中南地区供水厂水质稳定分析及防护技术

文章以中南地区40多个供水厂原水为主要研究对象,针对供水厂原水水质化学稳定性及其控制方法,进行了以下研究:(1)中南地区供水系统原水水质稳定性现状调查;(2)腐蚀产物的物理化学特性;(3)原水水质化学稳定性的变化规律;(4)供水系统水质稳定性的控制方法。为了全面、客观的评价水质化学稳定性问题,本文采用稳定指数和饱和指数配合使用来综合评价水质化学稳定性,并综合考虑pH值、钙离子含量、侵蚀性二氧化碳的影响,研究发现,饱和指数IL小于-0.6、稳定指数IR大于8以及含高浓度侵蚀性二氧化碳会增加水的腐蚀倾向,可根据不同的作用机理选择相应的防护技术。     

Molecular Characterization of a Complete Genome and 12 Nsp2 Genes of PRRSV of Southwestern China

One genome and 12 Nsp2 genes of porcine reproductive and respiratory syndrome virus (PRRSV), isolated from southwestern China during 2009?C2010, were sequenced and analyzed. The whole genome comparison analysis revealed that SCwhn09CD is a North American-type PRRSV with separate 30aa deletion in Nsp2 gene, and its sequence highly identical to highly pathogenic PRRSV (HP-PRRSV) outbreak in 2006 in almost half area of China. However, an extra 7aa deletion was detected in its Nsp2 coding region. Based on the phylogenetic analysis of Nsp2 gene, all the 12 viruses were grouped into North American-type PRRSV, but two in classical-PRRSV (C-PRRSV) subcluster without typical 30aa deletion and ten in HP-PRRSV subcluster with the signature deletion. In addition, many nucleotide substitutions were found in all 12 Nsp2 genes and extra three novel deletions were identified in three out of ten HP-PRRSV. Combining the above data, it may be concluded that: (1) HP-PRRSV and C-PRRSV co-existed in the local pig farms and the majority of the viruses is HR-PRRSV, and (2) the HR-PRRSV continues to undergo its genomic divergence although it does not outbreak in large-scale in recent years. Therefore, continuous surveillance on PRRSV is necessary for the controlling of the virus in this region.     

Sorption-enhanced chemical looping oxidative steam reforming of methanol for on-board hydrogen supply

Hydrogen is an indispensable energy carrier for the sustainable development of human society. Nevertheless, its storage, transportation, and in situ generation still face significant challenges. Methanol can be used as an intermediate carrier for hydrogen supplies, providing hydrogen energy through instant methanol conversion. In this study, a sorption-enhanced, chemical-looping, oxidative steam methanol-reforming (SECL-OSRM) process is proposed using CuO–MgO for the on-board hydrogen supply, which could be a promising method for safe and efficient hydrogen production. Aspen Plus software was used for feasibility verification and parameter optimization of the SECL-OSRM process. The effects of CuO/CH3OH, MgO/CH3OH, and H2O/CH3OH mole ratios and of temperature on H2 production rate, H utilization efficiency, CH3OH conversion, CO concentration, and system heat balance are discussed thoroughly. The results indicate that the system can be operated in auto-thermal conditions with high-purity hydrogen (99.50 vol％) and ultra-low-concentration CO (<50 ppm) generation, which confirms the pos-sibility of integrating low-temperature proton-exchange membrane fuel cells (LT-PEFMCs) with the SECL-OSRM process. The simulation results indicate that the CO can be modulated in a lower concentration by reducing the temperature and by improving the H2O/CH3OH and MgO/CH3OH mole ratios.     

Re-evaluating the asymmetric economic policy uncertainty,conventional energy,and renewable energy consumption nexus for BRICS

Environmental Science and Pollution Research - Economic policy uncertainty has increased throughout the world since the previous few decades. Moreover, economic policy uncertainty significantly...     

Urinary concentrations of polycyclic aromatic hydrocarbon and phthalate metabolite mixtures in relation to semen quality among men attending an infertility clinic

Environmental Science and Pollution Research - Previous studies have reported that exposure to phthalates and polycyclic aromatic hydrocarbons (PAHs) is individually associated with altered semen...     

亚热带典型小流域磷收支及流失特征对比研究

磷素（P）在环境中的过量累积是导致农业面源污染的主要因素。论文以湖南省长沙县脱甲河农区小流域（52 km²）和涧山河森林-农区小流域（50 km²）为研究单元,基于入户调查资料和连续4 a的流域把口站水文水质定位观测数据,采用物质流分析法,对比研究了亚热带丘陵区典型小流域P的收支平衡及流失特征。结果表明,农区小流域出口地表水总磷（TP）含量变化为0.03~0.68 mg·L^-1,平均含量为0.21 mg·L^-1,整体达到Ⅲ类水质标准;森林-农区小流域TP含量变化范围为0.01~0.35 mg·L^-1,平均为0.08 mg·L^-1,整体为Ⅱ类水质,表明森林-农区小流域地表水水质明显优于农区小流域。农区小流域P的环境滞留强度（32.0 kg·hm^-2·a^-1）显著高于森林-农区小流域（20.6 kg·hm^-2·a^-1）,对环境影响更大。以2013年为例,农区小流域P的主要输入项为饲料,占53.1%,森林-农区小流域则以肥料为主,占53.0%;两个流域的P输出项都以植物和畜禽产品输出为主,均占总输出量的94.0%左右。控制小流域肥料和饲料投入、增加循环利用途径以及提高P利用率是当前减轻水体富营养化的有效途径。     

