Demystifying polyphosphate-accumulating organisms relevant to wastewater treatment: A review of their phylogeny, metabolism, and detection

Currently,the most cost-effective and efficient method for phosphorus(P)removal from wastewater is enhanced biological P removal(EPBR)via polyphosphate-accumulating organisms(PAOs).This study integrates a literature review with genomic analysis to uncover the phylogenetic and metabolic diversity of the relevant PAOs for wastewater treatment.The findings highlight significant differences in the metabolic capabilities of PAOs relevant to wastewater treatment.Notably,Candidatus Dechloromonas and Candidatus Accumulibacter can synthesize polyhydroxyalkanoates,possess specific enzymes for ATP production from polyphosphate,and have electrochemical transporters for acetate and C4-dicarboxylates.In contrast,Tetrasphaera,Candidatus Phosphoribacter,Knoellia,and Phycicoccus possess PolyP-glucokinase and electrochemical transporters for sugars/amino acids.Additionally,this review explores various detection methods for polyphosphate and PAOs in activated sludge wastewater treatment plants.Notably,FISH-Raman spectroscopy emerges as one of the most advanced detection techniques.Overall,this review provides critical insights into PAO research,underscoring the need for enhanced strategies in biological phosphorus removal.

Effects of organic carbon consumption on denitrifier community composition and diversity along dissolved oxygen vertical profiles in lake sediment surface

At present,the understanding of the dynamics of denitrifiers at different dissolved oxygen(DO)layers under organic carbon consumption within the surface sediments remains inadequate.In this study,high-throughput sequencing and quantitative PCR targeting nirS gene were used to analyze the denitrifier abundance dynamics,community composition,and structure for aerobic(DO 0.5-6.9 mg/L),hypoxic-anoxic(DO 0-0.5 mg/L),and anoxic(DO 0 mg/L)layers in surface sediments under organic carbon consumption.Based on the analysis of nirS gene abundance,the values of denitrifying bacteria decreased with organic carbon consumption at different DO layers.When the bacterial species abundance at the genus level were compared between the high-carbon and low-carbon sediments,there was significant increase in 6 out of 36,7 out of 36 and 6 out of 36 genera respectively for the aerobic,hypoxic-anoxic and anoxic layers.On the other hand,14 out of 36,9 out of 36 and 15 out of 36 genera showed significant decrease in bacterial species abundance respectively for the aerobic,hypoxic-anoxic and anoxic layers.Additionally,14 out of 36,20 out of 36,and 15 out of 36 genera had no change in bacterial species abundance respectively for the aerobic,hypoxic-anoxic,and anoxic layers.This indicates that the carbon utilization ability of different denitrifiers on each DO layers was generally different from each other.Diversity of denitrifying bacteria also presented significant differences in different DO layers between the high-and low-carbon content sediment layers.Moreover,under the high-carbon and low-carbon content,the abundance of nirS gene showed a high peak within the hypoxic-anoxic regions,suggesting that this region might be the main distribution area for the denitrifying bacteria within the surface sediments.Furthermore,community of unique denitrifiers occurred in different DO layers and the adaptive changes of the denitrifier community followed the organic carbon consumption.

定向调控电子受体强化好氧颗粒污泥内源反硝化脱氮除磷

为强化内源反硝化作用,加强对有限碳源的高效利用,设置了1组厌氧/好氧/缺氧(A/O/A)和3组不同好氧时间分配的厌氧-两级短时好氧/缺氧(A/(O/A)_(2))序批式反应器,探究定向调控电子受体下污泥的颗粒化及反硝化聚糖菌(DGAOs)的富集情况.结果表明,采用两级短时好氧/缺氧的反应器好氧颗粒污泥结构更加致密、沉淀性能更好,缺氧段及好氧段电子受体更充足,DGAOs储存内碳源的能力得以强化,系统中反硝化聚糖菌和DGAOs对碳源的竞争达到平衡状态,系统有更高的内源反硝化脱氮率,实现了深度脱氮除磷.其中,两级短时好氧时间分配时间为前段60min/后段30min的R2的脱氮除磷效果最好,DGAOs含量最高,且颗粒沉降性能最佳.第45d,R2的COD、TN、TP去除率分别达到90.52%、85.71%、92.73%,内源反硝化效率达到58.59%,具有良好的污染物去除效果.

