Waste landfill plant and waste disposal plant efficiencies in China

Journal of Material Cycles and Waste Management - As resident awareness of environmental issues has grown, waste disposal has become an important part of urban environmental governance. Most...     

Gypsum treated fly ash as a liner for waste disposal facilities

Fly ash has potential application in the construction of base liners for waste containment facilities. While most of the fly ashes improve in the strength with curing, the ranges of permeabilities they attain may often not meet the basic requirement of a liner material. An attempt has been made in the present context to reduce the hydraulic conductivity by adding lime content up to 10% to two selected samples of class F fly ashes. The use of gypsum, which is known to accelerate the unconfined compressive strength by increasing the lime reactivity, has been investigated in further improving the hydraulic conductivity. Hydraulic conductivities of the compacted specimens have been determined in the laboratory using the falling head method. It has been observed that the addition of gypsum reduces the hydraulic conductivity of the lime treated fly ashes. The reduction in the hydraulic conductivity of the samples containing gypsum is significantly more for samples with high amounts of lime contents (as high as 1000 times) than those fly ashes with lower amounts of lime. However there is a relatively more increase in the strengths of the samples with the inclusion of gypsum to the fly ashes at lower lime contents. This is due to the fact that excess lime added to fly ash is not effectively converted into pozzolanic compounds. Even the presence of gypsum is observed not to activate these reactions with excess lime. On the other hand the higher amount of lime in the presence of sulphate is observed to produce more cementitious compounds which block the pores in the fly ash. The consequent reduction in the hydraulic conductivity of fly ash would be beneficial in reducing the leachability of trace elements present in the fly ash when used as a base liner.     

Environmental audits of hazardous waste disposal and treatment facilities

Hazardous waste generators have a duty of care in ensuring that their wastes are disposed of in an environmentally acceptable manner. Increasingly, generators are being made liable for environmental damage at the site of a waste disposal contractor if their wastes have been accepted by that facility. An audit procedure is described, that permits generators to examine the performance of waste vendors and to assess their potential liability as a result of using the site. Post-audit decisions in estimating the degree of risk and selecting appropriate waste contractors are also discussed.The purpose of this paper is to guide the prospective auditor through the site assessment procedure, highlighting areas of particular concern in relation to present or future potential liabilities. The audit procedure that is described, applies to all types of waste disposal operations in all countries, since the principles of good waste management do not vary.     

废旧电冰箱聚氨酯硬质泡沫塑料回收处理技木研究

从废旧电冰箱聚氨酯硬泡塑料的回收、处理、资源化等方面阐述了国内外的研究技术现状.近年来我国电冰箱报废量剧增,聚氨酯硬泡塑料是电冰箱最主要的塑料品种,具有资源性和环境污染的双重特性.从循环经济和清洁生产的理念出发,提出我国进行废旧电冰箱聚氨酯硬泡塑料的回收处理处置,有利于促进我国可持续发展和建设“美丽中国”.     

城市生活垃圾处理技术和资源化应用探讨

介绍我国城市生活垃圾处理技术和城市垃圾资源化现状,对北京阿苏卫生活垃圾综合处理进行详细分析,为城市生活垃圾的处理工艺选型和垃圾处理发展前景提供了参考依据。     

废弃印刷线路板中材料的资源化回收利用技术

废弃印刷线路板（WPCBs）既有污染环境的一面,又有可资源化回收利用的一面.通过机械物理法、热解、超临界流体氧化和离子液体溶解等方法对其进行分离和回收金属和非金属材料.初步分选的金属需要进一步提纯以实现高附加值.而非金属材料可以用热解法、微波处理、超临界流体技术、等离子技术等技术进行产气和能量回收,也可以通过制备建筑材料或填料和其它功能村料进行物料回收.总之,对WPCBs进行适当地处理不但可以减轻环境压力,还可以变废为宝,实现资源再生利用.     

