Recycling Network Research Articles

From Trash to Treasure: Assessing the Effectiveness of the Green@Community Recycling Network in Hong Kong

Municipal solid waste (MSW) is a growing problem worldwide posing a variety of environmental and human health impacts. Despite recycling being one major strategy to alleviate MSW production, the effectiveness of recycling has been equivocally dependent on local policy implementation and citizen environmental behavior. To enhance recycling effectiveness in Hong Kong, the government has established Green@Community, a unified community-based network for recycling and public environmental education. Since its establishment, the number of visitors to and the amount of recyclable materials collected at the network increased steadily over time. Our study is the very first to investigate the effectiveness of this territory-wide recycling network. Through a questionnaire survey, we found that respondents’ recycling traits were stronger if they have accrued gift tokens through participating in recycling activities. Visiting a Green@Community facility could also enhance knowledge of the types of acceptable recyclables, and respondents who had visited a Green@Community facility agreed that education and publicity could increase the recycling rate in Hong Kong. These findings highlighted the effectiveness and uniqueness of this community-based recycling network, its role in raising recycling knowledge, and its implications for policymakers and urban planners of densely populated cities to leverage society’s recycling participation, but also called for more efforts on developing, promoting, and incentivizing the usage of such a network to further enhance recycling and alleviate MSW production in Hong Kong.

Optimization of the rural domestic waste recycling network based on the path planning site selection model

IntroductionIn the context of rural revitalization strategies, effectively managing rural waste is a critical task for achieving ecological environmental sustainability. The current state of garbage collection and transportation is examined in this paper, focusing on the rural waste management practices in Dongfeng County, Liaoyuan City, Jilin Province, through mathematical modeling.MethodsBy analyzing the rural domestic waste collection network, the volume of waste generated at various points is fuzzified using the fuzzy mathematical theory.ResultsThe results of path optimization for waste collection and transportation were derived from a case study, demonstrating the feasibility and practicality of the rural domestic waste recycling network model.DicussionAdditionally, sensitivity analysis was conducted to assess the impact of changes on the total cost. Potential solutions for rural waste recycling and treatment are offered in this paper, providing valuable insights for the development of a rural domestic waste recycling network in Jilin Province.

Optimal design of a post-demolition autoclaved aerated concrete (AAC) recycling network using a capacitated, multi-period, and multi-stage warehouse location problem

Autoclaved aerated concrete is a popular building material in constructing one- and two-family houses because of its low thermal conductivity and fire resistance. Since autoclaved aerated concrete production rose significantly in the 1960s and 1970s, increasing post-demolition volumes can be expected in the following decades. However, these are currently landfilled as high-quality recycling options are still to be established.This study develops a new capacitated, multi-period, and multi-stage network model for optimising a Germany autoclaved aerated concrete recycling network. The multi-period character of the model enables the precise consideration of increasing post-demolition volumes by constantly allowing the move of recycling plants or opening new ones throughout the planning horizon. Additionally, the multi-stage formulation facilitates incorporating an optional second recycling step, which involves additional effort and higher revenues. The model aims to find a cost-minimised recycling network and identify optimal network transformations until 2050. Results show that recycling is preferred over landfilling. The optimised recycling network uses large recycling plants for economies of scale and opens new plants in the future to handle the expected increase in post-demolition autoclaved aerated concrete. Transport costs account for the largest share of total costs (50%), while fixed costs reach around 40%, and revenues offset approximately 20% of all costs. The total costs of the network reach about 2200 M€ until 2050, which is 4600 M€ (68%) less than without establishing recycling. The results offer new insights into cost-minimal network structures and their future development to encourage decision-makers to promote autoclaved aerated concrete recycling.

