Mechanical performance of woodfibre–waste plastic composite materials

Plastic products used for packaging are often discarded after a single use resulting in an inexhaustible supply of waste polymeric materials. The stiffness and strength of polymeric materials have been known to improve with the addition of lignocellulosic fibres available in abundance in nature. Hence, composite materials containing natural fibres and waste plastics would result in the reduction of solid wastes and the use of cheap, renewable resources. Composite specimens, consisting of waste plastics obtained from a Kerbside collection (high density polyethylene (HDPE) waste, Janitorial waste, Kerbside waste I and Kerbside waste II) and Pinus radiata woodfibres (medium density fibres (MDF)), have been produced through melt blending and injection moulding. The effects of fibre content, matrix type and interfacial bonding on the tensile and flexural properties of these composite materials have been determined through extensive testing at various conditions. The mechanical properties of these composites at room temperature and humidity depend on the amount of woodfibres, the mechanical properties of the waste plastics used and the presence of a suitable coupling agent. The tensile strengths of MDF/waste plastic composites do not generally change with fibre content except for 40% MDF/HDPE waste and 40% MDF/Kerbside waste II (plus 1% Epolene™) composites, where the tensile strengths increase by about 25% compared to those of the corresponding waste plastics. Flexural strengths of MDF/waste plastic composites increase with the addition of medium density fibres with the exception of MDF/Kerbside waste I composites. The tensile and flexural moduli of MDF/waste plastic composites mostly increase with increasing fibre content.     

Waste minimization study in a solvent-based paint manufacturing plant

Solvent-based paint manufacturing plants produce significant quantities of hazardous waste, which must be properly treated before it can be disposed. Since the cost for treating this waste is high, reducing the quantity of waste has become a crucial issue in this industry.Waste minimization options are beneficial for the owner of the plant as well as for the environment. The quantity of hazardous waste can be minimized by changing the plant's technology or by substituting hazardous substances, which are used in the paint manufacturing process, with environmentally friendly ones. Furthermore, separating the various waste streams makes it easier to recover raw materials and enhances the possibility of their reuse within the production process. This will decrease operational costs for the plant.This paper presents a case study of waste minimization in a solvent-based paint manufacturing plant. Source reduction, recovery, and recycling methods are taken into consideration. Its aim is to develop an understanding of the facility's waste generating processes, to suggest ways to reduce the waste production, and finally to select an appropriate waste minimization option to suggest to the plant. Some of the suggested methods are currently being practiced while others are at initial stage of development.     

Reusable and disposable cups: An energy-based evaluation

A group of five different types of reusable and disposable hot drink cups have been analyzed in detail with respect to their overall energy costs during fabrication and use. Electricity generating methods and efficiencies have been found to be key factors in the primary energy consumption for the washing of reusable cups and a less important factor in cup fabrication. In Canada or the United States, over 500 or more use cycles, reusable cups are found to have about the same or slightly more energy consumption, use for use, as moulded polystyrene foam cups used once and then discarded. For the same area paper cups used once and discarded are found to consume less fossil fuel energy per use than any of the other cup types examined. Details of this analysis, which could facilitate the comparative assessment of other scenarios, are presented.     

Sound management of brominated flame retarded (BFR) plastics from electronic wastes: State of the art and options in Nigeria

