Understanding the sources and composition of the incremental excess of fine particles across multiple sampling locations in one air shed

Well-designed health studies and the development of effective regulatory policies need to rely on an understanding of the incremental differences in particulate matter concentrations and their sources. Although only a limited number of studies have been conducted to examine spatial differences in sources to particulate matter within an air shed, routine monitoring data can be used to better understand these differences. Measurements from the US EPA Chemical Speciation Network （CSN） collected between 2002-2008 were analyzed to demonstrate the utility of regulatory data across three sites located within 100 km of each other. Trends in concentrations, source contribution, and incremental excesses across three sites were investigated using the Positive Matrix Factorization model. Similar yearly trends in chemical composition were observed across all sites, however, excesses of organic matter and elemental carbon were observed in the urban center that originated from local emissions of mobile sources and biomass buming. Secondary sulfate and secondary nitrate constituted over half of the PM2.5 with no spatial differences observed across sites. For these components, the excess of emissions from industrial sources could be directly quantified. This study demonstrates that CSN data from multiple sites can be successfully used to derive consistent source profiles and source contributions for regional pollution, and that CSN data can be used to quantify incremental differences in source contributions of across these sites. The analysis strategy can be used in other regions of the world to take advantage of existing ambient particulate matter monitoring data to better the understanding of spatial differences in source contributions within a given air shed.     

Isolation, identification and arsenic-resistance of Acidithiobacillus ferrooxidans HX3 producing schwertmannite

Schwertmannite, a ubiquitous mineral present in iron oxyhydroxides formed in iron- and sulfate-rich acid media, favors incorporation of some toxic anions in its structure. We reported an iron-oxidizing bacterial strain HX3 from a municipal sludge that facilitates the formation of pure schwertmannite in cultures. Ferrous iron oxidation by the isolated strain HX3 was optimum at an initial pH of 2.0-3.3 and temperature of 28-35°C. Pure schwertmannite was found through bacterial oxidation of ferrous iron at an initial pH 2.8and temperature 28°C. Following 16 S rDNA gene sequence analysis the bacterial strain HX3 was identified as Acidithiobacillus ferrooxidans. The arsenic-resistance A. ferrooxidans HX3 showed the potential of environmental application in arsenic removal from the As（Ⅲ）- and iron-rich acid sulfate waters directly by As（Ⅲ） adsorption or the formation of schwertmannite in the environment.     

2016—2020年云南省主要城市酸雨污染特征及趋势分析

为评价云南省酸雨的污染特征及变化趋势,收集了2016—2020年云南省21个主要城市连续5 a的降水监测数据,利用spearman秩相关系数法分析了云南省"十三五"期间城市酸雨污染的变化趋势,并与"十二五"末期进行对比,结果表明:5 a降水pH平均值均高于5.6,呈逐年上升趋势;酸雨发生频率呈逐年下降趋势;总体上酸雨污...     

硫氮沉降下西北荒漠煤矿区周边土壤性质的变化特点

近年来中国大部分区域大气硫、氮沉降速率趋于平稳甚至下降,但西北地区煤炭行业的快速发展使得硫、氮沉降速率加快.燃煤电厂作为酸前体物的主要排放源之一,在其周围开展硫、氮沉降效应研究,可为合理评价煤矿区大气污染物控制措施的实施效果提供数据支撑.该文以宁东能源化工基地3个燃煤电厂为采样点,研究了电厂周围土壤化学和生物学性质的变...     

