利用造纸废物生产全粉煤灰轻质建筑材料研究

近年来，随着我国火电建设的不断发展，其主要工业废渣-粉煤灰的排放量也在迅速增加，据预测，到明年，我国粉煤灰的年排放量达到0．16Gt，累计堆存量将达2．2Gt，占地面积将达29333hm^2。目前，国外发达国家对粉煤灰的综合利用率已达到50％～70％，少数发达国家甚至达到100％，而我国粉煤灰在建材制品中的利用量只占总量的34．8％，且呈下降趋势。专家认为，大规模开发粉煤灰在建材领域中的应用，是目前急待解决的问题。     

循环经济:低碳城市建设的路径与手段

气候变化逐渐成为全球共同面临的风险。大气中温室气体浓度增加,引起近50年来以变暖为主要特征的全球气候显著变化,对人类社会的生存和发展带来严重挑战。城市是二氧化碳等温室气体的高排放区,推进基于城市尺度的温室气体减排研究,加强低碳城市建设具有重要意义。从我国低碳城市与循环经济发展的现状出发,以循环经济思想为指导,从提高产业活动能效、开发可再生能源、生活垃圾资源化3方面提出建议。旨在为推进我国低碳城市建设提供借鉴。     

韩国修订废弃物管理法

韩国的废弃物管理法虽已多次进行修订，但1999年度的修订不仅幅度大，而且实施后对废弃物管理将会产生良好的效果。修订的主要内容如下： 　　(1)增加的废弃物管理制度 　　增加的废弃物管理项目包括建筑废弃物、污泥、矿渣、粉尘、废砂、固体处理物、废催化剂、废吸附剂及指定废弃物。规定废弃物排放者首先应提出废弃物处理计划书、废弃物分析结果报告书和委托确认书。另外，排放者必须把一年排出的指定废弃物的种类、数量和处理情况等的详细计算书在次年3月31日前提交环境部长官。 　　(2)增加了确保企业破产时废弃物的妥善处理制度 　　韩国由于受亚洲金融危机的影响，企业相继破产，留下的废弃物处理问题成为一大难题。为了妥善处理这个问题，应预先准备处理费用，按法律规定处理费用有以下三种负担方法： 　　①废弃物处理费用由互助会分担。 　　②为了保证妥善处理废弃物，企业须入废弃物处理保险。 　　③预交废弃物处理履行保证金。废弃物处理费用按下式计算： 　　A：前年预交金额+利息 　　B：今年预交金额=处理单价×允许保存量×1.5 　　若A＞B，则退还差额；若A＜B，则追加预交差额。 　　企业停产时，环境部长官则使用预交的废弃物处理履行保证金处理其放置的废弃物。 　　(3)现行制度中出现的不足之处的改进和补充 　　①禁止任意投放废弃物，否则判处7年以下徒刑或给予5000万韩元的罚款。 　　②对废弃物进行统计调查，并制订出指定废弃物的标准分类方法。 　　③为了防止二恶英的污染，禁止使用一定规模以下的焚烧炉。 　　④排放者不妥善处理废弃物时，环境部长官或特别市长、一般市长、广泛区域长官及自治区长官可命令排放者立即采取相应的措施。     

常熟市锻压机床厂与你携手共进

我国是一个人均资源相对贫乏的发展中国家，再生资源的开发利用是目前解决我国资源缺乏、环境污染等问题的现实途径。随着改革开放的不断深入，再生资源行业的结构正发生巨大变化，近年来，乡镇企业的迅速发展，个体私营企业的不断增加，回收加工机械需求多样化、小型化，质量可靠结构实用、价格适中的产品更受市场欢迎。依靠科技投入研制更好、更新的产品来适应日渐变化着的回收行业，使再生行业上一个新的台阶已是摆在回收加工机械生产企业面前的必然之路。 地处苏锡常经济三角区黄金腹地的常熟市锻压机床厂是我国专业生产金属、非金属打包机、剪断机、压缩机等系列产品的骨干企业，1955年建厂以来，逐步发展成为具有一定规模的机械加工企业。自20世纪70年代开始，就对市场进行调研、与有关科技单位协作，着手研制生产金属打包机和剪切机。改革开放后，回收行业逐渐走向市场化，企业领导适时调整自己的产品结构，不断推出规格齐、成本低、质量好、功能多、便于安装及维修的液压打包机、液压剪断机等产品，深受中、小型业主的欢迎，成为全国再生资源回收加工机械重点生产企业之一，产品销往全国二十六个省、市、自治区，为我国再生资源行业的发展作出了巨大贡献。     