Management of flame retarded plastics from waste electrical and electronic equipment (WEEE) has been posing a major challenge to waste management experts because of the potential environmental contamination issues especially the formation of polybrominated-dioxins and -furans (PBDD/F) during processing. In Nigeria, large quantities of electronic waste (e-waste) are currently being managed—a significant quantity of which is imported illegally as secondhand electronics. As much as 75% of these illegal imports are never reused but are rather discarded. These waste electronic devices are mostly older equipment that contains brominated flame retardants (BFRs) such as penta-brominated diphenyl ethers (PBDEs), and polybrominated biphenyls (PBBs) which are presently banned in Europe under the EU WEEE and RoHS Directives. Risk assessment studies found both to be persistent, bio-accumulative and toxic. The present management practices for waste plastics from WEEE in Nigeria, such as open burning and disposal at open dumps, creates potential for serious environmental pollution. This paper reviews the options in the environmentally sound management of waste plastics from electronic wastes. Options available include mechanical recycling, reprocessing into chemicals (chemical feedstock recycling) and energy recovery. The Creasolv^® and Centrevap^® processes, which are the outcome of the extensive research at achieving sound management of waste plastics from WEEE in Europe, are also reviewed. These are solvent-based methods of removing BFRs and they presently offer the best commercial and environmental option in the sound management of waste BFR-containing plastics. Because these developments have not been commercialized, WEEE and WEEE plastics are still being exported to developing countries. The industrial application of these processes and the development of eco-friendlier alternative flame retardants will help assure sound management of WEEE plastics.     

Assessment of plastic packaging waste: Material origin,methods, properties

The global plastics production has increased annually and a substantial part is used for packaging (in Europe 39%). Most plastic packages are discarded after a relatively short service life and the resulting plastic packaging waste is subsequently landfilled, incinerated or recycled. Laws of several European and Asian countries require that plastic packaging waste collected from households has to be sorted, reprocessed, compounded and reused. These recycling schemes typically produce milled goods of poly(ethylene terephthalate) (PET), poly(ethylene) (PE), isotactic poly(propylene) (PP), mixed plastics, and agglomerates from film material. The present study documents the composition and properties of post-consumer polyolefin recyclates originating from both source separation and mechanical recovery from municipal solid refuse waste (MSRW). The overall composition by Fourier transform-infrared (FT-IR) spectroscopy and differential scanning calorimetry (DSC) were determined and compared with the sorting results of the sorted fractions prior to the reprocessing into milled goods. This study shows that the collection method for the plastic packaging waste has hardly any influence on the final quality of the recyclate; however, the sorting and reprocessing steps influence the final quality of the recyclate. Although the mechanical properties of recyclate are clearly different than those of virgin polymers, changes to the sorting and reprocessing steps can improve the quality.     

Transitions of municipal solid waste management. Part II: Hybrid life cycle assessment of Swiss glass-packaging disposal

In policy support of municipal solid waste (MSW) management, life cycle assessment (LCA) can serve to compare the environmental or economic impacts of two or more options for waste processing. The scope of waste management LCAs generally focuses less attention on future developments, e.g., where will recycling take place, and more on the environmental performance of prototypes, e.g., the incineration of all waste compared to recycling. To provide more robust support for Swiss waste glass-packaging disposal, scenarios of Swiss waste glass-packaging are assessed from a life cycle perspective. The scenarios consist in schemes for the disposal of the total amount of Swiss waste glass-packaging, i.e., different combinations of recycling and downcycling in Switzerland or abroad developed in Part I, Meylan et al. (2013). In this article (Part II), the disposal schemes are assessed with respect to eco-efficiency, an indicator that combines total environmental impacts and gross value added in Switzerland. Results show that no policy alternative guarantees environmental impact reductions and gross value added gains under all developments of exogenous constraints. Downcycling to foam glass in Switzerland is not only an environmentally sound disposal option, but it also buffers gross value added losses in case domestic recycling (and thus glass-packaging production in Switzerland) ceases in the future. The substitution of products based on raw materials other than Swiss cullet is the main responsible for change in environmental and economic impacts. Hence, an eco-efficiency maximizing policy should consider the products of disposal schemes. The combination of scenario analysis and eco-efficiency assessment as presented in this paper can be applied to other contexts (i.e., countries, waste fractions).     

