Urban Mining in Developing Countries: An Ally to Circular Economy

The consumption behavior of contemporary society, based on products with reduced useful life, combined with poor and inefficient waste management systems, contributes greatly to the accumulation of materials in the environment. For decades, the level of urban pollution has been alarming. Rivers, seas, oceans, and even forest environments are relentless victims of the disregard that many governments have for the environmental issue. Fortunately, this behavior is changing. With the efforts of some political leaders and the activism of organized civil society, along with the engagement of corporations, environmental health stands out on international agendas. Discussions about sustainable practices in companies and a more vibrant performance of different actors in relation to this topic have boosted improvements regarding waste production. However, this is still hardly enough. Every year, tons of polymeric material are inappropriately disposed of without any sort of treatment [1]. This amount is constituted by several types of packaging, toys, fabrics, automotive components [2], and also in the form of hybrid materials in the composition of which there is at least some polymer component. Although the disposal of polymers causes undeniable impact on the environment [3-15], they have the potential to be reused, reclaimed, and/or recycled [16]. The above processes are technically and economically feasible and can be used on different materials. Their adoption constitutes a circular economy practice by allowing a material or part of it to be reintegrated into the production cycle. As these processes are assimilated by the productive sector and disseminated, the need to use virgin raw materials of petrochemical origin is reduced, thus preserving the oil and gas reserves. For this logic to be well established there needs to be an efficient system for screening, sorting, and processing waste. In this regard, urban mining becomes essential for prospecting waste that is suitable to be returned to the production chain [17-21]. Developing countries, notorious for their large urban waste generation, can generate foreign exchange by investing in urban mining practices.

Urban mining cannot be mistaken for recycling or waste treatment techniques alone, although they are integral parts of the whole. It requires the use of an industrial process which is capable of recovering elements of an artifact that for some reason has turned into urban waste. Like the original idea of mining, which involves extracting ores for refining and obtaining high value elements, urban mining requires prospecting and concentration in stages. In this sense, not just any man-made materials can be prospected, but only those in which there is technical and environmental feasibility to do so with a financial return [22,23] and with lower waste generation than that of previously used processes. Plastics recovery, through chemical recycling (where monomers are obtained from polymeric artifacts), requires both proper logistics and knowledge about the inventory of available landfills. Zhou and co-authors (2014) evaluated the characteristics of a decommissioned landfill in China that had operated for 15 years, with an estimated overall volume of 551,000m3. Out of this amount, plastic materials accounted for 5-15%, out of which 69% were used plastic bags (11% white PE bags, 30% colored PE bags) and 31% other plastic materials. Worldwide, it is estimated that less than 10% of the produced polymers were recycled [24-27]. In South America, the recycling rate lies below 20%, being Brazil one of the countries that has recycled polymer the least in the region [28]. In a scenario of undeniable environmental pollution, in which polymers account for a large portion of the urban waste, it is essential that waste management policies be implemented. The adoption of such policies, besides contributing to the reduction of environmental impacts, may represent business opportunities in the area of urban mining. Developing countries, such as Brazil, have the potential to disseminate such practices, reconciling the rigors of their environmental legislation with the need for generating employment and income.

Material preparation was performed by Harrison Lourenço Corrêa and Marco Gaya de Figueiredo. The first draft of the manuscript was written by Harrison. Both authors commented on previous version of the manuscript, read and approved the final version.

