催化铁与生物法耦合除磷工艺特性简

为了研究催化铁与生物耦合后对生物除磷特性的影响,实验采用人工配水用厌氧/好氧间歇流式富集培养聚磷微生物。对比发现,催化铁与生物耦合组中厌氧末段ORP降低了约60 mV,pH值小幅度的上升（≤0.3）,整个培养过程中铁离子的浓度开始快速增加,之后趋于稳定（约40 mg Fe/g MLSS）。对好氧末段污泥SVI值比较发现,耦合工艺污泥沉降性能得到改善。除磷曲线比较发现,耦合组中厌氧末段磷的释放量下降,而好氧阶段磷的吸收速率增加;胞内聚合物提取表明,耦合组厌氧末段聚磷菌细胞内PHA含量有提高,好氧末段糖原含量有下降。磷形态提取分析表明,耦合组好氧末段污泥中无机态PO^3-₄-P含量更高。低浓度铁离子可以起到与生物耦合同步除磷的目的,本工艺长期运行未发现耦合体系中催化铁对除磷的抑制作用。     

催化铁耦合生物除磷工艺中生物与化学除磷的关系

研究证明,将催化铁添加至传统生物除磷工艺的厌氧段,可使得生物除磷和化学除磷两者作用耦合。为了研究工艺中生物除磷与化学除磷的关系,采用不同催化铁投配率分别为0、1和2 g Fe/(mg P·d)的3组反应器进行实验。结果表明,催化铁投配率为1 g Fe/(mg P·d)时,系统的除磷效率最佳,去除率在90%以上,生物除磷与化学除磷耦合作用好;负荷为2 g Fe/(mg P·d)时,系统在未达到稳定之前即发生恶化,生物除磷作用受到抑制。铁化合物的积累量过多是系统出现恶化的主要原因:在污泥中铁含量小于30 mg Fe/g MLSS时,生物除磷作用与化学除磷作用两者协同,除磷效率提高;当污泥中铁含量超过52.8 mg Fe/g MLSS时,出现竞争,生物除磷作用受到抑制;通过排泥,降低污泥中铁含量,则除磷功能可以得到恢复。     

厌氧-立体循环一体化氧化沟除磷脱氮工艺中影响厌氧释磷的因素研究

本研究考察了厌氧-立体循环一体化氧化沟工艺(AN-IODVC)中厌氧释磷效果及诸影响因素.研究结果表明,AN-IODVC除磷脱氮系统中好氧污泥的VSS/MLSS值比厌氧污泥小,好氧污泥含磷量与厌氧污泥含磷量的差值和TP去除率、厌氧磷释放率及厌氧ORP呈良好的线性相关关系.厌氧磷释放的最佳条件为:污水COD/TP＞55,维持厌氧区ORP低于-400mV.     

厌氧-立体循环一体化氧化沟除磷脱氮工艺中影响厌氧释磷的因素研究

本研究考察了厌氧-立体循环一体化氧化沟工艺（AN-IODVC）中厌氧释磷效果及诸影响因素.研究结果表明,AN-IODVC除磷脱氮系统中好氧污泥的VSS/MLSS值比厌氧污泥小,好氧污泥含磷量与厌氧污泥含磷量的差值和TP去除率、厌氧磷释放率及厌氧ORP呈良好的线性相关关系.厌氧磷释放的最佳条件为：污水COD/TP＞55,维持厌氧区ORP低于-400mV.     