Denitrifying phosphorus removal in a step-feed CAST with alternating anoxic-oxic operational strategy

A bench-scale cyclic activated sludge technology （CAST） was operated to study the biological phosphorus removal performance and a series of batch tests was carried out to demonstrate the accumulation of denitrifying polyphosphate-accumulating organisms （DNPAOs） in CAST system. Under all operating conditions, step-feed CAST with enough carbon sources in influent had the highest nitrogen and phosphorus removal efficiency as well as good sludge settling performance. The average removal rate of COD, NH4^＋-N, PO4^3--P and total nitrogen （TN） was 88.2%, 98.7%, 97.5% and 92.1%, respectively. The average sludge volume index （SVI） was 133 mL/g. The optimum anaerobic/aerobic/anoxic （AOA） conditions for the cultivation of DNPAOs could be achieved by alternating anoxic/oxic operational strategy, thus a significant denitrifying phosphorus removal occurred in step-feed CAST. The denitrification of NO^x--N completed quickly due to step-feed operation and enough carbon sources, which could enhance phosphorus release and further phosphorus uptake capability of the system. Batch tests also proved that polyphosphate-accumulating organisms （PAOs） in the step-feed process had strong denitrifying phosphorus removal capacity. Both nitrate and nitrite could be used as electron acceptors in denitrifying phosphorus removal. Low COD supply with step-feed operation strategy would favor DNPAOs accumulation.

AOA-O模式下好氧颗粒污泥同步硝化内源反硝化除磷

为构建同步硝化内源反硝化除磷颗粒污泥系统,设置四组厌氧/好氧/缺氧(AOA)以及不同后置曝气时间(5min、10min、20min)的AOA-O序批式反应器,探究不同运行模式下污泥颗粒化和反硝化聚磷菌(DPAOs)富集情况.结果表明,后置短时曝气的反应器颗粒污泥结构致密、沉淀性能良好,可强化内碳源储存并分泌更多的胞外聚合物(EPS),具有更高的脱氮除磷率及DPAOs占比.其中,短时曝气时间10min的R3生物量最高,平均粒径最大,达到986μm,颗粒成熟且稳定.批次试验和三维荧光分析表明其聚磷菌中45.85%为DPAOs且EPS含量最高.稳定运行期间,R3的COD、TN、TP去除率分别为94.13%、89.41%、96.11%,内碳源储存效率为98.09%,具有良好的处理性能.

低温反硝化聚磷菌脱氮除磷性能研究

经过对兰州市安宁污水处理厂冬季曝气池的活性污泥筛选、驯化分离获得反硝化聚磷菌;对其进行生理生化鉴定及核糖体的RNA的亚基(16S rDNA)基因序列测序,鉴定为荧光假单胞菌属Pseudomonas sp.以模拟废水的出水总氮(TN)、总磷(TP)、pH等为指标,考察反应温度、原水pH、摇床转速、不同碳氮比(C/N)等单因素对反硝化除磷菌脱氮除磷性能的影响。使用软件design-expert8.0.6.1将数据进行分析,获得二次响应面回归模型,并探究pH、温度、转速与TN去除率、TP去除率的交互作用。在最佳反应条件,即反应温度为16℃,反应时间为10 h,原水pH为7,摇床转速为140 r·min^(-1),C/N质量浓度比为12时,TN与TP的去除率分别为82.7%与88.1%,为今后城市废水处理提供支持。

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.

