Sewage-sludge-based activated carbon as a sustainable adsorbent for near-complete removal of 6PPD-quinone at environmentally relevant levels

The traditional linear economy has created unstainable development. A circular economy (CE) is considered as a crucial means and has been adapted by many governments to achieve sustainable development goals. By narrative literature review, this article aims to discuss the concepts of linear and circular economies and CE models, examine countries’ CE development experiences, and make recommendations for successfully adapting a CE. The findings show that a CE is different from a linear one in terms of the step plan, focus, system boundaries, reuse, and business models. The CE model includes slowing and closing resource loops and a narrowing of resource flows and is based on the foundation of renewable and non-toxic resources as well as through long-lasting design, and reducing, maintaining, repairing, reusing, remanufacturing, refurbishing, recovering, and recycling. Many countries around the world have adapted a CE model with different circularity levels with the main focus to reduce waste. The paper also recommends that a CE should be percieved as the central point of socio-economic development programs and policies that must address the full cycle, from product design to production processes, consumption, and recycling rather than having only a waste reduction focus. Producers should use a CE framework as the basis for product design, manufacturing, and recycling strategies. Consumers should change their perception of CE and adjust their behaviors towards making decisions to buy and consume toward circularity. Also, there is a need to change the perceptions of policy makers and other stakeholders on the CE concepts and framework.

A closed loop system for micro-level conservation of fresh water at household user point has been developed in this work in a comprehensive circular economy (CE) framework encompassing technical, environmental and economic aspects in a concurrent manner. The system has been developed through field survey of households in an urban setting in Indian context and experimental investigation on membrane filtration and recirculation of grey water generated from domestic use like cooking, bathing, washing etc. Pollution load of the grey water utilized in the sample involved high alkalinity (pH = 9.00), total suspended solid (TSS = 536 mg/L), odour (TON 2). Membrane based filtration process has been developed to ensure that the reclaimed water is of acceptable quality as alkalinity decreases to 7.2, TSS reduces to 95 mg per litre and odour in terms of TON reduces to one. Economic feasibility of implementing such a system is assessed by cost benefit analysis. Estimated annualized total cost (capital and operating) for treating and reusing a cubic meter of waste water in this CE framework amounts to US $1.5 only. Preference score derived from utility estimates of conjoint analysis (CA) reveal that consumers have positive attitude to accept water conservation strategy in circular economy framework. The ideal composition of reclaimed grey water to be preferred is odourless (TON value near 1), low TSS (less than 102 mg/L) and neutral pH (nearly7.00) The study reveals that about half of fresh water demand per day per capita can be saved by developing a closed-loop production system at micro level, where grey water generated as waste from domestic use is not discharged as followed in traditional open-ended economic model. Instead of take-make-use-discharge, waste water is added in the production system as a resource. After applying an advanced cost-effective clean technology, grey water is kept in a material loop and usage creating further value for a longer period. Sustainable water system development by this holistic circular water conservation approach is no longer an option but a necessity to protect the life-sustaining valuable freshwater resource. Developing water conservation system in closed-loop model provides a novel solution as it will yield positive and significant utility and economic value in a very cost effective green design.

There are several sustainability issues that the linear economy of today’s society cannot adequately tackle (i.e. resource depletion, waste treatment, etc.). As a result, the scientific community and policymakers give high priority to the implementation of the circular economy concept. The sustainable development goals of the United Nations are in line with the European Union’s (EU) commitment to a smooth transition to a circular economy. Circular business models require a shift in technical elements involving R strategies to replace traditional business models (i.e. reuse, reduce, recycle, etc.). Monitoring circular economy to provide quantifiable, measurable data is necessary for a successful transition. Monitoring tools (i.e. Key Performance Indicators, quality protocols) enable decision-makers to measure circular economy performance and identify circularity’s advantages and disadvantages. To stimulate the adoption of a circularity model addressing critical issues of excessive waste production and resource use, this mini review aims to address the literature gap of waste metrics in the framework of circular economy and offer insights on circular economy indicators to aid for a seamless transition to a more sustainable society. For this purpose, Preferred Reporting Items for Systematic Reviews and Meta-Analysis method was chosen to assess literature. The authors collected and analysed data from 101 records, 70 articles and 31 reports related to the topic under consideration. Through the literature review, it is obvious that moving away from linear production model frequently leads to the development of new internal capabilities along the value chain and, eventually, high efficiency that reduces costs, increasing productivity, encourages brand names, minimizes threats, creates new products and fulfils regulations and green consumer expectations.