一体式PN/A耦合EBPR工艺高效低耗处理实际低C/N主流城市污水

针对低C/N城市污水脱氮除磷因碳源不足存在能耗、药耗高以及脱氮除磷效率低等问题,开发一体式短程硝化/厌氧氨氧化(PN/A)耦合强化生物除磷工艺(EBPR),以降低碳源消耗和能耗、提高脱氮除磷效率,从而实现高效低耗减污降碳。通过构建悬浮污泥和生物膜共存的混合系统,采用厌氧-好氧运行模式以及间歇曝气,考察短程硝化/厌氧氨氧化与强化生物除磷过程的耦合效果。结果表明,反应器能长期稳定运行,出水总无机氮(TIN)质量浓度稳定低于4 mg·L^-1,溶解态磷(DP)质量浓度约0.2 mg·L^-1,TIN平均去除率大于90%,DP的平均去除率大于85%,平均脱氮负荷为53 mg·(g·d)^-1,强化间歇曝气能够在系统内实现NOB抑制,亚硝氮积累率可达60%以上,甚至100%。控制悬浮污泥好氧污泥龄为3.5 d,NOB由悬浮污泥向填料转移。由于生物膜传质受限,系统的亚硝氮积累率并未受到影响。该系统内厌氧氨氧化活性提高了5倍,厌氧氨氧化菌以Candidatus Brocadia为主,相对丰度为1.1%,较主流条件下提高了2.75倍。本研究结...     

A2O工艺好氧末段溶解氧变化对脱氮除磷影响

采用连续流A2O工艺处理实际的生活污水,研究好氧末段在不同溶解氧(DO)浓度条件下对污泥沉降性能、系统脱氮除磷的影响,同时考察了DO对污泥硝化活性、厌氧释磷速率和反硝化脱氮速率的影响.结果表明,随着末段溶解氧的提高,污泥容积指数SVI从140降至100左右,后又升高到120～170;系统的硝化效果提高,氨氮的去除率从6...     

碳氮磷比例失调城市污水的同步脱氮除磷

为解决现行同步脱氮除磷工艺处理南方地区碳、氮、磷比例失调城市污水中，因C／N、C／P偏低，碳源不足而降低脱氮除磷效率的难题，试验以碳源偏低的广州市城市污水为研究对象，采用厌氧／好氧交替运行的SBR系统，通过对厌氧、好氧时段的合理调控，在无需额外添加碳源的条件下，有机物、氨氮、总氮和总磷的平均去除率分别可达90％、72％、41％和99％，不仅能使有机物和氮的出水指标达到国家排放标准，而且总磷出水浓度能达0．5mg／L以下。通过进一步分析同步高效脱氮除磷的影响因素和控制条件，得出合理污泥龄的控制是实现同步脱氮除磷的关键，厌氧／好氧交替运行的方式不仅强化了磷的释放和吸收，而且降低了碳源偏低和硝酸盐对同步脱氮除磷影响的结论。     

接种不同污泥源条件下厌氧氨氧化菌的特性

2组ASBR接种污泥源分别为好氧硝化污泥、好氧硝化污泥和厌氧氨氧化污泥按2：1比例}昆合的混合污泥。在相同条件下,经过驯化培养均实现了厌氧氨氧化的稳定运行。接种好氧硝化污泥的反应器的适应期为29d,经过105d的培养反应器成功启动;接种混合污泥的反应器的适应期为13d,经过49d反应器启动成功。从2组ASBR污泥中提取细菌总DNA,经过厌氧氨氧化菌特异引物Pla46rc／Amx820对污泥样品进行PCR扩增、克隆和测序等分析。实验结果表明,接种不同污泥源条件下的反应器中厌氧氨氧化菌的特性存在差异,接种污泥源为好氧硝化污泥的反应器中存在的厌氧氨氧化菌种为CandidatusKuenenia,而接种混合污泥的反应器中存在的厌氧氨氧化菌种为CandidatusAnammox—oglobus,与最初接种的混合污泥中的厌氧氨氧化菌相同。当接种污泥中存在厌氧氨氧化菌时,该菌株经过长时间的驯化可成为优势菌种,而当接种污泥中无厌氧氨氧化菌存在时,CandidatusKueneniasp．可以在反应器中占主导,具有更强的竞争优势。     