Life cycle assessment of EPS and CPB inserts: design considerations and end of life scenarios

Expanded polystyrene (EPS) and corrugated paperboard (CPB) are used in many industrial applications, such as containers, shock absorbers or simply as inserts. Both materials pose two different types of environmental problems. The first is the pollution and resource consumption that occur during the production of these materials; the second is the growing landfills that arise out of the excessive disposal of these packaging materials. Life cycle assessment or LCA will be introduced in this paper as a useful tool to compare the environmental performance of both EPS and CPB throughout their life cycle stages. This paper is divided into two main parts. The first part investigates the environmental impacts of the production of EPS and CPB from 'cradle-to-gate', comparing two inserts--both the original and proposed new designs. In the second part, LCA is applied to investigate various end-of-life cases for the same materials. The study will evaluate the environmental impacts of the present waste management practices in Singapore. Several 'what-if' cases are also discussed, including various percentages of landfilling and incineration. The SimaPro LCA Version 5.0 software's Eco-indicator 99 method is used to investigate the following five environmental impact categories: climate change, acidification/eutrophication, ecotoxicity, fossil fuels and respiratory inorganics.     

The raw material supply of the European Community : The importance of secondary raw materials

The availability and security of raw materials supply have taken on a new political dimension within the last few years. These issues influence the economic and political rank of nations, affecting their independence, their standards of living and the competitive position of their industries. The importance of raw materials supply will continue to grow, for both the developed industrial and the developing countries. The European Community depends on external sources for 50–100% of most of its raw materials. Although the degree of dependence varies considerably from commodity to commodity, sources are not diversified enough to guarantee supply. Yet 1700–2000 million tons of waste are generated annually in the Community, containing substances of potential value—including metals, glass, rubber, textiles, oil, plastics—of which 70– 80% are tipped. This represents a loss of materials as far as they could be reused economically. This article argues that efforts should be made to recover and reuse the maximum possible of these resources to reduce the Community's dependence on, and improve its security of, raw materials supplies, and to lower the balance of payments burden.     

Analysis of products from the pyrolysis and liquefaction of single plastics and waste plastic mixtures

Waste plastics in the form of two examples of real world municipal solid waste plastics and a simulated mixture of municipal waste plastics were pyrolysed and liquefied under moderate temperature and pressure in a batch autoclave reactor. In addition, the five main polymers which constitute the majority of plastics occurring in European municipal solid waste comprising, polyethylene, polypropylene, polystyrene, polyethylene terephthalate and polyvinyl chloride were also reacted. The plastics were reacted under both a nitrogen (pyrolysis) and hydrogen pressure (liquefaction) and the yield and composition of products are reported. The hydrocarbon gases produced were mainly methane, ethane, propane and lower concentrations of alkene gases. A mainly oil product was produced with the mixed plastic waste with significant concentrations of aromatic compounds, including single ring aromatic compounds. The composition of the oils and gases suggested that there was significant interaction of the plastics when they were pyrolysed and liquefied as a mixture compared to the results expected from reactions of the single plastics.     

聚苯乙烯树脂溶剂型可剥防锈塑料的研制

本实验通过对比实验方法,研制了一种具有优良耐腐蚀性能与机械性能的聚苯乙烯树脂溶剂型可剥防锈塑料,该产品采用废弃泡沫为主要成膜物质,即解决了白色垃圾问题,实现了废物利用,又解决了钢铁件的防锈问题。对该产品进行性能测试,所得到的产品膜层光亮、韧性好,易于涂施、流平性好。     

A comprehensive waste collection cost model applied to post-consumer plastic packaging waste

Post-consumer plastic packaging waste (PPW) can be collected for recycling via source separation or post-separation. In source separation, households separate plastics from other waste before collection, whereas in post-separation waste is separated at a treatment centre after collection. There are also two collection schemes, either curb side or via drop-off locations. These different schemes have impact on total costs of collection at the municipal level. It can also influence the facility choices and network design. Therefore, a method which can compare costs of various collection schemes is needed.A comprehensive cost model was developed to compare costs of municipal collection schemes of PPW. The ‘municipal waste collection cost model’ is based on variables including fixed and variable costs per vehicle, personnel cost, container or bag costs as well as on emission costs (using imaginary carbon taxes). The model can be used for decision support when strategic changes to the collection scheme of municipalities are considered. The model takes into account the characteristics of municipalities, including urbanization degree and taxation schemes for household waste management.The model was applied to the Dutch case of post-consumer plastic packaging waste. Results showed that that in general post-separation collection has the lowest costs and curb side collection in urban municipalities without residual waste collection taxing schemes the highest. These results were supported by the conducted sensitivity analysis, which showed that higher source separation responses are negatively related to curb side collection costs. Greenhouse gas emission costs are a significant part of the total costs when collecting post-consumer plastic packaging waste due to the low density to weight ratio of the materials collect. These costs can amount to 15% of the total collection costs.     