Telerobots for remote disposal of mixed waste

Two remote-controlled robotic submersible vehicles and an automated shredder are helping remove and dispose of highly reactive, sometimes explosive materials, dumped into a water-filled quarry at the U.S. Department of Energy's reservation in Oak Ridge, Tennessee. Human workers never enter the four-acre site, except for well-planned equipment maintenance and to shoot holes from a protected but into the retrieved containers, releasing pressure and exposing the contents to air and water. During its approximately two years of operation, the $8 million project has retrieved more than 15,000 items from the thirty feet of water at the bottom of the quarry.     

The willingness to household waste disposal practices of residents in rural China

Journal of Material Cycles and Waste Management - The increasing amount of household waste is becoming one of the major challenges in the sustainable development of rural areas in China. As most...     

Municipal solid waste disposal in Portugal

In recent years municipal solid waste (MSW) disposal has been one of the most important environmental problems for all of the Portuguese regions. The basic principles of MSW management in Portugal are: (1) prevention or reduction, (2) reuse, (3) recovery (e.g., recycling, incineration with heat recovery), and (4) polluter-pay principle. A brief history of legislative trends in waste management is provided herein as background for current waste management and recycling activities. The paper also presents and discusses the municipal solid waste management in Portugal and is based primarily on a national inquiry carried out in 2003 and directed to the MSW management entities. Additionally, the MSW responsibility and management structure in Portugal is presented, together with the present situation of production, collection, recycling, treatment and elimination of MSW. Results showed that 96% of MSW was collected mixed (4% was separately collected) and that 68% was disposed of in landfill, 21% was incinerated at waste-to-energy plants, 8% was treated at organic waste recovery plants and 3% was delivered to sorting. The average generation rate of MSW was 1.32 kg/capita/day.     

Waste catalysts for waste polymer

Catalytic cracking of high-density polyethylene (HDPE) over fluid catalytic cracking (FCC) catalysts (1:6 ratio) was carried out using a laboratory fluidized bed reactor operating at 450 degrees C. Two fresh and two steam deactivated commercial FCC catalysts with different levels of rare earth oxide (REO) were compared as well as two used FCC catalysts (E-Cats) with different levels of metal poisoning. Also, inert microspheres (MS3) were used as a fluidizing agent to compare with thermal cracking process at BP pilot plant at Grangemouth, Scotland, which used sand as its fluidizing agent. The results of HDPE degradation in terms of yield of volatile hydrocarbon product are fresh FCC catalysts>steamed FCC catalysts approximately used FCC catalysts. The thermal cracking process using MS3 showed that at 450 degrees C, the product distribution gave 46 wt% wax, 14% hydrocarbon gases, 8% gasoline, 0.1% coke and 32% nonvolatile product. In general, the product yields from HDPE cracking showed that the level of metal contamination (nickel and vanadium) did not affect the product stream generated from polymer cracking. This study gives promising results as an alternative technique for the cracking and recycling of polymer waste.     

Optimal service regions for solid waste facilities

An empirical method to determine the optimal size of a service region for a solid waste facility is presented. Population data from a region surrounding Green Bay, Wisconsin, U.S.A. and published cost data are used to illustrate the use of the method and to provide insight into the optimal values of the radius of the region when the facility is a landfill or an incinerator.     

Bentonite liners for isolation of waste disposal sites

The applicability of bentonite as a lining material for isolation of waste disposal sites was investigated on laboratory and field scale. The permeability of sand-bentonite mixtures depends on the type of bentonite, the bentonite content in the mixture and the dry bulk density. In laboratory experiments the saturated conductivity decreased at low hydraulic head gradients, indicating that water flow in these mixtures does not obey Darcy's law. The swelling of the bentonite, which is responsible for the low permeability, is a time-dependent process. The permeability decreased with time and even after two months the permeability had not reached a constant level. In sand-bentonite mixtures with 5% (w/w) bentonite, the saturated conductivity ultimately reached a level below 1 × 10⁻¹⁰ m s⁻¹, which is sufficiently low for surface capping of waste disposal sites. The sand-bentonite mixtures were 10–100 times more permeable for landfill leachate than for clean water. Bottom liners should, therefore, contain considerably more bentonite to prevent infiltration of leachate in the subsoil. Water-balance studies on experimental fields showed that there was no leakage at all through bentonite liners used for surface capping of a waste disposal site over a two-year period.     