Temporal Trends in Mercury Accumulation in Lake Sediments in Sweden

Lake sediment cores were analyzedto study the history of mercury (Hg) pollution andparticularly to determine whether recent sedimentconcentrations have declined in response todeclining atmospheric deposition of Hg. Sedimentcores from 6 forest lakes distributed fromsouthern to northern Sweden and 3 northernmountain lakes were analyzed for Hg using CVAAS. A400 cm sediment profile from Måkevatten insouthwest Sweden indicates that the onset of Hgpollution occurred in the 18th century. Anindisputable increase in Hg concentrationsoccurred concurrent with the appearance ofspheroidal carbonaceous flyash particles (SCP)derived from fossil-fuel combustion, in themid-19th century. There is a strong correlationbetween Hg and SCP concentrations in the sedimentcores (r=0.67 to 0.91), which suggests a strongrelationship between historical Hg pollution andfossil fuel burning. In contrast to sediment corestaken in 1979, maximum Hg concentrations are nowobserved below the sediment surface and declinetowards the sediment surface. This study confirmsthat reductions in atmospheric deposition of Hgover Sweden have resulted in a decreased transferof total Hg to aquatic environments as reflectedby lake sediments, and that lake sediment profilesof Hg concentrations reflect relative trends inthe atmospheric deposition of Hg rather thanpost-depositional diagenetic processes.     

Elemental Concentration in Lichen in Western Anatolia

The deposition patterns of Mn, Fe, Cr, Sb, Zn and As wereinterpreted together with enrichment factor calculations. Samples collected around iron-steel plant had very high concentrations and EF values of Mn, Fe, Cr, Sb and Zn implying that these plants are serious pollution sources in the region. High As concentrations around the settlementareas showed that coal combustion is another important anthropogenic source in the region.     

Volumetric changes in landfill gas flux in response to variations in atmospheric pressure

This paper develops a quantitative model which attempts to relate volumetric changes in landfill gas emissions to variations in the surface atmospheric pressure. The model considers gas emissions as the sum of two terms, one constant over a period of weeks, and the other able to vary on a scale of hours. Results from computer simulations are given which indicate that the magnitude of the variable factor is proportional to the rate at which surface pressure is changing, rather than the actual value of the surface pressure.     

Sulphate and Nitrate in Precipitation and Soil Water in Pine Forests in Latvia

The SO₄–S and NO₃–N concentrations and pH in bulk precipitation, throughfall, stemflow and soil water for the 1994–2004 period were studied in pine forests in Latvia (Rucava and Taurene Integrated Monitoring stations). The SO₄–S and NO₃–N concentrations decreased over the study period, simultaneously with a decrease of acidity in precipitation. The changes were more evident in the western part of Latvia, probably due to declining long-range air pollution from West Europe. The trend of decreasing sulphate concentrations and increasing pH in precipitation were not followed by respective changes in soil water. In the upper soil horizon sulphate ion concentrations and acidity increased in soil water. Over the observation period, nitrate concentrations also showed an increasing trend in soil water at Rucava and Taurene, but these changes were not statistically significant.     

Variations in the Fluoride Level in Precipitation in a Region of Human Impact

The research concerns the Wielkopolski National Park (West Poland), which suffered a huge human impact in the 1970s and 1980s owing to the nearby location of an industrial plant. Since then, fundamental technological changes that it introduced into its production of phosphate fertilizers have radically reduced the amount of pollution emitted. A three-year study (2002–2004) of fluorides in precipitation in open terrain and under tree crowns showed their concentrations to range from levels below the detection limit (0.003 mg/l) to 0.560 mg/l. Those registered under tree crowns were several times higher and indicated substantial dry deposition of fluorides on the trees. The highest values were recorded in 2003, with 43% of samples ranging from 0.01 to 0.05 mg/l, and with 51% of throughfall ranging from 0.10 to 0.50 mg/l. A strong connection was shown to exist between fluoride and sulphate concentrations in the precipitation. An analysis was made of the available data on F concentrations in the air and the dust levels around the factory, but these figures did not show an unequivocal effect on F concentrations in precipitation. A great similarity was found to occur between the fluoride content in rainwater in the Wielkopolski National Park and in the centre of the nearby Poznań metropolitan area, which indicates that there are also other F sources besides the local factory.     

