Recycling — Open Access Journal

Indium is one of the strategically important materials, which have been characterized as critical by various industrialized countries. Despite its high relevance, only low recycling rates are realized. Its main application is in indium tin oxide (ITO), which is used in the production of liquid crystal displays (LCD). However, recovery strategies for indium from LCDs are not yet being implemented in recycling practices. Although LCDs consist of a sandwich compound with additional materials such as glass (80% ± 5%) and polarizer foils (20% ± 5%), recently published recycling approaches focus mainly on the recovery of indium exclusively. This study, first of all, provides information about the quantity and quality of the materials applied in the LCD panels of the various equipment types investigated, such as notebooks, tablets, mobile phones, smartphones, PC monitors, and LCD TVs. The highest indium mass fraction per mass of LCD was determined in mobile phones and the least indium was found in smartphones. Additionally, we found the significant use of contaminating metals like antimony, arsenic, lead, and strontium in the glass fraction. Thus, specific recovery strategies should focus on selected equipment types with the highest indium potential, which is directly related to the sales of new devices and the number of collected end-of-life devices. Secondly, we have developed and successfully tested a novel recycling approach for separating the sandwich compound to provide single output fractions of panel glass, polarizer foils, and an indium concentrate for subsequent recycling. Unfortunately, the strongly varying content of contaminating metals jeopardizes the recycling of this output fraction. Nonetheless, economic recycling approaches need to address all materials contained, in particular those with the highest share in LCD panels such as polarizer foils and panel glass. Full article

Assessing product circularity performance is not straightforward. Meanwhile, it gains increasingly importance for businesses and industrial practitioners who are willing to effectively take benefits from circular economy promises. Thus, providing methods and tools to evaluate then enhance product performance—in the light of circular economy—becomes a significant but still barely addressed topic. Following a joint agreement on the need to measure product circularity performance, this paper provides an overview of mechanisms aiming to help industrial practitioners in this task. In fact, three existing approaches to measure product circularity performance have been tested on an industrial case study and criticized regarding both their applicability in industry and their accordance with circular economy principles. Although these methods and tools deliver a first and rapid trend of product circularity performance, the whole complexity of circular economy paradigm is far from being considered. In addition, operational guidance for engineers, designers or managers to improve their products in a circular economy context are missing. As a result, both recommendations for industrial practitioners and guidelines for the design and development of new frameworks, tools and indicators aiming at measuring product circularity performance are provided. This includes cornerstones, key requirements and practical implications to support enhanced circularity measurement that will be developed in further work, accordingly to circular economy paradigm and industrial reality. Full article

In cases where market policy instruments (e.g., taxes and quotas) are impractical tools to induce conservation behavior, information campaigns may be a valuable option. We use a difference-in-differences strategy to estimate the effectiveness a signage campaign for inducing paper recycling and reuse behavior in computer labs. We find that the implementation of signage with pro-environment appeals increases the probability of conservation behavior (i.e., recycling or reuse) by approximately 13%, despite the fact that pre-treatment levels of paper recycling and reuse were already at approximately 85%. Our results suggest that pro-environment campaigns can be an effective conservation tool and may be an important policy instrument for policy makers to consider. Full article

Several low-transition temperature mixtures (LTTMs), based on l-lactic acid and amino acids but also choline chloride, were synthesized and screened for their effectiveness in extracting antioxidant phenolics from industrial cereal solid wastes. In most cases, highly efficient LTTMs were those composed of l-lactic acid and choline chloride, but LTTMs composed of l-lactic acid and glycine or alanine also exhibited comparable extraction capacity. The extract from barley bran was shown to express powerful antioxidant activity, which was significantly higher than all the other extracts examined. This fact was attributed to the particularly high content in total flavanols. The data suggested that the most effective solvents, as revealed herein, merit further investigation as very promising means of extracting valuable chemicals from industrial agri-food residues. Additionally, barley bran should be more thoroughly examined for its prospect as a waste source of effective antioxidants, which could be used as nutritional supplements and active cosmetic ingredients. Full article

Households and businesses produce high levels of electrical and electronic waste (ewaste), fueled by modernization and rapid obsolescence. While the challenges imposed by e-waste are similar everywhere in the world, disparities in progress to deal with it exist, with developing nations lagging. The increase in e-waste generation highlights the need to develop ways to manage it. This paper reviews global and South African e-waste management practices with a specific case study on Cathode Ray Tube (CRT) waste. CRTs present the biggest problem for recyclers and policy makers because they contain lead and antimony. Common disposal practices have been either landfilling or incineration. Research into South African CRT waste management practices showed there is still more to do to manage this waste stream effectively. However, recent developments have placed e-waste into a priority waste stream, which should lead to intensified efforts in dealing with it. Overall, these efforts aim to increase diversion from landfill and create value-adding opportunities, leading to social and environmental benefits. Full article

