高浓度六价铬的两种测定方法比较

比较分析了饮用水及污水中高浓度六价铬的两种测定方法.实验结果表明,硫酸亚铁铵滴定法适合于高浓度六价铬废水中总铬的测定,重铬酸钾法适合于直接测定高浓度六价铬含量.     

QUAL2K模型的生化需氧量指标研究

QUAL2K模型是由美国环境保护署研制开发的一维河流水质模型,被广泛应用于北美、欧洲、亚洲等地的流域污染物总量控制和水质管理。由于国内与美国的水质评价指标不同,导致该模型在国内无法直接进行水质模拟与评价,如美国采用的生化水质指标是CBODu、CBODs和CBODf,而国内采用的是BOD5、CODCr和CODMn。为了促进该模型在国内的推广及应用,从有机物的生物氧化过程、生化需氧量的定义及其检测方法出发,对BOD5与CBODu两者之间的关系进行研究,推导出BOD5与CBODu的转换公式。     

长江河口九段沙中沙互花米草湿地植物-土壤间营养元素含量灰色关联分析

于2005年5—12月,采用GPS定位,逐月对长江河口九段沙中沙的互花米草(Spartina alterniflora)湿地植物样品与土壤样品进行采集,分析植物与土壤中的w(N),w(P)和w(K)并研究其动态变化.利用灰色关联分析方法,对湿地植物与土壤中w(N),w(P)和w(K)的时空分布进行了研究,旨在探明互花米草生长过程中对不同深度土壤营养元素与不同种类营养元素的吸收程度.结果表明,灰色关联分析是湿地生态系统植物与土壤营养元素动态关系研究的行之有效的方法.互花米草的生长与上层土壤(0～≤15 cm)中的w(N)、中层土壤(15～≤40 cm)中的w(K)和下层土壤(40～60 cm)中的w(P)关联密切.互花米草与上层、中层和下层土壤中营养元素的关联序分别为N>P>K,N>K>P和P>N>K.在互花米草整个生长过程中,初期植物-土壤间营养元素的关联较小;旺盛生长期,植物-土壤间N和P元素的关联度大,K元素的关联度小;生长末期,植物-土壤间K元素关联度增强.     

Effects of different sludge disintegration methods on sludge moisture distribution and dewatering performance

A key step in sludge treatment is sludge dewatering. However, activated sludge is generally very difficult to be dewatered. Sludge dewatering performance is largely affected by the sludge moisture distribution. Sludge disintegration can destroy the sludge structure and cell wall, so as change the sludge floc structure and moisture distribution, thus affecting the dewatering performance of sludge. In this article, the disintegration methods were ultrasound treatment, K2 Fe O4oxidation and KMn O4 oxidation. The degree of disintegration(DDCOD), sludge moisture distribution and the final water content of sludge cake after centrifuging were measured. Results showed that three disintegration methods were all effective, and K2 Fe O4oxidation was more efficient than KMn O4 oxidation. The content of free water increased obviously with K2 Fe O4and KMn O4 oxidations, while it decreased with ultrasound treatment. The changes of free water and interstitial water were in the opposite trend. The content of bounding water decreased with K2 Fe O4oxidation, and increased slightly with KMn O4 oxidation, while it increased obviously with ultrasound treatment. The water content of sludge cake after centrifuging decreased with K2 Fe O4oxidation, and did not changed with KMn O4 oxidation, but increased obviously with ultrasound treatment. In summary, ultrasound treatment deteriorated the sludge dewaterability, while K2 Fe O4and KMn O4 oxidation improved the sludge dewaterability.     

