Denitrifying phosphorous removal in anaerobic/anoxic SBR system with different startup operation mode

To achieve stable and efficient nitrogen and phosphorus removal and to investigate the characteristics of the A/A SBR enriched with denitrifying phosphorus removal bacteria(DPB),the whole course of startup was studied with two reactors operated in different mode.The reactor I was operated under anaerobic/settling/anoxic/settling mode,and the reactor II was operated under anaerobic/anoxic/settling mode.Differences between the two reactors in removal efficiency of COD,nitrogen and phosphorus were examined.The results indicated that efficient performance could be achieved in both reactors with different startup operation mode,while the phosphorus removal efficiency was improved sooner in reactor I than in reactor II,which suggested that reactor I would supply a more favorable condition for DPB proliferation.Meanwhile,it was observed that the amount of organic substrates consumption had a linear correlation to that of phosphorus release in anaerobic phase when DPB was accumulated in the A/A SBR denitrifying phosphorus removal system.

Kinetics model of aerobic phase in hybrid anoxic-oxic process

Kinetics models of COD degradation,biomass growth of the anoxic-oxic ( A/O) system as well as NH3-N degradation in aerobic phase were presented according to the mass balance theory,reaction-diffusion theory and Fick law. Then these models were testified by comparson with experimental results. It is demonstrated that the variation trends of theoretical and experimental values for COD degradation and biomass growth are similar. The deviation rate between theoretical and experimental values is always under 20% even it increases along with the fluctuation of influent organic loading. In terms of NH3-N degradation,nitrification can also be well simulated by the model as the substrates of influent are sufficient. It indicates that the model can accurately reflect the reaction in hybrid A/O process. Models presented herein provide a theoretical basis for the design, operation and control of hybrid A/O process.

Real-time control of aerobic/anoxic digestion for waste activated sludge

Experiments were conducted to study the performance characters of aerobic/anoxic （A/ A） digestion of sludge at 30± 1 ℃, while the sludge retention time （SRT） was kept 16 d. The varia tions of oxidation reduction potential （Eh ） and pH were continuously monitored during the A/A di gestion and the conversions of ammonium and nitrate were investigated. Important features on both Eh and pH profiles were identified to develop process control strategy. Since the feature point on Eh profile where d2 Eh/dt^2 =0 is very stable during anoxic cycle, it can be used to determine the end of denitrification. The end of nitrification can be identified according to dpH/dt = 0. A real-time control strategy of A/A digestion of sludge was developed and tested with pH and Eh as control parameters. It is shown that the performance of the real-time control strategy is better than that of a fixed time control strategy. While the real time controlled A/A digestion system can achieve a similar volatile suspended solids （VSS） destruction efficiency of 35.2 % as a continuously aerated system, it im proves the supernatant quality in a shorter aeration time（7. 75 d for a 20 d period）.

Performance Characteristics for Nitrogen Removal in SBR by Aerobic Granules

The sequencing batch reactor (SBR) was started up by seeding the anaerobic granular sludge and the aerobic granular sludge was successfully cultivated. The performance characteristic of the aerobic granules for nitrogen removal was investigated in detail. The experimental results demonstrated the relationship between operational parameters [dissolved oxygen (DO) and pH] and variation of chemical oxygen demand (COD), ammonium (NH4+-N)and total nitrogen (TN). In continuous flow pattern, COD was too low in the reactor at the later stage of a cycle,which restrained denitrification and decreased the removal of nitrogen, while in discontinuous flow pattern, the carbon source could be supplemented in time, which improved denitrification and increased the removal of TN from 66% to 81%.

Removal of nitrogen and phosphorus in a combined A^2/O-BAF system with a short aerobic SRT

