Quantitative PCR Detection and Characterisation of Human Adenovirus,Rotavirus and Hepatitis A Virus in Discharged Effluents of Two Wastewater Treatment Facilities in the Eastern Cape,South Africa

The occurrence of enteric viruses in reclaimed wastewater, their removal by efficient treatment processes and the public health hazards associated with their release into the environments are of great significance in environmental microbiology. In this study, TaqMan-based real-time polymerase chain reaction (qPCR) was used to assess the prevalence of human adenovirus (HAdV), rotavirus (RV) and hepatitis A virus (HAV) in the final effluents of two wastewater treatment plants in the Eastern Cape Province, South Africa, over a twelve-month sampling period. The correlation between the concentrations of viruses in the effluents samples and faecal coliform (FC) densities were assessed as to validate the use of FC as microbiological indicator in water quality assessment. HAdV was detected in 62.5 % (30/48) of the samples with concentrations ranging between 8.4 × 10¹ and 1.0 × 10⁵ genome copies/L while HAV and RV were only detected at concentrations below the set detection limits. FCs densities ranged from 1 to 2.7 × 10⁴ CFU/100 ml. Adenovirus species HAdV-B (serotype 2) and HAdV-F (serotype 41) were detected in 86.7 % (26/30) and 6.7 % (2/30) of the HAdV-positive samples, respectively. No consistent seasonal trend was observed in HAdV concentrations, however, increased concentrations of HAdV were generally observed in the winter months. Also, there was no correlation between the occurrence of HAdV and FC at both the treatment plants. The persistent occurrence of HAdV in the discharged treated effluents points to the potential public health risk through the release of HAdV into the receiving watersheds, and the possibility of their transmission to human population.     

DNA Heat Treatment for Improving qPCR Analysis of Human Adenovirus in Wastewater

PCR inhibitory substances in complex sample matrices can cause false negatives or under-estimation of target concentration. This study assessed DNA heat treatment for reducing inhibition during qPCR analysis of human adenovirus (HAdV) in wastewater samples. Inhibition was reduced by heat treating DNA, where mean HAdV concentration was increased by 0.71 log₁₀ GC/L (and up to 3.04 log₁₀ GC/L in one case), and replicate variability and false negatives were reduced. DNA heat treatment should be further investigated for improving reliability of HAdV concentration estimates in water, which can support more accurate assessment of health risks associated with viral pathogen exposure.     

Environmental Effectors on the Inactivation of Human Adenoviruses in Water

Environmental factors are highly relevant to the global dissemination of viral pathogens. However, the specific contribution of major effectors such as temperature and sunlight on the inactivation of waterborne viruses is not well characterized. In this study, the effect of temperature (7, 20, and 37 °C), UVB and UVA radiation on viral inactivation was evaluated in phosphate buffered saline (PBS), mineral water, wastewater, 1,000-fold diluted wastewater and seawater. The stability of human adenoviruses infectivity, known as human pathogens and indicators of fecal contamination, was monitored during 24 h, both in the dark and exposed to UV radiation by immunofluorescence assays. In the dark, no Human adenovirus (HAdV) inactivation was observed in PBS and mineral water at any of the temperatures studied, whereas at 37 °C in reactors with higher microbial concentration (wastewater, diluted wastewater, and seawater), decays between 2.5 and 5 log were recorded. UVB radiation showed a dramatic effect on HAdV inactivation and 6-log were achieved in all reactors by the end of the experiments. The effect of UVA showed to be dependent on the water matrix analyzed. At 20 °C, HAdV showed a 2-log decay in all reactors radiation while at 37 °C, results in wastewater, diluted wastewater, and seawater reactors were equivalent to those observed in the dark. These results suggest UVB radiation as the major environmental factor challenging viral inactivation, followed by biotic activity indirectly associated to higher temperatures and finally, by UVA radiation.     

