成都市郊区域农田中土壤镉形态研究

农田土壤是镉生态循环的重要介质，所含镉对人体健康的危害不可忽视。镉在土壤中以多种形态存在．可划分为水溶态、离子交换态，碳酸盐结合态、Fe及Mn氧化物结合态，有机结合态、残留态。不同存在形态镉的生物有效性各不相同，因而对环境和人体健康造成的影响也存在差异。水溶态镉，离子交换态镉具有很高的生物有效性。碳酸盐结合态镉在弱酸性条件下生物有效性较高，Fe及Mn氧化物结合态镉、有机结合态镉、残留态镉生物有效性很低。本研究采用连续提取法和原子吸收法对成都市某郊区基本农田的35份土壤样品中各形态镉进行了提取和测定。结果表明。成都市某郊区农田土壤的镉污染状况较为严重，37．14％的土壤含高生物有效性的水溶态镉或离子交换态镉。土壤中水溶态镉、离子交换态镉的存在与环境污染有密切联系。Fe及Mn氧化物结合态镉，有机结合态镉、残留态镉的存在受耕作因素和成土母质影响较大。     

曝气生物活性炭滤池深度处理垃圾渗滤液的效能研究

为了考察曝气生物活性炭滤池(BACF)深度处理垃圾渗滤液的效能,研究了填料填充度、曝气位置、气水比、水力停留时间和p H等影响因素对滤池去除有机物、氨氮和总氮的影响。结果表明,最佳的工艺运行条件为:填料填充度为80%,底部曝气,气水比为3:1,水力停留时间为8 h,p H为7~8。在最佳工艺条件下运行反应器,COD、氨氮和TN平均去除率分别达到85%、90%和57%,出水可达到实验设定水质要求。BACF具有较强的抗有机负荷能力,进水COD浓度在323至3 000 mg/L之间时,COD去除率稳定在80%。反应器受氨氮冲击负荷影响较大,氨氮进水浓度低于90mg/L时,出水可达到要求。     

生物脱氮组合工艺的研究及应用

为处理高浓度含氮废水,提出生物脱氮组合工艺,首先介绍3种生物脱氮技术原理,同时对其进行比较分析,找出现有技术在实际应用中存在的不足,从而归纳出生物脱氮组合工艺,即"短程硝化+厌氧氨氧化+反硝化"。该组合工艺可去除废水中各种形式的氮,且去除1 mol氨态氮消耗0.75 mol氧气。实际应用中总氮去除率最高可达87.5%,氨氮去除率最高可达91.8%。     

生化法净化低浓度挥发性有机废气的动力学模式研究

针对目前国际上常用的吸收－生物膜理论，在描述生化法净化低浓度挥发性有机废气机理过程中的存在问题，提出了吸附－生物膜的新理论，并依据这一新理论建立了生物膜填料塔净化低浓度甲苯废气的动力学模式。实验结果表明，其模拟计算值与实验值之间有很好的相关性，相关系数Ｐ〉０．９３，利用这一新理论及模式，可由已知操作参数对生物膜填料塔的净化效果进行预测计算，也能为有关的理论研究和实际操作提供参考。     

Recent improvements in oily wastewater treatment: Progress, challenges, and future opportunities

Oily wastewater poses significant threats to the soil, water, air and human beings because of the hazardous nature of its oil contents. The objective of this review paper is to highlight the current and recently developed methods for oily wastewater treatment through which contaminants such as oil, fats, grease, and inorganics can be removed for safe applications. These include electrochemical treatment, membrane filtration, biological treatment, hybrid technologies, use of biosurfactants, treatment via vacuum ultraviolet radiation, and destabilization of emulsions through the use of zeolites and other natural minerals. This review encompasses innovative and novel approaches to oily wastewater treatment and provides scientific background for future work that will be aimed at reducing the adverse impact of the discharge of oily wastewater into the environment. The current challenges affecting the optimal performance of oily wastewater treatment methods and opportunities for future research development in this field are also discussed.     

上海江湾机场植物群落多样性研究

以市区内江湾机场失去管理后出现的自然植被为研究对象，通过群落学调查研究，分析了群落的种类组成以及结构特征，阐明了群落的恢复过程和潜力。结果表明，江湾机场的植被可划分为4个外貌类型，16个群落类型。自然植被表现为以草本群落为主、辅以少量木本植物群落为特征的分布格局。非地带性因素主导着植被发生和演替，很难达到上海以亚热带常绿阔叶林为主的地带性植被类型。     

厌氧折流板反应器处理垃圾渗滤液的试验研究

试验所用废水取自于已经封场多年的广州市大田山垃圾填埋场的渗滤液,其方法是对比原有的ABR工艺与在原有的ABR工艺中加入生物接触氧化池进行可行性试验研究,以求达到更好的处理效果.研究结果表明,组合新工艺可使进水的CODCr去除41%,NH3-N去除17%,比原有单一工艺的处理效果好,从而减少了后续工艺的处理负荷.     

曝气生物滤池用于分散型污水处理及其动力学浅析

将曝气生物滤池用于分散型污水处理,分析了反应器在不同水力负荷条件下对污染物的去除效果,同时从动力学角度对反应器作了浅析,总结出一个动力学模型.实验证明,该模型对出水水质预测和水力负荷条件的确定具有一定的工程实践指导作用.     

