Revealing the changes of bacterial community from water source to consumers tap: A full-scale investigation in eastern city of China

This study profiled the bacterial community variations of water from four water treatment systems, including coagulation, sedimentation, sand filtration, ozonation-biological activated carbon filtration (O₃-BAC), disinfection, and the tap water after the distribution process in eastern China. The results showed that different water treatment processes affected the bacterial community structure in different ways. The traditional treatment processes, including coagulation, sedimentation and sand filtration, reduced the total bacterial count, while they had little effect on the bacterial community structure in the treated water (before disinfection). Compared to the traditional treatment process, O₃-BAC reduced the relative abundance of Sphingomonas in the finished water. In addition, ozonation may play a role in reducing the relative abundance of Mycobacterium. NaClO and ClO₂ had different effects on the bacterial community in the finished water. The relative abundance of some bacteria (e.g. Flavobacterium, Phreatobacter and Porphyrobacter) increased in the finished water after ClO₂ disinfection. The relative abundance of Mycobacterium and Legionella, which have been widely reported as waterborne opportunistic pathogens, increased after NaClO disinfection. In addition, some microorganisms proliferated and grew in the distribution system, which could lead to turbidity increases in the tap water. Compared to those in the finished water, the relative abundance of Sphingomonas, Hyphomicrobium, Phreatobacter, Rheinheimera, Pseudomonas and Acinetobacter increased in the tap water disinfected with NaClO, while the relative abundance of Mycobacterium increased in the tap water disinfected with ClO₂. Overall, this study provided the detailed variation in the bacterial community in the drinking water system.     

An investigation of changes in water quality throughout the drinking water production/distribution chain using toxicological and fluorescence analyses

Changes in water quality from source water to finished water and tap water at two conventional drinking water treatment plants(DWTPs) were monitored.Beside the routine water quality testing,Caenorhabditis elegans-based toxicity assays and the fluorescence excitation–emission matrices technique were also applied.Both DWTPs supplied drinking water that met government standards.Under current test conditions,both the investigated finished water and tap water samples exhibited stronger lethal,genotoxic and reprotoxic potential than the relative source water sample,and the tap water sample was more lethal but tended to be less genotoxic than the corresponding finished water sample.Meanwhile,the nearly complete removal of tryptophan-like substances and newly generated tyrosine-like substances were observed after the treatment of drinking water,and humic-like substances were identified in the tap water.Based on these findings,toxic pollutants,including genotoxic/reproductive toxicants,are produced in the drinking water treatment and/or distribution processes.Moreover,further studies are needed to clarify the potentially important roles of tyrosine-like and humic-like substances in mediating drinking water toxicity and to identify the potential sources of these contaminants.Additionally,tryptophan-like fluorescence may be adopted as a useful parameter to monitor the treatment performance of DWTPs.Our observations provided insights into the importance of utilizing biotoxicity assays and fluorescence spectroscopy as tools to complement the routine evaluation of drinking water.     

Removal and desorption of chromium in synthetic effluent by a mixed culture in a bioreactor with a magnetic field

Two chromium removal experiments were performed in bioreactors with and without a magnetic field under the same conditions.The release of the chromium present in the biomass was tested in two experiments one with the initial pH of the medium and one with pH 4.0.The objective was to remove Cr(Ⅵ) and total Cr from the effluent,this was carried out by placing biological treatments of synthetic effluent contaminated with 100 mg/L of Cr(Ⅵ) in a bioreactor with neodymium magnets that applied a magnetic field(intensity85.4 mT) to the mixed culture.The removal of Cr(Ⅵ) was approximately 100.0% for the bioreactor with a magnetic field and 93,3% for the bioreactor without a magnetic field for9 hr of recirculation of the synthetic effluent by the bioreactor.The removal of total Cr was61.6% and 48.4%,with and without a magnetic field,respectively;for 24 hr.The desorption of Cr(VI) in the synthetic effluent was 0.05 mg/L,which is below the limit established by Brazilian legislation(0.1 mg/L) for the discharge of effluent containing Cr(Ⅵ) into bodies of water.The results obtained for the removal of chromium in synthetic effluent suggested that there was no significant influence on the viable cell count of the mixed culture.The desorption of Cr(Ⅵ) in synthetic effluent after bioadsorption of chromium by the mixed culture in the process of removal of chromium in bioreactors with and without a magnetic field was not significant in either of the experiments with different initial pHs.     

