高,对TN的去除率从(34.96±4.91)%上升到(71.44±13.45)%,污泥浓度(MLSS)从1 800 mg/L上升到2 100 mg/L.当控制好氧池的DO在1.0 mg/L左右时,出水中发生了亚硝酸盐积累现象,从而证实了在低氧条件下利用连续流活性污泥法实现短程脱氮的可行性,在降低系统曝气能耗的情况下还提高了系统的脱氮效率.但当DO浓度降低时,污泥沉降性能将有所变差,污泥体积指数(SVI)从150 mL/g上升到300 mL/g左右.     

铁碳微电解耦合好氧颗粒污泥处理制膜工业废水

针对难降解制膜工业废水,采用铁碳微电解/好氧颗粒污泥耦合工艺进行处理,铁碳微电解为连续流,好氧颗粒污泥为序批式反应器(SBR)。耦合工艺系统成功培育出具有优异沉降性能的好氧颗粒污泥,120 d时SVI30在30 m L/g左右、平均粒径为316μm;出水COD、NH_4~+-N和TN浓度分别为130.1、6.6、23.7 mg/L,处理效果优于对照组。铁碳微电解预处理不但能提高废水的B/C值,而且能促进生化处理段颗粒污泥的形成,有利于难降解工业废水的处理。     

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。     

好氧颗粒污泥的培养及实现同步脱氮

采用厌氧颗粒污泥和少量活性污泥为种泥,进水为人工配水,在SBR反应器中采用逐渐减少污泥沉降时间的方法造成选择压,培养出了好氧颗粒污泥,颗粒污泥粒径在2 mm左右、SVI值为20 mL/g左右、MLSS为10 g/L左右。结果表明:成熟的好氧颗粒污泥对COD、NH4+-N和TN的平均去除率分别为94%、97.5%和68.6%,出水COD、NH4+-N和TN平均浓度分别为64.74、1.92和27.53 mg/L,出水NO3--N和NO2--N平均浓度分别为18.01和4.44 mg/L。结合微生物相观察,可以判断好氧颗粒污泥实现了同步脱氮。     

基于复合铁碳材料的好氧颗粒污泥培养及脱氮研究

通过投加复合铁碳材料,经过70 d,在序批式活性污泥反应器(SBR)内培养出粒径为0. 5～4 mm、具有良好脱氮效果的成熟好氧颗粒污泥。在此过程中复合铁碳材料在提高污泥沉降性、加快颗粒化进程、提高脱氮效率等方面发挥了积极的作用。成熟好氧颗粒污泥的脱氮性能会受到pH值、DO浓度、C/N值的影响,最佳pH值为7. 0、DO为(2. 0±0. 1) mg/L、C/N值为8,相应的NH_4~+-N去除率分别为95. 60%、95. 78%、97. 87%,TN去除率分别为93. 64%、94. 28%、96. 28%。     

SBBR脱氮工艺研究

对序批式生物膜法(SBBR)脱氮工艺进行了研究。结果表明:当进水COD_(Cr)为100～300mg/L,TN控制在40～65mg/L,温度在23～28℃,pH在6.5～7.5左右,好氧段DO为4.0～6.0mg/L,时,所得最佳水力停留时间为先好氧6h,后厌氧3h。运行一个周期,COD_(Cr)、TN去除率分别为90%、71%。其中好氧段TN去除率占TN损失的84.8%,好氧反硝化对整个周期的脱氮起着极其重要的作用,而厌氧段脱氮效率较低。DO控制在4.0～6.0mg/L,均可以获得一定的脱氮效果。DO= 5.5mg/L时,TN去除率达70%,脱氮效果最佳。碳氮比越大,脱氮效率越高。且随着进水有机物浓度的增加,TN去除率也相应升高。据此可推定好氧反硝化菌是一种异养型好氧菌。     

处理低碳源污水的倒置A~2/O工艺强化脱氮调控

重庆市某大型污水处理厂采用倒置A2/O工艺处理低碳源城市污水,针对其在运行中存在的反硝化能力不足、脱氮除磷效果不佳和调控技术的缺陷,进行了强化脱氮综合调控技术的生产性试验研究。在2008年的常温和高温季节,采取投加垃圾渗滤液(投配率为0.1%)、缩短初沉池的HRT为原来的1/3、提高污泥浓度到4 500 mg/L、设置好氧第1段为反硝化过渡段及提高回流比等措施后,增加可利用碳源达15%以上,出水NH3-N为2.5 mg/L,对其去除率为90%;出水TN为17 mg/L,对TN的去除率提高至54%,单位电耗减少了15%(降至0.22 kW.h/m3)。在2008年—2009年的低温季节,采取了提高污泥浓度到约6 000 mg/L、控制好氧区的DO为1.2 mg/L等措施,出水NH3-N为3 mg/L,对NH3-N的去除率为88%;出水TN为15.5 mg/L,对TN的去除率为62%。     