Corporations, including automotive manufacturers, are increasingly exploring extended circular economy strategies as a means to enhance the sustainability of their products. The circular economy paradigm focuses on reducing nonrenewable materials and energy, promoting renewable feedstocks and energy, and keeping products/materials in use across the life cycle of a system. As such, life cycle environmental burdens associated with vehicle manufacturing, use, and disposal could potentially be reduced through circular economy strategies; however, no such comprehensive circular economy framework currently exists for the automotive industry. We develop the first circular economy schematic of automobiles, derived from the Ellen MacArthur Foundation's framework. Further, we characterize the current automotive circular economy using metrics of renewable energy and recycled materials. Specifically, for current U.S. average sedans, we find that internal combustion engine vehicles (ICEVs) use ∼6% renewable life cycle primary energy and 27% recycled materials; for battery electric vehicles (BEVs), these measures are ∼8% and 21%, respectively. On a vehicle‐miles‐traveled basis, BEVs use ∼47% less nonrenewable life cycle primary energy than ICEVs, highlighting the importance of electrification as a strategy for automotive manufacturers to reduce environmental burdens. Our proposed circular economy framework is then applied to Ford Motor Company's sustainability programs and initiatives as an example. This schematic aims to provide a starting point for the automotive industry to operationalize circular economy strategies, the application of which could advance its overall sustainability performance.

Circular economy (CE) is an approach that decouples economic activity from the consumption of finite resources, designs out waste, and instead promotes an economic model based on sharing, leasing, reuse, repair, refurbishment and recycling, in an (almost) closed loop. This extensive literature review identified and categorised CE practices within all stages of the food and feed production chain in Europe to provide an overview of current and envisaged practices. Four broad macro areas were identified within which CE practices are envisaged or currently used in Europe: primary production of food and feed; reducing industrial/manufacturing/processing waste; reducing food and feed waste in wholesale, food retail, catering and households; and reducing food and feed packaging waste. In each macro area, there were a variety of practices of interest regarding emerging risk to plant, animal, human health and the environment. Following consultation with EFSA and wider stakeholders, a focused literature search was carried out to identify emerging risks to plant, animal, human health and the environment from ‘novel foods and feeds within the framework of CE’. The literature showed a bias towards research investigating the suitability of novel feeds in terms of animal productivity parameters rather than on emerging risks of novel food/feed for animal, human, plant health and the environment. Those studies that investigated risk were almost entirely focused on the biological and chemical hazards, risks to health, and environmental impacts of insects as food or feed and the substrates that they are reared on. Emerging risks are characterised and recommendations made for future research. We recommend that future primary research in novel food and feed in the CE focuses on areas other than insect farming, and that there are further investigations into the potential risks associated with importation into the EU of livestock/goods that may have been subject to different restrictions/legislation.

Measuring Circularity: Tools for monitoring a smooth transition to Circular Economy

Acid-washed oil palm wood-based activated carbon (OPAC) has been investigated for its potential application as a promising adsorbent in the removal of glycidyl esters (GEs) from both palm oil and oil model (hexadecane) solution. It was observed that the removal rate of GEs in palm oil was up to >95%, which was significantly higher than other adsorbents used in this study. In batch adsorption system, the adsorption efficiency and performance of acid-washed OPAC were evaluated as a function of several experimental parameters such as contact time, initial glycidyl palmitate (PGE) concentration, adsorbent dose, and temperature. The Langmuir, Freundlich, and Dubinin-Radushkevich models were used to describe the adsorption equilibrium isotherm, and the equilibrium data were fitted best by the Langmuir model. The maximum adsorption capacity of acid-washed OPAC was found to be 36.23 mg/g by using the Langmuir model. The thermodynamic analysis indicated that the adsorption of PGE on acid-washed OPAC was an endothermic and physical process in nature. The experimental data were fitted by using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. It was found that the kinetic of PGE adsorption onto acid-washed OPAC followed well the pseudo-second-order model for various initial PGE concentrations and the adsorption process was controlled by both film diffusion and intraparticle diffusion. The desorption test indicated the removal of GEs from palm oil was attributed to not only the adsorption of GEs on acid-washed OPAC, but also the degradation of GEs adsorbed at activated sites with acidic character. Furthermore, no significant difference between before and after PGE adsorption in oil quality was observed.

Circular Economy: A Product Life Cycle Perspective on Engineering and Manufacturing Practices

The hidden concept and the beauty of multiple “R” in the framework of waste strategies development reflecting to circular economy principles

The construction sector is one of the largest contributors to global waste generation, posing significant environmental challenges. In response to this issue, the concept of circular economy (CE) has gained prominence as a sustainable framework for managing construction and demolition (C&D) waste. A bibliometric review analyzing the research trends in CE practices applied to C&D waste was elaborated in this study. The study utilizes a comprehensive dataset of scholarly publications in the Scopus database, spanning publications in the year 2014 to 2023, and employs bibliometric analysis using a two-step literature selection process to map the evolution of research in the field. The review identified key thematic areas, scholarly authors, prolific journals, and co-occurrence networks using VOSviewer software. The findings revealed a growing interest in circular economy approaches for C&D waste, with a surge in research output that focused on circularity in resource efficiency and material flow, life cycle assessment of materials, and circularity in material recovery and recycling. The insights derived from this study contributed to a comprehensive understanding of the current state of C&D waste and facilitated the identification of knowledge gaps within the circular economy framework. It also provided a roadmap for researchers, policymakers, and industry stakeholders to identify research gaps and sustainable solutions for managing C&D waste within the circular economy framework.

