Waste Economy Research Articles

Effect of Solid Sodium Silicate on Workability, Hydration and Strength of Alkali-Activated GGBS/Fly Ash Paste

Based on economic and environmental considerations, the recycling economy of mineral waste has been found to have great potential and economic benefits worldwide, in which alkali-activated cementitious materials are one of the main developing directions. The alkali activators commonly used in alkali-activated cementitious materials are the composite activators of sodium silicate solution and solid sodium hydroxide, which not only need to deal with high viscosity and corrosive chemicals, but also need to be prepared in advance and properly stored. In this paper, ground granulated blast furnace slag (GGBS) and fly ash were used as precursors, while solid sodium silicate powder was applied as the alkali activator. In addition, the precursors were mixed with the activator in advance and activated by adding water to prepare alkali-activated GGBS/fly ash cement. The influence of precursor components, the dosage of the alkali activator and the liquid–solid ratio on the working performance, mechanical strength and hydration process of alkali-activated cement was studied. The results showed that the further incorporation of GGBS accelerated the alkali activation reaction rate and improved the strength of the specimen. However, in the specimen with GGBS as the main component of the precursor, the main hydration product was C-A-S-H gel, which was different in the structural order and quantity. The compressive strength indicated that there was the best amount of activator to match it in terms of the precursor with certain components. A too high or too low amount of activator will hinder the alkali activation reaction. This study can provide some significant reference material for the use of solid alkali activators in alkali-activated cementitious materials.

Tire-derived reclaimed rubber as a secondary raw material for rubber foams: in the framework of circular economy strategy

Improper disposal and accumulation of waste tire rubbers have posed a serious threat to the development of a circular economy, a sustainable environment, and human health. In light of the drawback of the current waste management of waste tires, the recycling and transformation of reclaimed rubber (RR) into valuable end products has received significant attention from industries and the academic field. Herein, we propose a facile method to reuse RR in developing closed-cell elastomeric foams based on ethylene propylene diene rubber (EPDM). Rheometry results revealed that the introduction of RR up to 20 phr, increased the cure rate from 11.7 to 13.48%/min, reduced curing time from 12.21 to 9.3 min and also increased ultimate torque from 6.51 to 7.24 N.m. Morphological studies indicated that the RR increased the cell density from 12 to 78 cell/mm3 and reduced the number average cell size from 940 to 110 µm. The mechanical results indicated that the introduction of RR could be a feasible alternative for the fabrication of high-performance EPDM foams with improved hardness and resilience. By increasing RR content of EPDM/RR foams, the relative density and cell density of EPDM/RR foams increased, while cell size decreased. The introduction of 10 phr of RR, increased the hardness and resilience of the EPDM foam by 37 shore A and 68%, respectively. The research verified that the attempt to use RR to produce a good foam structure was found to be successful. The results open a way for EPDM/RR foam composites to be applied for sealing and gasket industries as an eco-friendly replacement for virgin products.Highlights• Use of reclaimed rubber from waste tires as secondary raw material for EPDM rubber foams• Tire-derived reclaimed rubber/EPDM closed-cell foams support the circular economy of waste tires• Tire-derived reclaimed rubber/EPDM closed-cell foams exhibit superior mechanical properties at the low cost

Hazop Analysis of a Bioprocess for Polyhydroxyalkanoate (PHA) Production from Organic Waste: Part A

The number of bioprocesses for the circular economy of organic waste has grown in recent years. Implementation of new processes and technologies should consider occupational health and safety issues from the initial design stages. Among the process hazards analysis techniques, HAZard and OPerability (HAZOP) methodology is widely used for studying both the process’s hazards and their operability problems, by exploring the effects of any deviations from design conditions. In the present study, a modified version of HAZOP methodology has been applied to a three-steps process developed at pilot scale in the Treviso municipal wastewater treatment plant in order to produce polyhydroxyalkanoate (PHA) as the final high value product. This paper shows the results of HAZOP analysis applied to the first process step (acidogenic fermentation) aimed at volatile fatty acids production. The analysis has been applied to the process conditions corresponding to the maximum PHA content in the biomass. The HAZOP study results showed that this methodology allowed a comprehensive exploration of conventional chemical engineering process hazards and biological hazards. Final piping and instrumentation diagrams (P&IDs) for acidogenic fermentation have been designed, identifying all prevention measures aimed at managing the hazard and operability issues. The P&ID shows the interconnection of equipment and the instrumentation required for controlling the process.