A/A/O污水处理工艺脱氮效果模拟及优化

针对武汉某污水处理厂因进水总氮浓度高、碳氮比值低而导致脱氮效果不稳定的问题,基于ASDM模型建立了该污水处理厂A/A/O工艺模型,并利用历史数据对脱氮效果进行了优化模拟。分别对硝化液回流比(0~600%)、好氧段DO(1~6 mg/L)、缺氧段DO(0.005~0.2 mg/L)、温度(16~29℃)等工艺运行参数进行了模拟分析,通过模型模拟筛选出的最优运行参数如下:硝化液回流比为100%,好氧段DO为1 mg/L,污泥回流比为65%,排泥量为550 m3/d,且缺氧段DO浓度越低越有利于脱氮。根据以上结论并结合该污水处理厂实际情况,确定如下优化实施方案:硝化液回流比为300%,好氧段DO为3 mg/L以下,同时关闭硝化液回流点前的曝气头以降低缺氧段DO,并按90kg/d投加碳源(以COD计)。该污水处理厂按照上述方案实际运行2个月,脱氮效果明显提高,出水总氮达标率达到100%。     

水解-硝化反硝化二级SBR工艺处理明胶生产废水

采用厌氧水解-硝化反硝化二级SBR工艺处理明胶生产废水.结果表明,在进水COD为1 000～1 400 mg/L、TN为117～147 mg/L的情况下,该工艺降解COD及脱氮效果良好;系统出水COD＜100 mg/L,达到了《污水综合排放标准》（GB 8978-1996）的一级标准;水解工艺主要完成对进水中有机氮的氨化作用,硝化反硝化SBR可将水解产生的NH3-N全部转化;系统对TN的去除率＞80%,出水TN浓度为10～35 mg/L;污泥中CaCO3的少量积累不会影响系统的处理效果及运行的稳定性.     

曝气量对侧流除磷分段进水SBR脱氮除磷的影响

针对低碳源生活污水(COD/TN5,COD180 mg/L)的脱氮尤其是除磷效果差的问题,通过控制污泥外循环侧流除磷、分段进水、好氧/缺氧交替运行的SBR工艺的曝气量,实现了碳源的合理分配,获得了良好的脱氮除磷效果。控制曝气量为3.57 m3/(h.m3),在进水COD、氨氮、TN、TP平均浓度分别为121、29、31.4、4.6 mg/L的条件下,对各污染物的去除率分别为86%、98.6%、61.7%、93.6%。研究还发现,通过污泥外循环强化厌氧释磷可破坏聚磷菌的贮磷平衡,1次/d的污泥外循环侧流除磷不但保障了系统的除磷效果,还简化了侧流除磷工艺的运行过程。     

好氧反硝化在短程硝化反硝化工艺中的作用研究

采用SBR反应器处理垃圾渗滤液，研究了短程硝化反硝化过程中好氧反硝化的作用。结果表明，SBR反应器的亚硝化效果良好，氨氮几乎完全被氧化为NO2^- -N；该系统的活性污泥中同时存在能还原NO3^- -N和NO2^- -N的好氧反硝化菌，还原NO3^- -N的好氧反硝化菌和氨氧化菌的数量及其总活性高于NO2^- -N氧化菌，这是SBR反应器能够长期维持亚硝化状态的重要原因；有机物浓度越高则好氧反硝化速率越快，此时氨氮均被氧化为NO2^- -N，当有机物浓度达到某临界值时，好氧反硝化速率几乎保持不变；溶解氧浓度越低则好氧反硝化速率越快，释放出的OH^-会导致pH值升高。好氧反硝化对于维持和促进SBR反应器的短程硝化反硝化具有重要的作用。     

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.     