精神活性物质在北京市某污水处理厂中的污染特征与生态风险

为了解污水处理厂对精神活性物质的去除特征及总出水对受纳水体的生态风险,采用固相萃取-高效液相色谱-串联质谱法调查了北京市某污水处理厂中13种精神活性物质的浓度水平与负荷量变化,并运用RQ（risk quotient,风险熵）对总出水中精神活性物质进行风险评估.结果表明:①13种精神活性物质在总进水与总出水中均能检出,总质量浓度平均值分别为2 395.10和63.59 ng/L,其中ρ（EPH）（EPH表示麻黄碱）占比分别为93.9%和67.9%,其次为COD（可待因）与METH（甲基苯丙胺）.污水处理厂上游地表水中ρ（EPH）、ρ（METH）与ρ（KET）（KET为氯胺酮）均高于总出水及其下游地表水,说明上游沿河可能有新的污染源输入.②污水处理厂对NK（去甲氯胺酮）、BE（苯甲酰爱康宁）和MTD（美沙酮）均呈负去除,其他精神活性物质的去除主要发生在二级生物处理与三级处理（超滤膜与UV消毒）阶段.③污水处理厂服务区域内精神活性物质的周内负荷量存在一定波动,AMP（苯丙胺）、METH、MDA（3,4-亚甲二氧基苯丙胺）、MDMA（3,4-亚甲二氧基甲基苯丙胺）、KET与HER（海洛因）的负荷量均在周末升高.④污水处理厂总出水中精神活性物质的生态风险均较低（RQ < 0.10）.研究显示,污水处理厂不能完全去除污水中的精神活性物质,总出水中残留精神活性物质对受纳河流生态系统产生的长期混合效应不容忽视.      

生物炭复合青霉菌修复砷污染土壤对其微生物群落功能多样性的影响

真菌修复砷污染土壤是一种能够有效吸附固化环境中砷的重要措施.生物炭作为目前修复重金属的热点,其多空疏松的结构、较高的离子交换量、丰富的有机碳含量等都说明了其在土壤修复中的地位.为了探究生物炭与青霉菌在修复砷污染土壤的同时对土壤中微生物活性及其多样性的影响,在室内孵育条件下,运用Biolog法研究了3×3随机区组试验（3个生物炭梯度分别为0%、2%、4%,3个青霉菌梯度分别为0%、10%、20%）下土壤微生物对不同类型碳源的利用能力以及多种功能性指数的影响.结果表明:①添加青霉菌与生物炭后,土壤中有效砷含量较对照组显著下降,从而影响其微生物群落功能多样性.②砷污染土壤中微生物群落功能多样性、碳源利用丰富度随生物炭浓度梯度的升高呈先升后降的趋势.③高接菌量（20%）与低接菌量（10%）对砷污染土壤中微生物群落功能多样性的影响没有显著性差异.④2%生物炭与10%青霉菌处理土壤中微生物群落功能多样性、碳源利用丰度最高.⑤青霉菌对胺类及少部分酸类碳源的利用能力较弱（AWCD < 0.5,AWCD为Biolog微平板孔中溶液吸光值平均颜色变化率）,对氨基酸类中大部分碳源以及脂类碳源的代谢能力较强（AWCD>1.0）,对糖类、酚酸类的代谢能力稍弱（AWCD为0.3~1.0）,青霉菌对D-半乳糖醛酸、L-天冬酰胺酸、L-丝氨酸、L-精氨酸、r-羟基丁酸这5种碳源的利用率最高（AWCD>1.2）.研究显示,低浓度生物炭可增加砷污染土壤中微生物群落多样性,生物炭含量的继续增加会对微生物产生抑制作用;青霉菌添加到砷污染土壤后,会显著提升砷污染土壤中微生物的群落功能多样性,改善砷污染土壤中微生的物群落结构;青霉菌的优势碳源大多为植物根系分泌物,可为后续青霉菌与超积累植物复合修复砷污染土壤提供参考.      

我国燃煤电厂大气汞控制技术综合评估与对策探讨

采用模糊综合评价法与层次分析法或专家判定法相结合,对我国燃煤电厂非常规污染物大气汞控制技术进行了综合评估,以筛选出最佳控制技术.建立了环境、经济和技术为一级指标的三层指标体系,共22个评价指标;初步筛选出洗选煤+烟气净化协同脱除技术、烟气净化协同脱除技术、烟气净化协同脱除技术+活性炭吸附技术等七项技术及技术组合并对其开展评估.结果表明:强调环境因素的层次分析法综合评估结果表明,超低排放协同脱除技术+活性炭吸附技术得分最高（0.797 0）,为最佳控制技术.而专家判定法与强调经济因素的层次分析法的综合评估结果一致,洗选煤+烟气净化协同脱除技术最具经济优势,是专家认可的最佳可用技术（BAT）和最佳环境实践（BEP）.研究显示,我国现阶段可采用洗选煤+超低排放协同脱除技术对燃煤电厂的大气汞污染进行控制,但为达到发达国家的严格排放标准,必须采用超低排放协同脱除技术+活性炭吸附技术.      

