Resources Conservation and Recycling最新文献

Organic agriculture (OA) is the promoted sustainable agriculture model in the European Union (EU), yet its expansion is hindered by limited nutrient availability, particularly nitrogen (N). OA's main sources of N include biological N fixation by legume crops and manure from both conventional and organic livestock. However, potential stricter EU regulations on allowed external N resources for OA and pressure to reduce livestock numbers could impact N availability in OA. Understanding national-scale N flows is essential. Here, we analysed N flows in organic agri-food systems in France, the largest OA area in Europe. We show that approximately 20 % of the manure used to fertilise organic cropland came from conventional agriculture and 15 % from the dietary N nutritional requirements of organic livestock imported from outside France. N surplus is half that of the conventional agriculture at national scale. This first national assessment highlights biophysical and regulatory constraints providing insights into the possibilities of achieving the EU's target of having 25 % of agricultural land under OA.

Cement is responsible for the high carbon emissions reputation of the concrete industry. To cope with this issue, compression cast technology (CCT) is introduced as a potential low carbon production method for concrete components, as it could reduce the cement consumption and improve the mechanical performance. To evaluate the carbon reduction benefits of adopting the CCT in concrete components production, the Life Cycle Assessment (LCA) method is employed and carbon emissions per unit of compressive strength (CECS, kgCO₂eq/MPa) is selected as the main indicator. The results indicate that the CECS of concrete with CCT decreased by 21 %-45 % compared to conventional concrete. Considering the carbon reduction benefits of avoiding waste disposal, the CECS of concrete with CCT decreased by 7 %-43 % compared to green concrete using conventional cast technology with similar strengths. If adding waste rubber in concrete with CCT, its CECS could be decreased by 28 %-93 % compared to conventional concrete. If promoting the CCT in the concrete industry, the annual carbon emissions of the global concrete industry can be reduced by 7 %, 14 %, 20 %, and 27 % with replacement ratios 25 %, 50 %, 75 %, and 100 % from 2015 to 2060. The study indicates that implementing the CCT during concrete components production can significantly reduce carbon emissions of the concrete industry and the study provides guidance for carbon reduction efforts in the concrete industry.

Escalating demand for textiles has led to the entire supply chain contributing 8 % of global GHGs emissions. However, the carbon footprint (CF) and low carbon pathways of polyamide textile production remain ambiguous. Herein the CF of polyamide textile in China is evaluated using a "cradle to gate" life cycle system boundary allowing for comparison with other textile categories. To explore low carbon pathways of polyamide textile production, we introduce four groups of measures resulting in 12 scenarios. The CF of 1 kg polyamide textile is 35.37 kg CO₂-eq, 1.38 and 3.91 times that of polyester and cotton textiles, respectively. Direct emissions from energy combustion, and indirect emissions from raw materials and energy production contribute 43.87 % and 56.13 % of the total CF. Emission reduction potentials vary from 51.37 % to 88.52 % across scenarios. These explored low carbon pathways should serve as references for achieving low and net zero emissions in the textile sector.

Pre-consumer PET fabric scraps and post-consumer PET bottles, two common PET waste streams, are difficult to break down by the reported PET hydrolases. Our findings indicate that the lack of cold crystallization enthalpy (ΔH_c) is a key factor determining their low enzymatic degradability. Melt-quenching pre-treatment, with 0 °C water as the most effective quenching medium, can successfully raise ΔH_c in PET fabrics and bottles. Pre-amorphized PET fabrics and bottles showed a 54- and 404-fold increase in conversion rate by the LCC^ICCG enzyme as compared to their pristine counterparts, respectively. The technical-economic feasibility and energy effectiveness of the tandem pre-amorphization and enzymatic hydrolysis strategy for recycling pre-consumer PET fabric scraps and post-consumer PET bottles were assessed by constructing a kilogram-scale process, respectively. The results indicate that this efficient, energy-saving, and cost-effective method has greater economic potential for recycling pre-consumer PET fabric scraps than post-consumer PET bottles.