水解酸化-A2O污泥减量工艺的运行性能研究

生物处理单元采用水解酸化、多级串联接触曝气、连续流的除磷脱氮A2／O工艺,并辅以外排厌氧富磷污水侧流除磷,开发了一个新型的具有强化除磷脱氮功能的污泥减量HA—A／A—MCO工艺。用该工艺处理校园生活污水发现,在SRT60d、进水COD316～407mg／L、NH4＋-N30～40mg／L、TN35～53mg／L、TP8—12mg／L的条件下,出水COD≤18mg／L、NH4＋-N≤2．1mg／L、TN≤10．3mg／L、TP≤0．44mg／L。研究还发现,水解酸化池处理产生的VFA能有效促进生物除磷脱氮,导致厌氧释磷量达57mg／L,进入化学除磷池的侧流液量仅相当于进水量的13％;系统最主要的脱氮形式是SND和缺氧反硝化,SND脱氮占脱氮总量的50％,缺氧反硝化占26％;HA-A／A—MCO系统有效实现了生物相分离,并利用生物捕食作用获得较低的污泥产率,0．1gMLSS／gCOD。     

添加反硝化菌群的A2/O反硝化除磷低碳工艺启动

为探究反硝化除磷低碳工艺的实际效果,采用序批式反应器(SBR)根据底物反应速率来调节底物的流加速率,并以温度(20±2)°C、pH(7.5±0.2)和溶解氧(DO)为0的反应条件富集反硝化菌群。得到可同时利用亚硝酸盐和硝酸盐为电子受体的反硝化菌群,将其添加至厌氧-缺氧-好氧(A²/O)工艺中,以刺激反硝化细菌在反应器中发挥生物除磷功能,并开展工艺启动研究。结果表明：在加入反硝化菌群后,A²/O工艺发生了明显的反硝化除磷反应,且系统运行稳定;反硝化除磷途径的TP去除负荷均值约为0.014 8 kg·(m³·d)^-1;厌氧出水TP平均值为11.95 mg·L^-1,且缺氧吸磷量与好氧吸磷量的平均比率约为2.40,即平均反硝化除磷率高达73.34%。这表明在单污泥A²/O工艺中成功实现了反硝化除磷的启动,从而证明了反硝化菌群的生物强化作用,其中的反硝化除磷功能菌群的相对优势菌属包括Dechloromonas、Rhodobacter、Thermomonas等。本研究...     

Recovery of polyhydroxyalkanoate from activated sludge in an enhanced biological phosphorus removal bench-scale reactor.

A sequencing batch reactor was used to study the possibility of harvesting polyhydroxyalkanoate (PHA) from enhanced biological phosphorus removal (EBPR) processes without compromising treatment quality. Because, in EBPR, the highest PHA concentrations are observed after exposure of the sludge to anaerobic conditions, PHA accumulation was evaluated with collection of waste activated sludge (WAS) at the end of the anaerobic stage, in addition to the traditional removal after the aerobic stage. The system achieved good phosphorus removal, regardless of the point of WAS collection. When sludge was harvested at the end of the anaerobic stage, the PHA content of the sludge ranged from 7 to 16 mg PHA/100 mg mixed liquor volatile suspended solids. Although this level of PHA production is below levels obtained with pure cultures, the demonstrated ability to harvest PHA, while simultaneously satisfying phosphorus removal in an EBPR process, is a key initial step towards of the use of wastewater treatment plants for PHA production.     

Hybrid process for heavy metal removal from wastewater sludge.