Inventory of Electronic Waste (E-Waste) and Residues in Junkshops: A Step Towards Residual Waste Management

The improper management of Waste Electrical and Electronic Equipment (WEEE) constitutes a critical global environmental challenge, with a significant proportion of e-waste ending up in landfills, posing substantial ecological and health risks. In the Philippines, particularly in areas like Marilao and Bulacan, many individuals rely on the recycling of e-waste for their livelihoods, primarily through junkshops and informal recycling networks. Despite providing economic benefits, these practices often result in substantial residual waste, exacerbating landfill overflow and environmental degradation. This study aims to establish a detailed e-waste inventory and propose practical strategies for improving residual waste management. This research used a mixed-method approach to collect data via surveys, interviews, and direct observations at selected junkshops in Marilao. The findings enabled a comprehensive categorization of e-waste based on economic value, highlighting "temperature exchange equipment" as the most economically valuable category while identifying "small IT and telecommunication equipment" as the least. Among the significant residual wastes identified were base/black plastics, styrofoam, and glass, which are commonly mishandled. The study proposes several management strategies, including partnerships with local governmental bodies and recycling companies to enhance recycling processes, improving dismantling techniques to reduce waste, and implementing rigorous waste segregation practices to prevent contamination and improve recycling rates. This expansion is critical for a more comprehensive understanding and monitoring of e-waste management practices, facilitating the development of more effective and sustainable waste management solutions. By adopting these strategies, junkshops and informal recyclers can optimize e-waste management, reducing environmental impact while maintaining economic viability.

Optimizing the location choice of reverse logistics recycling network for end-of-life photovoltaic modules based on the EPR principle

With the rapid development of the photovoltaic (PV) industry, the collection and recycling of end-of-life PV modules is facing a new challenge. Based on the EPR principle (Extended Producer Responsibility principle), this paper investigates the location choice of reverse logistics recycling network for end-of-life PV modules from the perspective of different stakeholders. In this study, a mixed integer programming (MILP) model is established to optimize the reverse logistics network of end-of-life PV modules with the objective of minimizing the total cost of the reverse logistics network, taking into account a four-tier recycling network system with customers going to the recycling centre, dismantling and processing centre, remanufacturing centre and waste disposal agency, and three recycling solutions are designed according to the EPR principle, and the optimal solution is found with the help of CPLEX software. Optimal solution, so as to determine the siting of facilities in the network and the distribution among each node. We take Zhejiang Province, one of the leading regions in China for promoting distributed PV applications, as the research object, and plan and design the recycling network of end-of-life PV modules in Zhejiang Province, determine the siting of the network as well as the distribution of the traffic to validate the validity of the MILP model, and provide opinions and references for the recycling problem of end-of-life modules in the future.

Review and Research on Medical Waste Recycling Network

The mass production of medical wastes has tested the safety of urban public health, and the recovery and disposal of medical wastes is imminent. Under various environmental backgrounds, such as the sudden increase in the number of medical wastes, the late start of the medical waste recycling industry in China, the low disposal rate, and the improper treatment of medical wastes affecting the environment and personal safety, medical wastes should be managed in a timely and standardized manner, and effective strategies should be put forward to minimize the environmental pollution caused by medical wastes. Therefore, in recent years, this paper studies the optimization of medical waste recycling network and summarizes the current research status of medical waste recycling network in academic circles.

Optimising Express Packaging Recycling: A Tripartite Evolutionary Game Modelling Government Strategies under Extended Producer Responsibility

This study presents a tripartite evolutionary game model examining the interplay among government, producers, and recyclers within the express packaging recycling network. Emphasizing the government's role as an endogenous variable under the extended producer responsibility framework, our study elucidates the behavioural evolution and stability of network subjects under distinct government mechanisms. Leveraging MATLAB simulations, we analyse subject behaviours to validate the model, revealing insightful contrasts between static and dynamic subsidy mechanisms. Our findings highlight that in the context of a static subsidy mechanism, equilibrium among the three subjects remains elusive. Recyclers' disposal fees show an inverse correlation with subsidy limits, yet an enhanced recycling rate directly corresponds to subsidies. However, excessive subsidies risk triggering adverse government regulations. Thus, we advocate for refined punitive policies alongside judicious, moderate subsidy systems to optimize recovery rates and social welfare. Conversely, a dynamic subsidy mechanism drives all subjects towards a stable equilibrium point, demonstrating optimal incentive effects. This study underscores the importance of government policy refinement and moderation in subsidy systems for achieving sustainable express packaging recycling, emphasizing the delicate balance between incentivization and regulatory intervention within the recycling network.