Aquaponics presents promising green technology for food security and climate change. This study investigated the performance and nutrient dynamics in a novel aquaponics with onsite anaerobic treatment compared with conventional decoupled and coupled aquaponics. All systems demonstrated good performance with fish survival rates of >97 %, feed conversion ratios of 1.3, and high lettuce production of 6.9–11.8 kg/kg-feed. The recovery of N and P (from their concentrations in the feed) was 21 % and 16 % respectively in the decoupled aquaponics, and 24 % and 18 % in the coupled aquaponics. Recovery of N and P in the novel aquaponics was 41 % and 36 %, respectively, which led to enhanced total nutrient utilization efficiency of 76 % N and 80 % P. The latter was due to the high recovery of N and P from the fish sludge. The novel system also demonstrated 1.6× higher plant areal productivity, 2.1× lower water usage, and 16 % less energy consumption per kg of feed relative to the other tested (conventional) systems. It was postulated that coupled aquaponics with anaerobic digestion is a sustainable solution that may promote a circular economy, especially in arid zones with high radiation and temperature.

Delivering efficient, affordable and sustainable water treatment methods in the removal of heavy metals in wastewater often remains a challenge. This paper seeks to alleviate this challenge by reviewing and assessing the viability and efficiency of different water treatment methods within the realm of end-of-life (EoL) photovoltaic (PV) module recycling. Specifically, this paper evaluates the possible designs, pretreatment requirements, efficiency, relative cost and environmental footprint of adsorption, ion exchange and membrane process, applications of physical-chemical and tertiary treatments, to protect the receiving environment and realise treated water reuse in EoL PV module recycling process respectively. The current results suggest that the membrane process is a promising solution to the various heavy metals removal in EoL PV recycling due to its comparatively good performance in efficiency and environmental footprint. Meanwhile, specifical efforts should be put into the development of cost competitiveness membrane that excels in EoL PV recycling. More importantly, exploring the potential combination of different water treatment methods could also greatly broaden the range of solutions available for addressing the existing water issues in EoL PV recycling.

Plastics play a vital role in modern society but their non-biodegradable nature has led to environmental concerns. Biomass-derived biodegradable bioplastics offer an eco-friendly alternative and protein and starch-based bioplastics, sourced from agro-food residues, are gaining prominence due to their renewability. However, many bio-based materials face challenges and developing efficient processing methods is crucial for their industrial viability. Optimizing particle size and plasticizer proportion is vital to tailor the properties of bioplastics. This study evaluates rice bran-based bioplastics, produced via injection molding, considering particle size and the impact of glycerol ratio. Smaller particle sizes enhance interactions during processing and, the conditions achieved during mixing determined the relevance of biopolymer–plasticizer and biopolymer–biopolymer interactions, leading to different behaviors depending on their balance. The processability and final properties of the materials developed were also affected by the glycerol ratio, with higher rice bran proportion leading to better rheological and mechanical properties.

Understanding the scale transmission of the drivers underlying carbon sequestration and oxygen release (CSOR) is essential for climate change mitigation. However, the regional differences in the global contribution of the drivers remain unknown, limiting the effectiveness of climate policies. Based on the United Nations’ geographical divisions and data from 2000 to 2020, we show that vegetation, evapotranspiration, and temperature are the main contributors to CSOR in more than 70 % of the world and that there are spatial differences in their action direction (facilitating or inhibiting). Drivers show nonlinear effects on CSOR and have different thresholds in different regions. Significant interactions existed among the factors, either superimposed enhancement or mutual offset, depending on the regions. If regional differences in drivers’ global contributions are neglected, attempts to address climate change in various regions may offset each other. Considering both top-down and bottom-up scale transmission can improve the effectiveness of policy objectives.

Transitioning to a circular economy (CE) may create unintended social consequences. This systematic review analysed 45 published studies from 2009 to 2023 that evaluate these consequences using social lifecycle assessment (S-LCA), a tool based on the UNEP Guidelines. Most studies focused on circular activities like energy recovery and material recycling rather than reuse, remanufacturing, and repair. Worker-related issues like health, safety or fair wages were more frequently reported than impacts on consumers or society. Challenges in S-LCA application for CE include defining system boundary, identifying affected stakeholders, selecting relevant impact categories and indicators, obtaining verifiable data inventory, and addressing subjectivity in impact interpretation. A solution identified through the review was to enhance stakeholder involvement across industries to identify emerging social risks during the transition to CE. Periodically revising the UNEP Guideline based on these risks will provide a uniform framework for continued use of S-LCA in evaluating the transition to CE.