Actores sociales y gestión de la economía circular en el estado de Chihuahua, México

The article analyzes the participation of social actors in the management of the circular economy of urban solid waste in the state of Chihuahua, Mexico. The methodologyconsistedof semi-structured interviews, virtual interactive workshops(with the implementation ofelectronic surveys), surveysof municipalgovernments representatives,and personal communications. The resultsshow thatsocial actors barely glimpse the economic, social,and environmental meaning of betting on the circular economy. The article contributesto the analysis of the circular economy paradigm asa current sustainability tool.It is concludedthat little has been studied about the circular economy in Mexico and that the participation of non-state actors has not been valued and used efficiently. The articlereflects onwhat should and can be done with solid waste in Mexico in the future.

“Junk You Can't Abandon”: Hoarding and Waste in Andrew Lam and Karen Tei Yamashita

In the last decades a concern with waste has started to “surface” not just in the economic and social sciences, but also in the humanities, where it has lately clustered around Waste Studies and Waste Theory. This critical approach allows us to grapple with the consequences of our globalized economy of waste for both the planet and human beings. Although Waste Theory can be applied to virtually any literary tradition, I would argue that Asian American literature, which has been read along the lines of the waste/no-waste dialectics since Sau-ling Wong developed her Necessity/Extravagance thesis in 1993, proves particularly amenable to this methodology. In order to illustrate the multiple ways in which Waste Theory can productively interbreed with Wong’s dichotomy, I will explore the dynamics of hoarding and waste in Andrew Lam’s Perfume Dreams and Karen Tei Yamashita’s Sansei and Sensibility.

Novel chromatographic purification of succinic acid from whey fermentation broth by anionic exchange resins.

Replacement of the petroleum-based refineries with the biorefinery is regarded as an essential step towards a "zero" waste (circular) economy. Biobased succinic acid (SA) is listed by the United States Department of Energy among the top ten chemicals with the potential to replace chemicals from petroleum synthesis with renewable sources. Purification of bio-based succinic acid from fermentation by-products such as alcohols, formic acid, acetic acid and lactic is a major drawback of fermentative SA production. This study addresses this issue through a novel chromatographic separation using three distinct anionic resins: Amberlite IRA958 Cl (strong base anion exchange resin), Amberlite HPR 900 OH (strong base anion exchange resin) and Amberlyst A21 (week base anion exchange resin). The influence of process variables such as flow rate (0.18 BV/h, 0.42 BV/h and 0.84 BV/h), eluent concentration (1%, 5% and 10% HCl) and temperature (20, 30 and 40°C) were investigated. The results indicated SA separation efficiency of 76.1%, 69.3% and 81.2% for Amberlyst A21, Amberlite HPR 900 OH and Amberlite IRA958 Cl, respectively. As the regenerant HCl concentration increased from 1 to 10%, calculated succinic acid separation efficiencies decreased from 80.3 to 70.7%. Notably, as the regenerant strength increased from 1 to 10%, the total amount of organic acids desorbed from the resin sharply increased. At operation temperatures of 20, 30 and 40°C, SA separation efficacies were 81.2%, 73.9% and 76.4%, respectively. The insights from this study will be of great value in design of chromatographic separation systems for organic acids.

Efficiency of consumer behaviour and digital ecosystem in the generation of the plastic waste toward the circular economy

A circular economy can help reduce the impact of plastic waste using reaction, resilient, and digital approaches. In addition, it can facilitate reducing plastic consumption. In this regard, consumer behaviour and digitalization are deemed to be two main factors that play major roles in the implementation of a circular economy of plastic waste. The idea of this paper is to understand the relevance of consumer behaviour and digital ecosystem efficiency on plastic waste at the country level. Hence, the efficiency of eight European countries in the generation of plastic waste was analysed using international databases and the statistical method of receiver operation characteristic (ROC). For this purpose, the dependent actual state variables were defined as plastic waste generations, and the independent test variables were defined as digital ecosystem and consumer behaviour factors. ROC plots for the determination of the area under the curve (AUC) indices were produced between the mentioned state and test variables. The results revealed that consumer behaviour increases the higher generation of plastic waste (AUC >0.6), indicating that consumer behaviours have high effectiveness on the generation of plastic waste in European countries. Furthermore, the results indicated that the digital ecosystem has a controlling role in the generation of plastic waste in the study area (AUC <0.5), indicating the digital ecosystem factors associated with the low generation of plastic waste. The overall consumer behaviour in the selected European countries showed an unskilled role regarding the higher generation of plastic waste, while the digital ecosystem context showed a mitigating role in decreasing plastic pollution. The confirmation of the research hypotheses leads to some managerial propositions for the circular economy of plastic waste in the area of consumer behaviour and digitalization. The results propose an elaborated framework, including a reduction in waste generation, recycling in waste circulation, recovery in waste valorization, and efficiency in resource consumption by the digitalization of design technology and education in consumer behaviour for the circular management of plastic waste.

