Temporal Dynamics and Performance Association of the Tetrasphaera-Enriched Microbiome for Enhanced Biological Phosphorus Removal

Tetrasphaera have been recently identified based on the 16S ribosomal RNA(rRNA)gene as among the most abundant polyphosphate-accumulating organisms(PAOs)in global full-scale wastewater treatment plants(WWTPs)with enhanced biological phosphorus removal(EBPR).However,it is unclear how Tetrasphaera PAOs are selectively enriched in the context of the EBPR microbiome.In this study,an EBPR microbiome enriched with Tetrasphaera(accounting for 40%of 16S sequences on day 113)was built using a top-down design approach featuring multicarbon sources and a low dosage of allylthiourea.The microbiome showed enhanced nutrient removal(phosphorus removal~85%and nitrogen removal~80%)and increased phosphorus recovery(up to 23.2 times)compared with the seeding activated sludge from a local full-scale WWTP.The supply of 1 mg·L^(-1)allylthiourea promoted the coselection of Tetrasphaera PAOs and Microlunatus PAOs and sharply reduced the relative abundance of both ammonia oxidizer Nitrosomonas and putative competitors Brevundimonas and Paracoccus,facilitating the establishment of the EBPR microbiome.Based on 16S rRNA gene analysis,a putative novel PAO species,EBPR-ASV0001,was identified with Tetrasphaera japonica as its closest relative.This study provides new knowledge on the establishment of a Tetrasphaera-enriched microbiome facilitated by allylthiourea,which can be further exploited to guide future process upgrading and optimization to achieve and/or enhance simultaneous biological phosphorus and nitrogen removal from high-strength wastewater.

Enhanced Biological Phosphorus Removal with Pseudomonas putida GM6 from Activated Sludge

The enhanced biological phosphorus removal （EBPR） method is widely adopted for phosphorus removal from wastewater, yet little is known about its microbiological and molecular mechanisms. Therefore, it is difficult to predict and control the deterioration of the EBPR process in a large-scale municipal sewage treatment plant. This study used a novel strain isolated in the laboratory, Pseudomonas putida GM6, which had a high phosphate accumulating ability and could recover rapidly from the deteriorated system and enhance the capability of phosphorus removal in activated sludge. Strain GM6 marked with gfp gene, which was called GMTR, was delivered into a bench-scale sequencing batch reactor （SBR） of low efficiency, to investigate the colonization of GMTR and removal of phosphorus. After 21 days, the proportion of GMTR in the total bacteria of the sludge reached 9.2%, whereas the phosphorus removal rate was 96%, with an effluent concentration of about 0.2 mg L^-1. In the reactor with the addition of GMTR, phosphorus was removed quickly, in 1 h under anaerobic conditions, and in 2 h under aerobic conditions. These evidences were characteristic of EBPR processes. Field testing was conducted at a hospital sewage treatment facility with low phosphorus removal capability. Twentyone days after Pseudomonas putida GM6 was added, effluent phosphorus concentration remained around 0.3 mg L^-1, corresponding to a removal rate of 96.8%. It was therefore demonstrated that Pseudomonas putida GM6 could be used for a quick startup and enhancement of wastewater biological phosphorus removal, which provided a scientific basis for potential large-scale engineering application.

Effects of COD to Phosphorus Ratios on the Metabolism of PAOs in Enhanced Biological Phosphorus Removal with Different Carbon Sources

To elucidate the phosphorus removal and metabolism under various COD / P ratio,a sludge highly enriched in PAOs was used to investigate the impacts of COD / P in batch tests under different carbon supply conditions. Acetate,propionate and a mixture of acetate and propionate at a ratio of 3 ∶ 1( COD basis) was used as carbon sources with the COD / P of 20,15,10 and 5. 0 g COD /gP,respectively. The minimum COD / P ratios for complete P removal were found to be 8. 24 g COD /gP for acetate,11. 40 g COD /gP for propionate and9. 10 g COD /gP for the 3 ∶ 1 mixture of acetate and propionate. Converted to a mass basis,all three cases had a very similar ratio of 7. 7 g VFA /gP,which represented a useful guide for operation of EBPR plants to identify possible shortages in VFAs. The trend in PHV accumulation during the anaerobic period along with the decrease of COD / P ratios suggested that,PAOs may use the TCA pathway for anaerobic VFA uptake to maintain the required NADH production with reduced glycogen degradation. During the aerobic phase,the glycogen pool was reduced but remained enough compared to the requirement for anaerobic VFA uptake,and the synthesis and degradation of glycogen was not the inhibition factor of PAOs.