Human-, Ovine-, and Bovine-Specific Viral Source Tracking Tools to Discriminate Between the Major Fecal Sources in Agricultural Waters

This study evaluated the sources of fecal contamination in different river catchments, using a combination of microbial source tracking tools, for human, ruminant, ovine and bovine livestock, in order to define appropriate water management strategies. Every source of waterway pollution was evaluated in river water samples from one urban river catchment and two important farming regions in New Zealand. Fecal pollution was initially measured by testing Escherichia coli and evaluating the presence of human- and ruminant-associated DNA markers of Bacteroidales (BiAdo, BacHum-UCD, BacH, and BacR) and human and ruminant fecal sterols/stanols ratios. Then specific fecal pollution sources were assessed with previously reported quantitative PCR assays targeting human-, bovine-, and ovine-specific viruses: human adenoviruses (HAdV), human JC polyomaviruses, bovine polyomaviruses (BPyV), and ovine polyomaviruses (OPyV). High level of ruminant fecal contamination was detected all over the farming areas, whereas no ruminant sources were identified in the urban river sampling sites. BacR was the most frequently observed ruminant marker and OPyV and BPyV allowed the identification of ovine and bovine fecal sources. The human fecal viral marker (HAdV) was the most frequently observed human marker, highly abundant in the urban sites, and also present in farming areas. This is the first study using simultaneously the ovine and the bovine viral markers to identify and quantify both bovine and ovine fecal pollution.     

Quantification of Human Adenoviruses in European Recreational Waters

The presence of human adenoviruses (HAdV) in recreational water might cause disease in the population upon exposure. HAdV detected by PCR could also serve as indicators of the virological water quality. In order to assess the applicability of HAdV to the evaluation of the faecal contamination in European bathing waters, a real-time quantitative PCR assay was used for the quantification of HAdV in 132 samples collected from 24 different recreational marine and freshwater sites in nine European countries. Selected samples presenting positive nested PCR results for HAdV were analyzed using quantitative PCR and 80 samples from a total of 132 produced quantitative results with mean values of 3.2 × 10² per 100 ml of water, being human adenovirus 41 the most prevalent serotype between the samples where adenovirus was typified. HAdV were quantified in samples from all 15 surveillance laboratories. Statistical analysis showed no homogeneous linear relation between HAdV and E. coli, intestinal enterococci or somatic coliphages concentrations in the tested samples when considering all the data together. Significant correlations between HAdV and at least one of the other indicators were observed only when data from individual laboratories were considered. The quantification of HAdV may provide complementary information in relation to the use of bacterial standards in the control of water quality in bathing water.     

Assessment of the Virological Quality of Marine and Running Surface Waters in NW Greece: A Case Study

The virological quality of surface marine and running water samples collected from Igoumenitsa gulf and Kalamas river (NW Greece) was assessed from October 2012 to September 2013. Sampling sites were exposed to different land and/or anthropogenic effects. Seawater samples were collected monthly from five sampling stations (new harbor, old harbor, wastewater treatment plant outlet, protected Natura area, Drepano beach). Viral targets included human adenoviruses (hAdVs), as index human viruses, while noroviruses (NoVs) and hepatitis A virus (HAV) were also studied. Kalamas river samples were collected seasonally, from three sampling stations (Soulopoulo, Dam, Sagiada-estuaries), while viral targets included also porcine adenoviruses (pAdVs) and bovine polyoma viruses (bPyVs), as additional index viruses. All water samples were analyzed for standard bacterial indicators, as well. Physicochemical and meteorological data were also collected. Based on the standard bacterial indices, both sea and river water samples did not exceed the limits set according to Directive 2006/7/EU. However, positive samples for hAdVs were found occasionally in all sampling sites in Igoumenitsa gulf (23.3%, 14/60) showing fecal contamination of human origin. Moreover, HAV was detected once, in the sampling site of the old port (at 510 GC/L). Most of the Kalamas water samples were found positive for hAdVs (58.3%, 7/12), while human noroviruses GI (NoVGI) (8.3%, 1/12) and GII (NoVGII) (16.7%, 2/12) were also detected. HAV, pAdVs, and bovine polyomaviruses (bPyVs) were not detected in any of the analyzed samples. No statistically significant correlations were found between classic bacterial indicators and viral targets, nor between viruses and meteorological data. Overall, the present study contributed to the collection of useful data for the biomonitoring of the region, and the assessment of the overall impact of anthropogenic activities. It provided also valuable information for the evaluation of the risk of waterborne viral infections and the protection of public health. It was the first virological study in the area and one of the few in Greece.     

