Resources, conservation & recycling advances最新文献

The conversion of surf clam shells (SCS) and ocean quahog shells (QS) into three different grades of CaCO₃ products using water and lower-temperature processing was investigated. Coarsely ground shells were boiled in water for 2 h and then washed and dried, followed by fine grinding and heating. To produce the highest quality of CaCO₃, the washed ground shells were processed at 300 °C for 2 h. Process modeling and economic analysis were performed on these three products using SuperPro Designer. For a processing plant with an annual capacity of 10,886 MT of waste shells, the highest grade CaCO₃ product had the highest predicted economic performance with a net present value of $4.3 M, an internal rate of return of 12.7 %, and payback period of 5.6 years. The sensitivity analysis showed plant capacity and selling price were the predominant variables that affected production economic feasibility.

This study develops a framework for an assessment of the integrated processing of various types of waste in a single waste-to-energy (W2E) facility. The FUNdamental ENgineering PrinciplEs-based model for Estimation of Cost of Energy from Biomass and Municipal Solid Waste (MSW) (FUNNEL-Cost-Bio-waste) was developed and used to assess the conversion of MSW, agricultural residue, forest residue, and waste heat to electricity via gasification. A geographic information systems (GIS)-based model was developed to estimate the availability of wastes at collection points and the transportation distances to the facility. A case study for Alberta (Canada) was conducted to assess the techno-economic feasibility of a 199 MW gasification-based facility. Depending on whether one or two waste heat sources are used for drying MSW, internal rates of return and the costs of generating electricity were estimated to be 11.18 % and 8.09 % and US $21.90/MWh and US $33.23/MWh, respectively. This information can be used for investment decision-making.

A structure's sustainability depends not only on its components, but also on the manufacturing process. The adhesive layer mostly increases the structural weight, reducing weight-specific properties, beside hindering its disassembly and sorting at end-of-life. This study investigates an alternative joining method based on ultrasonic welding for upcycled honeycomb core sandwich panels. Thermoplastic composite skins, reinforced with flax or glass fibres, are connected to an upcycled polyethylene core made from disposed bottle caps and tested under quasi-static and dynamic loads. A life cycle assessment evaluates the environmental benefits of skin/core welding compared with adhesive bonding. Welded panels made from similar skins and cores presented similar to higher weight-specific flexural properties of adhesive-bonded structures (up to 45 % increase), while specific energy absorption under impact is increased by up to 23 % with welded joints. Skin/core welding reduces the panel environmental damage by up to 71 %, with an increment of up to 130 % in its eco-mechanical efficiency.

Littering is a problem in many human societies. In this study, 9 individual street bins were manipulated on a central street in the city of Gävle, Sweden. The aim was to explore if changing the appearance of the bins, thereby manipulating the different types of social norms they signal, can increase the amount of trash they collect and mitigate littering. A field experiment tested the effectiveness of two alternatives to the conventional grey street bin; one bin foliated with pictures drawn by school children containing a normative anti-littering message (explicit norm), and one bright orange salient bin (implicit norm). Observed behavioral data was collected, and both the weight and volume of trash in the bins were measured each day for a period of one month. The results showed a tendency for the salient orange bin to increase trash collection compared to other bins; an effect most tangible towards the end of the weeks. The biggest effect was, however, that the explicitly normative bin reduced trash collection overall. These results provide lessons on how the appearance of bins can influence trash collection, potentially resulting in both desirable and undesirable outcomes.

Wastewater treatment processes produce large amounts of excess biological sewage sludge, which disposal requires large amounts of energy and expenditure, and is not devoid of adverse environmental effects. Economic and sustainability considerations suggest that embedded resources in sludge (energy, nutrients, raw materials and process by-products) should be properly exploited to create and consolidate a virtuous wastewater-based Circular Economy cycle. This paper presents a review of sludge-to-energy and sludge-to-resources recovery routes with emphasis on recent developments, as well on the benefits and limitations of applicable technologies for ensuring sustainability and environmental efficiency through a critical analysis of current literature. In particular, improvement of anaerobic digestion final products exploitation, thermochemical technologies for sludge-embedded resources recovery, sludge biorefinery and nutrients recovery are discussed. In most cases, however, the technology readiness level (TRL) of the described technologies is still low for generalized adoption, hence, notwithstanding the excellent development prospects, it is probably still too early to predict the real impact of the many bioproducts recoverable from biological sludge on an actual global circular bioeconomy.