Decreased soil pH weakens the positive rhizosphere effect on denitrification capacity

The stimulating effect of rhizosphere on denitrification is considered to be an unavoidable loss of soil nitrogen(N)and detrimental to crop N use efficiency,which is regulated by crop growth and soil properties.Soil acidification,occurring rapidly in many intensive farming lands,affects both crop growth and soil properties,thereby altering rhizosphere effect on denitrification.However,the mechanism by which soil acidification regulates rhizosphere denitrification still remains unclear.Here,we determined the denitrification capacity(DC)and associated community compositions of nirK-and nirS-type denitrifiers in maize rhizosphere and bulk soils at four acidity gradients(pH=6.8,6.1,5.2,and 4.2).Results showed that the stimulating effect of rhizosphere on DC strongly depended on soil pH.Compared to bulk soil,rhizosphere soil had significantly higher DC at pH 5.2,but not at pH of 4.2.With increasing soil acidity,the stimulation of rhizosphere on DC(calculated as the difference in DC between rhizosphere and bulk soils)decreased from 8.01 to 0.01 mg N kg-1d-1.Moreover,soil acidification significantly reduced the differences in dissolved organic carbon(DOC)and abundance of key nirK-type denitrifier taxa between rhizosphere and bulk soils,both of which were positively related to the stimulation of rhizosphere on DC.These findings demonstrated that soil acidification could weaken the positive rhizosphere effect on denitrification via regulated C availability and associated nirK-type denitrifier community,potentially reducing N loss risk in rhizosphere soil.The independent role of soil p H should be fully considered when modelling N behaviour in plant-soil systems.

碳源和硝态氮浓度对反硝化聚磷的影响及ORP的变化规律

利用间歇试验研究了反硝化除磷过程中有机碳源和硝态氮浓度对厌氧放磷和缺氧吸磷的影响 ,同时对反硝化除磷过程ORP的变化规律及以其作为控制参数的可行性作了探讨 .试验结果表明 :厌氧段碳源COD浓度越高 (1 0 0～ 30 0mg/L) ,放磷越充分 ,则缺氧段反硝化和吸磷速率越大 ;但当碳源COD浓度高达 30 0mg/L时 ,未反应完全的有机物残留于后续缺氧段对缺氧吸磷产生抑制作用 .随着缺氧段硝态氮浓度升高 (5、1 5、4 0mg/L) ,反应初期反硝化和吸磷速率也随之升高 ;当硝态氮耗尽后 ,系统由缺氧吸磷转变为内源放磷 ,且随着初始硝态氮浓度的增高 ,这个转折点的出现时间向后延迟 .ORP可作为厌氧放磷的控制参数 ,在缺氧吸磷过程可预示反硝化的反应程度 。

污水处理反硝化除磷-诱导结晶磷回收工艺中除磷微生物特性

为探究反硝化除磷-诱导结晶磷回收工艺中缺氧池污泥释磷、吸磷以及微生物特征,利用荧光原位杂交(fluorescence in situ hybridization,FISH)技术、电子扫描显微镜(scanning electron microscope,SEM)观察了微生物的数量、分布和形态;通过批次试验考察了污泥在厌氧/好氧和厌氧/缺氧2种模式下的释磷和吸磷特征。结果表明:该双污泥系统缺氧池中聚磷菌占总细菌比例的69.7%,明显高于单污泥系统中富集的聚磷菌比例,污泥中的微生物多呈杆状;厌氧/好氧、厌氧/缺氧模式下单位污泥浓度(mixed liquor suspended solids,MLSS)总吸磷量(以PO43--P计)分别为22.84、18.60 mg/g,反硝化聚磷菌(denitrifying polyphosphate-accumulating organisms,DPAO)占聚磷菌(polyphosphate-accumulating organisms,PAO)的比例为81.44%,表明在长期的厌氧/缺氧运行条件下可以富集到以硝酸盐为电子受体的反硝化聚磷菌,同时还存在着仅以氧气为电子受体的聚磷菌;通过pH值和氧化还原电位(oxidation reduction potential,ORP)的实时监测可以快速地了解污水生物处理系统中各类反应的进程,对调控工艺参数有着重要的意义。综上所述,为保证污水生物处理工艺的正常稳定运行,将微生物分析与常规的化学参数分析结合起来考察将是未来发展的必然趋势。

强化生物除磷体系中的反硝化除磷

采用SBR反应器,研究了以硝酸盐作为电子受体的反硝化除磷过程.结果表明,反硝化聚磷菌存在于传统的强化生物除磷体系中.厌氧段磷的释放和COD的消耗成线性关系.通过厌氧/好氧交替运行方式,反硝化聚磷菌在聚磷菌中的比例从13.3%上升到69.4%.稳定运行的厌氧/缺氧SBR反应器具有良好的强化生物除磷和反硝化脱氮性能,缺氧结束时体系中磷浓度小于1mg/L,除磷效率大于89%.

