不同电子受体条件下的聚磷试验研究

在SBR系统内,研究了聚磷菌分别利用氧、硝酸盐及既利用氧又利用硝酸盐条件下的聚磷特性。试验表明：聚磷菌所利用的电子受体是以其存在的顺序而依次发生的,聚磷菌利用硝酸盐代替氧为电子受体可以实现反硝化聚磷,反硝化聚磷是稳定的代谢行为。在生物除磷系统中至少存在三类聚磷菌。     

Process optimization by decoupled control of key microbial populations: distribution of activity and abundance of polyphosphate-accumulating organisms and nitrifying populations in a full-scale IFAS-EBPR plant

This study investigated the abundance and distribution of key functional microbial populations and their activities in a full-scale integrated fixed film activated sludge-enhanced biological phosphorus removal (IFAS-EBPR) process. Polyphosphate accumulating organisms (PAOs) including Accumulibacter and EBPR activities were predominately associated with the mixed liquor (>90%) whereas nitrifying populations and nitrification activity resided mostly (>70%) on the carrier media. Ammonia oxidizer bacteria (AOB) were members of the Nitrosomonas europaea/eutropha/halophila and the Nitrosomonas oligotropha lineages, while nitrite oxidizer bacteria (NOB) belonged to the Nitrospira genus. Addition of the carrier media in the hybrid activated sludge system increased the nitrification capacity and stability; this effect was much greater in the first IFAS stage than in the second one where the residual ammonia concentration becomes limiting. Our results show that IFAS-EBPR systems enable decoupling of solid residence time (SRT) control for nitrifiers and PAOs that require or prefer conflicting SRT values (e.g. >15 days required for nitrifiers and <5 days preferred for PAOs). Allowing the slow-growing nitrifiers to attach to the carrier media and the faster-growing phosphorus (P)-removing organisms (and other heterotrophs, e.g. denitrifiers) to be in the suspended mixed liquor (ML), the EBPR-IFAS system facilitates separate SRT controls and overall optimization for both N and P removal processes.     

Bacterial phosphate metabolism and its application to phosphorus recovery and industrial bioprocesses

Enhanced biological phosphorus removal (EBPR) has become a well-established process and is currently applied in many full-scale wastewater treatment processes. Phosphorus recovered from EBPR waste sludge can be used as a raw material for the fertilizer industry, if a sound recycling strategy is developed and applied. In this review, we summarize our current knowledge on phosphate metabolism in bacteria, focusing on molecular mechanisms of bacterial polyphosphate (polyP) accumulation. A simple method for releasing polyP from EBPR waste sludge and recovering phosphorus in a reusable form for the fertilizer industry is presented. We also describe a recent development of bioprocesses for the expanded use of polyP in the production of value-added chemicals.     

ρ(P)/ρ(C)动态变化对SBR强化生物除磷系统微生物种群的影响

通过调节进水ρ(P)ρ/(C)的不同水平(2.9/100、1.4/100、0.57/100、0.29/100、1.4/100和2.9/100),考察了A/O-SBR系统强化生物除磷效果的动态变化;同时利用PCR-DGGE分子生物学技术,研究了聚磷菌和聚糖菌种群的竞争与演变.结果表明,当ρ(P)ρ/(C)逐渐降低时(2.9/100→1.4/100→0.57/100→0.29/100),吸收单位碳源的厌氧释磷量逐渐降低,而胞内糖原量逐渐升高.相应的DGGE图谱显示,微生物类群在ρ(P)/ρ(C)降低过程由11 OTUs升高到14 OTUs,最后降至7 OTUs;结合生化指标判断,系统优势菌种呈现的是从聚磷菌占优势、聚糖菌聚磷菌共存到聚糖菌占优势的动态变化.随后,提高进水ρ(P)ρ/(C)值从0.29/100到1.4/100再到2.9/100,污泥吸收单位碳源的厌氧释磷量逐渐升高,而胞内糖原量逐渐降低.这说明当聚糖菌占优势以后,通过调节ρ(P)ρ/(C)可重新培养获得聚磷菌优势系统,但DGGE图谱也显示,此时的聚磷菌优势种群较聚糖菌系统的优势种群已有较大变化,且与先前聚磷菌系统的优势种群也不尽相同.     