Enhanced Biological Phosphorus Removal in SBR Using Glucose as a Single Organic Substrate

Enhanced biological phosphorus removal(EBPR) was investigated in an anaerobic/aerobic sequencing batch reactor(SBR) supplied with glucose as a single organic substrate.The results illustrated that EBPR process could also occur successfully with glucose other than short chain fatty acids(SCFAs).High phosphorus release and poly-hydroxyalkanoate(PHA) accumulation in the anaerobic phase was found vital for the removal of phosphorus during the aerobic phase.The measurement of intracellular reserves revealed that glycogen had a higher chance to replace the energy role of poly-P under anaerobic conditions.Moreover,glycogen was also utilized as the carbon source for PHA synthesis,as well as a reducing power as reported earlier.The accumulated PHA in this system was mainly in the form of poly-hydroxyvalerate(PHV) instead of poly-hydroxybutyrate(PHB),and was inferred to be caused by the excess reducing power contained in glucose.Lactate as a fermentation product was also found released into the bulk solution.Applying fundamental biochemistry knowledge to the experimental results,a conceptual biochemical model was developed to explain the metabolism of the glucose-induced EBPR.

Effects of different external carbon sources and electron acceptors on interactions between denitrification and phosphorus removal in biological nutrient removal processes

The effects of two different external carbon sources （acetate and ethanol） and electron acceptors （dissolved oxygen, nitrate, and nitrite） were investigated under aerobic and anoxic conditions with non-acclimated process bi- omass from a full-scale biological nutrient removal-activated sludge system. When acetate was added as an external carbon source, phosphate release was observed even in the presence of electron acceptors. The release rates were 1.7, 7.8, and 3.5 mg P/（g MLVSS.h） （MLVSS： mixed liquor volatile suspended solids）, respectively, for dissolved oxygen, nitrate, and nitrite. In the case of ethanol, no phosphate release was observed in the presence of electron acceptors. Results of the experiments with nitrite showed that approximately 25 mg NO2-N/L of nitrite inhibited anoxic phosphorus uptake regardless of the concentration of the tested external carbon sources. Furthermore, higher deni- trification rates were obtained with acetate （1.4 and 0.8 mg N/（g MLVSS.h）） compared to ethanol （1.1 and 0.7 mg N/ （g MLVSS.h）） for both anoxic electron acceptors （nitrate and nitrite）.

化学除磷药剂对EBPR系统处理效能的影响

为研究化学除磷药剂的种类及投加浓度对强化生物除磷系统(EBPR)处理效率的影响,采用以厌氧/好氧方式运行的SBR反应器,以人工配制废水为进水,通过长期试验,分别考察了FeCl_3和AlCl_3两种除磷药剂的投加对系统出水水质的影响。结果表明:随着化学除磷药剂投加浓度的增加,出水COD浓度逐渐降低,而氨氮去除率未随化学除磷药剂投加量的增加而产生明显的变化;低浓度(Fe^(3+)和Al^(3+)的投加浓度分别不大于8 mg/L和6 mg/L)化学除磷药剂将提高微生物活性,高浓度(Fe^(3+)和Al^(3+)的投加浓度分别为24 mg/L和18 mg/L时)产生抑制效果。长期试验中,当Fe^(3+)、Al^(3+)投加量分别为8 mg/L和6mg/L时,即Fe^(3+)、Al^(3+)投加量分别为8.6、7.0 mg/(g VSS)时,系统厌氧释磷量及好氧吸磷量均达到较大值,系统除磷效果最好,此时磷酸盐去除率分别为96.5%和89.5%。

EBPR中两类细菌PAOs和GAOs竞争的研究进展

强化生物除磷(EBPR)工艺可以获取高效的除磷效果,已在很多污水处理厂得到广泛应用。但是大型污水处理厂在相当多的条件下,EBPR工艺也会出现周期性除磷效果的波动和不充分。针对这一难题,研究者试图采用许多手段来研究工艺中的主要微生物。文章针对典型的EBPR工艺和碳源、pH值、温度等因素对EBPR工艺中两类细菌聚磷菌(PAOs)和聚糖菌(GAOs)竞争的研究进展进行了论述,并展望了未来的研究方向。

