大气污染控制有效性的评估模型及应用

基于小波分析理论及BP神经网络,建立了大气污染控制有效性的评估模型.利用该模型解析天津市污染源排放及气象因素对大气污染物环境浓度的影响.结果表明,SO2浓度波动主要由污染源的季节变化引起,与天气过程有关的短期波动也不容忽视;而PM10浓度波动主要由污染源排放及气象条件的短期变化引起.2002~2003年的气象条件总体上不利于大气扩散,使SO2日均浓度长期分量增加约为3μg/m3;而2004年的气象条件有利于大气扩散,使SO2日均浓度长期分量减小约为5μg/m3.PM10日均浓度长期分量也有类似的规律,2002~2003年的不利气象条件使PM10日均浓度长期分量增高更显著,约为10μg/m3.     

Evaluation of the effectiveness of horizontal subsurface flow constructed wetlands for different media

Two media bed (gravel and Filtralite NR) were tested in a mesocosm to evaluate the removal of organic matter (as chemical oxygen demand (COD)),ammonia (NH4-N),nitrite,nitrate and solid matter (as total suspended solids (TSS)) for a synthetic wastewater (acetate-based) and a domestic wastewater.The use of Filtralite allowed average removal rates (6–16.8 g COD/(m2·day),0.8–1.1 g NH4-N/(m2·day) and 3.1 g TSS/(m2·day)) and removal effciencies (65%–93%,57%–85% and 78% for COD,NH4-N and TSS,respectively),higher than that observed in the experiments with gravel.The applied loads of COD,ammonia,nitrate and TSS seem to influence the respective removal rates but only for the treatment of domestic wastewater with higher correlation coefficients for Filtralite.Regardless the type of media bed and the type of wastewater,nitrate was completely removed for nitrogen loading rates up to 1.3 g NO3-N/(m2·day).There was no evidence of the influence of nitrate loads on the removal of organic matter.     

浅层平铺炭质吸附剂治理多氯联苯污染底泥的有效性评价研究

以颗粒活性炭和粉末活性炭为修复剂,并对其表面性质进行了表征.同时,应用三维荧光光谱、半透膜被动采样装置(SPMDs)和低密度聚乙烯膜(LDPEs)被动采样3种方法评价其治理多氯联苯污染底泥的效果.三维荧光实验结果表明,到第3个月,底泥修复开始显现了比较明显的效果,溶解性污染物明显减少.SPMDs试验结果显示,颗粒活性炭和粉末活性炭修复的底泥在修复后的第5个月,其目标污染物PCB40被摄取量的减少率分别达到88%和70%,LDPEs相应结果达到了91%和83%.试验表明,炭质吸附剂浅层平铺修复污染底泥效果显著,且颗粒炭比粉末炭修复效果更好.     

APEC会议期间北京市交通扬尘控制效果研究

为了评估APEC会议期间严格的交通扬尘控制措施的效果,选取北京地区不同类型道路,在会议之前和会议期间分别采集40个道路积尘负荷样品,并调研了道路车流量及车型比例等机动车活动水平变化.采用AP-42方法计算不同类型道路PM10排放因子和排放强度,基于Arc GIS平台应用自下而上的方法建立了排放清单,分析交通扬尘PM10排放的空间分布特征,评估APEC会议期间北京市道路交通扬尘控制效果.结果表明:APEC会议期间北京市日均车流量减少12%,快速路、主干道、次干道、支路、郊区道路的积尘负荷分别下降31%、58%、73%、54%和46%,PM10排放因子分别下降63%、67%、86%、63%和40%,排放强度分别下降73%、71%、87%、78%和49%.在空间分布上,城区道路交通扬尘PM10排放量减少77%,郊区道路减少49%.     

基于土壤中多环芳烃解吸特性的生物修复效果评价

采用XAD-2树脂辅助解吸方法测试了生物堆修复前后土壤中荧蒽、苯并(a)蒽、苯并(a)芘、苯并苝这4种PAHs的解吸特性,并根据解吸结果进行了生物修复效果评价.结果表明,土壤中这4种PAHs的累计解吸量随解吸时间延长而增加,但解吸速率逐渐降低,符合"两阶段"解吸模型,生物修复前土壤中不同种类PAHs"快解吸"量占PAHs总量的32%～70%,修复后土壤中不同种类PAHs"快解吸"量占PAHs总量的14%～39%.经过6个月的生物修复,基于生物可利用含量变化的荧蒽、苯并(a)蒽、苯并(a)芘、苯并苝修复效率依次为82.9%、79.7%、64.9%、54.3%,,明显高于基于PAHs总含量的生物修复效率61.0%、51.7%、37.2%、38.7%.     