基于Shapley值的农村非政府应急组织激励模型构建

农村非政府应急组织是以共同应对农村突发事件为纽带自愿结成的互助性合作联盟,成员间的利益分配关系是组织生存与发展的重要基础。而Shapley值法正是解决多人合作利益分配问题的一种简便易行的数学方法。基于Shapley值法构建农村非政府应急组织利益分配激励模型能较好地促进其成员间的信任、合作与共享信息,使其收益透明化,有助于全面提升应急服务效益和充分发挥应急服务功能。首先,介绍了基于Shapley值法构建农村非政府应急组织激励模型的研究现状,然后初步探索了构建步骤及其实施建议,以进一步促进农村非政府应急组织的稳定运行与健康发展。     

低浓度VOCs废气处理技术进展

叙述了低温等离子体、光催化和生物处理三种新技术的废气净化原理和国内外研究进展情况,并对其发展前景和研究方向进行了探讨.这些新技术不但可有效解决以往的技术难题,而且具有投资少、运行费用低、停留时间短、高效、稳定、反应彻底且无二次污染等,克服了传统方法中的许多缺陷,将在低浓度VOCs废气治理方面发挥重要的作用.     

非热平衡等离子体处理VOCs的研究

非热平衡等离子体技术在处理挥发性有机物(VOCs),特别是低浓度VOCs治理方面具有重要作用.介绍了非平衡等离子体产生的方法、处理VOCs的机理以及几种放电方法在脱除VOCs方面的研究现状和成果,最后探讨了非平衡等离子体发展的趋势.     

非离子表面活性剂在人工光源辐照下的光催化降解

在光催化氧化对5种典型非离子表面活性剂（NIS）和实际印染废水中NIS的去除效果的实验中,未见TiO₂有明显催化作用．光解30min,几种NIS的光降解率均达60％以上．NIS的光降解速率受NIS浓度和DO的影响较小;pH值降低有利于NIS的光降解,而在中性或弱酸性条件下,NIS光降解效率仍较好;投加H₂O₂可提高NIS的光降解速率,最适投加量为4.4×10^-4mol/L．对于实际印染废水,NIS的光降解去除率比生化法高且处理时间短得多,同时对COD、MBAS亦有较好的去除效果,表明光催化氧化是一项很有前途的NIS处理技术．     

水稻籽粒镉积累模型

通过文献调研与分析,建立了水稻籽粒镉含量(CdR,mg/kg)与土壤全镉含量(CdT,mg/kg)、pH值及有机质含量(SOM,g/kg)关系的统计模型:CdR=0.560 exp[0.995 log(CdT)-0.173 pH 0.018 SOM](决定系数R2=0.62,P＜0.001,n=156).相关分析和残差分析结果表明,该模型具有较好的解释性,可用于水稻籽粒镉含量的估算.     

Pollution profiles and physicochemical parameters in old uncontrolled landfills

The long-term effectiveness of the geological barrier beneath municipal-waste landfills is a critical issue for soil and groundwater protection. This study examines natural clayey soils directly in contact with the waste deposited in three landfills over 12 years old in Spain. Several physicochemical and geological parameters were measured as a function of depth. Electrical conductivity (EC), water-soluble organic carbon (WSOC), Cl⁻, NH₄⁺, Na⁺ and exchangeable NH₄⁺ and Na⁺ were used as parameters to measure the penetration of landfill leachate pollution. Mineralogy, specific surface area and cationic-exchange capacities were analyzed to characterize the materials under the landfills. A principal component analysis, combined with a Varimax rotation, was applied to the data to determine patterns of association between samples and variables not evident upon initial inspection. The main factors explaining the variation in the data are related to waste composition and local geology. Although leachates have been in contact with clays for long time periods (13-24 years), WSOC and EC fronts are attenuated at depths of 0.2-1.5 m within the clay layer. Taking into account this depth of the clayey materials, these natural substrata (>45% illite-smectite-type sheet silicates) are suitable for confining leachate pollution and for complying with European legislation. This paper outlines the relevant differences in the clayey materials of the three landfills in which a diffusive flux attenuation capacity (A_c) is defined as a function (1) of the rate of decrease of the parameters per meter of material, (2) of the age and area of the landfill and (3) of the quantity and quality of the wastes.