The visionary concept of zero waste advocates a systematic process of designing out waste and recovering resources from waste. A strategic zero waste framework (ZWF) is essential for developing and executing systematic waste management activities to achieve the overarching goals. This study identifies the key principles for the development of a strategic ZWF based on a waste experts’ survey analysis. Around 68 experts from different regions responded and provided their views on the key elements of a strategic ZWF though an online questionnaire survey. Eighteen strategic elements of waste prevention, management, treatment and assessment were identified as the key principles of the zero waste framework. As the study followed a generalized approach, it is important to acknowledge that all identified and proposed strategic elements may need to be contextualized based on the local conditions in order to achieve zero waste goals. Based on the findings, the study suggests the following three fundamental strategic action plans that need to be implemented simultaneously for moving towards zero waste societies: (i) sustainable production through a cradle-to-cradle design and product stewardship; (ii) collaborative and responsible consumption of natural resources; and (iii) zero waste management through conservation of resources. In addition, a constant evaluation of progress towards zero waste goals is essential. It is anticipated that by considering local circumstances, the proposed strategic guidelines would be beneficial for local authorities and relevant stakeholders while developing their zero waste strategy. Full article

Fuel cell driven cars belong to the ‘zero emission’ vehicles and should contribute to lower CO₂ emissions. However, they contain platinum, which is known as a critical material in the European Union. This study investigated the potential contribution of recycling fuel cell vehicles (FCV) to satisfy the platinum demand arising from a widespread deployment of fuel cell vehicles in Europe. Based on a qualitative examination of the four consecutive steps in the recycling chain (collection, dismantling, disassembly and pre-processing, material recovery) of fuel cell vehicles, two recycling scenarios were developed. Using dynamic material flow analysis, these two recycling scenarios were applied to two scenarios for the market penetration of fuel cell vehicles in nine European lead markets to deliver both the associated impact on platinum demand and the contribution of recycling for meeting this demand. The diffusion of FCV in Europe will not cause a depletion of platinum resources in the short term, as the calculated 537.06 t and 459.24 t in cumulative platinum requirements are far below the currently estimated global reserves. However, concerns regarding the future development of platinum supply and demand remain. Full article

Soil contamination by mine wastes is an enormous challenge for both mining companies and competent authorities. Mine wastes are usually considered a major source of impacts on human health and the environment. Thus, the prevailing strategy is to reduce or completely remove the contaminants of concern through appropriate in situ or ex situ remediation techniques. Nonetheless, today’s mine waste may become tomorrow’s ore. In order to keep this option open, however, several things need to change in the concept and practice of mine waste management. This paper presents a case study from Greece, where mine waste (mainly metallurgical slags) have been disposed of, posing excess risks to human health and the environment. Complete restoration of the site would not only be cost-prohibitive but would also eliminate any possibility of future exploitation of contained resources. Considering both the protection of human health and the environment and the storage of waste for future use, a risk assessment and management approach was adopted that allowed the selection of cost-effective measures in order to: eliminate health hazards, re-use the site for recreational purposes, and secure the opportunity for resource recovery in the future. Full article

The volume of batteries, especially high-energy batteries, in electric and electronic devices is increasing. They are mainly used in small electric and electronic devices, e.g., mobile phones, laptops, household equipment, and tools. With regard to WEEE, these batteries will either remain in the used appliances or be removed by their users for separate collection. Batteries must be removed at the latest during dismantling in order to avoid loss or damage when WEEE is shredded. A representative sample of 2 mg of small WEEE was collected from take-back points in a German city in order to obtain an impression of consumer behavior. The batteries not removed from used electric and electronic appliances submitted by their owners were examined with regard to their type and condition, i.e., whether they were damaged or not. About 20% of all WEEE ran either completely or partially on batteries. Almost half of the batteries had been removed before the used electronic appliances were submitted at the take-back points. By contrast to standard batteries, the volume of special batteries (mainly Li ion or NiCd accumulators) remaining in the appliances amounted to about 75%. Some further conclusions on the way consumers handle batteries could be drawn from the results. Full article