Cassava stillage and its anaerobic fermentation liquid as external carbon sources in biological nutrient removal

The aim of this study was to investigate the effects of one kind of food industry effluent, cassava stillage and its anaerobic fermentation liquid, on biological nutrient removal （BNR） from municipal wastewater in anaerobic- anoxic-aerobic sequencing batch reactors （SBRs）. Experiments were carried out with cassava stillage supernatant and its anaerobic fermentation liquid, and one pure compound （sodium acetate） served as an external carbon source. Cyclic studies indicated that the cassava by-products not only affected the transformation of nitrogen, phosphorus, poly-13-hydroxyalkanoates （PHAs）, and glycogen in the BNR process, but also resulted in higher removal efficiencies for phosphorus and nitrogen compared with sodium acetate. Furthermore, assays for phosphorus accumulating or- ganisms （PAOs） and denitrifying phosphorus accumulating organisms （DPAOs） demonstrated that the proportion of DPAOs to PAOs reached 62.6% （Day 86） and 61.8% （Day 65） when using cassava stillage and its anaerobic fer- mentation liquid, respectively, as the external carbon source. In addition, the nitrate utilization rates （NURs） of the cassava by-products were in the range of 5.49-5.99 g N/（kg MLVSS.h） （MLVSS is mixed liquor volatile suspended solids） and 6.63-6.81 g N/（kg MLVSS.h）, respectively. The improvement in BNR performance and the reduction in the amount of cassava stillage to be treated in-situ make cassava stillage and its anaerobic fermentation liquid attractive alternatives to sodium acetate as external carbon sources for BNR processes.

不同丙酸/乙酸长期驯化的活性污泥对EBPR的影响

通过长期驯化的SBR增强生物除磷系统,研究了不同丙酸/乙酸对磷和PHA转化的影响,以及微生物代谢PHA及其组分的计量学.结果表明,随着丙酸/乙酸的升高,系统的除磷能力增强;污水中合适的丙酸/乙酸(C-mol比)为2∶1.计量学研究表明,聚磷菌消耗1 C-mol乙酸生成0.65 C-mol PHB和0.33 C-mol(PHV+PH2MV),消耗1 C-mol丙酸生成极小量PHB和1.21C-mol(PHV+PH2MV).磷去除率与(PHV+PH2MV)代谢有良好的相关性.

碳硫比和硝酸根投加量对DS-EBPR工艺的影响研究

为获得适宜的硫循环协同反硝化生物除磷工艺(DS-EBPR)运行条件,采用批次实验研究了进水m(C)/m(S)和NO_3^--N投加量对DS-EBPR的影响,同时对工艺代谢机理进行初步研究。结果表明,m(C)/m(S)为150/200时有最大吸磷速度2.4 mg/(g·h),而PHA的储存和消耗速度却最低,同时poly-S的储存和消耗速度却最大。DS-EBPR释磷段和吸磷段的反应进行能量平衡分析,说明poly-S在DS-EBPR工艺运行中可作为潜在的能量来源。poly-S在吸磷段可调节NO_3^--N的反硝化作用,可减少NO_3^--N对下一周期释磷段的影响,以达到良好的释磷效果。DS-EBPR工艺的反应机理明显不同于传统的EBPR工艺。

微好氧EBPR系统污泥的同步脱氮及吸磷特性

反硝化聚磷菌在污水同步脱氮除磷,尤其有限碳源污水的处理,具有广阔的应用前景,而亚硝酸盐型反硝化除磷因仅将硝化进行到亚硝酸盐阶段可进一步降低污水的处理费用.采用一个2L的SBR反应器,通过控制好氧段溶解氧并调整NO_2^-投加时间,在EBPR系统内成功富集了兼具稳定除磷和脱氮性能的污泥,用以考察污泥的缺氧吸磷特性及同步脱氮能力.结果表明:微好氧条件下(DO=0.2mg/L)反应器具有很高的氮、磷去除性能,系统内的NH4^+-N能100%硝化且无NO_X^--N的积累,出水磷浓度低于0.5mg/L.此外,该除磷污泥能利用亚硝酸盐进行缺氧吸磷,NO_2^--N投加浓度为10mg/L和50mg/L时的最大比吸磷速率分别为最大比好氧吸磷速率的44.9%和87.2%.批式试验证明:NH4^+-N通过同步硝化反硝化而非厌氧氨氧化去除,但微好氧条件下氨氧化菌和亚硝酸盐氧化菌活性均较聚磷菌差,因此,低DO条件下,吸磷总是优先于氨氧化进行.