Evaluation of the effectiveness of low frequency workpiece vibration in deep-hole micro-EDM drilling of tungsten carbide

The application of micro-electrical discharge machining (micro-EDM) in deep-hole drilling is still limited due to the difficulty in flushing of debris and unstable machining. Present study introduces a simplistic analytical model to evaluate the effectiveness of low frequency workpiece vibration during the micro-EDM drilling of deep micro-holes. In addition, experimental investigation has been conducted to validate the model by studying the effects of workpiece vibration on machining performance, surface quality and dimensional accuracy of the micro-holes. The effect of vibration frequency and amplitude for three different settings of aspect ratios has been studied experimentally. Moreover, the vibration experiments have been conducted at different levels of gap voltages and capacitances in order to understand the effect of electrical parameters and effectiveness of low-frequency workpiece-vibration at different levels of discharge energies. It has been shown analytically that the effectiveness of low frequency workpiece vibration during micro-EDM drilling can be evaluated by a parameter ‘K_v’ (ratio of maximum acceleration of the vibrating plate in gravitational direction to gravitational acceleration ‘g’), which can be determined from the vibration frequency, amplitude and phase angle of the vibrating workpiece. The theoretical model reveals that for K_v > 1, the position of debris particles will be above the workpiece; thus can be flushed away from machined zone effectively. The experimental reasons for improved micro-EDM drilling performance at the setting of K_v > 1 are found to be the increased effective discharge ratio, reduced short-circuits and improved dielectric flushing. The experimental results also reveal that the low frequency vibration is more effective at the low discharge energy level, thus making it more suitable for micro-EDM. Considering the effect on both the machining characteristics and micro-hole accuracy parameters, vibration frequency of 750 Hz and amplitude of 1.5 μm was found to provide improved performance for the developed vibration device.     

平板显示器回收的新挑战

显示屏（监视器和电视机）经历了从阴极射线管到平板显示器技术的快速变化。截至目前为止,只有少量的平板显示器已记录在废物收集点。平板显示器的数量越来越多,在未来需要足够的用于回收的基础设施。本文旨在通过液晶显示屏幕的回收对经济影响的案例研究来提供数量、成分、回收利用技术和经验的基本数据。对于组件和材料也适用于其他类型的电子产品,如黑色金属和有色金属,印刷电路板或电缆,回收途径和技术是众所周知的和可用的。目前,液晶显示器（LCD）在欧洲不回收。处置时,例如,通过焚烧,有价值的材料,其成分是不再可用。例如：铟具有重要战略意义的应用,如,太阳能光伏作为一种稀缺资源。液晶显示器在欧洲具有回收基础设施,因此是有用的。     

Evaluating the long-term effectiveness of the Phoenix IM240 program

In an earlier analysis of the Phoenix Enhanced I/M program, we found that the effectiveness of the program decreased in the few months following final I/M testing. In this analysis we tracked individual cars over two successive I/M cycles. We find that 60% of cars that failed their initial I/M test and eventually passed a retest (presumably after repairs) passed their next biennial I/M test. However, 40% failed their next biennial test. Half of these repeat failures failed for the same combination of pollutants in each I/M cycle, suggesting that repairs were never made or were somehow deficient. More importantly, emissions of cars that passed their initial test in the first cycle increased dramatically over the two years between I/M tests; most of this increase came from older cars. This suggests that more frequent testing of older vehicles could make I/M programs more effective. The net result is that the overall emission reductions from a given fleet of cars over two biennial I/M cycles appear to have been rather small, less than 10% for each pollutant. These emission reductions are the minimum attributable to the program; reductions from what emissions would have been without the I/M program would likely have been greater. In addition, large numbers of failing cars did not appear to be completing program requirements, further limiting program effectiveness. And cars immigrating into the area from other states appeared to have slightly higher emissions than the native car fleet. I/M program managers should conduct similar analyses to determine how effective their programs are in reducing emissions, and how to address identified shortcomings.     

Field testing of the effectiveness of bacterial fertilizer in Nepal

In Nepal, where fertilizer is badly needed to replenish the severely eroded soil, nitrogen-fixing bacterial inocula were tested in field trial studies in various localities. Inocula of Azospirillum brasilense and Azotobacter chroococcum were prepared in carrier mixtures of soil and cattle manure. Field trials using these bacterial fertilizers were performed on rice, wheat, and maize over a period of 3 years.Azospirillum inoculum on rice seedlings increased yield by an average of 29.4%, from about 2.1–2.8 Mt ha⁻¹, statistically significant at the 1% level. The effects of Azospirillum on wheat and Azotobacter on maize were not statistically significant at the 5% level, nor were the effects of other compared treatments, namely, urea, compost and green manure. Since the coefficients of variation were high and the sample sizes were small, more trials and replications should be done to establish reliable conclusions.     

