京津冀区域市政污水厂活性污泥种群结构的多样性及差异

【背景】活性污泥中微生物的种群结构影响着污水生物处理的高效性及稳定性,是有效保证污水处理效果的关键。【目的】研究活性污泥中细菌的群落结构组成及多样性,并分析相应菌群的主要功能,旨在更好地发挥细菌的净化作用、保持污水处理过程的稳定及提高污水的处理效率。【方法】以京津冀区域内典型市政污水厂活性污泥为研究对象,通过IlluminaMiSeq高通量测序及实时定量PCR技术,对5个污水厂活性污泥的微生物种群结构特征进行了详细解析,研究不同工艺参数下活性污泥中优势种群及脱氮菌群丰度的差异。【结果】5个污水厂活性污泥种群结构具有一定差异,其中Hengshui (HS)厂污泥的群落结构受温度的影响最大,而Shahe (SH)、Daoxianghu (DXH)、Nangong(NG)厂活性污泥群落结构则受总氮、总磷与氨氮的共同影响,氨氮对SH厂活性污泥种群结构影响最大。DXH、NG和HS厂污泥中优势菌均为Anaerolineaceae,而SH和Hejian (HJ)厂的优势菌则为Saprospiraceae与Lactobacillus。活性污泥中反硝化菌丰度最高的为HJ厂,丰度最低的为HS厂,反硝化功能基因nirS比nirK分布更为广泛。【结论】对于不同污水厂,影响其活性污泥群落结构组成的环境因素也是不同的,并且特殊的进水水质也会对污泥菌群组成和生物多样性产生影响。     

Identity, abundance and ecophysiology of filamentous Chloroflexi species present in activated sludge treatment plants

Filamentous Chloroflexi species are often present in activated sludge wastewater treatment plants in relatively low numbers, although bulking incidences caused by Chloroflexi filaments have been observed. A new species-specific gene probe for FISH was designed and using phylum-, subdivision-, morphotype 1851- and species-specific gene probes, the abundance of Chloroflexi filaments were monitored in samples from 126 industrial wastewater treatment plants from five European countries. Chloroflexi filaments were present in 50% of the samples, although in low quantities. In most treatment plants the filaments could only be identified with phylum or subdivision probes, indicating the presence of great undescribed biodiversity. The ecophysiology of various Chloroflexi filaments was investigated by a suite of in situ methods. The experiments revealed that Chloroflexi constituted a specialized group of filamentous bacteria only active under aerobic conditions consuming primarily carbohydrates. Many exo-enzymes were excreted, e.g. chitinase, glucuronidase and galactosidase, suggesting growth on complex polysaccharides. The surface of Chloroflexi filaments appeared to be hydrophilic compared to other filaments present. These results are generally supported by physiological studies of two new isolates. Based on the results obtained in this study, the potential role of filamentous Chloroflexi species in activated sludge is discussed.     

Actinomycete diversity associated with foaming in activated sludge plants

Large numbers of mycolic acid-containing actinomycetes were isolated from foam and scum samples taken from three activated-sludge sewage-treatment plants using several selective isolation media. Organisms presumptively identified as gordonae formed the dominant population in all of the samples. A representative set of these strains have chemical properties consistent with their classification in the genusGordona. Forty-eight of theGordona strains were compared through 165 unit characters with the type strains of validly described species ofGordona. The resultant data were examined using the Jaccard and simple matching coefficients and clustering achieved using the unweighted pair group method with arithmetic averages algorithm. The numerical classification was only marginally affected by the statistics used or by test error, estimated as 3.92%. The isolates were assigned to five multi-membered and 28 single-membered clusters defined by the simple matching coefficient at the 89% similarity level. With few exceptions, the isolates were sharply separated from theGordona marker strains. Essentially the same classification was obtained when the test strains were examined using a Curie-point pyrolysis mass spectrometric procedure. It can be concluded that the gordonae form a heterogeneous taxonomic group, the members of which can be distinguished from representatives of validly described species ofGordona.     