EBPR工艺污泥中聚磷菌多样性与除磷潜力评价方法

自1970年代研究者发现聚磷菌(polyphosphate accumulating organism,PAO)并提出经典的强化生物除磷(enhanced biological phosphorus removal,EBPR)工艺“厌氧释磷-好氧摄磷”机理以来,随着EBPR工艺中PAO新菌株的不断发现和生理生化特征研究的不断深入,研究者们对EBPR机理的认识一直在不断更新.及时总结近40年来EBPR机理的研究进展,基于活性污泥中PAO菌株信息全面归纳PAO多样性特征,以此为依据客观评价目前活性污泥中PAO除磷潜力评价方法的不足并展望未来重点研究方向,对于推动EBPR工艺优化升级将具有非常重要的理论与实际意义.本文全面调研了1980—2021年国际期刊相关文献,发现传统EBPR机理中厌氧内碳源合成、厌氧释磷意义等受到了较多质疑,反硝化聚磷新机理已获得广泛认同;活性污泥中PAO具有异常丰富的多样性,包含Acinetobacter(29%)、Pseudomonas(15%)、Tetrasphaera(4%)、Alcaligenes(4%)等42个菌属,部分PAO具有反硝化聚磷和异养硝化能力.在目前主流的活性污泥PAO除磷潜力评价方法中,荧光原位杂交和定量PCR技术只以Accumulibacter或Acinetobacter属PAO为检测对象,高通量测序和变性梯度凝胶电泳技术基于片面的PAO多样性信息作为分析依据,在此基础上PAO丰度所反映的PAO除磷潜力的准确性尚存在疑问,未来需要加强面向活性污泥PAO多样性的探针或特异性引物的研发.与传统方法相比,EDTA法胞内多聚磷酸盐颗粒含量检测技术较为先进,但需要以PAO和非PAO菌株为参照深入阐明检测结果的边界.

亚硝酸盐对EBPR工艺除磷效率的影响

[目的]比较亚硝酸盐对不同进水碳源驯化的强化生物除磷(EBPR)污泥除磷活性的抑制作用,分析亚硝酸盐影响EBPR污泥除磷效率的机制。[方法]采用厌氧-好氧型序批式生物反应器(SBR),分别以乙酸(SBR-1)和丙酸(SBR-2)为进水碳源驯化EBPR污泥,待反应器达到稳态运行状态后取1个运行周期,定期取样测定混合液中磷酸根和亚硝氮质量浓度的周期变化,比较亚硝酸盐对2种EBPR污泥除磷活性的影响,测定2种EBPR污泥的脱氮活性;通过研究亚硝酸盐对运行周期中聚磷菌胞内聚羟基烷酸(PHA)和糖原合成与分解代谢的影响,分析亚硝酸盐抑制EBPR除磷活性的机制。[结果]以乙酸为进水碳源的SBR-1和以丙酸为进水碳源的SBR-2分别经过8和11 d的驯化期成功实现了稳定的EBPR功能,除磷效率稳定在98%以上;较高浓度的亚硝酸盐对乙酸驯化的EBPR污泥和丙酸驯化的EBPR污泥均可产生抑制作用,其中以丙酸驯化的EBPR污泥对亚硝酸盐更为敏感,在亚硝氮质量浓度大于或等于5 mg·L^(-1)时即会丧失磷的吸收功能;乙酸驯化的EBPR污泥和丙酸驯化的EBPR污泥均有一定的脱氮能力,以乙酸为碳源驯化而成的EBPR污泥其脱氮活性明显高于丙酸驯化而成的EBPR污泥;在亚硝酸盐抑制除磷活性的同时聚磷菌胞内PHA和糖原代谢也受到明显的抑制作用。[结论]与乙酸驯化的EBPR污泥相比,丙酸驯化的EBPR污泥对亚硝酸盐引起的抑制作用更为敏感,以乙酸为进水碳源有利于EBPR工艺的稳定运行。