Difficulties in applying extended producer responsibility policies in developing countries: case studies in e-waste recycling in China and Thailand

Developing Asian countries have started to apply the principle of extended producer responsibility (EPR) to electronics and electrical equipment waste (e-waste). This policy approach aims to give electronic appliance manufacturers and importers responsibility for the collection and recycling of discarded electronic equipment. China and Thailand have drafted regulations on the recycling of e-waste with common characteristics such as the financial responsibility of producers and subsidies for collection. Although the proposed system is sensible, taking into account the fact that e-waste is a market-traded commodity, there are two major difficulties in implementing EPR in developing countries. First, it may be difficult for governments to collect funds from producers or importers if smuggled, imitation, or small shop-assembled products have a large share in the market. Second, the system creates incentives for collectors and recyclers to over-report the amount of collected e-waste in order to gain extra subsidies from the fund. Other policy measures such as the enforcement of pollution control regulations on informal recyclers, the prevention of smuggling, and the protection of intellectual property rights should accompany EPR policies.     

Medical wastes characterisation in healthcare institutions in Mauritius

This study was initiated to characterize solid and liquid wastes generated in healthcare institutions and to provide a framework for the safe management of these wastes. The project was carried at three major medical institutions, namely, the Jeetoo Hospital, the Sir Seewoosagur Ramgoolam National (SSRN) Hospital and the Clinic Mauricienne. A waste audit carried out at these sites revealed that approximately 10% of solid wastes was hazardous in nature, consisting mainly of infectious, pathological and chemical wastes. The average amount of hazardous wastes per patient per day was found to be 0.072 kg at Jeetoo hospital, 0.091 kg at SSRN hospital and 0.179 kg at the clinic. The amount of hazardous wastes generated as a function of the number of occupied beds was found to follow a relationship of type y=0.0006x-0.19, where y was the amount of hazardous wastes generated per bed per day and x was the number of occupied beds. The waste quantifying process also revealed that at SSRN Hospital, 0.654 m(3) of water was being consumed per patient per day and the amount of wastewater produced was 500 m(3)/day. Further analysis revealed that the wastewater was polluting with chemical oxygen demand (COD), biological oxygen demand (BOD(5)), total suspended solids (TSS) and coliform content well above permissible limits.     

Future trends in computer waste generation in India

The objective of this paper is to estimate the future projection of computer waste in India and to subsequently analyze their flow at the end of their useful phase. For this purpose, the study utilizes the logistic model-based approach proposed by Yang and Williams to forecast future trends in computer waste. The model estimates future projection of computer penetration rate utilizing their first lifespan distribution and historical sales data. A bounding analysis on the future carrying capacity was simulated using the three parameter logistic curve. The observed obsolete generation quantities from the extrapolated penetration rates are then used to model the disposal phase. The results of the bounding analysis indicate that in the year 2020, around 41–152 million units of computers will become obsolete. The obsolete computer generation quantities are then used to estimate the End-of-Life outflows by utilizing a time-series multiple lifespan model. Even a conservative estimate of the future recycling capacity of PCs will reach upwards of 30 million units during 2025. Apparently, more than 150 million units could be potentially recycled in the upper bound case. However, considering significant future investment in the e-waste recycling sector from all stakeholders in India, we propose a logistic growth in the recycling rate and estimate the requirement of recycling capacity between 60 and 400 million units for the lower and upper bound case during 2025. Finally, we compare the future obsolete PC generation amount of the US and India.     

膜生物反应器中污泥自消化技术进展

介绍了国内外膜生物反应器(MBR)中污泥的消化技术,分析了控制运行条件法、物理法、化学法污泥消化技术及生物法污泥自消化技术的优缺点,指出了在MBR中没置局部厌氧区域法污泥自消化技术的重要意义.     

Material reuse and recycling in construction works in Japan

Journal of Material Cycles and Waste Management - The status of material reuse and recycling in Japan is reviewed with an emphasis on the efforts by the national government. First, the national...