渗滤液难降解物质物化性质研究

渗滤液是生活垃圾处理过程的必然产物,经过近15年的研究,其产生机理和处理方法获得了一定进展,但随着<生活垃圾填埋场污染控制标准GB16889-2008>标准的实施,现有处理技术出水大都不能达标,特别是老龄渗滤液或经一定处理后的渗滤液尾水,其处理极限COD大约在300 mg·L-1以上.渗滤液难降解物质的表征可能是解决渗...     

Influence of atmospheric stability on the mass concentration and chemical composition of atmospheric particles: a case study in Rome, Italy

PM(10) concentration and chemical composition (ions and carbon compounds) at three sampling stations in Rome and in its surroundings was determined daily during a one-month field study, carried out during December 2003. PM concentration at the traffic station was considerably higher than at the urban background and semi-rural stations; elemental carbon was detected as one of the chemical components responsible for this increase. The difference in the concentration of sulphate and ammonium was negligible, as it was expected for secondary pollutants. A negative artefact in the determination of ammonium nitrate by means of heated automatic monitors was highlighted. The dilution properties of the lower atmosphere were traced by means of a natural radioactivity monitor. This parameter has been found to play an essential role in pollution buildup. A considerable increase in PM concentration was observed to coincide with periods of atmospheric stability. The main difference in PM composition between periods of high concentration and periods of "clean" air was found to be in the increase of ammonium nitrate concentration.     

Adding virtual measuring stations to a network for urban air pollution mapping

Maps of pollutants concentration are usually generated by means of interpolation and extrapolation methods. The quality of the results depends mainly of the number of permanent or temporary measuring stations. This paper deals with a method for the virtual densification of the network of stations. The method creates "virtual measuring stations". It aims at improving the quality of interpolation by increasing the number of data on pollutant concentration. The virtual stations are determined by the means of a classification method applied to each pixel of the area under concern. Discriminating elements are pollutants emission classes, land cover types, urban morphological indicators created to this purpose and distance to major roads. A first implementation was made for particulate matter (PM) for the city of Strasbourg (France) using thin-plates spline interpolation method in Arcview 9 GIS. The relative Root Mean Square Error decreases from 49% for five input stations down to 15% for the virtual stations.     

Pyrene partition behavior to the NOM: Effect of NOM characteristics and its modification by ozone preoxidation

Hydrophobic organic contaminants (HOCs)—pyrene, and natural organic matters (NOM) from different sources were taken as the test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’ partition to the NOM in this study. The effects of solution property, NOM characteristics, and modification by ozone preoxidation on pyrene partition to NOM were systematically evaluated. According to the fluorescence quenching method, the partition coefficient K _oc of pyrene to NOM was calculated, which was found to have a great relationship with the aromatic structures and hydrophobic functional groups of the NOM. The NOM characteristic modification corresponding to solution property could influence the interactions between the NOM and pyrene. Preozonation could destroy the aromatic or hydrophobic structures of the NOM and decrease K _oc of pyrene.     

污水厂二级出水中难凝聚有机物的臭氧化特性

以城市污水处理厂二级出水为原水,研究臭氧化处理对水中难凝聚有机物的去除效果.结果表明单独混凝对水中有机物的去除率较低,混凝过程中未被去除的有机物属于难凝聚有机物,加入臭氧进行氧化,随着臭氧投加量的增加,二级出水色度和UV254去除率逐渐增大,而DOC去除率变化较小.当臭氧投加量(以O3/DOC计)增加至1.5 mg·mg-1时,色度、UV254和DOC的去除率分别为45%、34%和20%,说明臭氧易于与不饱和结构有机物反应,而直接氧化的矿化能力较弱.为进一步明确二级出水有机物种类和含量的变化,测定了混凝和不同臭氧投加量下有机物的相对分子质量和三维荧光光谱.结果表明混凝对有机物含量的影响很小,而臭氧能够优先氧化分解难凝聚有机物中的大分子物质,明显减弱腐殖质类物质的荧光峰强度,但不改变荧光峰位置.同时采用光电子能谱分析有机物结构的变化规律,结果表明混凝能够去除含羧基类官能团有机物,而臭氧则易于与含苯环类难凝聚有机物反应,随着臭氧投加量的增大,脂肪类饱和有机物含量有所升高.     