Review of the Circular Economy of Plastic Waste in Various Countries and Potential Applications in Indonesia

One of the main environmental problems faced by the world, including Indonesia, is plastic waste. Plastic waste has polluted the soil, rivers, and the sea. The nature of plastic that is not easily biodegradable, takes hundreds of years to decompose naturally. Plastic waste management which is believed to be effective, in addition to efforts to reduce use is by recycling plastic waste. In many countries, recycling plastic waste has led to a circular economy. This circular system allows plastic waste to be recycled into new products. In fact, this concept is claimed to be able to encourage environmentally friendly economic growth. This study uses a literature study to identify the application of a circular economy of plastic waste in various countries. As a result, 21 papers were collected and analyzed based on year of publication, geographical location and research methodology. Furthermore, this study highlights the obstacles faced by many countries towards a circular economy followed by a comparison of their plastic waste recycling rate achievements. This research also discusses the state of plastic waste management and the potential for adoption of circular economy best practices in Indonesia.

Circular Economy Initiatives: Strategic Implications, Resource Management, and Entrepreneurial Innovation in a Brazilian Craft Beer Ecosystem during the COVID Era

A new brewery is founded in Brazil every two days. Yet with climate change, drinking water is increasingly scarce. Previous studies have begun exploring the brewing industry, but an examination of circular economy initiatives in Latin America is lacking, particularly during the COVID era. This study analyzes strategic implications of circular economy initiatives, together with their role in the coevolution of the craft beer sociotechnical system in Brazil from a resource perspective during the COVID pandemic. Using a qualitative methodology based on analytic induction, 11 in-depth semi-structured interviews were carried out with key actors from the craft beer sociotechnical system in Guarapuava. For the content analysis, we triangulated the interviews with an analysis of 74 related documents. We found evidence of circular economy practices and sociotechnical transitions with the simultaneous coevolution of the system actors. Increasing rejection of the linear take–make–waste economy was observed as subject organizations largely adopted a regenerative model reducing operational waste. Hence, entrepreneurial innovation was apparently crucial for resource allocation during the COVID era. This work contributes to further understanding resource configurations in the circular economy, with practical implications for integrating sustainability into strategy, business models, and production.

The Current State, Challenges, and Opportunities of Recycling Plastics in Western Australia

In 2018–2019, 85% of discarded plastics were landfilled in Australia. In Western Australia (WA), only 5.6% of plastics were recovered for reprocessing. With several Asian Countries imposing import restrictions, which were the prime destination for recyclables from Australia, the whole scenario for the waste industry has changed. Australia has now adopted export bans for recyclables, including plastics. WA is at a fork in the road; WA needs to rethink its relationship with plastic materials. This study explores how to create local markets for recycled plastics underpinning circular principles. The study examines barriers and drivers to enable markets for recycled plastics in WA through questionnaires, surveys, and interviews with relevant stakeholders. Poor source separation, low and inconsistent plastic waste feedstock, and virgin plastic competition are some of the challenges, while new investments in recycling infrastructure, WA’s take-back scheme for beverage containers and circularity frameworks are drivers. This study concludes that a modulated fee-based product stewardship model focused on product design, along with strategies such as green procurement and landfill management modifications would promote a circular plastic waste economy in WA. This can create markets for secondary recycled plastics, minimize the over-reliance on fossil fuels and prevent plastics from leaking into ecosystems.

