Designing a sustainable reverse logistics network for used cell phones based on offline and online trading systems

Unsustainable production and consumption are driving a significant increase in global electronic waste, posing substantial environmental and human health risks. Even in more developed nations, there is the challenge of low collection rates. In response, we integrate offline and online trading systems and design a material efficiency strategy for used cell phones. We propose a new multi-objective optimization framework to maximize profit, carbon emissions reduction, and circularity in the process of recycling and treatment. Considering multi-period, multi-product, multi-echelon features, as well as price sensitive demand, incentives, and qualities, we established a new multi-objective mixed-integer nonlinear programming optimization model. An enhanced, Fast, Non-Dominated Solution Sorting Genetic Algorithm (ASDNSGA-II) is developed for the solution. We used operational data from a leading Chinese Internet platform to validate the proposed optimization framework. The results demonstrate that the reverse logistics network designed achieves a win-win situation regarding profit and carbon emission reduction. This significantly boosts confidence and motivation for engaging in recycling efforts. Online recycling shows robust profitability and carbon reduction capabilities. An effective coordination mechanism for pricing in both online and offline channels should be established, retaining offline methods while gradually transitioning towards online methods. To increase the collection rate, it is essential to jointly implement a transitional strategy, including recycling incentives and subsidy policies. Additionally, elevating customer environmental awareness should be viewed as a long-term strategy, mitigating the cost of increasing collection rates during the market maturity stage (high collection rates).

Synergizing environmental, social, and economic sustainability factors for refuse derived fuel use in cement industry: A case study in Espirito Santo, Brazil

The cement industry has been under pressure due to the environmental impact of high cement production, which demands a significant amount of energy and results in greenhouse gas (GHG) emissions. In many developed countries, the cement industry has sought to replace conventional fossil fuels with alternatives to minimize GHG emissions; however, Brazil has underexploited this possibility. Considering the potential of refuse-derived fuel (RDF) to reduce the non-recycled waste disposed in landfills, and its suitable performance as an alternative fuel for cleaner cement production, this paper presents a reverse logistics network analysis for RDF production planning with respect to local economic incentives, social euqity and justice, pollution prevention, and global environmental concerns regarding carbon emissions reduction. The reverse logistics network involves important stakeholders related in waste management in Espirito Santo, Brazil, especially harmonizing social sustainability concerns between waste pickers' cooperatives and waste retailers. By considering the waste generated in 78 municipalities in the Espírito Santo state, the possible levels of fuel replacement in cement industries reflects the economic sustainability of the timeframe of the solid waste management policy implementation. The results showed that the RDF to be produced varies from 42,446.5 tonnes in 2024 with a small fuel replacement by cement industries, to 567,092.1 tonnes in 2040 if all non-recyclable waste available can be used to produce RDF. The avoided annual disposal costs via this network analysis vary from $3,855,412.0 in the initial years to $47,822,876.8 in the year 2040 under optimistic conditions, representing around 25% of the total cost in the network. The cost and GHG emitted reduced significantly in all simulated scenarios; however, the financial incentives are essential for achieving the network social sustainability.

Reverse logistics network for municipal solid waste management: The inclusion of waste pickers as a Brazilian legal requirement

This study proposes a reverse logistics network involved in the management of municipal solid waste (MSW) to solve the challenge of economically managing these wastes considering the recent legal requirements of the Brazilian Waste Management Policy. The feasibility of the allocation of MSW material recovery facilities (MRF) as intermediate points between the generators of these wastes and the options for reuse and disposal was evaluated, as well as the participation of associations and cooperatives of waste pickers. This network was mathematically modelled and validated through a scenario analysis of the municipality of São Mateus, which makes the location model more complete and applicable in practice. The mathematical model allows the determination of the number of facilities required for the reverse logistics network, their location, capacities, and product flows between these facilities. The fixed costs of installation and operation of the proposed MRF were balanced with the reduction of transport costs, allowing the inclusion of waste pickers to the reverse logistics network. The main contribution of this study lies in the proposition of a reverse logistics network for MSW simultaneously involving legal, environmental, economic and social criteria, which is a very complex goal. This study can guide practices in other countries that have realities similar to those in Brazil of accelerated urbanisation without adequate planning for solid waste management, added to the strong presence of waste pickers that, through the characteristic of social vulnerability, must be included in the system. In addition to the theoretical contribution to the reverse logistics network problem, this study aids in decision-making for public managers who have limited technical and administrative capacities for the management of solid wastes.