Resources, conservation & recycling advances最新文献

Popular media has reinforced ideas of what products are or are not environmentally detrimental, often only considering a fraction of the overall product life cycle, such as the end of life for single use products, or a single environmental consideration. This leads to counterintuitive sustainability examples, where a product is commonly thought to be much more environmentally impactful than its counterparts, but that actually is not universally true. Single use plastic drinking straws are one such example, which were used as the course project in a project based life cycle assessment (LCA) course. Students’ perceptions of which straws were the best and worst for the environment were surveyed both before and after the course, in order to see first the effect of the popular media on the initial ranking and second how the ranking changed after completion of the course project. Reflections on the course experience were also utilized to gauge how the students’ understanding of both LCA and sustainability changed as a result of the course. In general, students’ understanding of which straw option had the greatest and least environmental impact changed as a result of the course, in particular enabling a more nuanced view of environmental impact. The guided student reflections indicated four major areas of focus regarding the relationship between sustainability and LCA: LCA as revealing truth, LCA for decision making, single use products are not always the most environmentally impactful, and using LCA to change their concept of what is sustainable.

Circular Economy (CE) has received widespread attention from various stakeholders as a preferred solution in response to global issues of environmental changes and resource scarcity. The Australian state of Victoria is in the process of transitioning to CE. In comparison to other states and countries, the literature and practice related to CE implementation in this state are limited. In this context, the research aims to understand CE development through the investigation of CE awareness, drivers, challenges, enablers, and barriers across stakeholders. Semi-structured interviews with major stakeholders were employed to understand how to optimise a CE transition. The research findings suggest that enhancing CE understanding with a focus on CE systems, principles, and processes is crucial to support a genuine CE transition and reduce misinterpretation of CE in being synonymous with recycling and waste management. The relationship between enablers, challenges, drivers, and barriers contributes to the development of CE strategic plans and roadmaps for a state-wide transition.

Incineration has been widely used to dispose municipal solid wastes (MSWs) with heat recovery. The generation of fly ash (FA, around 3∼5 wt% of the fed amount) that is normally defined as hazardous wastes remains a serious problem. It is ideal to work out a way to reutilize FA for valuable use instead of landfilling. As a novel utilization technology for municipal solid waste incineration (MSWI) fly ash, geopolymerization can produce geopolymer as construction materials with the advantages of low energy consumption, low pollution and high utilization rate. In this paper, metakaolin (MK) and washed fly ash (WFA) were used to prepare MSWI fly ash-based geopolymer (FAG) with alkali activator. Besides, the strength, heavy metals immobilization and acid resistance of FAG were in detail studied. Under the proper formulation, all the prepared FAGs exhibited strength higher than MU15 level (≥15 MPa) and the maximized one reached MU30 (≥30 MPa). Heavy metals including Cr, Mn, Cu, As, Pb, Zn and Cd had a immobilization rate of more than 92%, and others like As, Pb and Zn were nearly fully immobilized. As for the simulated testing for acid rain scenario, FAG could still fix up the heavy metals well indicating a controllable risk for the environment, which could be ascribed be its high acid neutralization capacity. In a word, this work reports a feasible method for treatment and resource reutilization of MSWI fly ash.

Cobalt is an element in high demand for products manufactured and used in the United States. However, a detailed estimation of future cobalt needs under different conditions for specific product groups is still lacking. In the present work, we build upon the Shared Socioeconomic Pathways scenarios such that they address cobalt demand, use, recycling, and loss in the United States from 2020 to 2050. We find that cobalt demand depends strongly on energy storage (highly dependent on electric vehicles) and superalloys (highly dependent on international air travel). If the United States were to substitute cobalt in batteries and superalloys with alternative materials and, at the same time, set up efficient battery recycling programs, it could eventually recover more cobalt than it needs, allowing potential cobalt sales to other countries.

Hydroxyapatite (HAP) precipitation is considered to be one of the most promising approaches for phosphorus recovery, though it often requires sophisticated control of local pH, the concentration of Ca²⁺ and PO₄³⁻ to minimize the side effects. In many cases, additional Ca sources are needed to adjust the pH and Ca concentration of the solution, that makes the cost of HAP precipitation process relatively high. Herein, we studied the possibility of using Ca-rich fly ash (CFA) as Ca sources and pH adjuster to provide suitable environment for HAP precipitation from the toilet press filtrate. The main factors that affect the HAP formation were identified and the performance of CFA on P recovery from real toilet press filtrate was examined and the mechanism was proposed. Rsults indicated that the strong buffering property of CFA rendered it workable in a wide pH range from 5 to 12. Products characterization and Visual MINTEQ simulative analysis illustrated that the removal of PO₄³⁻ by CFA was mainly through the formation of HAP. Moreover, the results of PO₄³⁻ removal by CFA in toilet press filtrate proved that when the concentration of CFA was 4 g/L, the removal rate of PO₄-P reached 87.0%.