Recycling and reducing packaging waste: How the United States compares to other countries

This report summarizes current developments in the United States and 18 other industrial countries regarding packaging waste. It presents available data concerning the types, amounts, and methods of managing such waste and provides information concerning the policies established or under consideration to reduce the amount of such waste being disposed. The countries discussed are all members of the Organisation for Economic Co-operation and Development (OECD).In recent years, waste disposal capacity has become more scarce in most OECD countries. As a result, waste management policies have focused on efforts to reduce and recycle major components of the waste stream. Packaging represents about one-third of municipal solid waste in many countries. Because of this, measures to reduce the amount and toxicity of packaging and to encourage its recycling are currently being considered in at least 18 OECD countries. In addition, the EC and the Nordic Council are developing programs to address packaging on a regional basis.The report is divided into four main sections. Section I summarizes available information for the OECD countries. The second section discusses waste generation and recycling rates for six types of packaging material: paper, glass, metal, plastic, wood, and composites. The third section discusses key questions raised by the information presented in the report. The fourth briefly discusses packaging waste issues facing the Congress.In general, the report finds, other countries use less packaging than the United States, recycle more of it, and are considering policy measures stronger than the measures generally being considered in America. As noted in detail, other countries have adopted or are developing requirements that:

• • set mandatory requirements for packaging waste reduction;

• • require reusable or refillable packaging;

• • impose taxes to discourage single-use packages;

• • prohibit the use of non-recyclable packaging,

• • prohibit or limit disposal of packaging, and

• • require manufacturers of packaging materials to collect and recycle post-consumer waste.

Perhaps the most fundamental issue raised by these approaches is whether local governments will continue to bear responsibility for funding and operating recycling programs or whether all or some of this responsibility might be shifted to industry. To date, this issue has not been joined in the Congress directly; however, there is a growing consensus in other countries concerning the advantages of industry responsibility.     

Recyling of plastic wastes via pyrolysis

Pyrolysis for the simultaneous generation of oils and gases can be convenient to obtain hydrocarbons and even to recover crude petrochemicals or to generate energy from waste plastics. A Gray–King apparatus has been used to pyrolyze waste polyethylene (PE), polystyrene (PS), both separately and with different compositions. Thermogravimetric analysis of waste plastics indicated the critical temperatures, which should be effective for pyrolysis. The chosen heating rate was low in order to achieve higher liquid yields. The results showed that waste PS yielded higher liquid, and waste PE yielded higher gaseous products. The dominant liquid product of PS waste was styrene whereas for waste PE, prophenylbenzene was the dominant pyrolysis product.     

缫丝废液的综合利用

缫丝废液中含有丰富的蛋白质，直接排入严重污染环境，废液中的蛋白质能用化学或生物化学方面水解成有用的氨基酸，后者是化学，医药，食品，饲料工业的重要原料，本文报道了缫丝废液中蛋白质酸水解和酶水解的研究结果以及部分酶水解的规律。     

小型砂滤池在废水处理中的应用

本文通过湿式除尘后的废水治理及工程实例,探讨了小型砂滤池在废水处 理中应用的可行性。     

可用作原料的固体废物进口可行性评价指标体系探索研究

合理利用境外的可用作原料的固体废物,可以弥补我国国内资源的相对不足,但固体废物固有的废物属性仍不可避免地会带来一定的环境负面影响。建立可用作原料的固体废物进口可行性评价体系,对于在合理利用境外废物资源的同时,保护和改善环境具有重要意义。本文论述了我国建立可用作原料的固体废物进口可行性评价体系的理论和原则,并根据影响可用作原料的固体废物进口可行性评价的因素分析,构建了可用作原料的固体废物进口可行性评价指标体系框架。     