乳酸作为EBPR进水碳源的可行性研究

[目的]探索乳酸作为强化生物除磷(EBPR)进水碳源的可行性。[方法]首先采用厌氧-好氧型序批式生物反应器,以乳酸为唯一进水碳源驯化EBPR污泥(SBR-2),并与以乙酸为唯一进水碳源的EBPR污泥(SBR-1)对比;待SBR-2达到稳态运行后,在1个运行周期定期取样,测定混合液中化学需氧量(COD)、磷酸根、氨氮和硝氮等参数的周期变化,并与SBR-1比较;通过研究不同进水磷浓度对2个反应器除磷效率的影响,比较2种EBPR污泥的除磷能力。[结果]以乙酸为进水碳源的SBR-1和以乳酸为进水碳源的SBR-2分别经过8和31 d的驯化期实现了稳定的EBPR功能;与乙酸驯化的EBPR污泥类似,乳酸驯化所得的EBPR污泥也表现出典型聚磷菌(PAO)的代谢特征。以乳酸为碳源驯化而成的EBPR污泥其主要特征参数如有机酸吸收速率、磷释放速率和磷吸收速率均明显低于以乙酸为碳源驯化而成的EBPR污泥,但是由于其厌氧释放的磷浓度较低,结果仍可在相同的时间内完成磷的吸收。在进水磷酸根质量浓度小于等于12 mg·L-1时,以乳酸为进水碳源的反应器可以实现稳定高效的除磷效果,出水磷酸根质量浓度稳定在0.3 mg·L-1以下。[结论]采用乳酸作为EBPR的进水碳源是可行的。

EBPR系统中聚糖菌及其反硝化代谢机理的研究进展

聚糖菌(GAOs)作为强化生物除磷(EBPR)系统中重要的微生物组成部分,具有反硝化脱氮的作用,但目前国内外关于GAOs的富集培养及反硝化代谢机理的研究尚不完善。综述了GAOs的种群类型以及反硝化聚糖菌(DGAOs)的代谢机理,着重归纳了碳源、pH、温度等因素对GAOs富集生长的影响,并在此基础上,对GAOs的研究现状及其研究方向进行了总结和展望,以期对GAOs的生理性能及强化生物除磷系统的稳定运行提供理论参考。

硫酸盐还原产物对EBPR系统影响的研究进展

温暖沿海地区的污水中含有大量硫酸盐,而其在厌氧条件下的还原产物--硫化物及聚硫颗粒(polymeric sulfur compound, poly-S)会对强化生物除磷(enhanced biological phosphorus removal, EBPR)过程产生重要影响.综述了硫化物对传统强化生物除磷(conventional enhanced biological phosphorus removal, CEBPR)系统营养物去除、沉降性能和聚磷菌(polyphosphate accumulating organisms, PAO)的影响及作用机理,硫循环协同强化生物除磷(sulfur cycle-associated enhanced biological phosphorus removal, S-EBPR)系统的创建及特征(主要包括其生物转化过程、优势功能菌及除磷效果的影响因素),以及poly-S在S-EBPR系统中的功能作用.发现了硫化物和poly-S在硫循环参与的生物除磷过程中发挥着重要的积极作用,并且通过适当调控,或许能实现生物除磷系统对低ρ(C)/ρ(P)且含硫废水处理效果的强化;提出了当前研究存在的不足以及未来的研究方向,以期为EBPR系统的稳定高效运行及低ρ(C)/ρ(P)含硫污水的处理提供理论基础.