Companies design circular business models through experimentation. However, most companies do not consider the environmental impact of their new business model ideas during experimentation, an iterative phase of high uncertainty. Previous research shows that companies typically use ‘rules of thumb’ to estimate environmental impact in this stage due to limited time and reliable information to guide decision-making. This might prevent innovators from detecting unintended rebound effects that offset positive environmental gains of new business models. To mitigate this and let innovators think more profoundly about rebound effects during the circular business model experimentation phase, we propose an evidence-based business model ideation tool, the Circular Rebound Tool, designed around lifecycle thinking, the zero-waste hierarchy, and increased rebound effects awareness. The tool's development follows the design science research method, undergoing continuous improvement through 15 workshops. Our tool can help business innovators gain insights into the environmental impact of their early-stage business ideas.

An increasing rate of urbanization, lack of knowledge, low willingness to pay for sustainable waste management, and absence of legal landfills inhibit the rate at which Circular Economy (CE) is implemented. The successful CE adoption for construction and demolition waste (CE-CDW) involves navigating a complex tapestry of interconnected factors that enable or inhibit CE-CDW success. We used a participatory system thinking and modeling approach to analyze the interaction of inhibiting factors that impact CE-CDW in Aysén, Chile. Barriers to CE-CDW were identified in the literature and modeled in a workshop with experts from different areas of construction industry, policy, and academia. The emerging CE-CDW system model was analyzed using structural factor and network analysis techniques to identify leverage points for policy and practice. Findings pointed to limited strategic vision of policy and regulation as a key barrier impacting the necessary financial and technical elements needed to implement and scale-up CE-CDW.

Low-carbon policies will have a significant impact on air quality. This study builds an integrated assessment model to systematically assess the impacts of different carbon neutral pathways and air pollution control policies in Shaanxi province. We found that the contribution rate of low-carbon policies to air quality improvement will be greater than end-of-pipe control. Carbon neutral pathways could prevent 5 to 10 thousand premature deaths and bring 5.7 to 10.4 billion USD in environmental health benefits. From the perspective of cost-benefit, low-carbon policies can bring positive benefits of 0.27% of GDP before 2030. Carbon reduction costs will increase rapidly after 2035, and the loss of total social-economic benefits in 2060 is 3.16% to 16.57%. Achieving carbon neutrality means a disruptive technological shift, reducing the policy costs of climate governance by aggressively developing more zero-carbon and negative-carbon technologies.

Current building design practices largely focus on operational efficiency and initial material optimisation in the pursuit of sustainable construction. These short-term carbon savings are potentially detrimental to the long-term futureproofing of a building. As such, the suggestion to design buildings for adaptability has gained traction in recent years. An adaptable building is one that could be easily modified to suit its changing requirements, allowing it to avoid premature demolition and reconstruction, and the associated carbon emissions. This paper explores what is meant by adaptability in the built environment, suggestions for design strategies and the benefits and drawbacks of each. The paper expressly emphasises the importance of balancing the needs of the present day, through upfront carbon reductions, with the consequences in the long-term, through accelerated building obsolescence, demolition and rebuild. The paper concludes with the recommendation that further research is needed into the true benefits of adaptability design strategies, factoring in the uncertainty of future predictions and the time-value of carbon.

The manufacture of building materials consumes vast quantities of raw materials and accounts for a large proportion of global material flows and GHG emissions. Recycling demolition waste is thus a useful and practical way to conserve resources in the construction sector. For climate protection, it is important to investigate the material-induced grey energy of the recycling process. In this study we ask how grey energies induced by construction products based on secondary differ from equivalent products based on virgin materials. To evaluate this, we use a novel multi-stage assessment method presented in this paper. With this method, for the first time, we are able to calculate grey energy of entire recycling process chains starting from construction and demolition waste and ending with the new secondary material based building product, taking into account all the adjustments necessary to guarantee its functional equivalence to primary material based products. In 15 of the 19 process chains analysed, the use of RC material leads to in part rather significant positive grey energy impacts i.e. energy savings. In nine cases, the savings are over 50%, in six cases they are lower. The most important influential factors is the quality of both, the initial demolition material and the final construction product, defined by the product requirements. Furthermore, we conclude that an integrated recycling system is essential to ensure the recycling of co-products discharged during individual processing steps and provide evidence for further scientific discussion on how recycling can contribute to climate-neutral construction.