A bench-scale anaerobic/anoxic/aerobic process-biological aerated filter （A^2/O-BAF） combined system was carded out to treat wastewater with lower C/N and C/P ratios. The A^2/O process was operated in a short aerobic sludge retention time （SRT） for organic pollutants and phosphorus removal, and denitrification. The subsequent BAF process was mainly used for nitrification. The BAF effluent was partially returned to anoxic zone of the A^2/O process to provide electron acceptors for denitrification and anoxic P uptake. This unique system formed an environment for reproducing the denitdfying phosphate-accumulating organisms （DPAOs）. The ratio of DPAOs to phosphorus accumulating organisms （PAOs） could be maintained at 28% by optimizing the organic loads in the anaerobic zone and the nitrate loads into the anoxic zone in the A^2/O process. The aerobic phosphorus over-uptake and discharge of excess activated sludge was the main mechanism of phosphorus removal in the combined system. The aerobic SRT of the A^2/O process should meet the demands for the development of aerobic PAOs and the restraint on the nitrifiers growth, and the contact time in the aerobic zone of the A^2/O process should be longer than 30 min, which ensured efficient phosphorus removal in the combined system. The adequate BAF effluent return rates should be controlled with 1--4 mg/L nitrate nitrogen in the anoxic zone effluent of A^2/O process to achieve the optimal nitrogen and phosphorus removal efficiencies.

Re-activation characteristics of preserved aerobic granular sludge

In some industrial plants, wastewater was intermittently or seasonally generated. There may be periods during which wastewater treatment facilities have to be set into an idle phase over several weeks. When wastewater was generated again, the activated sludge flocs may have disintegrated. In this experiment, re-activation characteristics of aerobic granular sludge starved for 2 months were investigated. Specific oxygen utilization rate(SOUR) was used as an indicator to evaluate the metabolic activity of the sludge. The results revealed that aerobic granular sludge could be stored up to two months without running the risk of losing the integrity of the granules and metabolic potentials. The apparent color of aerobic granules stored at room temperature gradually turned from brownish-yellowish to gray brown. They appeared brownish-yellowish again 2 weeks after re-activation. The velocity and strength of granules after 2-month idle period could be fully restored about 3 weeks after re-activation. Metabolic activity, however, dropped to 15 8 mg O_2/(g MLVSS·h), i.e. 74 % reduction after 2 months of storage. After restarting the reactor, it took 2 weeks that SOUR of up to 48 5 mg O_2 /(g MLVSS·h) was achieved. A stable effluent COD concentration of less than 150 mg/L was achieved during the re-activation process.

Characteristics of extracellular fluorescent substances of aerobic granular sludge in pilot-scale sequencing batch reactor

The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.

Function of anaerobic portion in a conventional sequencing batch reactor

The performance of SBRs treating two kinds of wastewater(synthetic wastewater con- taining polyvinyl alcohol and effluent from a coke-plant wastewater treatment system)was investi- gated in this study,in order to examine the exact function of anaerobic portion in a conventional SBR.The set up of 4-or 8-hour anaerobic mixing period in a SBR's cycle did not benefit for PVA degradation.While an anaerobic reactor seeded with anaerobic sludge could partly hydrolyse and acidify PVA into readily-degradable intermediates.During the anaerobic fill period of an SBR treat- ing the effluent from a coke-plant wastewater treatment system,the organic concentration was re- duced to certain extent due to the adsorption of activated sludge and dilution of the mixed liquor from the previous cycle.Parts of readily-degradable organics in the influent were utilised by denitri- fiers as carbon source.The biomass in a conventional SBR was alternatively imposed to aerobic and anaerobic conditions in its operating cycle,the environmental conditions needed for anaerobic hy- drolization and acidification of refractory organics could not occur in such an SBR.

SBR工艺交替硝化反硝化运行方式的可行性研究

将交替好氧、缺氧运行方式应用于间歇式污水处理系统(SBR工艺),分别在原水碱度充足和碱度不足情况下考察该运行方式的可行性.结果表明:原水碱度充足时,交替硝化反硝化的运行方式在处理效率上并没有体现出优势;原水碱度不足时,交替硝化反硝化与传统硝化反硝化相比,处理效率与出水水质明显提高,出水氨氮可以达到检测水平.当原水碱度的不足量低于所需碱度理论值的1 3时,采取交替硝化反硝化,无需额外补充碱度就可以达到原水碱度充足情况下的处理效率.如果原水碱度的不足量已超过1 3,采取交替硝化反硝化可最大限度节省额外投加碱度的量,降低处理成本,是一种理想的运行方式.