Investigation on the effectiveness of pretreatment in stormwater management technologies

The effectiveness of presettling basins as component of stormwater best management practice （BMP） technologies was investigated. Storm event monitoring and sediment collection were conducted from May 2009 to November 2012 on the presettling basins of the three BMP technologies designed to capture and treat stormwater runoff from highly impervious roads and parking lots. Data on captured runoff and sediment, total suspended solids （TSS） loadings, rainfall and runoff rate, sediment accumulation rate, as well as particle distribution and pollutant concentrations of sediment were gathered and analyzed along with the physical design characteristics of the presettling basins such as surface area and storage volume. Regression models were generated to determine significant relationships between design parameters. Results revealed that the storage volume ratio （ratio of storage volume of presettling basin to BMP） was an important parameter in designing the presettling basin of the BMP. For practicality, optimizing the design of the presetfling basin means that the storage volume ratio should be determined based on the desired captured amount of runoff and sediment from runoff to limit the frequency of maintenance caused by the accumulation of sediment. It was recommended that pretreatment of runoff should be employed when the site in which the BMP is to be sited has high TSS loading and runoff rate, and is subjected to high intensity rainfall.     

建设项目环境监理工作有效性管理的探讨

透视建设项目环境监理发展的历程,环境保护工作的伟力与孱弱并存本文就是针对这方面问题展开论述,探讨有效的管理措施,以便为建设项目环境监理工作提供参考。     

基于AHP-模糊综合评价法的城市排水管网状态和运行效能评价—以淮安市淮安区为例

掌握排水管网的建设状态及运行状况,有利于有针对性地制定排水管网养护与修复决策。构建了基于服务性能、建设状态、维护管理的包含14项指标的城市排水管网状态和运行效能评价指标体系,并结合层次分析法（AHP）-模糊综合评价法,对淮安市淮安区管网的状态和运行效能进行了综合评价。结果表明：影响淮安区排水管网状态和运行效能的因素主要为生活污水集中收集率、雨污分流比、污水处理率和管网维护水平,这4项指标权重之和大于另外10项指标的权重之和;淮安区排水管网综合评价水平为中等偏上,其中排水管网的服务性能以及维护管理处于中等偏上水平,建设状态处于中等偏下水平。结合淮安区管网普查的结果,提出在日后的管网维护工作中,应重点开展管网病害和管道缺陷治理。

     

土石山区小流域土壤磷素的空间分布特征与有效性

以汉江余姐河小流域为研究区域,运用经典统计学与地统计学方法,分析流域不同土地利用类型下表层(0~20 cm)土壤全磷和速效磷的空间分布特征及磷素有效性.结果表明:流域农地、林地和草地土壤全磷含量平均值分别为0.368 g·kg~(-1)、0.347 g·kg~(-1)和0.348 g·kg~(-1),土壤速效磷含量均值分别为17.52 mg·kg~(-1)、19.23 mg·kg~(-1)和17.90 mg·kg~(-1).土壤全磷和速效磷空间分布的最优模型均为高斯模型且均具有中等空间相关性.克里格插值表明研究区土壤全磷呈斑块状分布,速效磷含量的高值区沿河流呈网状分布,尤其是速效磷含量为10~20 mg·kg~(-1)和20~30 mg·kg~(-1)的区域从流域上游至下游以河流为主线依次连通.经ANOVA检验,土地利用类型对土壤全磷和速效磷的空间分布影响不显著(p0.05),不同土地利用下每平方米土壤全磷含量表现为草地农地林地,分别为0.092 kg·m~(-2)、0.089 kg·m~(-2)和0.087 kg·m~(-2),速效磷含量表现为草地林地农地,分别为4.67 g·m~(-2)、4.11 g·m~(-2)和3.89 g·m~(-2),流域土壤磷素的有效性呈现出林地草地农地的特征.     

Ensuring the environmental effectiveness of linked emissions trading schemes over time

Linking emissions trading schemes allows the combined emissions cap to be achieved at lower cost. Linking is usually environmentally neutral, but some design features can lead to higher aggregate emissions if schemes are linked. Technical solutions to limit the potential emissions increases due to design differences implemented when schemes are linked are not sufficient to ensure the environmental effectiveness of the linked schemes over time. Technological, economic, administrative and other changes that can lead to higher aggregate emissions are inevitable. The administrators of the linked schemes must ensure the stringency of the emissions cap relative to the “business as usual” emissions of affected sources, the accuracy of the emissions reported by affected sources, the integrity of the allowance registry, effective compliance enforcement, and the environmental integrity of the credits issued for emission reduction projects over time. This will require a process for agreeing on revisions to the regulations of the linked schemes, a mechanism to provide assurance of the environmental effectiveness of each of the linked schemes, and a procedure for terminating the linking agreement.