Bioleaching processes have been demonstrated to be effective technologies in removing heavy metals from wastewater sludge, but long hydraulic retention times are typically required to operate these bioprocesses. A hybrid process (coupling biological and chemical processes) has been explored in laboratory pilot-scale experiments for heavy metals (cadmium [Cd], copper [Cu], chromium [Cr], and zinc [Zn]) removal from three types of sludge (primary sludge, secondary activated sludge, and a mixture of primary and secondary sludge). The hybrid process consisted of producing a concentrate ferric ion solution followed by chemical treatment of sludges. Ferric iron solution was produced biologically via oxidation of ferrous iron by A. ferrooxidans in a continuous-flow stirred tank (5.2 L) reactor (CSTR). Wastewater sludge filtrate (WSF) containing nutrients (phosphorus and nitrogen) has been used as culture media to support the growth and activity of indigenous iron-oxidizing bacteria. Results showed that total organic carbon (TOC) concentrations of the culture media in excess of 235 mg/L were found to be inhibitory to bacterial growth. The oxidation rate increased as ferrous iron concentrations ranged from 10 to 40 g Fe2+/L. The percentage of ferrous iron (Fe2+) oxidized to ferric iron (Fe3+) increased as the hydraulic retention time (HRT) increased from 12 to 48 h. Successful and complete Fe2+ oxidation was recorded at a HRT of 48 h using 10 g Fe2+/L. Subsequently, ferric ion solution produced by A. ferrooxidans in sludge filtrate was used to solubilize heavy metals contained in wastewater sludge. The best solubilization was obtained with a mixture of primary and secondary sludge, demonstrating a removal efficiency of 63, 71, 49, and 80% for Cd, Cu, Cr, and Zn, respectively.     

Fe^0钝化膜的生物还原及其脱氮除磷

微生物的异化Fe（Ⅲ）还原是一种能够利用Fe（III）作为末端电子受体在无氧条件下氧化有机物的产能过程。结合这一特性,考察了在兼性厌氧／严格厌氧条件下Fe^0钝化膜作为Fe（111）源时的生物还原能力以及对N、P等营养元素的去除效果。结果表明,严格厌氧条件下微生物异化Fe（Ⅲ）还原能力较好,富集培养至7d,累计Fe（II）浓度达到最大,最大产生速率为98．69mg／（L·d）,同时TP去除率高达97．1％以上。而体系对NH4-N、TN的去除相对滞后,培养至13d,去除率开始增大,最终分别达到86．6％和76．1％。这为装填有海绵铁＋聚氨酯泡沫载体的SBBR中填料的原位再生问题提供了解决思路。     

Biodegradation of triclosan and formation of methyl-triclosan in activated sludge under aerobic conditions

Triclosan is an antimicrobial agent which is widely used in household and personal care products. Widespread use of this compound has led to the elevated concentrations of triclosan in wastewater, wastewater treatment plants (WWTPs) and receiving waters. Removal of triclosan and formation of triclosan-methyl was investigated in activated sludge from a standard activated sludge WWTP equipped with enhanced biological phosphorus removal. The removal was found to occur mainly under aerobic conditions while under anoxic (nitrate reducing) and anaerobic conditions rather low removal rates were determined. In a laboratory-scale activated sludge reactor 75% of the triclosan was removed under aerobic conditions within 150 h, while no removal was observed under anaerobic or anoxic conditions. One percent of the triclosan was converted to triclosan-methyl under aerobic conditions, less under anoxic (nitrate reducing) and none under anaerobic conditions.     

COD对强化生物除磷系统的影响及OUR的变化规律

以实际生活污水为研究对象,在SBR系统中采用厌氧/好氧运行方式,考察强化生物除磷(EBPR)系统中好氧阶段COD浓度对聚磷菌除磷性能的影响以及不同好氧阶段COD浓度下的OUR变化规律.实验分4个阶段进行,分别为不投加外碳源、厌氧结束时投加不同体积的乙酸钠作为外碳源,使COD分别提高50、100和300mg/L.4种工况...     