Viruses Surveillance Under Different Season Scenarios of the Negro River Basin,Amazonia, Brazil

The Negro River is located in the Amazon basin, the largest hydrological catchment in the world. Its water is used for drinking, domestic activities, recreation and transportation and water quality is significantly affected by anthropogenic impacts. The goals of this study were to determine the presence and concentrations of the main viral etiological agents of acute gastroenteritis, such as group A rotavirus (RVA) and genogroup II norovirus (NoV GII), and to assess the use of human adenovirus (HAdV) and JC polyomavirus (JCPyV) as viral indicators of human faecal contamination in the aquatic environment of Manaus under different hydrological scenarios. Water samples were collected along Negro River and in small streams known as igarapés. Viruses were concentrated by an organic flocculation method and detected by quantitative PCR. From 272 samples analysed, HAdV was detected in 91.9 %, followed by JCPyV (69.5 %), RVA (23.9 %) and NoV GII (7.4 %). Viral concentrations ranged from 10² to 10⁶ GC L^?1 and viruses were more likely to be detected during the flood season, with the exception of NoV GII, which was detected only during the dry season. Statistically significant differences on virus concentrations between dry and flood seasons were observed only for RVA. The HAdV data provides a useful complement to faecal indicator bacteria in the monitoring of aquatic environments. Overall results demonstrated that the hydrological cycle of the Negro River in the Amazon Basin affects the dynamics of viruses in aquatic environments and, consequently, the exposure of citizens to these waterborne pathogens.     

Adenovirus and Norovirus Contaminants in Commercially Distributed Shellfish

Shellfish complying with European Regulations based on quantification of fecal bacterial indicators (FIB) are introduced into markets; however, information on viruses, more stable than FIB, is not available in the literature. To assess the presence of noroviruses (NoVs) GI and GII and human adenoviruses (HAdV) in domestic and imported mussels and clams (n = 151) their presence was analyzed during winter seasons (2004–2008) in north-west Spanish markets through a routine surveillance system. All samples tested negative for NoV GI and 13 % were positive for NoV GII. The role of HAdV as viral indicator was evaluated in 20 negative and 10 positive NoV GII samples showing an estimated sensitivity and specificity of HAdV to predict the presence of NoV GII of 100 and 74 % (cut-off 0.5). The levels of HAdV and NoVs and the efficiency of decontamination in shellfish depuration plants (SDP) were evaluated analyzing pre- and post-depurated mussels collected in May–June 2010 from three different SDP. There were no statistically significant differences in the prevalence and quantification of HAdV between pre- and post-depurated shellfish and between seawater entering and leaving the depuration systems. Moreover, infectious HAdV were detected in depurated mussels. These results confirm previous studies showing that current controls and depuration treatments limiting the number of FIB do not guarantee the absence of viruses in shellfish.     

A 1-Year Study on the Detection of Human Enteric Viruses in New Caledonia

Human enteric viruses occur in high concentrations in wastewater and can contaminate receiving environmental waters. Due to the lack of data on the prevalence of enteric viruses in New Caledonia, the presence and the concentrations of enteric viruses in wastewater and seawater were determined. Untreated wastewater and seawater samples were collected monthly for 1 year from a wastewater treatment plant (WWTP) and from the WWTP’s outlet, located directly on a popular recreational beach. Samples were tested for norovirus genogroups I and II (NoV GI and GII), astroviruses (AsV), sapoviruses (SaV), enteroviruses (EV), hepatitis A viruses (HAV), rotaviruses (RoV), human adenoviruses (HAdV) and human polyomaviruses (HPyV). To support these data, faecal samples from cases of gastroenteritis were tested for the first time for NoV and detected in the population. NoV GI, NoV GII, EV, SaV, HAdV and HPyV were detected in all wastewaters, RoV in 75 % and AsV in 67 %. HAV were not detected in wastewater. Overall, 92 % of seawater samples were positive for at least one virus. HPyV were detected most frequently in 92 % of samples and at concentrations up to 7.7 × 10³ genome copies/L. NoV GI, NoV GII, EV, SaV, RoV and HAdV were found in 33, 66, 41, 33, 16 and 66 % of seawater samples, respectively. AsV were not detected in seawater. This study reports for the first time the presence of NoV and other enteric viruses in New Caledonia and highlights the year-round presence of enteric viruses in the seawater of a popular beach.     

