Approaches to eliminate waste and reduce cost for recycling glass

In recent years, the issue of environmental protection has received considerable attention. This paper adds to the literature by investigating a scheduling problem in the manufacturing of a glass recycling factory in Taiwan. The objective is to minimize the sum of the total holding cost and loss cost. We first represent the problem as an integer programming (IP) model, and then develop two heuristics based on the IP model to find near-optimal solutions for the problem. To validate the proposed heuristics, comparisons between optimal solutions from the IP model and solutions from the current method are conducted. The comparisons involve two problem sizes, small and large, where the small problems range from 15 to 45 jobs, and the large problems from 50 to 100 jobs. Finally, a genetic algorithm is applied to evaluate the proposed heuristics. Computational experiments show that the proposed heuristics can find good solutions in a reasonable time for the considered problem.     

Environmental impacts and use of brominated flame retardants in electrical and electronic equipment

Management of waste electrical and electronic equipment (WEEE) or e-waste is becoming a major issue as around 20–50 million tons of such waste is generated worldwide and increasing at a higher rate than other solid waste streams. Electrical and electronic equipment (EEE) contains over 1,000 materials of which brominated flame retardants (BFRs) such as polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) have been the target of the regulators forcing manufacturers to adopt halogen-free flame retardants. As far as these alternatives are concerned, key consideration should be its performance during the whole life cycle through design, use and end-of-life management. The global halogen-free flame retardant movement has reached a point of no return. The most important issue as far as the environment is concerned, for which the transformation to halogen-free retardants was initially targeted, is to make sure that life span of the EEE using the alternatives to BFRs is not shortened thereby resulting in unforeseen increases in e-waste to deal with. The aim of this article is to investigate the environmental issues and current developments related to the use of BFRs in EEE manufacture. It describes the sources, toxicity and human exposure of BFRs, EOL management such as recycling and thermal treatments, exposure of BFRs from e-waste processing facilities and the environment around them and examines the developments and feasibility of the alternatives to BFR in EEE manufacture.     

Investigating household preferences for kerbside recycling services in London: a choice experiment approach

Recent developments in national and European Union waste management policy have prompted considerable interest in alternative waste management programs, such as recycling, which could divert a portion of the municipal solid waste stream from landfills. This paper examines household preferences for kerbside recycling services and uses a stated preference choice experiment method to estimate households' valuation of such services. Using a sample of 188 households in the London area, the empirical analysis yields estimates of the willingness to pay for the number of 'dry' materials collected, the collection of compost, textile collection and the frequency of collection.     

Recycling process for yttria-stabilized tetragonal zirconia ceramics using a hydrothermal treatment

The recycling process for 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) sintered at 1450°–1550°C was examined by applying low-temperature degradation of zirconia ceramics under hydrothermal conditions. Hydrothermal treatment at a temperature from 200° to 240°C can lead to the spontaneous disintegration of 3Y-TZP sintered bodies into powdery particles. The hydrothermally obtained zirconia powder was found to consist of primary particles and aggregated particles. Detailed X-ray diffraction measurement revealed the formation of a cubic zirconia phase in the 3Y-TZP sintered bodies, which seemed to inhibit the disintegration of aggregated particles toward the primary particle level. The reclaimed 3Y-TZP powder was sintered again through a conventional powder processing route. The mechanical properties and microstructure of recycled 3Y-TZP sintered specimens were examined by comparison with those of the original 3Y-TZP sintered bodies. Dense recycled 3Y-TZP sintered at a higher temperature exhibited higher fracture toughness to some degree than the original 3Y-TZP.     

Material flows of end-of-life home appliances in Japan

In Japan, the Law for the Recycling of Specified Kinds of Home Appliances came into effect in April 2001. This law aims to introduce appropriate waste treatment and promote the efficient use of resources so that we can achieve a sound material-cycle society. The law introduces a new framework for recycling that places obligations principally on the manufacturers and retailers of home appliances. Material flow analysis of this new framework is essential for evaluation of the system and for finding any problems that may exist. We therefore analyzed the material flows in facilities that recycle electrical home appliances. The mass balances in the recycling facilities were appropriately estimated. Then the potential destinations were surveyed and analyzed, even though the legal framework does not include flows after the recycling facilities. The potential destination after the facilities varies and depends on both the economy and the related regulations. Currently, considerable amounts of recovered materials are exported and recycled. However, the sustainability of these trades is unknown. Therefore, we should keep a close eye on the situation and make sure that our recycling system is adaptable to meet any future changes.     

Postconsumer polyethylene terephthalate (PET)/polyolefin blends through reactive processing

Increasing awareness of environmental and energy problems has promoted greater governmental interest in selected waste collection and consequently has attracted the interest of several research groups to the challenge of converting recovered plastics into useful materials. The reactive blending of postconsumer polyethylene terephthalate (PET) with different polyolefins (PO) was studied in attempts to obtain a new material with enhanced properties with respect to the starting materials. The success of the project depends mainly on the possibility of obtaining a compatibilized blend between two starting polymers that, from chemical and thermomechanical viewpoints, are very different. This was approached by employing polyolefins bearing functional groups capable of specific interaction or chemical reaction with PET end groups. Ternary blends of very low density polyethylene (VLDPE)/PET/functionalized polyolefin (FPO) in a weight composition of 70/20/10 and binary blends of FPO/PET in a weight composition of 90/10 were prepared and studied to obtain reinforced polyolefin thermoplastic materials. Reactive blending was achieved in a Brabender Plastograph with a mixing chamber of 30 or 50cm³, at 250°C, and 40rpm for 10min. Differential scanning calorimetry, scanning electron microscopy, and tensile tests were used to investigate the phase behavior, the efficiency of compatibilization, and the mechanical properties of the blends.     