Policy effectiveness and acceptance in the taxation of environmentally damaging chemical compounds

Taxes on chemical compounds still constitute a fairly small share of the total environmental tax base in Europe, but proposals for new chemical tax schemes have become common. The overall purposes of this paper are to analyze: (a) the economics and politics of taxing chemical compounds; and (b) the future potential for increased implementation of such taxation policies in Europe. While much of the discussion is general in scope, the empirical part focuses on the case of fertilizer taxation in Austria, Denmark, the Netherlands, Norway and Sweden. There exists an inevitable trade-off between costly monitoring on the one hand and the achievement of a cost-effective allocation of nitrate leaching abatement measures on the other. This is true for many types of chemicals and our analysis of the fertilizer case provides a number of general lessons for future implementation of environmental taxes in the chemicals field. The choice of tax scheme design matters not only for the cost effectiveness of the policy, but can also be an important mean of reducing any political opposition towards environmental taxes. The European experience in fertilizer taxation indicates that some kind of earmarking of tax revenues can be effective in increasing the legitimacy of the tax policy, and taxes which achieve a close proportionality to damage done will often be perceived as fair. The latter implies that taxation close to environmental damages and the reduction of the associated transaction costs should be policy priorities. Finally, an important feature of many legal provisions – including the EC Nitrate Directive – is the weight given to goal fulfilment, and although taxes are in no way prohibited they may be abandoned since their impacts on environmental quality (and ultimately on goal fulfilment) can be hard to predict.     

我国畜禽污染现状与治理政策的有效性分析

针对我国农村畜禽养殖散户和专业户的畜禽粪便处理方式进行实地调查,分析了我国畜禽粪便污染现状及变化趋势,并运用计量经济模型估计了不同治理政策对减少畜禽粪便废弃的有效性.结果表明:随着我国畜禽养殖模式的转变和劳动力成本的提高,畜禽粪便污染呈现明显增长趋势,污染治理的压力进一步增加;散户和专业户的畜禽粪便处理方式存在较大差异.模型估计结果表明:制定垃圾管理规章制度、专人监管垃圾投放、建立沼气池等措施能有效减少散户的畜禽粪便污染,但对于专业户只有专人监督垃圾投放才能发挥作用.随着我国农村畜禽养殖从散养向专业户养殖方式转变,建议政府部门重点加强对养殖专业户畜禽粪便污染的管理,通过出台更严格的环境监管措施和补贴等激励机制减少其畜禽粪便环境污染.     

An assessment of the effectiveness and impact of electrokinetic remediation for pyrene-contaminated soil

The effectiveness of electrokinetic remediation for pyrene-contaminated soil was investigated by an anode-cathode separated system using a salt bridge. The applied constant voltage was 24 V and the electrode gap was 24 cm. Two types of soil （sandy soil and loam soil） were selected because of their different conductive capabilities. The initial concentrations of pyrene in these soil samples were 261.3 mg/kg sandy soil and 259.8 mg/kg loam soil After treatment of the sandy soil and loam soil for seven days, 56.8% and 20.1% of the pyrene had been removed respectively. Under the same power supply voltage, the removal of the pollutant from the sandy soil was greater than that from the loam soil, due to the higher current and lower pH. Further analysis revealed that the effectiveness of electrokinetic remediation was affected by the energy expenditure, and was associated with changes in soil properties.     

不同饮食习惯下镉摄入对肠道菌群结构的影响

为了探究不同饮食习惯下Cd摄入对肠道菌群结构的影响,将C57BL/6小鼠给予不同的饲养方式(正常饮食(ND)、正常饮食+10 mg/L CdCl2(ND+Cd)、高脂饮食(HFD)、高脂饮食+10 mg/L CdCl2(HFD+Cd))20周后,借助16S rRNA高通量测序技术分析了各组小鼠肠道菌群的组成,并探讨了H...     

广州市不同人群硒摄入量研究

通过酸消解、原子荧光-氢化物发生法测定了广州市市售109种常见食物中硒的含量,结合膳食结构计算了广州市不同人群的每日硒摄入量.结果表明,广州市不同食品硒含量有较大差异,均值为4.97～457.3 μg·kg-1,其中动物性食品硒含量明显高于植物性食品硒含量,硒含量较高的食品有动物内脏、鱼虾类、蛋及蛋制品、猪肉等,均大于150 μg·kg-1.广州市不同人群膳食硒摄入量有明显差别,不同收入人群的摄入量为高收入人群(102.6 μg·d-1)＞中收入人群(83.8 μg·d-1)＞低收入人群(66.6 μg·d-1);老人硒摄入量为73.3 μg·d-1,儿童为44.3 μg·d-1,大学生为86.8 μg·d-1,工人为69.7 μg·d-1;标准人摄入量为98.5 μg·d-1.动物性食品是广州居民硒摄入量的主要来源;其次是大米;蔬菜、水果和豆类及制品等植物性食品贡献很小.广州市不同人群每日硒摄入量处于良好水平.