不同微生物处理工艺对全氟化合物的去除效果

以辽宁省4个采用不同微生物处理工艺的污水处理厂为研究对象,采用WAX固相萃取分离富集和高效液相-质谱联用(HPLC/MS/MS)方法测定了4个污水处理厂中13种PFCs(全氟化合物)〔9种PFCAs(全氟羧酸类化合物,C₄~C₁₂)和4种PFSAs(全氟磺酸类化合物,C₄、C₆、C₈、C₁₀)〕的质量浓度. 研究发现,9种PFCAs(C₄~C₁₂)(记为∑PFCAs)和2种PFSAs(C₄、C₈)(记为∑PFSAs)均有不同程度的检出,水体中各PFCs浓度水平与碳链长度呈显著负相关. 进水中ρ(∑PFCAs)和ρ(∑PFSAs)分别为81.5~135.9和3.7~4.6 ng/L,出水中ρ(∑PFCAs)和ρ(∑PFSAs)分别为47.4~63.3和2.8~3.7 ng/L. 进、出水受PFCAs尤其是短链PFCAs污染较为严重. 4个污水处理厂对PFCs的去除呈现相似的去除效果及规律,即PFCs的去除主要靠活性污泥的吸附作用,而与污水处理厂所采用的微生物处理工艺相关性不大.      

Microbial Source Tracking Analysis Using Viral Indicators in Santa Lucía and Uruguay Rivers,Uruguay

The aim of this study was to determine the origin (human, bovine or porcine) and the concentration of the fecal sources of contamination in waters from Santa Lucía basin and Uruguay River in Uruguay by using host-specific viral markers (adenoviruses and polyomaviruses) as microbial source tracking (MST). Between June 2015 and May 2016, monthly collections of surface water samples were performed in six sites in Santa Lucía basin and four sites in Uruguay River (n = 120 samples). Viral concentration was carried out using an absorption-elution method. Detection and quantification of human and porcine adenovirus (HAdV and PAdV, respectively) and human and bovine polyomavirus (HPyV and BoPyV, respectively) were performed by quantitative PCR (qPCR). To evaluate the infectivity of circulating HAdV, an integrated cell culture-qPCR (ICC-qPCR) was used. A logistic regression analysis was carried out to estimate the influence of environmental variables on the virus presence in surface waters. Overall, HAdV was the prevalent (18%; 21/120) followed by BoPyV (11%; 13/120) and HPyV (3%; 3/120), whereas PAdV was not detected in this study. The mean concentration ranged from 1.5 × 10⁴ genomic copies/L (gc/L) for HAdV to 1.8 × 10² gc/L for HPyV. Infective HAdVs were observed in two out of ten analyzed samples. A significant effect of environmental temperature (p = 0.001) and river (p = 0.012) on the presence of human viruses was found. These results suggest that fecal contamination could affect the water quality of these rivers, showing deficiencies in the procedure of sewage discharge from regional cities, livestock and dairy farms.