运行条件对强化生物除磷颗粒污泥系统性能及微生物群落的影响

为了了解SBR强化生物除磷(EBPR)颗粒污泥系统的影响因素,为颗粒污泥生物除磷工艺的实际应用提供技术支持,采用有效容积为12 L的SBR反应器,以乙酸钠为碳源、KH2PO4为磷源,对EBPR颗粒污泥系统的启动和除磷性能及污泥颗粒化过程进行研究.结果 表明:若进水碳磷比过低(C∶ P=200∶ 15),除磷效率较低.与...     

污泥回流比对厌氧释磷效果的影响

为系统研究厌氧污泥回流比对生物除磷效果的影响,以实际生活污水作为研究水样,研究不同污泥回流比R在厌氧段对COD（化学需氧量）、N（氮）、P（磷）的去除效果;深入研究污泥回流比对生物强化除磷代谢过程的影响。结果表明,在厌氧环境中,污泥回流比对NH4＋-N（氨氮）的去除没有明显影响,但对硝态氮、TP（总磷）、COD的去除影响较大。最佳回流污泥比应控制在60%到80%左右,在这两个工况下,PAOs（聚磷菌）释磷量能达到24.13 mg/L,这样能使PAO在厌氧池有效地利用碳源,充分释磷,从而提高除磷效率,同时应控制最佳厌氧有效时间为2到3个小时,如果厌氧时间过长或者过短都对PAO释磷产生一定的负作用。     

基于结构化P2P系统的层次聚类算法

利用结构化CAN系统中数据严格按照规律分布的特点,将系统坐标空间与聚类数据空间重叠,使相邻数据存储在同一(或相邻)节点上并设计了层次聚类SOC(Structure Overlay Cluster),使CAN系统数据聚类达到与集中式聚类算法相同的结果。通过分析SOC算法的聚类过程得到在数据维数一定的情况下,算法的时间复杂度是O(N),即与节点数量成正比,并通过仿真实验得到证明。     

Enhanced post-denitrification without addition of an external carbon source in membrane bioreactors

This study investigates a post-denitrification process without the addition of an external carbon source combined with an enhanced biological phosphorus removal (EBPR) in a membrane bioreactor (MBR). Three trial plants, with two different process configurations, were operated on two different sites, and a variety of accompanying batch tests were conducted. It was shown that even without dosing of an external carbon source, denitrification rates (DNR) much above endogenous rates could be obtained in post-denitrification systems. Furthermore, the anaerobic reactor located ahead of the process had a positive impact on the DNR. Given these surprising results, the project team decided to identify the carbon source used by the microorganisms in the post-denitrification process. Batch tests could demonstrate that lysis products do not play a major role as a C-source for post-denitrification. The following hypothesis was proposed to explain the observations: the glycogen, internally stored by the substrate accumulating bacteria, if anaerobic conditions are followed by aerobic conditions could act as carbon source for denitrification in post-denitrification system. First exploratory batch tests, where the glycogen evolution was monitored, corroborate this assumption.     

Experimental assessment and modelling of the proton production linked to phosphorus release and uptake in EBPR systems

The modelling of the enhanced biological phosphorus removal (EBPR) process is a recent focus of interest. The pH profile is a promising output variable for EBPR modelling as it is very sensitive to the consumption or production of acid and base species (e.g. phosphate or VFA). pH-based EBPR modelling is based on the assumption that phosphorus is released and taken up as H₂PO₄⁻, but this assumption has not been experimentally confirmed yet with enriched EBPR biomass. Therefore, the objective of this work was to assess the species in which P is released and taken up under different pH conditions. Several batch experiments were performed with an enriched culture of Accumulibacter (around 70 ± 10% of total microorganisms). The total observed proton production, inorganic carbon, ammonium, phosphate and VFA were measured to evaluate the titrimetric contribution of anaerobic P-release and aerobic P-uptake over the total observed proton production. The results show that the only phosphorus form involved in P-release and P-uptake is equivalent in terms of proton production to H₂PO₄⁻ in the pH range of 6.5-8.5. Finally, proton production and pH in several SBR cycles were modelled and resulted in good agreement with the experimental profiles.