Review and prospect of emerging contaminants in waste – Key issues and challenges linked to their presence in waste treatment schemes: General aspects and focus on nanoparticles

The presence in waste of emerging pollutants (EPs), whose behaviours and effects are not well understood, may present unexpected health and environmental risks and risks for the treatment processes themselves. EP may include substances that are newly detected in the environment, substances already identified as risky and whose use in items is prohibited (but which may be present in old or imported product waste) or substances already known but whose recent use in products can cause problems during their future treatment as waste. Several scientific studies have been conducted to assess the presence of EP in waste, but they are mostly dedicated to a single category of substance or one particular waste treatment. In the absence of a comprehensive review focused on the impact of the presence of EP on waste treatment schemes, the authors present a review of the key issues associated with the treatment of waste containing emerging pollutants. This review presents the typologies of emerging pollutants that are potentially present in waste along with the major challenges for each treatment scheme (recycling, composting, digestion, incineration, landfilling and wastewater treatment). All conventional treatment processes are affected by these new pollutants, and they were almost never originally designed to consider these substances. In addition to these general aspects, a comprehensive review of available data, projects and future R&D needs related to the impact of nanoparticles on waste treatment is presented as a case study.     

Alkali activation processes for incinerator residues management

Incinerator bottom ash (BA) is produced in large amount worldwide and in Italy, where 5.1 millions tons of municipal solid residues have been incinerated in 2010, corresponding to 1.2–1.5 millions tons of produced bottom ash. This residue has been used in the present study for producing dense geopolymers containing high percentage (50–70 wt%) of ash. The amount of potentially reactive aluminosilicate fraction in the ash has been determined by means of test in NaOH. The final properties of geopolymers prepared with or without taking into account this reactive fraction have been compared. The results showed that due to the presence of both amorphous and crystalline fractions with a different degree of reactivity, the incinerator BA geopolymers exhibit significant differences in terms of Si/Al ratio and microstructure when reactive fraction is considered.     

PET containers in Brazil: Opportunities and challenges of a logistics model for post-consumer waste recycling

The use of post-consumer materials is directly related to reducing the cost of production and extraction of natural resources. Non-recyclable materials are randomly disposed in the environment. Brazil is one of the largest consumers of PET (polyethylene terephthalate) bottles. The purpose of this paper is to describe the opportunities and challenges of the logistics model for post-consumer PET bottle recycling in Brazil, while providing knowledge of its practices along the recycling chain. The results describe the need to educate those directly and indirectly involved in the process; to reduce consumption in order to reduce the amount of waste generated; to structure the post-consumer reverse chain and engage industrial sectors and government, through public policies, to support cleaner technologies along the PET bottle production chain.     

Financing electronic waste recycling Californian households' willingness to pay advanced recycling fees

The growth of electronic waste (e-waste) is of increasing concern because of its toxic content and low recycling rates. The e-waste recycling infrastructure needs to be developed, yet little is known about people's willingness to fund its expansion. This paper examines this issue based on a 2004 mail survey of California households. Using an ordered logit model, we find that age, income, beliefs about government and business roles, proximity to existing recycling facilities, community density, education, and environmental attitudes are significant factors for explaining people's willingness to pay an advanced recycling fee (ARF) for electronics. Most respondents are willing to support a 1% ARF. Our results suggest that policymakers should target middle-aged and older adults, improve programs in communities with existing recycling centers or in rural communities, and consider public-private partnerships for e-waste recycling programs.     

Integration of the recycling processes to the life cycle analysis of construction products

The life cycle analysis of a product enables one to assess its environmental quality. A simple, transparent method taking into account the processes of recycling in the life cycle is developed here. It permits dealing with all types of open loops of all sectors. The principles on which the proposed method is grounded are discussed.     