Barriers and Challenges to Waste Management Hindering the Circular Economy in Sub-Saharan Africa

More and more, waste generated in most parts of the Western world has been recycled and transformed into new circularity products. However, managing waste within Sub-Saharan Africa (SSA), such as in Ghana, has become a challenge due to the continued practice of the old traditional linear waste economy, that is, the taking, making and disposing methods of management, representing a threat to global environmental sustainability. Despite the need to revise current linear waste management (WM) in order to turn to the circular economy (CE) model, which consists of the concept of renew, remake and share, to advance sustainable development, a number of factors restrict the CE realization in practice, specifically in developing countries. An integrative methodology was used in this article to identify some of the challenges that hinder the achievement of CE in SSA countries. The results revealed the absence of educational programs and public awareness of waste management activities. The findings also highlight the lack of political will, funding and national policies on WM as some of the most significant issues. The study contributes to further encouraging policymakers and policy implementers, entrepreneurs and relevant interested groups to commit resources to sustainable WM services aiming to advancing CE in SSA countries.

Upcycling End of Life Solar Panels to Lithium-Ion Batteries Via a Low Temperature Approach.

The massive adoption of renewable energy especially photovoltaic (PVs) panels is expected to create a huge waste stream once they reach end-of-life (EoL). Despite having the highest embodied energy, present photovoltaic recycling neglects the high purity silicon found in the PV cell. Herein, a scalable and low energy process is developed to recover pristine silicon from EoL solar panel through a method which avoids energy-intensive high temperature processes. The extracted silicon was upcycled to form lithium-ion battery anodes with performances comparable to as-purchased silicon. The anodes retained 87.5 % capacity after 200 cycles while maintaining high coulombic efficiency (>99 %) at 0.5 A g-1 charging rate. This simple and scalable process to upcycle EoL-solar panels into high value silicon-based anodes can narrow the gap towards a net-zero waste economy.

Barriers to recycling e-waste within a changing legal environment in South Africa

Electronic waste (e-waste) recycling presents an opportunity to reclaim materials from a secondary resource and to create jobs and other economic opportunities. E-waste consists of various materials such as metals, plastics, glass, and other chemical substances. Some of these materials are hazardous if processed or disposed of improperly. Therefore, e-waste is classified as hazardous in South African law up until the hazardous components are removed. With the appropriate infrastructure and technology, a large portion of materials contained in e-waste can be reclaimed, and any adverse impacts of irresponsible management prevented. The private sector has played a proactive role in shaping the South African waste economy, and the government is taking strides to draw up enabling regulatory frameworks. Through a literature review and stakeholder engagements, this paper unpacks the organisation of the South African e-waste recycling industry. We consider whether the legal environment drives a common vision for a circular e-waste economy and probe the barriers to e-waste recycling across the value chain. The findings indicate that the development of the e-waste recycling sector in South Africa is dependent on a robust collection network and the enabling of local end-processing, refining, and manufacturing capacity. The availability and quality of input material and the development of local refining and manufacturing capacity are co-dependent and should be addressed simultaneously.Significance: E-waste recycling is an emerging industry in South Africa and the enablers and constraints for the development of this industry are still being explored. The legislative environment with regard to e-waste recycling is evolving and needs to be continuously reviewed to assess its ability to enable/activate the development of the sector. Local end-processing is currently limited to very small volumes of selected fractions of e-waste. The potential to activate upper levels of the e-waste value chain, such as end-processing, is important to the development of the sector.

Circular Economy of Construction and Demolition Wood Waste—A Theoretical Framework Approach

A considerable amount of construction and demolition wood waste (CDWW) is generated, mostly landfilled, contributing to severe environmental effects. The management of CDWW is a significant challenge as it is a hazardous contaminated waste. In this context, the circular economy (CE) concept is a solution as it comprises waste minimisation and efficient recovery of resources. Although much research is found in the literature on CDWW end-of-life management, research on CE implementation considering every life cycle stage is still scarce. In this review, we endeavour to integrate CE in CDWW to identify the waste management strategies involved in the life cycle phases. The databases were searched from 2009 to 2020 and were analysed using CiteSpace version 5.7.R1 software. Forty-nine articles were identified, and the six life cycle stages were explored. The analysis shows that CE for wood waste is essential and has greater growth potential. While the LCA studies are limited to environmental viewpoints, combining economic and social perspectives is necessary for sustainable development. Overall, based on the research findings, a theoretical framework was proposed. This study, as a consequence, promotes the application of recycled wood into multiple valuable products and thus encourages waste management to boost CE and sustainability.