The application of the circular economy (CE) in the building industry is critical for achieving the carbon reduction goals defined in the Paris Agreement and is increasingly promoted through European policies. In recent years, CE strategies have been applied and tested in numerous building projects in practice. However, insights into their application and decarbonisation potential are limited. This study analysed and visualised 65 novel real-world cases of new build, renovation, and demolition projects in Europe compiled from academic and grey literature. Cases were analysed regarding the circular solution applied, level of application in buildings, and decarbonisation potential reported, making this study one of the first comprehensive studies on the application and decarbonisation potential of circular strategies in the building industry in practice. The identified challenges of using LCA for CE assessment in buildings are discussed and methodological approaches for future research are suggested.

The work presents on the relationship between temperature, time and carbon content in the preparation of a carbon fibre cloth from end-of-life cotton textiles. The aim of this investigation was to identify the minimum energy requirements for this textile recycling opportunity. The composition of the carbon fibre was studied using elemental combustion instruments and X-ray fluorescence. The structure of the carbon fibres was studied through scanning electron microscopy and X-ray diffraction. Through this process it was determined that the optimum temperature and time requirements were 1150 °C and 30 min to prepare a carbon fibre under the conventional definition, which requires carbon content to be in excess of 90%. The minimum temperature and time requirements for a lower grade carbon fibre of 80% carbon content are 650 °C and 30 min. This research can support efforts to improve circularity of cotton textiles for high value applications in environmental management or electronic markets. This in turn could support these industries to reduce their carbon footprint and meet their sustainable procurement targets for greater uptake of recycled content materials.

This paper analyses the status quo of the circular economy in Andalusia with the special focus on public and non-governmental initiatives in the field. Regional authorities have undertaken a number of actions in order to stimulate public-private collaboration and implementation of projects that can benefit from the EU funding aiming to accelerate the transformation of Andalusian economy and to make it more circular and less carbon intensive. While the private enterprises in the region focus mainly on recovery of agricultural and food waste, the citizen initiatives target primarily the reduction of residential waste, promoting the reutilization of furniture, home appliances and closing.

Unfortunately, the initiatives of Andalusian authorities often lack harmonization with both the EU and Spanish strategies in the field. The main documents that govern the development of circular economy in the region frequently set imprecise qualitative goals, rather than binding quantitative targets to be achieved within a certain period of time. As a corollary, there is a poor coordination among the public administration, business sector and the society and insufficient provision of public funding for circular projects.

We, therefore, recommend Andalusian government to build up the framework of regulatory, fiscal and economic tools that can incentivize the circular economy and to increase transparency, monitoring, reporting, and recognition of progress. It is essential to introduce both the rewarding and penalization schemes that enable behavioral changes of producers and consumers, to set the concrete numerical goals and to harmonize the main programs with the Spanish and the EU strategies in the field of circular economy.

Steel and cement industries are essential for developing economies and challenges for global climate change mitigation. Low carbon (LC) forecasting that couples steel and cement, focusing on circular economy (CE) and industrial symbiosis (IS) concepts, are scarce. Considering such concepts, this paper proposes an intersetorial model for these industries, based on the Brazilian case. The findings indicate sustainable charcoal-based steelmaking as the greatest CE emissions abatement measure. Regarding IS, we have found that the more fly ash is available, the lower is the average abatement cost, but such an strategy is not gainful for overall abatement, given sizable coal-fired power plants’ emissions. CE and IS can avoid 2.75 billion tCO₂e or 52% of the business-as-usual emissions up to 2050 at US$ 10/tCO₂e by intensifying existing processes in Brazil. CE and IS approaches extend the opportunities for economic savings and carbon reduction, therefore they must be part of future LC portfolios.

Existing scenario models of future material flows often exclude or place a ‘black-box’ around the mining industry and disregard important industry dynamics such as mineral exploration. This lack of sophistication prevents formation of knowledge required to answer key questions pertaining to future mining output, the amount of companion metals that can be supplied and the investments and lead times needed to fulfil future metal demand. To address this, we introduce the Primary Exploration, Mining and Metal Supply Scenario (PEMMSS) model, which allows for mine-by-mine modelling with full regionalisation and linkages to geological deposit types. PEMMSS allows for the assessment of required rates of mineral deposit discovery, mine development and co-product recovery overtime for a range of socio-economic and sustainable development linked primary material demand scenarios. The model can be calibrated using mineral resource grade, tonnage and density probability distribution functions for regions and deposit types to stochastically model scenarios for future greenfield discoveries and understand uncertainities. Applying PEMMSS will facilitate improved understanding of how future urbanisation across the globe and low-carbon transitions will translate into altered requirements for the exploration and primary mineral and metal supply sectors and their associated environmental impacts. A hypothetical case study is presented for a four co-product commodity system to highlight potential model behaviours and key drivers of model sensitivity.