Communities of ammonia-oxidizing bacteria in activated sludge of various sewage treatment plants in Tokyo

We investigated ammonia-oxidizing bacteria in activated sludge collected from 12 sewage treatment systems, whose ammonia removal and treatment processes differed, during three different seasons. We used real-time PCR quantification to reveal total bacterial numbers and total ammonia oxidizer numbers, and used specific PCR followed by denaturing gel gradient electrophoresis, cloning, and sequencing of 16S rRNA genes to analyze ammonia-oxidizing bacterial communities. Total bacterial numbers and total ammonia oxidizer numbers were in the range of 1.6 x 10(12) - 2.4 x 10(13) and 1.0 x 10(9) - 9.2 x 10(10)cellsl(-1), respectively. Seasonal variation was observed in the total ammonia oxidizer numbers, but not in the ammonia-oxidizing bacterial communities. Members of the Nitrosomonas oligotropha cluster were found in all samples, and most sequences within this cluster grouped within two of the four sequence types identified. Members of the clusters of Nitrosomonas europaea-Nitrosococcus mobilis, Nitrosomonas cryotolerans, and unknown Nitrosomonas, occurred solely in one anaerobic/anoxic/aerobic (A2O) system. Members of the Nitrosomonas communis cluster occurred almost exclusively in association with A2O and anaerobic/aerobic systems. Solid residence time mainly influenced the total numbers of ammonia-oxidizing bacteria, whereas dissolved oxygen concentration primarily affected the ammonia-oxidizing activity per ammonia oxidizer cell.     

Temporal dynamics of activated sludge bacterial communities in two diversity variant full-scale sewage treatment plants

Bacterial community in activated sludge (AS) is diverse and highly dynamic. Little is known about the mechanism shaping bacterial community composition and dynamics of AS and no study had quantitatively compared the contribution of abiotic environmental factors and biotic associations to the temporal dynamics of AS microbial communities with significantly different diversity. In this study, two full-scale sewage treatment plants (STPs) with distinct operational parameters and influent composition were sampled biweekly over 1 year to reveal the correlating factors to whole and sub-groups of AS bacterial community diversity and dynamics. The results show that the bacterial communities of the two STPs were entirely different and correlated with the influent composition and operating configurations. Bacterial associations represented by cohesion metrics and the environmental factor temperature were the primary correlated factors to the temporal bacterial community dynamics within each STP. The STP with high diversity and evenness could treat influent with higher suspended solid and a shorter sludge retention time, and was less correlated with environmental factors, implying the importance of diversity for AS system.

     

Quantification of Microthrix parvicella in activated sludge bacterial communities by real-time PCR

AIMS: This study was to develop a simple and reliable method for quantifying Microthrix parvicella 16S rRNA gene copies and its application to activated sludge samples collected from wastewater treatment plants (WWTP) with and without foaming problems. METHODS AND RESULTS: The relative frequency of M. parvicella was determined by combining real-time PCR assays for quantification of total bacterial 16S rRNA gene copies and M. parvicella 16S rRNA gene copies. The developed method was applied to analyse 32 activated sludge samples obtained from German WWTP. The level of M. parvicella 16S rRNA gene copies in the 18 nonfoaming samples was below 3% of the total number of 16S rRNA gene copies and in the range of 0-18% for the 14 foaming samples. CONCLUSIONS: The described method allows reliable monitoring of the amount of M. parvicella in activated sludge samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The described method may become an important component of a warning system for forthcoming bulking and foaming episodes.     