Solving Solar: How Past Policy Collides With Future Technology

This Comment discusses the importance of developing a solar waste management plan. Specifically, this Comment presents the argument that the United States should not create a large federal regulatory framework that includes expansive subsidies for solar panel recycling, but instead should invest in solar recycling technologies that offer solar recyclers the opportunity to profitably recycle junk panels. Ultimately, the federal government’s role should be limited to one of investment and support as states craft solar waste management systems that work for them.
 In support of this argument, this Comment explores the history and future of solar panel development, the current state of solar production and recycling, and the magnitude of the threat solar waste presents. Additionally, this Comment discusses how nations outside the United States are addressing the solar waste problem, the advent of new solar recycling technologies, how Congress may adapt the existing Resource Conservation and Recovery Act to include solar panels and encourage recycling of junk panels, the success story of lead-acid battery recycling, and what the solar recycling network of the future may look like.
 Ultimately, this Comment concludes that given recent advancements in recycling technology, with proper planning, encouragement, and investment from both state and federal governments, the private sector will be incentivized to recycle used solar panels without burdensome government intervention while sustaining a profitable business. Such a result will create a truly clean and renewable source of energy and relieve American taxpayers from bearing the cost of expensive solar recycling subsidy programs.

The optimization of an EV decommissioned battery recycling network: A third-party approach

In this paper, we solve the urgent problem to construct a recycling network of decommissioned batteries of Electric Vehicles (EVs) and clarify the recycling entities that will be responsible for its reverse logistics (RL) process. We consider the third-party recycling entities to develop a recycling network and conduct a case-study of Xi'an, a key industry of EVs in China to provide a reference for the government and enterprises to develop recycling plans. We scientifically optimize our recycling network, which will have a significant impact on the environmental and economic benefits of electric vehicles (EVs) in Xi'an in the future. Specifically, we consider the costs of transportation, construction, operation, recycling, packaging, and emission, as well as the profits achieved through sales revenue and subsidy offerings. We collect the actual data of potential facility locations in Xi'an, predict the quantity of decommissioned batteries in the future, and develop a fuzzy-based model to solve the optimal results of battery traveling path and distribution in the recycling process network. Our results show that with the rapid growth of the number of decommissioned batteries, third-party revenues will reach about 53.08 billion by 2035. When the facilities split the recycling process load appropriately, the network has increase in revenue while the utilization rate of facilities will decrease. We expect that splitting will be a major trend in the future development of recycling network in Xi'an. Finally, a sensitivity analysis finds that with the environmentally conscious and safe operation of recycling, the negative impact on the third-party enterprises' revenue will be small. Our proposed methodology can serve as a critical framework for other cities and governments to plan their recycling networks and formulate regulations, reflecting on the realistic projection of the scale of decommissioned batteries of EVs and the potential siting and sizing of the recycling facilities.