     

贵州某规模化养猪场废水中抗生素的污染特征及去除效果

为了解贵州某规模化养猪场废水处理过程中抗生素的污染特征及废水处理工艺对抗生素的去除效果,使用固相萃取-液相色谱-串联质谱仪(SPE-LC-MS)技术,对2家规模化养猪场(猪场A和猪场B)废水处理工艺各处理单元进出水中10种兽用抗生素的去除进行调查研究.结果表明, 2家规模化养猪场废水处理工艺对常规污染物(COD、NH~+_4-N、TN和TP)的去除率在88.10%以上. 2家养猪场废水处理工艺各处理单元进出水中均有多种抗生素检出,检出浓度范围在ND～120 842.74 ng·L~(-1)之间.其中,主要的污染单体为磺胺间甲氧嘧啶(SMM)、磺胺对甲氧嘧啶(SMD)、土霉素(OTC)和氧氟沙星(OFL),最高单体污染浓度达120 842.74 ng·L~(-1)(SMM).调查的10种抗生素在处理工艺中的去除效果较好,总去除率为99.23%～100.00%,在猪场A的废水处理工艺中,"USR+2级A/O+消毒池+氧化塘"组合工段能有效去除废水中残留的抗生素,其中对SMM、SMD和OTC的总去除率达100.00%;在猪场B的废水处理工艺中,"超滤(UF)+纳滤(NF)"组合工段能有效去除废水中的抗生素,最终废水中99.23%以上的抗生素被去除.但最终出水中大部分抗生素的浓度高于欧盟水环境抗生素阈值(10 ng·L~(-1)).通过冗余分析发现废水中常规指标(COD、NH~+_4-N、TN、TP和pH)与部分抗生素的降解具有相关性.     

MBR与SMBR脱氮除磷特性及膜污染控制

为提高污水深度处理效能和工艺运行的稳定性,研究以序批式膜生物反应器(SMBR)与传统膜生物反应器(MBR)为对象,对比研究其脱氮除磷特性、缺氧时间对工艺效率的影响及膜污染控制策略,同时应用分子生物学技术对两种工艺中微生物群落结构和组成进行分析.结果表明,间歇曝气能强化系统脱氮,使SMBR工艺去除总氮效果优于MBR,而在氨氮、总磷、COD、浊度去除方面两者无明显差异,去除率分别为94%、78%、80%、97%.延长SMBR工艺缺氧时间对COD、氨氮去除无显著影响,降低了总氮、总磷的去除率,总氮去除率由61%下降到46%,总磷由74%下降到52%.采用间歇曝气和投加一定浓度的粉末活性炭(PAC)均有利于减缓膜污染.微生物群落分析发现,两种工艺中微生物群落结构和组成无显著差异,硝化螺菌属(Nitrospira)和脱氯单胞菌属(Dechloromonas)为系统中的高丰度功能菌群,为工艺高效运行提供了生物学基础.     

Shifts in microbial community structure and diversity in a MBR combined with worm reactors treating synthetic wastewater

The chemical oxygen demand (COD) and NH₃-N removal, membrane fouling, sludge characteristics and microbial community structure in a membrane bioreactor (MBR) coupled with worm reactors (SSBWR) were evaluated for 210 days. The obtained results were compared to those from a conventional MBR (C-MBR) operated in parallel. The results indicated that the combined MBR (S-MBR) achieved higher COD and NH₃-N removal efficiency, slower increase in membrane fouling, better sludge settleability and higher activities of the related enzymes in the activated sludge. Denaturing gradient gel electrophoresis was used to analyze the microbial community structures in the C-MBR and the S-MBR. The microbial community structure in the S-MBR was more diverse than that in the C-MBR. Additionally, the slow-growing microbes such as Saprospiraceae, Actinomyces, Frankia, Clostridium, Comamonas, Pseudomonas, Dechloromonas and Flavobacterium were enriched in the S-MBR, further accounting for the sludge reduction, membrane fouling alleviation and wastewater treatment.     