Characteristics of intracellular polyphosphate granules and phosphorus-absorption of a marine polyphosphateaccumulating bacterium, Halomonas sp. YSR-3

Halomonas sp.YSR-3 was isolated from the Yellow Sea and identified as a polyphosphate-accumulating bacterium and the characteristics of its intracellular polyphosphate(polyP)granules and phosphorus absorption were studied.Most YSR-3 cells stored one or two polyP granules in regular appearance and high-density.The diameter of the granules was about 400 nm measuring by a transmission electron microscope(TEM).After stained with 4,6-diamidino-2-phenylindole(DAPI)and visualized by a fluorescence microscope,the cells turned blue and the granules were bright yellow.The composition of granules includes P(major ingredient),Mg,S,K,and Ca as detected by an energy dispersive X-ray spectrometer(EDS).When inorganic phosphorus(po34-)and ferric ion(Fe3+)were added into media,the biomass increased and the cells formed intracellular polyP granules owing to the phosphorus assimilation from media.The YSR-3 obtained higher biomass by adding 0.02 g/L FePO4 than 0.005 g/L and 0.01 g/L FePO4;however,the phosphorus absorption was higher with 0.01 g/L FePO4 than 0.005 g/L and 0.02 g/L FePO4.The optical density at wavelength 480 nm(OD480nm)was 0.79 and 100%cells could form intracellular polyP granules.These results show that strain YSR-3 is able to acquire higher biomass and absorb more inorganic phosphorus when 0.01 g/L FePO4 is added.The characteristics of absorbing and storing phosphorus as intracellular inorganic polyP granules have a potential for application in high-efficiency phosphorus removal in wastewater treatment.

Influence of Azo Dye on Metabolism of Phosphorus Accumulating Organisms Linked to Transformation of Intracellular Storage Products

In this study, the influence of azo dye of methyl red (MR) on COD, dye and phosphorus removal and the transformation of polyhydroxyalkanoate (PHA) and glycogen of phosphate accumulating organisms in enhanced biological phosphorus removal (EBPR) system were investigated. The results indicated COD and dye removal efficiencies were decreased from 97.9% to 72.8% and 99.7% to 82.0%, respectively, when MR concentration was increased from 0 to 40 mg/L. Low MR concentration (5 mg/L) had no influence on P removal and transformation of PHA and glycogen. However, P removal, PHA production and consumption, and glycogen replenishment were seriously inhibited at high MR concentration, while glycogen hydrolysis was simulated at MR concentration of 20 and 40 mg/L. The transformations of PHA and glycogen at aerobic condition were more sensitive to those at anaerobic condition at high MR concentration. These results demonstrated dye and its intermediate products would inhibit the metabolism of polyphosphate accumulating organisms, which should be taken into account in future work.

ZnO NPs对EBPR系统影响的研究进展

针对纳米氧化锌(ZnO NPs)对污水强化生物除磷(EBPR)的抑制作用,阐述了ZnO NPs对EBPR系统除磷效率和污泥特性的影响,分析了ZnO NPs对微生物代谢过程的作用机制。现有研究表明:ZnO NPs可促进聚糖菌活动,使水生物释放大量抑制剂而降低聚磷菌的活性;不同浓度的ZnO NPs对菌种的影响具有选择性;ZnO NPs在水中释放出的Zn^2+可增加活性氧产量,Zn2+和活性氧的共同作用抑制了聚磷菌的活性;在短期暴露条件下,ZnO NPs可导致系统除磷效率迅速降低。

多因素对Accumulibacter代谢机制及分支水平的影响综述

“Candidatus Accumulibacter phosphatis”(简称Accumulibacter)是污水处理系统中最常见的聚磷菌(PAOs)。该文从碳源、温度、电子受体及相关质子化产物——游离亚硝酸、磷源等方面综述了其对除磷效能、Accumulibacter分支水平以及代谢机制等的影响。综合不同的研究得出如下相似的结果:(1)碳源类型会改变胞内聚合物——聚羟基烷酸的种类和含量,影响强化生物除磷(EBPR)系统的脱氮除磷效能,且与其他碳源相比,以丙酸为碳源的系统中Accumulibacter的富集程度更高,除磷效率更好;(2)低温环境有利于Accumulibacter的生长,其天然竞争菌“Candidatus Competibacter phosphatis”(简称Competibacter)在高温环境中表现出竞争优势;(3)FNA抑制和磷匮乏条件下,Accumulibacter的TypeⅡ型表现出较强的耐受性与灵活的代谢机制转变等。然而,截至目前,尚未有研究建立EBPR系统中各功能菌属与除磷效能之间的关系。因此,对单一菌种及其进化枝的培养和对单一菌种与侧翼菌群之间关系的研究,有利于为进一步提高EBPR系统除磷效能及其稳定性提供理论支撑。