Gram-staining characterisation of activated sludge filamentous bacteria by automated colour analysis

An automated image analysis method has been developed for the monitoring of the Gram-staining characteristics of filamentous bacteria in activated sludge. The binary method of pixel classification agreed with manual estimation (level of correlation of 0.9 for Gram-positive bacteria). Its robustness has been assessed by repeatability tests. Population shifts in terms of Gram-staining characteristics have been monitored in laboratory-scale experiments with two feeding schedules using this technique.Revisions requested 22 September 2004; Revisions received 11 October 2004     

Enhancement of the activated sludge process by activated carbon produced from surplus biological sludge

Surplus biological sludge from wastewater treatment operations was converted into activated carbon and then added to the aerated vessel of an activated sludge process treating phenol and glucose. The addition of activated carbon, either sludge-based or commercial, enhanced phenol removal from 58 to 98.7% and from 87 to 93% for COD with feed concentrations of 100 mg phenol l^–1 and 2500 mg COD l^–1. No differences were found between the activated sludge-activated carbon bench scale continuous reactors operating with either commercial or sludge-based activated carbon in spite of the higher adsorption capacity of the former.     

Molecular detection and diversity of medium-chain-length polyhydroxyalkanoates-producing bacteria enriched from activated sludge

AIMS: Knowledge of the species composition of complex bacterial communities is still very limited. The main objectives of this study were to identify medium-chain-length polyhydroxyalkanoates (mcl-PHAs)-producing bacteria from activated sludge fed with methanol as well as to characterize their PHA operon. METHODS AND RESULTS: The identification was based on PCR amplification of mcl-PHA synthase gene fragments. In the analysed sample, four isolates possessing mcl-PHA synthesis systems were distinguished. The results of a 16S rDNA sequence analysis revealed that three strains belonged to Pseudomonas species and the fourth one was characterized as Comamonas testosteroni. CONCLUSIONS: The results of this study indicate that the PCR-RFLP approach is an excellent way to identify mcl-PHA-synthesizing micro-organisms. The discovery of 4 genetic variants, among the 20 analysed, demonstrates that microbial diversity of activated sludge is high and thus offers a great opportunity for the discovery of novel gene forms. SIGNIFICANCE AND IMPACT OF THE STUDY: An important discovery of this study is that C. testosteroni could harbour mcl-PHA operon. Moreover, the results obtained indicate that PHAs synthesis ability can be spread by horizontal gene transfer. The results of a comparative phylogenetic analysis revealed that mcl-PHA-synthesizing bacteria can be divided into Pseudomonas fluorescens and Pseudomonas aeruginosa groups.     

Targeted metagenomics reveals extensive diversity of the denitrifying community in partial nitritation anammox and activated sludge systems

The substantial presence of denitrifiers has already been reported in partial nitritation anammox (PNA) systems using the 16S ribosomal RNA (rRNA) gene, but little is known about the phylogenetic diversity based on denitrification pathway functional genes. Therefore, we performed a metagenomic analysis to determine the distribution of denitrification genes and the associated phylogeny in PNA systems and whether a niche separation between PNA and conventional activated sludge (AS) systems exists. The results revealed a distinct abundance pattern of denitrification pathway genes and their association to the microbial species between PNA and AS systems. In contrast, the taxonomic analysis, based on the 16S rRNA gene, did not detect notable variability in denitrifying community composition across samples. In general, narG and nosZa2 genes were dominant in all samples. While the potential for different stages of denitrification was redundant, variation in species composition and lack of the complete denitrification gene pool in each species appears to confer niche separation between PNA and AS systems. This study suggests that targeted metagenomics can help to determine the denitrifying microbial composition at a fine‐scale resolution while overcoming current biases in quantitative polymerase chain reaction approaches due to a lack of appropriate primers.     

Identity and ecophysiology of filamentous bacteria in activated sludge

Excessive growth of filamentous bacteria in activated sludge wastewater treatment plants (WWTPs) can cause serious operational problems. With some filaments there may be the problem of bulking, where inadequate flocculation and settling of the biomass in the secondary clarifier results in a carryover of solids with the final treated liquid effluent. Their proliferation often encourages the development of stable foams on the surface of the reactors, and these foams may impact negatively on plant performance and operation. The availability of culture-independent molecular methods now allows us to identify many of the more common filamentous organisms encountered in WWTPs, which are phylogenetically diverse, affiliating to seven separate bacterial phyla. Furthermore, the extensive data published in the past decade on their in situ behaviour from the application of these culture-independent methods have not been summarized or reviewed critically. Hence, here, we attempt to discuss what we now know about their identity, ecophysiology and ecological niches and its practical value in better managing activated sludge processes. Some of this knowledge is already being applied to control and manage full-scale WWTPs better, and the hope is that this review will contribute towards further developments in this field of environmental microbiology.     