Nitrogen removal and simultaneous nitrification and denitrification in a fluidized bed step-feed process

For urban wastewater treatment, we conducted a novel four-stage step-feed wastewater treatment system combined with a fluidized bed laboratory experiment to investigate chemical oxygen demand (COD), NH₄⁺-N, and total nitrogen (TN) removal performance. The removal rates of COD, NH₄⁺-N and TN were 88.2%, 95.7%, and 86.4% with effluent concentrations of COD, NH₄⁺-N and TN less than 50, 8, and 10 mg/L, respectively. Biomass and bacterial activities were also measured, with results showing more nitrobacteria in the activated sludge than in the biofilm; however, bacterial activity of the biofilm biomass and the activated sludge were similar. Nitrogen concentrations during the process were also detected, with simultaneous nitrification and denitrification found to be obvious.     

One-year Surveillance of Human Enteric Viruses in Raw and Treated Wastewaters,Downstream River Waters,and Drinking Waters

Human enteric viruses are a major cause of waterborne diseases, and can be transmitted by contaminated water of all kinds, including drinking and recreational water. The objectives of the present study were to assess the occurrence of enteric viruses (enterovirus, norovirus, adenovirus, hepatitis A and E virus) in raw and treated wastewaters, in rivers receiving wastewater discharges, and in drinking waters. Wastewater treatment plants’ (WWTP) pathogen removal efficiencies by adenovirus quantitative real-time PCR and the presence of infectious enterovirus, by cell culture assays, in treated wastewaters and in surface waters were also evaluated. A total of 90 water samples were collected: raw and treated wastewaters (treated effluents and ultrafiltered water reused for industrial purposes), water from two rivers receiving treated discharges, and drinking water. Nested PCR assays were used for the identification of viral DNA/RNA, followed by direct amplicon sequencing. All raw sewage samples (21/21), 61.9 % of treated wastewater samples (13/21), and 25 % of ultrafiltered water samples (3/12) were contaminated with at least one viral family. Multiple virus families and genera were frequently detected. Mean positive PCRs per sample decreased significantly from raw to treated sewage and to ultrafiltered waters. Moreover, quantitative adenovirus data showed a reduction in excess of 99 % in viral genome copies following wastewater treatment. In surface waters, 78.6 % (22/28) of samples tested positive for one or more viruses by molecular methods, but enterovirus-specific infectivity assays did not reveal infectious particles in these samples. All drinking water samples tested negative for all viruses, demonstrating the effectiveness of treatment in removing viral pathogens from drinking water. Integrated strategies to manage water from all sources are crucial to ensure water quality.     

Characterization and biodegradation kinetics of a new cold-adapted carbamazepine-degrading bacterium, Pseudomonas sp. CBZ-4

Carbamazepine is frequently detected in waters and hardly eliminated during conventional wastewater treatment processes due to its complicated chemical structure and resistance to biodegradation. A carbamazepine-degrading bacterium named CBZ-4 was isolated at a low temperature （10℃） from activated sludge in a municipal wastewater treatment plant. Strain CBZ-4, which can use carbamazepine as its sole source of carbon and energy, was identified as Pseudomonas sp. by the 16S rRNA gene sequence. The composition and percentage of fatty acids, which can reveal the cold-adaptation mechanism of strain CBZ-4, were determined. Strain CBZ-4 can effectively degrade carbamazepine at optimal conditions： pH 7.0, 10℃, 150 r/min rotation speed, and 13% inoculation volume. The average removal rate of carbamazepine was 46.6% after 144 hr of incubation. The biodegradation kinetics of carbamazepine by CBZ-4 was fitted via the Monod model. Vmax and Ks were found to be 0.0094 hr^-1 and 32.5 mg/L, respectively.     

Quantitative Detection and Characterization of Human Adenoviruses in the Buffalo River in the Eastern Cape Province of South Africa