为置缺氧区的改良型Pasveer氧化沟工艺脱氮除磷性能研究

针对传统Pasveer氧化沟内缺氧段碳源难以被反硝化菌充分利用的问题,采用内置缺氧区的改良型Pasveer氧化沟工艺,并进行中试规模实验研究,考察了不同内回流比条件下系统的脱氮除磷效果。研究结果表明,在内回流比为200％的情况下,系统的脱氮除磷效果最好,出水TN和TP的浓度分别降至12．7mg／L和0．34mg／L,去除率分别达到61．9％和89．2％。内置缺氧区的设置一方面能使有限的碳源充分用于反硝化,另一方面,促使了反硝化吸磷现象的发生,这使得系统在进水碳源较低的情况下仍能够获得上佳的脱氮除磷效果。但是,过高的内回流比会导致好氧区亚硝酸盐的积累,这对生物除磷是不利的。     

活性污泥体系中聚糖菌的富集与鉴定

活性污泥体系中,聚糖菌(GAOs)在厌氧环境下与聚磷菌(PAOs)形成对底物的竞争关系,对聚糖菌的研究对于优化生物除磷工艺有重要意义。以葡萄糖为惟一碳源,在磷限制条件下,利用特殊运行方式对活性污泥进行驯化培养出了稳定的聚糖菌颗粒污泥,厌氧阶段磷释放量与有机物吸收量浓度(mg/L)比从7.4%下降为0.25%。从培养好的活性污泥反应器中分离获得2株聚糖菌,经菌落PCR和16S rRNA序列分析确定了所得聚糖菌菌株G1和菌株G2分别是枯草芽孢杆菌(Bacillus subtilis)和解鸟氨酸克雷伯氏菌(Klebsiella ornithinolytica)。     

Changes in anoxic denitrification rate resulting from prefermentation of a septic, phosphorus-limited wastewater.

A preliminary bench-scale study of parallel University of Cape Town (UCT) biological nutrient removal systems showed improvement in anoxic denitrification rates resulting from prefermentation of a septic (i.e., high volatile fatty acid [VFA] content), phosphorus-limited (i.e., total chemical oxygen demand/total phosphorus [TP] ratio < 40:1) wastewater. Net phosphorus removals due to enhanced biological phosphorus removal (EBPR) were only improved marginally by prefermentation in spite of significant increases in anaerobic phosphorus release, polyhydroxyalkanoate formation, and higher anoxic and aerobic uptakes. This probably was due to the high VFA/TP ratio in the raw influent relative to the VFA requirements for EBPR because enough VFAs were already present for phosphorus removal prior to prefermentation. An additional assessment of prefermentation using parallel UCT systems with step feed of 50% of the influent to the anoxic zone was completed. This second phase quantified the effect of prefermentation in a step-feed scenario, which prioritized prefermentation use to enhance denitrification rather than EBPR. While specific denitrification rates in the anoxic zone were significantly improved by prefermentation, high denitrification in the clarifiers and aerobic zones (simultaneous denitrification) made definitive conclusions concerning the potential improvements in total system nitrogen removal questionable. The prefermented system always showed superior values of the zone settling velocity and sludge volume index and the improvement became increasingly statistically significant when the prefermenter was performing well.     

Production of polyhydroxyalkanoate during treatment of low-phosphorus-content wastewater.

To evaluate whether poly-beta-hydroxyalkanoate (PHA) production and wastewater treatment could be combined in a single biological process, a bench-scale sequencing batch reactor was operated with sequential anaerobic and aerobic stages and removal of excess sludge at different stages of treatment. The reactor treated synthetic wastewater with a high organic and low nutrient content, simulating industrial wastewater. Chemical oxygen demand removal efficiency was more than 90% in all cases. Poly-beta-hydroxyalkanoate accumulation was significant, although it did not appear to be induced by oxygen limitations during the anaerobic stage. Sphaerotilus natans was apparently the dominant PHA-accumulating organism at the end of each reactor run and corresponded to a PHA accumulation of 16 to 20% of the total dry cell mass. Before S. natans dominated the reactors, PHA accumulation was approximately 17% when biomass was removed at the end of the aerobic stage and 6.6% when sludge removal also occurred during the anaerobic stage.