The incessant disposal of drywall waste, generated predominantly from construction and demolition sites, has been associated with many environmental problems. In landfill sites, it has long been linked with the generation of hydrogen sulphide, a toxic and foul-smelling gas, while the incineration of this waste results in the potential release of sulphur dioxide gas, a contributor to acid rain formation. The traditional disposal methods also result in the loss of a valuable resource. Therefore, proper management of this waste through recycling programs and subsequent returns to the end market will ensure that a valuable resource is not lost and that environmental impacts are mitigated. Many potential end markets have been identified for recycled drywall. The application as a bulking agent for composting is one of these markets, which could also provide additional calcium and sulphur nutrients to the soil. Despite the benefits of drywall waste recycling, certain challenges have crippled its recycling rate in North America. This review summarises the current situations with drywall recycling and disposal, existing markets, and the availability of competing markets. Furthermore, the potential use of drywall as a compost-bulking agent is discussed. Finally, a possible solution to improving the recycling rate and market demands for drywall is presented. Full article

For over two decades China has faced a veritable e-waste challenge due to the continuous increase in quantities of Waste Electrical and Electronic Equipment (WEEE) coming from foreign and domestic sources. Over more than a decade, the government’s response has been focussed on developing large-scale recycling facilities so as to recover the valuable materials within WEEE. Simultaneously, China is home to a vast, informal segment, which engages in the collection, refurbishment, and processing (dismantling, extraction of components and materials) of obsolete electronics, thus directly competing with the formal system for devices and for the profits that they generate. The official discourse and most of the existing research concentrates primarily on WEEE recycling. However, project-based field research and interviews by the author in Beijing and Guangdong province have indicated that the repair, refurbishment, and reuse of discarded electronics are widespread and profitable practices of the informal domain. This paper aims to analyse the institutional, i.e., rule-based, mechanisms behind these activities and, via an institutional economics approach, to highlight how formal and informal rule-based practices structure WEEE refurbishment and reuse in China. The results show that informal activities are dominant due to the well-developed collection and transfer networks, the division of labour amongst informal actors, and the high responsiveness to market prices and consumer demand. Full article

Recycling information can be complex and often confusing which may subsequently reduce the participations in any waste recycling schemes. As a result, this research explored the roles as well as the importance of a holistic approach in designing recycling information using 15 expert-based (in-depth) interviews. The rationale was to offer a better understanding of what constitutes waste, recycling, and how recycling information should be designed and presented to make recycling more attractive/convenient. Based on the research participants’ perceptions with supports from the existing studies, this research sub-categorised recycling information into three different themes, termed the “WWW” (what, when, and where) of recycling information components. As a result, these components (or attributes) were extensively described (using findings of semi-structured interviews) to elicit pragmatic guidance for practitioners, policy-makers, and other stakeholders in designing structured communication or information strategies that may simplify and subsequently increase waste recycling practices. The policy implications of holistic information in enhancing recycling are further discussed. Full article

Developing cities have historically looked to developed cities as exemplary models for waste management systems and practices without considering the consequent resource requirements or the key characteristics of the local setting. However, direct adoption of developed cities’ approaches without proper consideration of the local circumstances may lead to unsustainable future waste management in developing cities. This study evaluates waste management in London and Kuala Lumpur, representing developed and developing cities, focusing on the integration of policy changes, socio-economic background and waste data trends on a multi-decadal scale. This analysis reveals the gradual implementation of initiatives, the challenges faced and the attempted solutions that were applied differently in both cities. Conceptual models of waste management status in different scenarios for both cities were developed. These models highlight that societal behaviour shifts from minimal waste generation (wasteless) to throw-away society (wasteful) and a drive to achieve sustainable waste behaviour with integration of resource recovery and waste minimization (wasting less). A detailed understanding of the evolution of waste management systems towards fulfilling public needs alongside rapid urbanization can provide new perspectives on future waste scenarios, especially in developing cities. Ultimately, reliable and accurate data are crucial to avoid inaccuracies in planning for future waste management. Full article

This paper provides an overview of ongoing European policy actions to improve the circular management of non-ferrous metals. After explaining why metals are at the center of the European Union’s circular economy initiative, the authors outline a number of issues that still need tackling to “close the loop”, and prevent Europe’s metals from being landfilled, incinerated, or exported without guarantee of high-quality treatment. Electronic waste is focused on in detail during this analysis, because of the special challenges in environmentally sound recovery of smaller quantities of valuable and precious metals. In particular, the authors find that a mandatory certification scheme for recyclers of electronic waste, in or out of Europe, would help to incentivize high-quality treatment processes and efficient material recovery. More generally, the article finds that the European Commission’s waste legislation proposals and Action Plan begins to address key challenges, provided the requirements are implemented strongly and consistently across Member States. In particular, it is crucial that EU policy establishes level playing field conditions for European metals recyclers Full article