SBR系统中同步硝化反硝化好氧颗粒污泥的培养

采用人工配制的模拟生活污水 ,研究序批式反应器 (SBR)中好氧颗粒污泥的培养 .实验结果表明 :通过对进水碳源进行调控 ,反应器中形成了高活性具有同步硝化反硝化能力的好氧颗粒污泥 ,反应器中COD和NH3 N的去除率分别为 74 0 %～ 92 8%和 82 3 %～ 98 5 %.颗粒污泥的粒径一般为 0 5～ 1 0mm ,MLSS达到 4 5 g·L- 1以上 ,SVI值约为 3 2 5 。

SBR工艺污泥颗粒化对生物脱氮除磷特性的研究

采用模拟配制的生活污水 ,研究循序间歇反应器 (SBR)工艺的脱氮除磷效果和污泥沉降性能 .试验结果表明 ,通过了状态调控阶段 ,反应器中形成了同时具有脱氮除磷能力的好氧颗粒化污泥 .其中 ,反应器对COD和P的去除率分别为 90 %和85 %左右 ;NH3 N和TN去除率分别达到 90 %和 80 % ;颗粒污泥的SVI值约为 5 0 ,出水水质好 .

进水碳氮比对缺氧/好氧SBR亚硝化系统的影响

为研究不同进水碳氮比对缺氧/好氧SBR亚硝化系统的影响,在室温下(18～20℃),调节进水的碳氮比为0,2/3,1,4/3,2,3,6,对反应器的运行情况进行研究.结果表明:在进水COD和氨氮负荷分别为0. 2,0. 3 kg/(m^3·d)时,仅历经24 d就成功获得了亚硝化絮状污泥,比进水无COD的污泥系统能较快启动亚硝化工艺.在碳氮比小于6时,污泥系统均能保持良好的亚硝化性能,亚硝化率大于90%;碳氮比为6时,亚硝化率下降至70%.进水碳氮比为4/3时,异养菌充分利用进水COD进行脱氮,总氮的去除率达到49. 8%,且COD的去除率保持在80%以上;进水碳氮比小于4/3时,污泥系统缺乏碳源,总氮去除率随着碳氮比的增加而增加;当碳氮比为4/3～2时,COD和总氮去除率几乎没有变化;当碳氮比为2～6时,由于进水氨氮负荷的降低,COD和总氮的去除率呈下降趋势,运行末期(154 d),COD和总氮的去除率分别为64. 8%,18%.由COD的增加而引起碳氮比的增加时,蛋白质(PN)呈逐渐增加的趋势,多糖(PS)几乎不变,而由氨氮的减少引起碳氮比的增加,PN和PS均下降,但PN与PS比呈上升趋势.

SBR法交替缺氧好氧模式下短程硝化效率的优化

采用SBR法以实际生活污水为研究对象,通过交替缺氧好氧的运行模式实现了短程硝化的快速启动.在不同的缺/好氧时间比条件下考察了短程硝化的启动时间、污染物处理效果以及氨利用速率的变化.结果表明,在缺氧/好氧时间比为1：1和2：1条件下,分别用了31,55d使得两系统的亚硝酸盐积累率达到90%,短程状态稳定.氨氮去除率达到95%以上,COD出水在50mg/L以下,总氮去除率提高20%,污染物的去除效率有所提高.由全程到短程的转变期间,系统氨利用速率分别提高了67.5%和89.8%,同时提高了短程硝化的效率.期间,污泥沉降性较好,污泥容积指数稳定在60~80m L/g.

SBR中厌氧颗粒污泥向好氧颗粒污泥的转化

在SBR反应器中以醋酸钠为碳源 ,UASB厌氧颗粒污泥作为接种污泥 ,在好氧曝气条件下运行 .通过观察污泥颗粒形态、结构等的变化 ,发现在运行中污泥颗粒经历了形态保持 ,成分置换的过程 .污泥浓度先增加后降低 ,在运行 35d后逐渐稳定在 5 g/L ,SVI值稳定在 30～ 4 0mL/g的水平 .在 4 0～ 6 0d内反应器中颗粒污泥一直占主体成分 ,悬浮相浓度低于 0 .5 g/L .在好氧条件下最终颗粒污泥形态、大小稳定 ,表明好氧颗粒污泥已经成功获得 ,好氧颗粒污泥与接种污泥相比在粒径、沉降速度、含水率以及惰性成分的含量上都有一定的变化 .电镜观察还表明 ,原厌氧颗粒污泥中的微生物以球菌为主 。