环境行政公益诉讼中检察机关与公众的合作机制研究

《中华人民共和国行政诉讼法》的最新修改增加了检察机关提起行政公益诉讼的规定。从此前试点情况看,生态环境和资源保护案件在行政公益诉讼案件中占比最大,加之"生态文明"入宪,此类案件在今后一段时间依然会是行政公益诉讼的重点。制度虽已建立但落实千头万绪,检察机关面临诸多困境。在党的十九大提出的构建"全民共治"的环境治理体系框架下,基于此类诉讼的公益性,寻找公众与检察机关之间的合作空间,可以实现多赢。     

碳质材料和溶解性有机质对沉积物中全氟化合物在摇蚊幼虫体内富集的影响

全氟化合物(PFASs)是一类具有疏水基团和亲水基团的新型污染物.目前,在环境条件对PFASs生物富集影响方面已开展了诸多研究,但有关碳质材料(CMs)和溶解性有机质(DOM)共存对PFASs在生物体内富集的影响还未见报道。为探讨这一问题,研究了沉积物-水体系中2种碳质材料木炭(W400)、多壁碳纳米管(MWCNT10)和4种DOM(丹宁酸、富里酸、蛋白胨和腐殖酸)对6种典型PFASs在摇蚊幼虫体内生物富集的影响。结果表明,暴露10 d后(已达到富集平衡状态),无论体系中是否存在CMs,添加1~50 mg C·L-1不同类型的DOM对PFASs在摇蚊幼虫体内生物富集的影响不显著。无论体系中是否存在DOM,添加CMs均能降低摇蚊幼虫体内PFASs的含量,且MWCNT10对PFASs生物富集的降低比例显著高于W400。与对照相比,添加0.4%的MWCNT10对摇蚊幼虫体内PFASs含量的降低比例为21%~56%,而同等添加量的W400对其降低比例均低于20%。这表明,在沉积物-水体系中,当CMs和DOM共存时,CMs是影响PFASs在摇蚊幼虫体内富集的主要因素,而少量DOM的引入对其影响不大。     

Exponential Collapse of Benthic Depurative Capacity in A Eutrophic Tropical Marine Ecosystem: A Threshold Response to Organic Nitrogen Loading

Microbial decomposition of particulate organic matter in sediments can substantially modulate eutrophication of nearshore marine environments. Flux budgets for nitrogen compounds and quantification of rates of microbial transformation can provide important information on the process of eutrophication. This survey documents sediment nitrogen budgets for a eutrophic nearshore marine environment at La Parguera on southwest coast of Puerto Rico, including consideration of the organic fraction in addition to microbial transformations.

Sediments of the inshore channel at La Parguera denote the input of heavy organic loads with low redox potentials and high ammonium contents. Benthic fluxes of dissolved organic nitrogen are below those recorded for ammonium. These observations suggest that nearshore tropical sediments subject to heavy nitrogen loads act as a sink for organic nitrogen and that ammonification is a key process in the release of nitrogen from sediments to the water column. Nitrification and denitrification rates are low overall and inversely related to the redox potential. Depuration of excess nitrogen through denitrification is ineffective in these sediments. in contrast to more robust temperate environments, our work demonstrates that tropical marine systems are particularly susceptible to eutrophication given their limited capacity for depuration of excess nitrogen.     

Pyrene partition behavior to the NOM: Effect of NOM characteristics and its modification by ozone preoxidation

Hydrophobic organic contaminants (HOCs)—pyrene, and natural organic matters (NOM) from different sources were taken as the test compounds to investigate the impact of physicochemical characteristics of NOM on HOCs’ partition to the NOM in this study. The effects of solution property, NOM characteristics, and modification by ozone preoxidation on pyrene partition to NOM were systematically evaluated. According to the fluorescence quenching method, the partition coefficient K _oc of pyrene to NOM was calculated, which was found to have a great relationship with the aromatic structures and hydrophobic functional groups of the NOM. The NOM characteristic modification corresponding to solution property could influence the interactions between the NOM and pyrene. Preozonation could destroy the aromatic or hydrophobic structures of the NOM and decrease K _oc of pyrene.