Buffalo River is an important water resource in the Eastern Cape Province of South Africa. Over a 1-year period (August 2010?CJuly 2011), we assessed the prevalence of human adenoviruses (HAdVs) at a total of 6 sites on the river and three dams along its course. HAdVs were detected by real-time quantitative PCR in about 35?% of the samples with concentrations ranging from 1.2?×?10¹ genome copies (GC)/l to 4.71?×?10³ GC/l. HAdVs were detected at 5 of the 6 sampling sites with the detection rate ranging from 8.3?% at Rooikrantz Dam to 92?% at Parkside. The HAdV concentrations across the sampling sites were as follows: Parkside (3.25?×?10²?C4.71?×?10³?GC/); King William??s Town (1.02?×?10²?C4.56?×?10³?GC/l); and Eluxolzweni (1.17?×?10²?C3.97?×?10² GC/l). Significantly (P?<?0.05) higher concentrations were detected at the non-dam sites compared to the dam sites. A very low mean concentration of 1.86?×?10¹ HAdV GC/l was observed at Bridle Drift Dam. While HAdVs were detected only once at Rooikrantz Dam (1.74?×?10¹?GC/l), no HAdV was detected at Maden Dam. Epidemiologically important serotypes, Ad40/41, constituted 83.3?%, while Ad21 made up 16.7?% of the all HAdVs detected and were characterized by qualitative PCR. The Buffalo River presents a public health risk heightened by the presence of Ad 40/41 and Ad21. Our results make imperative the need for assessing water sources for viral contamination in the interest of public health. This work is a significant contribution to the molecular epidemiology of adenoviruses and to the best of our knowledge this is the first report on detection of enteric virus from surface waters in the Eastern Cape.     

基于宏基因组与宏转录组分析石化废水生物处理系统脱氮功能菌群

石化行业是我国的支柱产业,长期以来,石化废水处理一直是水污染治理领域的重难点,阻碍了石化行业高质量可持续的发展.由于石化企业和园区多临河或临海而建,其废水排放易造成流域性或区域性水生态风险,尤其石化废水中的氮素污染,严重威胁了水生态安全及人民群众身体健康.因此,从上海某化工区的某条石化废水A/O脱氮工艺线中采集了污泥样品,通过宏基因组和宏转录组对比分析了出水水质稳定时期与出水水质波动时期的不同污泥中微生物的群落结构,脱氮菌群的功能特征和关键的氮代谢途径.结果表明,工艺的氨氧化功能易波动,而亚氮和硝氮的去除相对稳定.菌群研究发现该A/O工艺主体脱氮途径为硝化-反硝化脱氮途径,未发现工艺内有厌氧氨氧化相关基因片段.体系脱氮关键功能基因中约有90%与反硝化作用相关,只有约0.17%的基因参与了硝化过程中氨氮的转化.进一步研究发现,氨氧化功能菌在工艺中丰度极低且结构单一,主要的氨氧化功能菌属是Nitrosomonas.这可能是工艺线出水氨氮浓度易波动的主要原因.     

UVC Inactivation of dsDNA and ssRNA Viruses in Water: UV Fluences and a qPCR-Based Approach to Evaluate Decay on Viral Infectivity

Disinfection by low-pressure monochromatic ultraviolet (UVC) radiation (253.7 nm) became an important technique to sanitize drinking water and also wastewater in tertiary treatments. In order to prevent the transmission of waterborne viral diseases, the analysis of the disinfection kinetics and the quantification of infectious viral pathogens and indicators are highly relevant and need to be addressed. The families Adenoviridae and Polyomaviridae comprise human and animal pathogenic viruses that have been also proposed as indicators of fecal contamination in water and as Microbial Source Tracking tools. While it has been previously suggested that dsDNA viruses may be highly resistant to UVC radiation compared to other viruses or bacteria, no information is available on the stability of polyomavirus toward UV irradiation. Here, the inactivation of dsDNA (HAdV2 and JCPyV) and ssRNA (MS2 bacteriophage) viruses was analyzed at increasing UVC fluences. A minor decay of 2-logs was achieved for both infectious JC polyomaviruses (JCPyV) and human adenoviruses 2 (HAdV2) exposed to a UVC fluence of 1,400 J/m², while a decay of 4-log was observed for MS2 bacteriophages (ssRNA). The present study reveals the high UVC resistance of dsDNA viruses, and the UV fluences needed to efficiently inactivate JCPyV and HAdV2 are predicted. Furthermore, we show that in conjunction with appropriate mathematical models, qPCR data may be used to accurately estimate virus infectivity.