生物酸化污泥回用在批式运行的污泥生物淋滤工艺中的效果

以制革污泥为对象,利用上批淋滤结束后的生物酸化污泥既含大量微生物又具有较强酸度的特点,用其回流以达到使原始污泥预酸化和接种微生物的双重效果,建立用生物淋滤技术序批式处理制革污泥的工艺.用硫酸调节原始污泥pH至5.5左右,接入质量分数为20%的菌种和0.4%的能源物质进行污泥中重金属的生物淋滤处理,取淋滤过程不同阶段中pH3.5、3.0、2.5、1.95的生物酸化污泥作菌种,同时用硫酸对待处理污泥预酸化进行下批生物淋滤处理.此外,采用刚淋滤结束的pH1.95的生物酸化污泥代替硫酸进行污泥的预酸化和接种.结果表明,用淋滤过程中pH3.5～1.95的生物酸化污泥作菌种,污泥的pH值都能够下降到2.0以下,而且不同pH值的生物酸化污泥作菌种的淋滤效果差异并不显著,说明淋滤过程中pH在3.5以下的污泥都可以作为菌种,接入到下一批次待处理的污泥中进行生物淋滤.连续6批次的污泥淋滤试验表明,用刚淋滤结束的pH<2的生物酸化污泥回流既能完全代替浓硫酸对原始污泥进行预酸化,并又兼有接种作用.每批处理4d均能稳定完成淋滤过程.因此,工程应用中只需在待处理污泥中添加上批淋滤结束的酸化污泥便可,使生物淋滤持续批式运行,大大简化了处理工艺.     

以pH和ORP作为脉冲SBR工艺的实时控制参数

为了实现脉冲SBR深度脱氮的实时控制,以某污水处理厂市政污水为处理对象,考察了脉冲SBR在深度脱氮过程中pH及ORP的变化规律.试验结果表明,pH及ORP的变化规律与脉冲SBR有机物去除、硝化与反硝化过程存在较好的相关关系.可以根据pH和ORP变化曲线上的特征点对脉冲SBR进行实时控制.并考察了污水C/N(COD/NH4 -N)对pH及ORP的变化规律的影响.在硝化过程中,C/N对pH及ORP曲线变化点的出现没有影响;在反硝化过程中,应结合pH值"硝酸盐峰"和ORP"硝酸盐膝"来判断低C/N污水反硝化的终点.在该试验中,出水TN低于2 mg/L,TN去除率可达到96%以上.     

论温室气体的科学特征与法律属性

人为原因造成的温室气体过量排放是导致全球气候变化的主要原因,为此全球已在国际法和国内法等诸多层面对温室气体排放进行管控。在科学属性上,二氧化碳是主要的温室气体的主要类型,其他类型气体都有通过全球升温潜值(GWP)换算为二氧化碳单位。在法律属性上,无论在气候变化国际法,还是在主要国家的国内法层面,尚未将温室气体作为主要的大气污染物类型。碳排放交易制度是管控温室气体排放的重要制度型工具,其有效实施有赖于在科学层面对温室气体的深入探索,以及在法律层面对这类气体法律属性的有效界定。     

pH值调控对电镀废水处理的影响

采用化学沉淀法处理电镀废水时，pH值的调控至关重要。文中以电镀工厂排放的酸性含铜废水为实验研究对象，用氢氧化钠调控溶液的pH值，测定上清液中Cu^2＋含量与pH值的关系；通过实验数据与理论计算，分析阐明了pH值调控对出水中二价铜离子含量的影响，给出了怎样合理调控pH值以使废水处理效果最佳的建议。     

测定总氮时影响空白吸光值的因素

针对测定水质中总氮时遇到实验空白值偏高的情况，分析了实验用水、试验及环境因素对空白值的影响。     

pH,H_2及H_2S对厌氧消化有机物降解的影响研究

本文研究了不同负荷条件下猪粪厌氧消化过程中pH值、氢气和硫化氢对于有机物降解的影响。结果表明,氢气的浓度变化从1-27ppm,硫化氢的浓度从900-3800ppm,系统的pH值则保持相对的温度。一级动力学模型能够很好的预测厌氧消化有机物的降解过程,三种因子对于有机物降解动力学的影响顺序为pH>H_2>H_2S。同时随着负荷的升高,pH值和氢气对厌氧消化的影响增大,而硫化氢则没有明显变化。