序批式膜生物反应器中反硝化聚磷菌的富集

采用序批式膜生物反应器(SBMBR)对以硝酸盐作为电子受体的反硝化聚磷菌的富集进行了研究.结果表明,经过厌氧-好氧和厌氧-缺氧-好氧2个阶段的富集,反硝化聚磷菌占全部聚磷菌的比例从19.4%上升到69.6%,每周期缺氧段投加硝酸盐氮120mg时,SBMBR系统运行最为稳定.稳定运行的SBMBR反硝化强化除磷体系具有良好的强化除磷和反硝化脱氮性能,缺氧段脱氮和除磷效率分别达到100%和84%,膜出水总磷浓度平均低于0.5mg/L,系统除磷率达到96.1%.此外,氨氮去除率保持在92.2%,氨氮被去除的同时并没有发现亚硝酸盐氮和硝酸盐氮的明显积累.

3株反硝化聚磷菌的分离与鉴定

通过烛缸法培养富集、分离,结合除磷试验、硝酸盐还原产气试验及异染颗粒和PHB颗粒染色辅助检验相结合的方法筛选,得到3株具有较高脱氮除磷效率的反硝化聚磷菌DNPA8,DNPA9和DNPA10。在富氮富磷培养基中培养48 h,各菌株的脱氮率均大于75%,除磷率均大于78%。采用多相分类的方法确定了3株反硝化聚磷菌的分类地位,DN-PA8为嗜麦芽寡养单胞菌,DNPA9为水生丛毛单胞菌属首次发现的反硝化聚磷菌;DNPA10为约翰逊氏不动杆菌。该研究结果为富营养化水体的治理提供了有效的菌种资源。

颗粒污泥的反硝化除磷研究

借助SBR反应器,采用厌氧/好氧/缺氧的运行方式,对富集的以反硝化聚磷菌(DNPAOs)为优势菌的活性污泥进行颗粒化培养,约35d后得到了较成熟的颗粒污泥。考察了该颗粒污泥的脱氮除磷性能,结果表明:当以厌氧/缺氧方式运行时系统具有良好的反硝化除磷性能,缺氧结束时除磷率>96%,对氨氮的去除率为95%左右;外加NO3--N的浓度对缺氧段的反硝化吸磷速率有一定影响;颗粒污泥中的DNPAOs可以利用内碳源进行反硝化吸磷,从而实现了同步脱氮除磷。

不同进水条件对SBR工艺脱氮除磷效能的影响

采用人工配水,研究进水在不同pH值,碳源类型,碳氮比条件下,厌氧/好氧/缺氧(A/O/A)SBR工艺对生物法脱氮除磷效能的影响。结果表明:不同的进水条件对反应器的影响较大,当pH值为7.5,乙酸钠为碳源,碳氮比为1.4时,反应器运行效果最佳,系统对PO43--P,NH4+-N的去除率分别达到97.28%,99.5%。NO3--N,NO2--N的出水浓度平均为2.8 mg/L,0.9 mg/L。进水条件良好时,A/O/A SBR反应器适合反硝化聚磷菌的富集,解决了反硝化菌和聚磷菌世代周期不同,争夺碳源等矛盾,能够很好的实现同步脱氮除磷。

影响添加反硝化聚磷菌的SBR脱氮除磷主要因素

以添加反硝化聚磷菌株后获得稳定生物脱氮除磷效果的SBR装置为研究对象,探讨各种因素对其脱氮除磷效果的影响。结果表明,最适温度为25℃,系统出水COD、氨氮和磷的去除率分别达到90.3%、88.1%和96.2%;进水pH为7.0时,释磷率达到8.1mg·L-.1h-1,系统脱氮除磷效果最好;系统最佳HRT为厌氧2h、缺氧4h;系统污泥龄为10d时,系统污泥含量和性能正常,厌氧释磷能力较强,运行效果最好。