缺氧-SBR工艺处理焦化废水

对焦化废水进行曝气吹脱 ,1 0h氨氮去除率达 73 .7% ;用缺氧 -SBR工艺处理焦化废水 ,进水浓度为COD 1 474mg/L、NH3-N 82 6.8mg/L时 ,缺氧SRT 1 0h ,SBR曝气 1 0h ,沉降 2h ,出水COD 1 86mg/L、NH3-N2 90 .2 5mg/L ,去除率分别达到 87.83 %、64 .9%。

SBR工艺运行条件对好氧污泥颗粒化和除磷效果的影响

采用模拟配制生活污水 ,研究循序间歇反应器 (SBR)工艺在不同运行条件下对好氧污泥颗粒化和生物除磷效果的影响 .试验分别对进水中不同COD/TN比 ( 1 1 .79,1 8 85,2 0 72 ,2 4 .66)、COD/TP比 ( 2 7 85,4 4 53,4 8 93、58 2 5)、TN/TP比 ( 4 0 0 ,2 .36,1 54)、温度 ( 2 2℃ ,1 5℃ ,8℃ )和污泥龄 ( 1 6d ,1 0d ,5d)作比较 ,发现进水中较高的COD/TN比 ( 2 4 66)、COD/TP比 ( 58 2 5)、温度 ( 2 2℃ )和较低的污泥龄 ( 1 0d)对生物除磷和颗粒的形成有利 ;适当的TN/TP比 ( 2 36)、接种污泥的选择是好氧颗粒污泥形成的关键 .

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0.40.5来控制好氧时间,中间的每一次硝化反应以pH值下降0.81.0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。

预加好氧颗粒对SBR中好氧颗粒污泥形成的影响

以活性污泥曝气池中的絮状活性污泥为接种污泥,采用人工配制的模拟生活污水,通过观测颗粒形态和粒径的变化,研究预先加入15%成熟好氧颗粒污泥对好氧颗粒污泥形成过程的影响.对比研究发现,2个反应器内小颗粒（0.1～0.3 cm）的形成均较快,但大颗粒的形成速度相差明显.培养过程中还能明显观察到丝状菌缠绕和絮状污泥黏附在小颗粒表面.反应器启动第1、71、4 d,污泥平均体积粒径分别从0.10、0.16 cm上升到0.23、0.30 cm,最终达到0.28、0.43 cm.研究结果表明,预先加入15%成熟好氧颗粒污泥,能加速好氧颗粒污泥在反应器内形成.

悬浮填料SBR处理畜禽废水效果研究

在传统SBR反应器中悬挂悬浮填料用于处理畜禽废水,研究该系统处理畜禽废水的最佳工艺参数及运行模式,结果表明:当MLSS维持在2000～2500mg/L、曝气时间为5h时,系统对畜禽废水的处理效果最佳;在该条件下,采用交替好氧/缺氧运行模式出水中COD、TP、NH3和TN的去除率分别由原来传统SBR运行模式的93.21%、65.33%、84.75%、79.35%提高到94.21%、65.87%、88.83%、82.68%。

高氮渗滤液缺氧/厌氧UASB-SBR工艺低温深度脱氮

在低温条件下,采用缺氧/厌氧UASB-SBR组合工艺处理实际垃圾填埋场渗滤液.结果表明,该工艺可实现有机物和氮的同步、深度去除.在进水COD平均为11950.2mg/L,NH4+-N为982.7mg/L的条件下,出水分别为390.1mg/L和2.9mg/L,去除率分别为96.7%和99.7%.同时,缺氧UASB1反应器的最大COD负荷达到13kg/(m3?d),最大COD去除速率为12.39kg/(m3?d),具有高效缺氧反硝化和高效厌氧降解有机物反应的双重功效,在SBR反应器的缺氧段和缺氧UASB,反应器内获得了99%以上的反硝化率.对于冬季水温分别为14.9,14.1,13.5,11.05℃的低温条件下,SBR反应器实现了完全硝化和反硝化,出水TN分别为4.1,5.7,14.1,16.5mg/L,达到了深度脱氮的目的.此外,在上述温度范围内,温度对反硝化速率(rN)的影响大于对硝化速率(rDN)的影响,rN/rDN比值相对恒定.