中国废旧农用塑料薄膜的回收与利用

介绍了中国废旧农用塑料薄膜回收利用的现状;重点阐述了中国废旧农膜再生造粒技术,从工艺、成本利益、再生粒料的应用市场等各方面对该技术进行了详细的介绍和剖析,在论述其优越性的同时,指出了再生造粒技术存在的问题,为研究人员今后的研究工作指明了方向;最后对废旧农膜再生造粒技术的应用前景进行了展望.     

Costing and cost recovery for waste disposal and recycling

World Bank research on appropriate technology for water supply and waste disposal has revealed a need for further research and development in integrated systems for recovery and utilization of household and community wastes. Technology options including resource recovery are reviewed with special emphasis on constraints arising particularly in developing countries. Cost control and recovery is complex, and it has rarely if ever been demonstrated that a potential exists for making a solid waste management project profitable in its entirity. Solid waste management represents a net cost which may be minimized by better operations and appropriate recycling. Financial and economic backgrounds including tax structures have an overriding influence on apparent costs, and sound financial management is essential. Hazards of relying on the commercial sector alone to manage waste collection and disposal are emphasized as well as the long term problems with highly sophisticated equipment in countries that lack Foreign exchange and local skills for their maintenance and repair.     

Using MCDA and GIS for hazardous waste landfill siting considering land scarcity for waste disposal

The main aim of this study was to develop a procedure that minimizes the wasting of space for the siting of hazardous waste landfills as part of a solid waste management system. We wanted to tackle the shortage of land for waste disposal that is a serious and growing problem in most large urban regions. The procedure combines a multi-criteria decision analysis (MCDA) approach with a geographical information system (GIS). The GIS was utilised to obtain an initial screening in order to eliminate unsuitable areas, whereas the MCDA was developed to select the most suitable sites. The novelty of the proposed siting procedure is the introduction of a new screening phase before the macro-siting step aimed at producing a “land use map of potentially suitable areas” for the siting of solid waste facilities which simultaneously takes into consideration all plant types. The issue of obtaining sites evaluations of a specific facility was coupled with the issue of not wasting land appropriate to facilitate other types of waste management options. In the developed case study, the use of an innovative criteria weighting tool (the “Priority Scale”) in combination with the Analytic Hierarchy Process was useful to easier define the priorities of the evaluation criteria in comparison with other classic methods such as the Paired Comparison Technique in combination with the Simple Additive Weighting method.     

Industrial hazardous waste treatment facilities in Thailand

In Thailand, hazardous waste is becoming a major problem, especially toxic chemicals and heavy metal pollutants discharged from factories. The Industrial Works Department (IWD), which has full responsibility for the control of all factory pollution problems, has initiated a joint hazardous waste treatment programme for handling industrial liquid, sludge and solid hazardous wastes from all factories situated in and around Bangkok and the eastern seaboard region. Four industrial hazardous wastes treatment centres are planned. Secure landfills together with research and development centres will also be provided nearby for the ultimate disposal of the inert-salt sludges. The investment, operation and management of the centres is to be handled by private companies which can generate revenue by charging service fees directly to their customers. Since both governmental and private sectors have no experience in this field, a grant system for a pilot centre has been launched by the Government which has reduced the operating costs by providing land, treatment facilities, infrastructure and secured landfills. The first treatment centre which was officially planned in 1985 was put into operation in July 1988 at Samea Dam, Bangkhuntien District, a western suburb of Bangkok. The construction of all necessary facilities was paid for by the Government. The operation and management of the centre is handled by a private contractor, Siam Control Company (SCC) under a 5-year lease. The users will pay service fees directly to the contractor and the Government will receive a rental and royalty fee from the contractor.     

Pb-Laden CRT glass as classifying hazardous waste definition or exemption in landfill disposal in China

Journal of Material Cycles and Waste Management - Disposal of waste CRT glass is now an urgent environmental protection issue. We collected waste CRT glass from monochrome and color television...