Life cycle assessment of filament production in distributed plastic recycling via additive manufacturing

Distributed recycling via additive manufacturing (DRAM) emphasizes an emerging approach to locally recycle waste plastic by 3D-printing it into valuable products. Although major progress has been reported in the last decade to validate the technical feasibility, and economic viability of the DRAM as an unitary operation, the environmental evaluation of this approach is still at its early stage as a distributed recycling network. The purpose of this study is to evaluate the environmental impact of a DRAM unit as a baseline scenario, compared to two scenarios of the virgin supply chain plastic filament used in the printing process. To achieve this goal, a comparative environmental performance using a life cycle assessment (LCA) is performed to estimate the multidimensional potential impacts of virgin and recycled polylactic acid (PLA). The study takes place using a physical recycling demonstrator developed at a university in Nancy, France. Four impact categories were considered: climate change, potential eutrophication (Freshwater and Marine), resource depletion (Fossil and Water), and ion radiation. For the first three impact categories, the results demonstrate a minimum 97% reduction in environmental impact compared to a virgin supply chain. However, in terms of ion radiation, the amount of emissions is approximately 2.8 times higher than that of the virgin plastic scenario. This increase is mainly due to the specific situation in France, where most of the energy is generated using nuclear means. This study aims to expand on the environmental assessment of the plastic recycling network system to better understand the implementation of these systems for waste plastic management, which can help extend the lifetime of plastic material. The findings provide an environmental overview of the benefits and disadvantages of developing a DRAM system in a particular context.

Design of urban medical waste recycling network considering loading reliability under uncertain conditions

The ongoing global coronavirus pandemic (COVID-19) has significantly increased urban medical waste. Such waste often contains pathogenic microorganisms, harmful chemicals, and even radioactive and defective substances, hence imposing disease transmission and public health risks. Nevertheless, due to multiple factors, the amount of medical waste produced in medical institutions is stochastic. This paper proposed an optimization model for a waste recycling network consideration of loading reliability to minimize the collective cost of location, vehicle usage, and transportation. A modified ant colony algorithm combined with the K-means clustering method based on a genetic algorithm is then proposed (MACO-GKA) to solve the optimal location problem and the vehicle routing problem (LP-VRP). The numerical examples are then conducted in Xuzhou City, China to evaluate the performance of the proposed model. Taking the loading reliability level θ=0.9 as an example, the results show that the total cost will reach $100546.53 when collection points are not set, but decrease to $86,907.11 when they are set. In the latter case, the total cost was reduced by 13.57%. The detailed results indicate that the selection and establishment of medical waste collection points are essential factors in designing an urban medical waste recycling network. The proposed MACO-GKA algorithm also outperforms the CPLEX solver.

Waste recycling through a decentralized network of mobile facilities

Mobile and modular recycling facilities have been developed in recent years, which can promote both the expansion of recycling capacity and the decentralization of waste treatment. Due to the miniaturization of these recycling units and their installation in standard containers, it is possible to relocate them from site to site at short notice, allowing for a more agile response to spatial and temporal waste generation. The planning of such a network involves the integration of location, production, and transport decisions. Therefore, this article presents a mixed-integer programming model to plan the relocation of the mobile recycling units so that the total costs of transport, recycling, and facility relocation are minimized. In addition, the economic value and environmental impact of mobile recycling networks are investigated through a sensitivity analysis, showing the benefit of movable recycling capacities. A case study analysis reveals that deploying modular units reduces overall recycling costs by about 10%, although extra costs are required to operate and relocate the mobile recycling units.

Designing a new recycling network for post-demolition autoclaved aerated concrete (AAC) in Europe