好氧/缺氧循环SBR工艺的脱氮研究

当原水碱度不足时，针对SBR工艺，采用好氧／缺氧循环的运行方式进行脱氮性能及其过程控制的研究。结果表明，通过在线监测pH值的变化可以判断硝化反应过程中碱度是否充足、氨氮是否全部被氧化，相应的控制策略为：如果好氧／缺氧的循环次数超过2次，那么第一次硝化反应以pH值下降0．4～0．5来控制好氧时间，中间的每一次硝化反应以pH值下降0．8～1．0来控制好氧时间，最后一次硝化过程根据DO与pH值变化曲线上的跃升点控制反应时间；每次的缺氧反硝化都根据ORP与pH值曲线上拐点的出现来控制缺氧时间。与传统运行方式相比，采用好氧／缺氧循环运行方式及上述控制策略可使脱氮效率得到明显提高。     

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。     

SBR工艺污泥沉降性能的影响因素研究

分别研究了运行方式、运行时间、硝酸盐浓度、曝气量、污泥负荷及曝气时间对SBR工艺中污泥沉降性能的影响.试验结果表明,以厌氧/好氧方式运行时,厌氧≥1 h且好氧≥3h可获得沉降性良好的污泥;以缺氧/好氧方式运行时,缺氧段硝酸盐浓度过高会导致污泥膨胀,缺氧段时间宜控制在1h左右;当有机负荷较高时,曝气量较高或较低均可能导致污泥膨胀,通过降低有机负荷可有效改善污泥沉降性能;在污泥负荷较低、曝气量适当且氮磷充足的条件下,曝气6h时污泥的沉降性较差,将曝气时间延长至10 h,污泥浓度保持稳定,沉降性较好.     

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.     

低溶解氧下微膨胀污泥对污染物的去除性能

维持SBR反应器好氧段的平均DO为0.30 mg/L,采用好氧/缺氧的运行方式研究了微膨胀污泥在低溶解氧状态下去除污染物的效果.结果表明:在丝状菌污泥微膨胀状态下反应器的除污效果仍较好,出水SS含量很低,对COD、氨氮的去除率分别可达80%、90%以上,同时可以节省曝气量约25%.可见,在低溶解氧状态下采用微膨胀活性污泥处理生活污水是可行的.     

Combined phosphate and nitrogen removal in a sequencing batch reactor using the aerobic denitrifier, Microvirgula aerodenitrificans

A phosphate removal sludge was bioaugmented with the aerobic denitrifier, Microvirgula aerodenitrificans in order to reduce the nitrate produced during the aerobic nitrifying-phosphate uptake phase. Fluorescent in situ hybridization (FISH) was used to follow the fate of the added strain. In order to maintain the pure strain in the complex ecosystem, diverse physiological and kinetic based strategies of bioaugmentation were tested under the sequencing batch reactor (SBR) type culture. The nature of the M. aerodenitrificans inoculum (adapted to nitrate-aerobic conditions or to anoxic one) had no influence on the SBR performances and did not enhance aerobic denitrifying performances. The optimum quantity of the added strain (10% of the total biomass) seemed to have much more positive influence on the long term maintenance of the pure strain than on the SBR performances. A small but daily supply of M. aerodenitrificans gave exactly the same result than a massive and 1-day supply, i.e. no enhancement of performances and no amelioration of the length of maintenance. A continuous supply of carbon during the first hour of the aerobic phase combined to a 10% supply of M. aerodenitrificans gave the best compromise in terms of phosphate removal, nitrification and aerobic denitrification performances. It was accompanied too by a decreased number of the ammonia and nitrite-oxidizing bacteria and a modification of the nitrite-oxidizing floc structure. FISH on M. aerodenitrificans revealed that (i) before bioaugmentation, the strain was already present in the phosphate removal sludge and (ii) the added bacteria almost disappeared from the reactor after 16 HRT. In a last experiment, M. aerodenitrificans embedded in alginate beads allowed enhancement of both aerobic denitrifying performances and length of strain maintenance.     

Denitrification on poly-beta-hydroxybutyrate in microbial granular sludge sequencing batch reactor

Microbial granules were successfully cultivated in an alternating aerobic-anaerobic sequencing batch reactor (SBR) for removing organic carbon and nitrogen. It was found that almost all input ammonium was converted to nitrite and nitrate in the aerobic phase, while the efficiency of denitrification was highly related to the availability of external carbon source in the anaerobic phase. Complete denitrification was achieved with sufficient supply of external carbon, while only partial denitrification was observed with no addition of external carbon. Results showed that in the absence of external carbon source, pre-accumulated poly-beta-hydroxybutyric acid (PHB) in microbial granules could be utilized for cell maintenance and denitrification. With supply of external carbon but no addition of nitrate, PHB accumulation accounted for the main mechanism of the organic removal. Under balanced growth conditions (with organic carbon and nitrogen supply), external organic carbon was consumed simultaneously for denitrification, PHB storage as well as for cell functions. It was revealed that the potential role of PHB for denitrification by microbial granules was very limited, i.e. less than 28 mg nitrate-nitrogen l(-1) was found to be denitrified with internally accumulated PHB. This study for the first time shows the limiting capacity of PHB as reducing power for denitrification by microbial granules.