The current situation of solid waste generation and its environmental contamination in China

In China, controlling environmental pollution resulting from solid waste (SW) and hazardous waste (HW) has become one of the most pressing tasks in the field of environmental engineering. It is reported that the annual generation of industrial solid waste (ISW) in China exceeded 0.6 billion tons in the 1990s, and is increasing every year. Although ISW management has been strengthened in recent years, about 40% of SW is put in uncontrolled landfill without appropriate treatment. According to statistics from the national Environmental Protection Agency, the cumulative ISW uncontrolled landfill in China had reached 6.6 billion tons by the end of 1995, occupying around 55 000 hectares of land. Although some major uncontrolled landfills were constructed, nonetheless groundwater contamination resulted from the use of low-standard liners and poor management. Furthermore, about 20 million tons of ISW was discharged into the environment illegally, and a third of this waste was discharged directly into water bodies, making ISW one of the greatest pollution sources for surface water and ground water. Environmental pollution accidents resulting from SW occur about 100 times a year in China, and environmental issues frequently arise because of ISW pollution. The practices of SW management, treatment, and disposal started relatively late in China, and for a long time the management of SW pollution has received little attention compared with water and air pollution management. China faces problems such as the insufficiency of management laws and regulations, insufficient investment, inadequate treatment and disposal technology, and a lack of qualified technicians. At present, most treatment and disposal technology cannot meet the requests for solid waste pollution control. In order to protect, restore, and improve environmental quality in China and to realize sustainable development, the safe management and disposal of solid and hazardous wastes is a pressing challenge. In recent years, much attention has been paid to SW management in China, and investment to develop management and treatment technologies has increased. In 1995, the Law for Solid Waste Pollution Protection was issued, and work on solid waste treatment and disposal began to be legally managed. SW treatment and disposal facilities have been constructed, and now operate in some large and medium-sized cities. In particular, rapid improvements have been seen in ISW recycling, collection, and disposal of municipal solid waste and regional HW management. All the figures in this paper are from 1995, and represent the situation in China in that year. Received: April 18, 2000 / Accepted: May 15, 2000     

Converting waste polystyrene into a polymer flocculant for wastewater treatment

We have succeeded in converting waste polystyrene from electrical appliances into a polymer flocculant for treating some kinds of wastewater after chemical modification. Waste polystyrene, such as polystyrene foam and additive-containing TV cabinets, was converted into a water-soluble polymer, polystyrene sulfate (PSS), and PSS of various degrees of aqueous viscosity was obtained by introducing sulfone bridges during sulfonation. We examined the relationship between the degree of flocculation of wastewater and the aqueous viscosity of the PSS, and found that PSS with medium viscosity is most suitable for flocculating inorganic wastewater from a factory, and PSS with high viscosity is most suitable for dewatering organic domestic wastewater. We report how PSS containing sulfone bridges works as a polymer flocculant for treating wastewater. Received: July 19, 2000 / Accepted: September 21, 2000     

The impact of the European landfill directive on waste management in the United Kingdom

The European Union Landfill Directive calls on member states to reduce the amount of biodegradable municipal solid waste disposed of to landfill. In addition, national waste strategies will require the constituent parts of the United Kingdom to achieve increased household waste recycling and recovery rates. Both these measures will require the development of the infrastructure to support national high-intensity recycling and composting schemes and the construction of at least 35 new municipal waste to energy incinerators. Before plans can be developed for meeting the targets several areas relating to municipal solid waste need to be clarified. Depending on the definition of municipal solid waste, its composition and likely future growth rates the number of incinerators required could be up to 170.     

Trade and recycling of used tyres in Western and Eastern Europe

Truck tyres can cause significant environmental pressure through the life cycle. The main aim of this paper is investigate to what extent international policy measures on foreign trade, international recycling and harmonisation of legislation can contribute in effectively reducing environmental pressure caused in the truck tyre life cycle. A two-region simulation model, representing Western and Eastern Europe, is developed that integrates the complete life cycle, incorporates environmental impacts in its economic analysis, is technically dynamic by accounting for learning-by-doing effects, and allows for variations in trade of new and old truck tyres. In this study the economic, environmental and social effectiveness of harmonisation and trade measures in the European life cycle for truck tyre is tested. Several conclusions can be drawn from the model simulations. First, the environmental effects caused by the trade of used tyres from Western to Eastern Europe are of limited impact on the overall environmental damage caused by truck tyres. The consumption stage is by far the main contributor to environmental damage. Within the marginal analysis of trade, harmonisation of disposal fees illustrated to generate very limited positive results. The private and external costs in the solid waste management (SWM) stage are too limited to have a notable impact on the overall configuration of the European tyre life cycle. The introduction of strict laws on tread depth in Eastern Europe has a much stronger impact on material flows than the harmonisation scenario. This suggests that domestic policy measures should be the primarily focus on interventions in this stage of the life cycle, for instance, by improving the management of tyre pressure. Because trade of used tyres has little impact on the consumption stage, this issue should not get priority in European environmental programs.