Metals in biomass

Background, Aim and Scope

Metal ions generally share the ability/tendency of interacting with biological material by forming complexes, except possibly for the heavy alkali metals K, Rb and Cs. This is unrelated to the metals being either essential for sustaining life and its reproduction, apparently insignificant for biology, although perhaps undergoing bioconcentration or even being outright toxic, even at low admission levels. Yet, those different kinds of metal-biomass interactions should in some way depend on properties describing coordination chemistries of these very metals. Nevertheless, both ubiquitously essential metals and others sometimes used in biology should share these properties in numeric terms, since it can be anticipated that they will be distinguished from nonessential and/or toxic ones. These features noted above include bioconcentration, the involvement of metal ions such as Zn, Mg, Cu, Fe, etc. in biocatalysis as crucial components of metalloenzymes and the introduction of a certain set of essential metals common to (almost) all living beings (K, Mg, Mo, Mn, Fe, Cu and Zn), which occurred probably very early in biological evolution by ‘natural selection of the chemical elements’ (more exactly speaking, of the metallomes).

Materials and Methods

The approach is semiempirical and consists of three consecutive steps: 1) derivation of a regression equation which links complex stability data of different complexes containing the same metal ion to electrochemical data pertinent to the (replaced) ligands, thus describing properties of metal ions in complexes, 2) a graphical representation of the properties-two typical numbers c and x for each metal ion-in some map across the c/x-space, which additionally contains information about biological functions of these metal ions, i.e. whether they are essential in general (e.g. Mg, Mn, Zn) or, for a few organisms of various kinds (e.g. Cd, V), not essential (e.g. rare earth element ions) or even generally highly toxic (Hg, U). It is hypothesized that, if coordination properties of metals control their biological ‘feasibility’ in some way, this should show up in the mappings (one each for mono and bidentate-bonding ligands). 3) eventually, the regression equation produced in step 1) is inverted to calculate complex stabilities pertinent to biological systems: 3a) complex stabilities are mapped for ligands delivered to soil (-water) by green plants (e.g. citrate, malate) and fungi and, compared to their unlike selectivities and demands of metal use (photosynthesis taking place or not), 3b) the evolution of the metallome during late chemical evolution is reconstructed.

Results

These maps show some ‘window of essentiality’, a small, contrived range/area of c and x parameters in which essential metal ions gather almost exclusively. c and x thus control the possibility of a metal ion becoming essential by their influencing details of metal-substrate or (in cases of catalytic activities) metal-product interactions. Exceptions are not known to be involved in biocatalysis anyhow.

Discussion

Effects of ligands secreted, e.g. from tree roots or agaric mycelia to the soil on the respective modes (selectivities) of metal bioconcentration can be calculated by the equation giving complex stability constants, with obvious ramifications for a thorough, systematic interpretation of biomonitoring data. Eventually, alterations of C, N and P-compounds during chemical evolution are investigated — which converted CH₄ or CO₂, N₂ and other non-ligands to amino acids, etc., for example, with the latter behaving as efficient chelating ligands: Did they cause metal ions to accumulate in what was going to become biological matter and was there a selectivity, a positive bias in favour of nowessential metals (see above) in this process? Though there was no complete selectivity of this kind, neither a RNA world in which early ribozymes effected most of biocatalysis, nor a paleoatmosphere containing substantial amounts of CO could have paved the way to the present biochemistry and metallomes.

Conclusions

This way of reasoning provides a causal account for abundance distributions described earlier in the Biological System of Elements (BSE; Markert 1994, Fränzle &; Markert 2000, 2002). There is a pronounced change from chemical evolution, where but few transformations depended on metal ion catalysis to biology.

Recommendations and Perspectives

The application of this numerical approach can be used for modified, weighted evaluation of biomonitoring analytical data, likewise for the prediction of bioconcentration hazards due to a manifold of metal ions, including organometallic ones. This is relevant in ecotoxicology and biomonitoring. In combining apoproteins or peptides synthesized from scratch for purposes of catalysing certain transformations, the map and numerical approaches might prove useful for the selection of central ions which are even more efficient than the ‘natural’ ones, like for Co²⁺ in many Zn enzymes.

     

UV-H2O2 based AOP and its integration with biological activated carbon treatment for DBP reduction in drinking water

The presence of disinfection byproducts (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs) in drinking water is of great concern due to their adverse effects on human health. Emerging regulation limiting the concentration of DBPs in drinking water has increased demands for technologies and processes which reduce the formation of DBPs in drinking water. In this study, UV-H₂O₂ based advance oxidation process (AOP) was used to treat raw surface water. Experiments were conducted using low pressure mercury vapor UV lamps in collimated beam and flow-through annular photoreactors. The effect of UV fluence (0–3500 mJ cm⁻²) and hydrogen peroxide concentration (0–23 mg l⁻¹) in reducing the concentration of THMs and HAAs was examined. The UV-H₂O₂ AOP was then coupled with a downstream biological activated carbon (BAC) treatment to assess the synergetic benefits of combining the two treatments. It was observed that UV-H₂O₂ AOP was only effective at reducing DBPs at UV fluences of more than 1000 mJ cm⁻²and initial H₂O₂ concentrations of about or greater than 23 mg l⁻¹. However, the combined AOP–BAC treatment showed significant reductions of 43%, 52%, and 59% relative to untreated raw water for DBPs, TOC, and UV₂₅₄, respectively.