Various Applications of Processing of Olive Leaves Waste Extracted with RSLDE: A Green Technology

AbstractThere is no waste in nature. Everything that is produced has a purpose and everything that becomes waste can be transformed into a new resource, triggering a virtuous circuit that feeds itself. The circular economy of waste means a system in which the production‐consumption‐disposal process is overcome to replace it with a circular model, where the final waste product is re‐introduced into the circulation as a secondary raw material. The logic to follow is that after consumption and before any disposal, it is necessary to activate virtuous processes such as reduce, reuse, and recycling. This work focuses on the possible uses of a vegetable waste matrix, such as olive leaves.The olive tree (Olea europaea) is a fruit tree, cultivated for more than 3500 years for its fruits and edible oil. However, just like oil, olive leaf contains a high amount of polyphenols, in particular oleuropein, one of the most powerful natural antioxidants known and hydroxytyrosol, which also has powerful antiseptic properties. Therefore, olive leaf extracts, thanks to the presence of oleuropein associated with hydroxytyrosol, represent a powerful natural antioxidant, a valid ally of the cardiovascular system. In addition, olive leaves are an excellent regulator of the digestive system: they regulate intestinal transit and above all eliminate fungi and other unwanted parasites from the body. Starting from these premises, in this work, a green extraction technique such as rapid solid liquid dynamic extraction (RSLDE) is compared with conventional maceration to obtain an olive leaf extract rich in antioxidants to be used in various sectors.

Circular economy of waste in agrifood supply chain: A review

AbstractThrough a systematic literature review (SLR), this study aims to analyze the progress achieved in international literature regarding the circular economy (CE) of food waste. As a result, we realized that most of the authors considered had proposed different mathematical models, chemical and thermal treatment methods, statistical, and conceptual frameworks, besides that quantitative and qualitative studies to explain the processes related to the waste and CE in the agrifood sector. Furthermore, in business, management, and accounting, the CE of food waste focuses on added value and optimizing energy use rather than approaching the principles of reduction, reuse, and recycling. This study constitutes a first attempt at understanding the CE of food waste in business, management, and accounting fields of knowledge. This SLR can assist decision‐makers, managers, and governments to formulate policies and strategies to effectively implement CE in agrifood supply chains.

The Economy of Waste

The Economy of Waste

Exploring the Intersection Where Business Models, a Circular Economy and Sustainability Meet in the Waste Economy: A Scoping Review

The authors endeavor to investigate the intersection and relationship between sustainability, business models and a circular economy. These three concepts are believed to be at the heart of finding a solution to creating and implementing a circular economy. The three pillars of sustainability (society, environment and economics) have been identified as the golden thread when applied to developing circular economies and the business models used in these circular economies. These three pillars highlighted the areas of intersection and engagement between the circular economy and business models. The three pillars, or stakeholders, need to be considered equally and, where there is sacrifice and benefits, they need to be balanced. A scoping review was chosen, as the starting point, to ascertain the literature in the field. The results of the scoping review showed a lack of research conducted at the point of intersection between these three fields. Finding a solution by creating and implementing a circular economy will have positive effects on the economy, environment and society, as there is, proverbially, “not much time left” and everyone in the process will sacrifice and benefit. The research has highlighted the need to explore the intersection and relationship between sustainability, business models and the circular economy as a concept, and future research should develop frameworks to guide the development and implementation of this intersection to include all relevant stakeholders.

Development of alternative disposals for waste rice husk and dredged harbor sediment by sintering as lightweight aggregates

ABSTRACT This study developed the alternative disposals for dredged harbor sediments by co-sintering with waste rice husk into lightweight aggregates (LWA) to benefit resource sustainability and waste valorization. The effects of rice husk addition and sintering temperature on LWA performances such as water absorption, particle density, crushing strength, weight loss, volume shrinkage, and open porosity were investigated. The key parameters (e.g. C/Fe ratio in raw materials) controlling the LWA performances and engineering applications were determined. Results showed that dredged harbor sediments could be made into suitable LWA for engineering applications from the controlled rice husk addition and sintering temperature. The addition of rice husk led to lower LWA particle density, but raised water absorption and reduced crushing strength. The increase of sintering temperature reduced water absorption and improved crushing strength. The aggregates with 10–15% rice husk, sintered at 1150 °C had appropriate particle density (1.60–1.73 g/cm3), water absorption (11.8–16.6%), and crushing strength (6.0–10.6 MPa), which could be suitable for lightweight concrete applications. Low water-soluble chloride and heavy metals leachabilities aligned with Taiwan’s regulatory standards for concrete aggregates. Co-treating waste rice husk and dredged harbor sediment into LWA can benefit the waste reduction and circular economy, and reduce the environmental impacts associated with their disposals.

The Economy of Waste

The Economy of Waste