反硝化聚磷菌菌种筛分与除磷特性分析

目的研究反硝化聚磷菌除磷特性,筛分同时具有反硝化和吸磷能力的菌种.方法采用平板分离和DGGE技术相结合,对实验室反硝化除磷系统菌种进行分纯和菌种鉴定,并对富集培养后的每株单菌分别进行反硝化吸磷效果试验.结果最终共得到15株单菌.结果表明有11株菌均具有不同程度反硝化吸磷能力,其中假单胞菌属的JB2和产碱菌属的JB3脱氮除磷效果最好,8 h后磷的去除量分别为13.76 mg/L和11.85 mg/L.DGGE试验结果表明,系统中反硝化聚磷菌优势种群可主要分为7个群,分别是Anaerolineae,Actinobacteria,Bacte-roidetes,TM7,α-proteobacteria,δ-proteobacteria和γ-proteobacteria菌群.结论Actinobacteria中的LB9号菌和γ-proteobacteria中的JB2号菌为反硝化除磷系统中占优势的反硝化聚磷菌.试验结果同时证明同一菌种可以同步完成反硝化和吸磷任务.

高效反硝化聚磷菌株的筛选及其生物学特性

为研究反硝化聚磷菌的生物学特性，通过吸磷试验、硝酸盐还原产气试验及异染颗粒和PHB颗粒染色辅助检验，从稳定运行的厌氧／缺氧SBR反应器中分离筛选出4株高效反硝化聚磷菌H16、H19、H24和Xg．经鉴定，前3者属于假单胞菌属（Pseudomonas），后者属于肠杆菌属（Enterobacter）．测定了这4株菌的生长曲线，研究了温度和pH值对这4株菌的生长及除磷效能的影响，结果表明，菌株的生长最适温度均在35℃左右，除磷反应的最适温度均在25℃左右；在中温条件下，H16、H19和H24生长的最适pH为6～8，菌株xg生长的最适pH值为7～9；4株菌除磷反应的最佳pH值均为中性偏碱．

一株反硝化聚磷菌生长及脱氮除磷特性

In order to further explore the mechanism of denitrifying phosphorus removal,the growth characteristics and denitrifying phosphorus removal characteristics of a typical denitrifying phosphate accumulating bacteria(DPB) which was isolated by previous experiment were studied.The effect of different electron acceptors on the efficiency of nitrogen and phosphorus removal was investigated by pure bacteria and reactor statics simulation tests.The growth curve of the DPB was typical,and its incubation period was less than 1 h and the logarithmic phase about 14 h.The result showed that the stain could utilize both nitrite and nitrate as different electron acceptors to take up phosphorus.And there was a good linear correlation between P removal and NO-3-N removal during phosphorus removal process.The sensitivity to nitrite of the strain was low.The effect of electron acceptors on phosphorus removal was not significant.The efficiency of removal for phosphorus and the nitrate was both above 60%,and that for nitrite was 100%.

连续流双污泥系统反硝化除磷脱氮特性

以生活污水为处理对象 ,对基于缺氧吸磷理论开发出的连续流厌氧 /缺氧 -硝化 (A2 N)双污泥新工艺反硝化除磷脱氮的性能进行了考察 .试验结果表明 :A2 N双泥系统能使硝化菌和反硝化聚磷菌分别在各自最佳的环境中生长 ,利于系统脱氮除磷的稳定和高效 ,可控制性也得到了提高 .研究发现 ,当进水 ρ(C) / ρ(N)为 3.97时 ,ρ(总氧 ,TN) / ρ(总磷 ,TP)和化学耗氧量 (COD)去除率分别为 80 .99% ,92 .87%和 91% ;而当提高进水 ρ(C) / ρ(N)至 6 .4 9时 ,可进一步提高脱氮除磷效果 ,ρ(TN) ,ρ(TP)和COD去除率分别达到 92 .7% ,97.95 %和 95 % .可见 ,该工艺较适合进水COD/ ρ(TN) 偏低的城市污水脱氮除磷处理 .