废弃家电的环境危害及其黑色金属的再生资源化

废弃家电对环境的污染日趋严重，同时废弃家电中含有大量可再生利用的资源。论述了废弃家电中黑色金属再生利用的现状，分析了废弃家电的材料组成特点和再生黑色金属中夹杂元素的危害及其在冶炼中的行为，并提出应开展废弃家电中黑色金属再生利用技术的专门研究。     

冷却水处理中臭氧的阻垢作用研究

试验研究了臭氧在循环冷却水处理中的阻垢作用.结果表明,在蒸馏水中,臭氧不能直接参与碳酸盐平衡体系,不影响碳酸钙沉淀的晶型.但是,在工业水质条件下,通入臭氧后,可以影响所形成的碳酸钙晶体的稳定性.在冷却水中,臭氧与某些能和Ca2 发生配位作用的物质发生氧化还原反应,造成体系中醛基和羧基的总数增加,使水对钙的配位能力增加,致使水中的Ca2 浓度增加,从而产生一定的阻垢效果.臭氧可以氧化循环冷却水中的有机物,生成二氧化碳,水溶液中二氧化碳浓度的增加,可使碳酸钙转化为碳酸氢钙,这样就使冷却水中Ca2 浓度增加.当水中不含有机物时,臭氧没有阻垢作用.     

An Eco-balance of a Recycling Plant for Spent Lead–Acid Batteries

This study applies Life Cycle Assessment (LCA) methodology to present an eco-balance of a recycling plant that treats spent lead–acid batteries. The recycling plant uses pyrometallurgical treatment to obtain lead from spent batteries. The application of LCA methodology (ISO 14040 series) enabled us to assess the potential environmental impacts arising from the recycling plants operations. Thus, net emissions of greenhouse gases as well as other major environmental consequences were examined and hot spots inside the recycling plant were identified. A sensitivity analysis was also performed on certain variables to evaluate their effect on the LCA study. The LCA of a recycling plant for spent lead–acid batteries presented shows that this methodology allows all of the major environmental consequences associated with lead recycling using the pyrometallurgical process to be examined. The study highlights areas in which environmental improvements are easily achievable by a business, providing a basis for suggestions to minimize the environmental impact of its production phases, improving process and company performance in environmental terms.     

Household Demand for Waste Recycling Services

Municipalities everywhere are coping with increasing amounts of solid waste and need urgently to formulate efficient and sustainable solutions to the problem. This study examines the use of economic incentives in municipal waste management. Specifically, we address the issue of recycling, if and when this waste management option is—on social welfare grounds—a preferred solution.A number of studies have recently assessed the monetary value of the externalities of alternative solid waste management options. In the present context, these subsidies could be interpreted as the implicit value of the benefits from reducing environmental externalities associated with landfilling as perceived by local government authorities. We surmise that the difference between mean households willingness to pay (WTP) for recycling services, via the purchase of a subsidized waste disposal facility, and the above (proxy) value of externalities reflects the difference between private and public perception regarding the negative externality associated with landfilling. We believe that this information is useful in determining the level of subsidization needed (if at all) to sustain any recycling program.The study is unique in the sense that its conclusions are based on revealed household behavior when faced with increased disposal costs, as well as information on WTP responses in hypothetical but related (and, therefore, familiar) scenarios. The article also explores the influence of the subsidization schemes on recycling rates. It was found that with low levels of effort needed to participate in a curbside recycling program, households participation rates are mainly influenced by economic variables and age, and households are willing to pay a higher price for the recycling scheme. When the required effort level is relatively high, however, households would pay a lower price, and the rate is influenced mainly by their environmental commitment and by economic considerations. We found that in both cases a subsidy would be required in order to achieve an efficient level of recycling. The median price that households are willing to pay for recycling devices is found to be about NIS 370 (New Israeli Shekel, approximately $90).     

Scrap tires to crumb rubber: feasibility analysis for processing facilities

Crumb rubber can be produced from scrap tires in a wide range of particle sizes and quality levels. Ideally, the revenue stream includes tipping fees paid to receive the raw materials; sales of variously-sized crumb products to different end-user markets; and potential sales of scrap metal and fiber contained within the tires. General demand has been increasing, and submarkets for crumb products are growing in size and variety. However, the optimistic expectations of potential investors and government agencies contrast sharply with the experiences of many current and former producers. Production planning and operation is complex, real-dollar crumb prices have fallen, and many producers recount difficulties finding stable markets and competing against newer, state-subsidized competitors. This paper examines the engineering economics of crumb rubber facilities. Following a literature review and interviews with producers, a financial model of a nominal processing operation was created to aid the analysis of different market, crumb size, and production scenarios. The profitability of a crumb facility appears to be particularly sensitive to crumb rubber prices, operating costs, and raw material availability. Better analysis of market and production impacts on financial viability for proposed processing facilities would aid overall market efficiency.