The stockpiling of tailings around coal mines poses a major environmental problem. Nonetheless, this clay mineral (kaolinite)-based waste can be reused as a supplementary cementitious material (recycled metakaolinite) in the manufacture of future eco-efficient cements. This paper explores the most significant scientific questions posed in connection with the conversion of this waste into pozzolans, such as the variation in product mineralogy depending on the sintering temperature and its effect on reaction kinetics in the pozzolan/Ca(OH)₂ system over a period of 365 days. The findings show that the optimal sintering temperature is 600 °C, such that the cementitious properties of the activated product are determined solely by the conversion of kaolinite into metakaolinite and are unaffected by the other clay minerals (micas). The presence of 20% activated coal waste favors the formation of larger amounts of aluminous phases such as C₄AH₁₃ and C₄AcH₁₂ than in the reference paste and enhances C–S–H gel polymerization. Full article

This paper discusses circular economy (CE) as an option to mitigate the environmental impacts of mining operations, and a framework based on the three dimensions of sustainability, the possible uses of mining wastes, the life cycle, and the systems approaches to determine the policies that will induce initiatives towards designing out wastes for a mining-based circular economy. Previous research has been reviewed to determine CE configuration and the basis for the framework to guide in the development of CE-related mining policies. The Chinese model of circular economy, noted for the introduction of industrial symbiosis through eco-industrial parks at the meso level, and public participation at the macro level, forms the basic structure of the framework aimed at curbing mining waste, and closing the loop in mining. Holistic research is important in taking proactive CE technology actions, strategic measures, and policies, which can use life cycle assessment (LCA) methods (environmental and social LCA and life cycle costing) and systems dynamic modeling. With systems dynamic modeling, the framework introduced in this work can be expanded to cover as many important aspects as possible, and can check for areas of policy resistance that have been the reason for most policy failures. Full article

Composites of recycled high-density polyethylene and micro fibres of sugarcane bagasse were studied, in order to create an upcycled material to produce masonry bricks. We ranged the polymer/filler ratio from 100–0 to 60%–40%. The materials were assessed through scanning electron microscopy, thermogravimetry/derivative thermogravimetry, differential scanning calorimetry, rheological measurements and compressive strength test. The composites showed a good dispersion and adhesion of the filler into the polymeric matrix. There was no significant variation on the melting and crystallizing temperatures of the materials if compared to those of neat polymer, indicating that there was no relevant change in the average size of the polymeric crystals. We assumed that some transcrystallization has happened, because the degree of crystallinity of the composites increased to all filler contents, while the crystallizing temperature remained the same. There was a rise in the compressive moduli of the composites, ranging from 37% to 63%. The modulus at the crossover point and the complex viscosity also rose due to the fibres ratio. The results show that the combination of these materials led to the reinforcement of the compressive strength of the polymer, and have interesting properties as a potential building material. Full article

A novel natural low transition temperature mixture (LTTM), composed of glycerol and ammonium acetate (molar ratio 3:1), was tested for its efficacy as a solvent in recovering phenolics from chlorogenate-rich agri-food solid wastes, including potato peels (PPs), eggplant peels (EPPs), and spent filter coffee (SFC). The efficacy of this solvent was compared with other eco-friendly solvents, including aqueous glycerol, aqueous ethanol, and water. The LTTM was demonstrated to be by far the most efficient in extracting chlorogenates and superior or equally efficient with the other solvents in recovering flavonoids. LTTM extracts produced from waste were also more potent radical scavengers, but results on the reducing power were inconclusive. Liquid chromatography-diode array-mass spectrometry analysis showed that the polyphenolic profiles of all waste extracts obtained with the LTTM were rich in caffeoylquinic and p-coumaroylquinic acid conjugates. Full article

Worldwide volume production and consumption of engineered composite materials, namely fiber reinforced polymers (FRP), have increased in the last decades, mostly in the construction, automobile, aeronautic and wind energy sectors. This rising production and consumption have also led to an increasing amount of FRP waste, either end-of-life (EoL) products or manufacturing rejects. Taking into account the actual and impending EU framework on waste management, in which clear targets are set with concrete measures to ensure effective implementation, landfill and incineration will be progressively unavailable as traditional end-routes for this kind of waste. Recycling techniques and end-use applications for the recyclates have been investigated over the past twenty years, but even so, more cost-effective and feasible market outlets for the recyclates should be identified that meet both the economic and the environmental points of view. This paper is aimed at enclosing and summarizing an update overview regarding all these issues: current legislation, recycling techniques and end-use applications for the recyclates. Additionally, as a case study, the assessment of the potential improvements that could be made on the eco-efficiency performance (sustainability) of a typical FRP composite materials’ industry by recycling and re-engineering process approaches is also reported. Full article