Autoclaved aerated concrete (AAC) is a widely used building material for masonry blocks. Its porous structure and mineral composition lead to low thermal conductivity and fire resistance. European AAC production and usage strongly increased in the 1960s and 1970s. Therefore, assuming limited buildings’ lifetimes, significant post-demolition AAC volumes can be expected in the following decades. However, post-demolition AAC recycling in high-value environmentally friendly applications is still to be established as most post-demolition AAC is currently landfilled. Different recycling options for post-demolition AAC are presently being researched. However, a recycling network to implement these options is neither designed nor established. This contribution focuses on creating a European recycling network, including mathematical modelling, data acquisition, and solving the model. i.e. minimising the total costs. The mathematical modelling uses a capacitated warehouse location problem with multi-sourcing and direct delivery. Results show that recycling plants of smaller capacity (100,000 t input/a) are placed in the recycling networks in 2020 and 2025. With higher waste quantities being expected from 2030 onwards, plants with a larger capacity (200,000 t input/a) are added, especially in Poland, where the highest pd-AAC amount in Europe is expected. The recycling network shows a decentralised structure with numerous recycling plants to keep transport costs low. Most network costs result from variable processing costs, showing the highest cost increases from 2020 to 2050. Fixed costs increase with the higher number of recycling plants and account for the second-largest share of total network costs. Transport costs are comparatively low thanks to the decentralised structure of the network. Overall, waste generation is expected to increase by 226% from 2020 to 2050, while the total costs of the recycling network are expected to rise by 151% only. The results support decision-makers in fostering recycling and implementing a circular economy for post-demolition AAC.

Uncovering the key features of gold flows and stocks in China

Gold is an important strategic mineral resource in China, mainly used in jewelry, investment, catalysts, emerging industries, and other fields. With the influence of increased geopolitical risks, energy crisis, housing costs, food prices and other factors, global inflation is becoming increasingly severe. As one of the best performing assets addressing stagflation, the price of gold continues to rise. This study aims to investigate gold metabolism in China from 2001 to 2020 by employing dynamic material flow analysis. The results show that China's gold consumption gradually increased, in which the jewelry sector had the largest gold consumption, while the gold coin and several industrial sectors also increased their gold consumptions. Also, the domestic gold production cannot meet its future gold demand, and the domestic gold recycling is still immature. Based on these research findings, policy recommendations for sustainable gold resource management are proposed, including the optimization of gold trade structure, the development of gold recycling network.

Optimizing plastics recycling networks

Plastic pollution is a serious sustainability issue facing the global community. Fragments of macroplastics and microplastics pollute terrestrial and aquatic ecosystems, while nanoplastics can also degrade air quality. The recent COVID-19 pandemic also exacerbated the problem. Large-scale commercial use of plastics recycling technologies is hindered by various socio-economic barriers. In particular, cross-contamination of mixed plastic streams is prevalent due to imperfect waste segregation. The concept of Plastics Recycling Networks is introduced to facilitate planning of reverse supply chains using optimization models. In this work, basic Linear Programming and Mixed-Integer Linear Programming models are developed for matching sources of waste plastic with plastic recycling plants within Plastics Recycling Networks. These models allocate streams while considering the ability of recycling plants to tolerate contaminants. Two illustrative case studies are analyzed to demonstrate the effectiveness of the models, and policy implications for mitigation of plastic pollution are discussed. These models enable planning of networks with some tolerance for contaminants in plastic waste, and can be the basis for developing new variants to handle additional real world aspects.

The influence of carbon emission reduction instruments on blockchain technology adoption in recycling batteries of the new energy vehicles

The new energy vehicle (NEV) is emerging as an important alternative in the automobile industry in its potential to alleviate environmental pollution and contribute to carbon neutrality. The rapid growth of NEVs has been reflected in the scaling up of electric vehicle battery production. The dramatic increase of retired batteries, however, exposes the technological limitations in current recycling operations, which will ultimately impede the sustainable development of the NEV supply chain. Blockchain technology (BT) adoption provides a solution by contributing to the construction of an efficient recycling network. Our research investigates the influence of carbon reduction instruments on the uptake of BT. The key findings are as follows. Under a carbon tax system, (1) carbon emission reduction encourages the battery supplier to adopt BT; (2) BT adoption increases the profits of NEV supply chain stakeholders. Under carbon cap-and-trade regulations, (1) the unit outsourcing fee and the performance of the BT impact the investment decision of the manufacturer; (2) the profit of the third-party enterprise is increased by introducing the BT. Under both policies, improving the efficiency of BT helps to upgrade the traceability level and contribute to carbon neutrality in the NEV supply chain.