In circular economy framework, how to enhance enterprise competitiveness is a key issue. This article discussed the relationship between circular economy and enterprise competitiveness, proposed how to build enterprises competitiveness through perspective of circular economy. In detail, green R&D, technology improvement and innovation, clean production, and green management will be helpful to build enterprises competitiveness in circular economy framework. Besides, national policy and service support is important as well.

In the context of resource scarcity and food energy security in the midst of increasing food demand, the circular economy (CE) is a promising strategy to address the sustainable use of resources. This article aims to propose measurement elements in raw materials with recyclable concepts in implementing CE in the food and beverage industry. However, the CE framework has not been adapted to the needs of the Food And Beverages Industry. This article attempts to address this gap by analyzing the range of available indicators to measure trade in recyclable raw materials, namely by looking at the difference between the value of exports and imports. Thus, the differences in the CE framework can theoretically be adapted to the production system in the Food And Beverages Industry. So that the implementation of CE can be implemented in accordance with its functions, strategies and principles in managing a business model that replaces the concept of "end of life" by recycling raw materials which aims to create a quality environment, economic prosperity and benefits for future generations.

To decouple economic growth from environmental degradation, the Chinese government proposed the circular economy (CE) strategy as part of its 11th 5-Year Plan. This strategy expands the application of CE from individual enterprises to eco-industrial parks (EIPs) and to the cities, provinces, and regions. We carried out field studies in three EIPs in Baotou, Suzhou, and Shanghai. In this paper, we discuss the current state of CE and the sustainable development of EIPs in China. We first provide detailed information on the three EIPs' infrastructures, preferential policies, CE frameworks, and eco-chains. We then examine the status of sustainable development in the three EIPs from the perspectives of socio-economic, resource and material efficiency, and environmental performance. The results indicate that the overall performance of the three EIPs is reasonably good with respect to socio-economics, resources and materials, and efficiency and environmental protection, whereas green management is rather weak and thus requires further improvement. We found that the CE frameworks along with eco-chains within the EIPs are effectively improving resource and material efficiency. Moreover, we demonstrate that there are positive associations among socio-economic, resource and material, and environmental indicators. Given the large presence of EIPs in the local economies, these results suggest that EIPs play a key role in promoting sustainable development in China.

PurposeGiven the lacuna in sustainability studies which investigate collaborative supply chain relationships in the context of the circular economy (CE), the purpose of this paper is to explore how farmers manage stakeholder relationship in the supply chain to reduce food waste within the CE framework.Design/methodology/approachA qualitative approach using semi-structured interviews is used to collect primary data for this research. Interviews are conducted with farmers across different farming types in the UK. A thematic analysis is used to discuss the most prominent themes.FindingsThe findings extend previous research investigating collaboration in sustainability settings. Farmers adopt collaborative relationships to manage exchanges of food waste and to share knowledge of waste management practices. However, contrary to extant literature, the study finds that geographic proximity is still relevant in the CE framework, although its importance is determined by the type of exchange: i.e. physical or non-physical.Practical implicationsBased on the study’s findings, recommendations for further research are proposed. The study also advises on practical considerations for supply chain managers wishing to adopt collaborative relationships to support circular models of supply chains.Originality/valueThe study contributes to the sustainability literature by adding new knowledge to the relatively new theory of the CE. It demonstrates that factors of collaboration identified in previous sustainability research are still relevant in the CE framework, and thus require further investigation into the significance of collaboration. The study is also of relevance to supply chain managers wishing to adopt the CE framework in the transition to more sustainable supply chains.

PurposeThe circular economy (CE) is an evolving subject transitioning from conceptualization to empirical testing. Over the past decade, researchers have done an exhaustive study to understand the concept of CE and its realized values both financially and environmentally on organizations that have traditional business models based on linear consumption. For understanding the transitional phenomena completely, the paper aims to review the current and emerging research trends in CE to ascertain future direction.Design/methodology/approachThe research was conducted on 91 articles published in the study area during the past decade (2016–2021) in renowned peer-reviewed journals. The criteria set to review literature are based on the following assortment: CE drivers, CE barriers, definitions by different authors, yearly distribution of the publication, research publisher and journals, google citation and methodology used in the selected research articles.FindingsThe study suggests that researchers from the selected years are keen to understand the transition and its critical factors by bringing forward frameworks and incorporating CE with digital technologies. The digital technology implied are Industrial Technology (IR) 4.0, Big Data, Internet of Things (IoT), Artificial Intelligence, Blockchain and Data Analytics to increase organizational and environmental performance. CE researchers need to use empirical testing in different sectors to understand and bring forward more improvised business models and practices according to the dynamics of the industry.Originality/valueThe literature review suggests gaps exist to integrate the micro, meso and macro levels to get CE implementation's system-wide benefits. The study has also identified that many CE frameworks available in the literature for implementation must be empirically tested to yield performance results.