溶解有机质对生物富集因子计算的影响:以东江鱼体中多溴联苯醚的生物富集为例

准确获取化合物的生物富集因子(BAF)对于判定化合物是否属于潜在毒害性污染物、评价其生态环境风险都具有重要的意义。为探究水体中溶解有机质(DOM)对BAF值的影响,以东江三角洲流域为研究区域,以多溴联苯醚(PBDEs)为目标化合物,研究了PBDEs各单体在3种鱼体中的富集特征。结果表明,PBDEs在3种鱼体中的浓度范围为42~825 ng·g-1脂肪,log BAF值位于5.0~7.4之间。由于脱溴代谢的种间差异,3种鱼类表现出2种PBDE的组成模式。在缺乏脱溴代谢途径的鱼体内,log BAF与化合物辛醇/水分配系数(log KOW)之间存在统计意义上的抛物线关系。但当BAF进行DOM的校正之后,二者之间抛物线形式的相关性消失,而呈现出显著的正线性相关性。以往研究对BAF值在化合物的log KOW达到一定程度后(7~8附近)出现下降的解释是高KOW化合物较大的分子体积降低了其穿过生物膜的可能性,但我们的研究结果表明,这种下降很可能是由于忽视了水体中DOM影响的结果。     

太湖西部入湖口沉积物中有机物分布及其潜在指示意义

太湖作为重要的工农业用水水源以及周边居民饮用水源,其水质安全受到高度关注。在太湖西部入湖口采集7个沉积物样品,研究了合成麝香、多环芳烃(PAHs)、有机磷酸酯阻燃剂/增塑剂(OPs)和有机氯农药(OCPs)含量水平和分布规律。研究结果表明,沉积物中多种污染物分布广泛,含量水平差异较大。其中,Σ15PAHs含量371 ng·g~(-1)~2.53$103ng·g~(-1),主要来源于生物质燃烧和化石燃料高温裂解;沉积物中检出4种多环麝香,主要组分为佳乐麝香(HHCB)(0.0792 ng·g~(-1)~1.17 ng·g~(-1))和吐纳麝香(AHTN)(0.123 ng·g~(-1)~1.29 ng·g~(-1)),它们指示了太湖水体已遭受一定程度生活污水输入影响;沉积物中Σ6OPs含量范围为1.63 ng·g~(-1)~21.9 ng·g~(-1),主要污染组分为磷酸三(2-氯丙基)酯(TCPP)和磷酸三(2-氯乙基)酯(TCEP),并呈现明显的点源排放特征;沉积物中六六六系列(HCHs)(0.310 ng·g~(-1)~1.11 ng·g~(-1))和滴滴涕系列(DDTs)(0.551 ng·g~(-1)~6.40 ng·g~(-1))主要来源于历史残留。位于太滆流域的几个入湖口沉积物中多种污染物含量多高于浙江省辖区3个入湖口沉积物。     

Microbial community structure and dynamics of starch-fed and glucose-fed chemostats during two years of continuous operation

The microbial community structures of two mesophilic anaerobic chemostats, one fed with glucose, the other with starch as sole carbon sources, were studied at various dilution rates (0.05–0.25 d^–1 for glucose and 0.025–0.1 d^–1 for starch) during two years continuous operation. In the glucose-fed chemostat, the aceticlastic methanogen Methanosaeta spp. and hydrogenotrophic methanogen Methanoculleus spp. predominated at low dilution rates, whereas Methanosaeta spp. and the hydrogenotrophic Methanobacterium spp. predominated together when dilution rates were greater than 0.1 d^–1. Bacteria affiliated with the phyla Bacteroidetes, Spirochaetes, and Actinobacteria predominated at dilution rates of 0.05, 0.1, and 0.15 d^–1, respectively, while Firmicutes predominated at higher dilution rates (0.2 and 0.25 d^–1). In the starch-fed chemostat, the aceticlastic and hydrogenotrophic methanogens coexisted at all dilution rates. Although bacteria belonging to only two phyla were mainly responsible for starch degradation (Spirochaetes at the dilution rate of 0.08 d^–1 and Firmicutes at other dilution rates), different bacterial genera were identified at different dilution rates. With the exception of Archaea in the glucose-fed chemostat, the band patterns revealed by denaturing gradient gel electrophoresis (DGGE) of the microbial communities in the two chemostats displayed marked changes during long-term operation at a constant dilution rate. The bacterial community changed with changes in the dilution rate, and was erratic during longterm operation in both glucose-fed and starch-fed chemostats.