Public participation in plastics recycling schemes

Without public contributions, recycling from domestic waste would not be possible. In order to support recycling projects it is important to try to understand who recycles, how they recycle, and why they recycle. This paper presents the results of a structured survey of 500 members of the public served by schemes to collect plastics waste for recycling. Data were gathered on the characteristics, behaviours and motivations of recyclers. The authors also sought to discover how the public perceive plastics compared to other materials, and as a recyclable material. Responses were collected in such a way that the awareness of the recyclability of materials could be compared with the recycling behaviour of respondents. An element of comparison was introduced between those served by a system of bottle banks (bring scheme) and those covered by a household collection (collect scheme). The survey results are reported and their implications for the management of post-consumer plastics waste collection schemes are discussed.     

An analysis of variables influencing the material composition of automobiles

The use of materials is studied broadly, because of the environmental problems related to extraction, production, consumption and waste treatment. The use and substitution of materials in products is therefore a relevant issue for environmental policy making. Studies have been done to describe the material flow or to measure the impact of materials or products on the environment. However, these studies do not often consider economic, substitution and dynamic aspects of material flows. Other studies on material flows analyse the relationship between the use of materials and economic growth, but they do not consider substitution between materials. For environmental policy making economic, technological and environmental aspects of the use of materials need to be considered. Especially, substitution of materials is important. In various countries material and product policies are imposed on a variety of materials and products. For evaluation of these policies their environmental and economic effects need to be examined in detail. This study aims to analyse the economic and technological factors influencing the use of materials and the substitution between different materials dynamically. The goal is to obtain an insight in the effect that material levies may have on the use and substitution of materials. The statistical analysis is performed on a specific product-group because decisions on the use of materials are taken on a product-level. The case study is performed on automobiles. The results show that the material use is largely an autonomous development. The price of aluminium has a positive, significant effect on the use of that material. The price of plastics has a positive, but not significant effect on the use of plastics. Reasons may be that the costs of a raw material are small relative to the processing costs, and that the production process can only be changed slowly. Other factors, like competitiveness and consumers' tastes, may be more important for substitution. This implies that levies or subsidies on certain materials is not a promising policy to change the use of materials. Besides time, there are two other factors that have a positive and significant relationship with the use of aluminium and plastics: the fuel efficiency, which is the distance driven divided by the energy used; and, the road tax, which depends on the weight of a car. However, these effects are caused by their positive relationship with time. The main conclusion of the case study is that imposing a levy on materials may not have the desired or expected effect of reduction in material use.     

新型环保节能建筑材料——泡沫玻璃

主要介绍了泡沫玻璃的概念、所用原料及生产,以及做为一种新型环保节能建筑材料的优良性能和使用技术,并分析了它的使用前景.     

An approach for analysing the potential for material efficiency improvement

Material efficiency improvement saves energy and reduces the consumption of primary resources and reduces the volume of waste. In this article an approach for analysing the potential for material efficiency improvement is proposed and discussed. In this approach the product functions performed by the materials and various improvement measures are taken into account. The potential for material saving and associated energy saving is assessed and evaluated economically. In this paper the approach is tested in an analysis of the potential for material efficiency improvement with respect to plastic packaging in the Netherlands. The technical reduction potential is found to be 34 ± 7% (157 ± 30 ktonne virgin plastics). Realization of this potential would improve the energy efficiency of the lifecycle of plastic packaging by 31% (10 PJ in 1988). From our study we conclude that our approach can indeed be used to investigate the potential for material efficiency improvement. However, a reliable technical and particularly an economical assessment of reduction measures cannot be made until more detailed data become available.