德州市夏季臭氧敏感性特征及减排方案

近年来德州市臭氧污染频发,2018年夏季（6~8月）,德州市发生了严重臭氧污染事件,臭氧日最大8 h浓度值超标天数达60 d,超标率65%,3个月平均值为176 μg ·m^-3,最高达262 μg ·m^-3.本研究利用WRF-CAMx耦合的HDDM模块,分析期间德州臭氧敏感性特征及减排方案.结果表明,在空间上,德州市中心城区为VOCs控制区,而郊区为NO_x与VOCs协同控制区.在时间上,VOCs敏感值每日为正值,但dO₃_V₅₀在6月（城区18.7 μg ·m^-3,郊区19.7 μg ·m^-3）和8月（城区15.3 μg ·m^-3,郊区16.4 μg ·m^-3）高于7月（城区13.0 μg ·m^-3,郊区11.8 μg ·m^-3）,NO_x敏感值城区呈正负交错,郊区大部分为正值,并与VOCs敏感值接近.对于城区减排方案应考虑以仅VOCs削减为优先,而郊区由于NO_x和VOCs对臭氧减排效果相当,建议以NO_x：VOCs=1：1为优.     

深圳市综合水质指数研究及其在水资源资产评估上的应用

自然资源资产评估技术是开展自然资源资产负债表实践和实行环境责任离任审计的重要技术支撑。水资源作为一项重要自然资源,如何有效评估水资源资产是不可回避的问题。论文以深圳市为研究区域,一是采用综合污染指数法和主成分分析法,以总氮、氨氮、总磷、化学需氧量、生化需氧量、固体悬浮物为指标参数构建了深圳市综合水质指数以评价水资源综合水质。二是以该综合水质评估模型为基础,通过采用治污成本法分析综合水质与治污成本间的关系,从而构建深圳市景观水和饮用水资源的价值量评估模型。论文还以深圳市大鹏新区为试点开展了水资源价值量评估,评估结果显示,2015年大鹏新区景观水和饮用水资源的价值量分别为3.60亿、0.35亿元。     

Human viral pathogens are pervasive in wastewater treatment center aerosols

Wastewater treatment center(WTC) workers may be vulnerable to diseases caused by viruses, such as the common cold, influenza and gastro-intestinal infections. Although there is a substantial body of literature characterizing the microbial community found in wastewater, only a few studies have characterized the viral component of WTC aerosols,despite the fact that most diseases affecting WTC workers are of viral origin and that some of these viruses are transmitted through the air. In this study, we evaluated in four WTCs the presence of 11 viral pathogens of particular concern in this milieu and used a metagenomic approach to characterize the total viral community in the air of one of those WTCs. The presence of viruses in aerosols in different locations of individual WTCs was evaluated and the results obtained with four commonly used air samplers were compared.We detected four of the eleven viruses tested, including human adenovirus(h Ad V),rotavirus, hepatitis A virus(HAV) and Herpes Simplex virus type 1(HSV1). The results of the metagenomic assay uncovered very few viral RNA sequences in WTC aerosols, however sequences from human DNA viruses were in much greater relative abundance.     

Relationship between physicochemical properties and dewaterability of hydrothermal sludge derived from different source

Sewage sludge (SS) and deinking sludge (DS) were used to comparatively study the hydrothermal dewatering of sludge with different components. For a better overview, an insight into the relationship between physicochemical properties and dewaterability of hydrothermal sludge was provided. Results found that not all kinds of sludge were suitably conditioned by hydrothermal treatment (HT) in term of the elevation of dewaterability. Higher hydrothermal temperature tended to enhance the dewaterability of SS rather than DS, which was supported by the variation of their physicochemical properties (including water distribution, bonding energy, extracellular polymeric substance (EPS), particles size, acid functional groups and zeta potential in this study). In addition, the changes in surface morphology suggested that the reverse effect of HT on sludge dewaterability was mainly due to their dewatering behavior. For SS, the destruction of EPS structure leaded to the release of bound water, thereby strengthening sludge dewatering. Conversely, “Bridging effect” generated by lignocellulose in DS was beneficial for sludge dewatering; however, the increasing hydrothermal temperature degraded part of lignocellulose and weakened “bridging effect”, finally resulting in worse dewaterability of DS.