城市污水处理厂活性污泥生物泡沫研究进展

城市污水处理厂运行过程中一旦发生活性污泥生物泡沫,就会影响污泥沉降和处理厂运行效能,对出水水质、作业安全和公共健康带来一系列挑战。生物泡沫是自活性污泥法诞生以来长期困扰污水处理厂运行的难题。生物泡沫的形成需要气泡、表面活性物质和疏水物质等3点基本的要素,在其中主要富集了诺卡氏型丝状细菌(Nocardioformfilamentousbacteria)和微丝菌(Candidatus Microthrix parvicella)这两种类型微生物。多种环境和运行因素包括温度、溶解氧、pH、污泥龄、特别是营养物质种类和浓度等均会对这些丝状微生物的生长产生影响。抑制丝状细菌生长的常用控制策略包括选择器、生长动力学控制、投加化学药剂以及噬菌体等方法,通过降低两类丝状细菌在生化池中的浓度以期消除生物泡沫现象。本文总结了生物泡沫的类型、成因、表征生物泡沫程度的指标、影响生物泡沫的环境因素以及常用的调控策略的原理及优缺点等,尽可能全面地介绍活性污泥生物泡沫的研究现状,并探讨未来研究方向和控制策略,期望能够为今后研究活性污泥微生物和污水处理厂运行调控提供有价值的参考。     

Comparison of bacteriophage and enteric virus removal in pilot scale activated sludge plants

AIMS: The aim of this experimental study was to determine comparatively the removal of two types of bacteriophages, a somatic coliphage and an F-specific RNA phage and of three types of enteric viruses, hepatitis A virus (HAV), poliovirus and rotavirus during sewage treatment by activated sludge using laboratory pilot plants. METHODS AND RESULTS: The cultivable simian rotavirus SA11, the HAV HM 175/18f cytopathic strain and poliovirus were quantified by cell culture. The bacteriophages were quantified by plaque formation on the host bacterium in agar medium. In each experiment, two pilots simulating full-scale activated sludge plants were inoculated with viruses at known concentrations, and mixed liquor and effluent samples were analysed regularly. In the mixed liquor, liquid and solid fractions were analysed separately. The viral behaviour in both the liquid and solid phases was similar between pilots of each experiment. Viral concentrations decreased rapidly following viral injection in the pilots. Ten minutes after the injections, viral concentrations in the liquid phase had decreased from 1.0 +/- 0.4 log to 2.2 +/- 0.3 log. Poliovirus and HAV were predominantly adsorbed on the solid matters of the mixed liquor while rotavirus was not detectable in the solid phase. In our model, the estimated mean log viral reductions after 3-day experiment were 9.2 +/- 0.4 for rotavirus, 6.6 +/- 2.4 for poliovirus, 5.9 +/- 3.5 for HAV, 3.2 +/- 1.2 for MS2 and 2.3 +/- 0.5 for PhiX174. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrates that the pilots are useful models to assess the removal of infectious enteric viruses and bacteriophages by activated sludge treatment. Our results show the efficacy of the activated sludge treatment on the five viruses and suggest that coliphages could be an acceptable indicator of viral removal in this treatment system.     