Resource saving and carbon footprint reduction potential of urban symbiosis strategy in express packaging waste recycling network

The booming express delivery industry corresponds to the environmental challenges caused by massive express packaging waste (EPW). An efficient logistics network is necessary link to support EPW recycling. This study, therefore, designed a circular symbiosis network for EPW recycling based on urban symbiosis strategy. The treatment of EPW in this network includes reuse, recycling and replacing. An optimization model with multi-depot collaboration combining material flow analysis and optimization methods was developed and a hybrid non-dominated sorting genetic algorithm-II (NSGA-II) was designed as technical support for designing the circular symbiosis network while quantitatively assessing the economic and environmental benefits of the network. The results show that the designed circular symbiosis option has better resource saving and carbon footprint reduction potential than both the business as usual option and circular symbiosis option without service collaboration. In practice, the proposed circular symbiosis network can save EPW recycling costs and reduce carbon footprint. This study provides a practical guideline for the application of urban symbiosis strategies to help urban green governance and the sustainable development of express companies.

The governance of E-waste recycling networks: Insights from São Paulo City

Electronic waste is an environmental problem because its production volume exceeds its recycling capacity. Academic and managerial production affirm two reasons: (a) dominant market logic and; (b) unresolved asymmetries among actors, causing conflicts to work together. Following the qualitative methodology, we investigate the e-waste situation in São Paulo City. The results allow us to propose that governance constructed by local actors could be a thoughtful way to promote e-waste recycling. Examples from around the world sustain this proposition. The theoretical principle is that the social process of constructing the mechanisms for collective action can solve challenges because the rules, roles, and actions are discussed and assumed by the actors working together. We present a matrix of indicators to be used in future studies in order to refine the proposition of constructed governance.

Optimal Design of Reverse Logistics Recycling Network for Express Packaging Considering Carbon Emissions

With the development of China’s express delivery industry, the number of express packaging has proliferated, leading to many problems such as environmental pollution and resource waste. In this paper, the process of reverse logistics network design for express packaging recycling is given as an example in the M region, and a four-level network containing primary recycling nodes, recycling centers, processing centers, and terminals is established. A candidate node selection model based on the K-means algorithm is constructed to cluster by distance from 535 courier outlets to select 15 candidate nodes of recycling centers and processing centers. A node selection model based on the NSGA-II algorithm is constructed to identify recycling centers and processing centers from 15 candidate nodes with minimizing total cost and carbon emission as the objective function, and a set of Pareto solution sets containing 43 solutions is obtained. According to the distribution of the solution set, the 43 solutions are classified into I, II, and III categories. The results indicate that the solutions corresponding to Class I and Class II solutions can be selected when the recycling system gives priority to cost, Class II and Class III solutions can be selected when the recycling system gives priority to environmental benefits, and Class III solutions can be selected when the society-wide recycling system has developed to a certain extent. In addition, this paper also randomly selects a sample solution from each of the three types of solution sets, conducts coding interpretation for site selection, vehicle selection, and treatment technology selection, and gives an example design scheme.

Optimal Manufacturer Recycling Strategy under EPR Regulations

Under extended producer responsibility (EPR) regulations, trade-in programs allow manufacturers to play a vital role in recycling. Simultaneously, third-party recyclers (TPRs) can use their recycling network to compensate for manufacturers having only a single recycling channel, which increases the competition between them. To study whether companies should authorize TPRs, we constructed and analyzed a Stackelberg game model with trade-in programs under EPR regulations by focusing on three different closed-loop supply chain (CLSC) structures and differentiating consumer categories. The analytical results showed that when the government does not act as the decision maker, the optimal product selling price of the manufacturer does not change under each strategy. Otherwise, the manufacturer’s decision is affected by the cost structure and amount of subsidy, as well as funds determined by the government under the optimal environmental benefit. Furthermore, when the residual value coefficient of the used products is high, manufacturers authorize TPRs to recycle used products.