活性污泥中菌群多样性及其功能调控研究进展

活性污泥是污水处理厂生物处理工艺的功能主体,活性污泥中菌群的种类、数量及活性是提高污水处理能力与效果的重要基础。本文综述了活性污泥处理工艺中的主要功能细菌(絮凝菌、脱氮菌、除磷菌等)生物群落的多样性与生态特征,并对目前主流的菌群鉴定方式进行总结,最后从运行条件、定向驯化及生物强化3个方面对菌群调控进行论述,以期为活性污泥法污水处理工艺提供一些理论指导。     

Analysis of the phylogenetic diversity of estrone-degrading bacteria in activated sewage sludge using microautoradiography-fluorescence in situ hybridization

In situ uptake of [2,4,6,7-3H(N)]estrone ([3H]E1) by the major phylogenetic groups present in activated sludge samples from two different municipal wastewater treatment plants was investigated using microautoradiography-fluorescence in situ hybridization (MAR-FISH). Approximately 1-2% of the total cells confined in the samples by an EUB probe mix contributed to E1 assimilation. Almost all the detected E1-assimilating cells involved in the early phase of E1 degradation were affiliated with the Beta- and Gammaproteobacteria. In the early phase of E1 degradation, no E1-assimilating cells affiliated with the Alphaproteobacteria, Actinobacteria, the Cytophaga-Flavobacterium cluster of phylum Bacteroidetes, or the phyla Chloroflexi, Nitrospira and Planctomycetes were detected. Bacteria affiliated with the Betaproteobacteria in the shape of long rods or chains of rods were found to contribute most to in situ E1 degradation. They contributed 61% and 82% of total E1-assimilating cells in cultures from two sources of activated sludge spiked with [3H]E1. The E1-degrading bacteria related to the Betaproteobacteria differed phylogenetically from the aerobic E1-degrading bacterial isolates reported in previous studies. In addition, MAR-FISH revealed the significant contribution of E1-degrading bacteria affiliated with the Gammaproteobacteria in the degradation of E1 in activated sludge.     

几种花卉植物对污泥中铅的富集特征

土地利用是资源化利用城市污水厂污泥的有效途径。为了解污泥中重金属污染物在土壤、植物之间的迁移富集规律,选用8种园林用植物进行污泥混配土种植实验。结果表明,植物对污泥混配土土壤中铅的富集能力,以及铅在植物中各器官的富集系数均不同,且不同种类植物差别较大。植物根部对铅有较强的富集能力,其次是叶和茎。菊花对铅的富集能力较强。植物对土壤中铅的富集能力也受土壤铅含量和赋存形态影响。     

Isolation of rhodoquinone-containing chemoorganotrophic bacteria from activated sludge

Abstract Several strains of Gram-negative aerobic chemoheterotrophic bacteria which produced rhodoquinone were isolated from activated sludge. All isolates contained a rhodoquinone with eight isoprene units as a major component in addition to the corresponding homologue of ubiquinone. The isolates seemed to make up a single taxon because of their homogeneity in phenotypic and chemotaxonomic properties, but could not be allocated to any known taxa of Gram-negative bacteria.     

Pyrosequencing reveals the inhibitory impact of chronic exposure to erythromycin on activated sludge bacterial community structure

The study investigated changes in the microbial population structure sustained at two different sludge ages of 10 d and 2 d under chronic impact of erythromycin. It intended to observe the experimental correlation between variable process kinetics and changes in the composition of the microbial community induced by erythromycin. Samples from two fill/draw reactors operated with continuous erythromycin dosing of 50 mg/L were collected for the analysis of microbial population structure using high-throughput sequencing of 16SrRNA gene. Significant changes were observed in the composition of microbial community during the exposure period. Richness analysis for slower growing culture indicated that most microbial fractions were inactivated and eliminated in favor of fewer more resistant species in different phyla. Sludge age appeared to control the impact of erythromycin on microbial composition. At a sludge age of 2 d, erythromycin appeared to generate richer community with faster growing and more compatible species. For slower growing culture, elimination of vulnerable species was supported by decrease in the number of shared level OTUs. For faster growing culture, shared species level OTUs also decreased significantly upon exposure to erythromycin, suggesting rapid washout and replacement by more resistant species. Resistance gene analysis yielded positive results for mph(A) gene indicating presence of erythromycin-resistant components in the microbial community.