1. Chandas M (2021) Chemical aspects of polymer recycling. Advanced Industrial and Engineering Polymer Research 4(3): 133-150.
2. Oberoi I, Rajkumar P, Das S (2021) Disposal and recycling of plastics. Materials Today: Proceedings.
3. Wolfe D (1987) Persistent plastics and debris in the ocean: An international problem of ocean disposal. Marine Pollution Bulletin 18(6): 303-305.
4. Eriksen M, Mason S, Wilson S, Box C, Zellers A, et al. (2013) Microplastic pollution in the surfaces waters of the Laurentian Great Lakes. Marine Pollution Bulletin 77(1-2): 177-182.
5. Depledge M, Galgani F, Panti C, Caliani I, Casini S, et al. (2013) Plastic litter in the sea. Marine Environmental Research 92: 279-281.
6. Briassoulis D, Babou E, Hiskakis M, Kyrikou I (2015) Analysis of long-term degradation behaviour of polyethylene mulching films with pro-oxidants under real cultivation and soil burial conditions. Environ Sci Pollut R 22(4): 2584-2598.
7. Li K, Ma D, Wu J (2016) Distribution of phthalate esters in agricultural soil with plastic film mulching in Shandong Peninsula, East China. Chemosphere 164: 314-321.
8. Maaβ S, Daphi D, Lehmann A, Rillig MC (2017) Transport of microplastics by two colembolan species. Environ Pollut 225: 456-459.
9. Brouwer R, Hadzhiyska D, Ouderdorp H (2017) The social costs of marine litter along European coasts. Ocean and Coastal Management 138: 38-49.
10. Wang JJ, Zheng LX, Li JH (2018) A critical review on the sources and instruments of marine microplastics and prospects on the relevant management in China. Waste Management Res 36(10): 898-911.
11. Markic A, Niemand C, Briedson JH, Mazouni GN, Gaertner J, et al. (2018) Double trouble in the South Pacific subtropical gyre: increased plastic ingestion by fish in the oceanic accumulation zone. Marine Pollution Bulletin 136: 547-564.
12. Hahladakis J, Velis C, Weber R, Iacovidou E, Purnell P (2018) An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling. Journal of Hazardous Materials 344: 179-199.
13. Boucher J, Faure F, Pompini O, Plummer Z, Wieser O, et al. (2019) (Micro) plastic fluxes and stocks in Lake Geneva basin. TrAC Trends in Analytical Chemistry 112: 66-74.
14. Dong Q, Dang T, Guo S, Hao M (2019) Effects of mulching measures on soil moisture and N leaching potential in a spring maize planting system in the southern Loess Plateau. Agricultural Water Management 213: 803-808.
15. Rizzi M, Rodrigues F, Medeiros L, Ortega I, Rodrigues L, et al. (2019) Ingestion of plastic marine litter by sea turtles in southern Brazil: Abundance, characteristics and potential selectivity. Marine Pollution Bulletin 140: 536-548.
16. Dadamo I, Falcone P, Martin M, Rosa P (2020) A sustainable revolution: Let´s go sustainable to get our globe cleaner. Sustainability 12(11): 4387.
17. Arora M, Paterok K, Banerjee A, Saluja MS (2017) Potential and relevance of urban mining in the context of sustainable cities. IIMB Management Rev 29(3): 210-224.
18. Koutamanis A, van Reijin B, van Buerren E (2018) Urban mining and buidings: A review of possibilities and limitations. Resources, Convervation and Recycling 138: 32-39.
19. Zhang L, Zhong Y, Geng Y (2019) A bibliometric and visual study on urban mining. J Cleaner Production 239: 118067.
20. Arora M, Raspall F, Cheah L, Silva A (2020) Buildings and the circular economy: Estimating urban mining, recovery and reuse potential of building components. Resources, Conservation and Recycling 154: 104581.
21. Kazançoglu Y, Ada E, Ozturkoglu Y, Ozbiltekin M (2020) Analysis of the barriers to urban mining for resource melioration in emerging economies. Resurces Policy 68: 101768.
22. Corrêa HL, Figueiredo MAG (2020) Urban mining: A brief review on prospecting technologies. Brazilian Journal of Development 6(5).
23. Zeng X, Xiao T, Xu G, Albalghiti E, Shan G, et al. (2021) Comparing the costs and benefits of virgin and urban mining. Journal of Management Science and Engineering.
24. Geyer R, Jambeck JR, Law KL (2017) Production, use and fate of all plastics ever made. Science Advances 3(7): e1700782.
25. USEPA (2018) Facts and figures about materials, waste and recycling United States Environmental Protection Agency, USA.
26. Ferronato N, Torretta V (2019) Waste mismanagement in developing countries: A review of global issues. Int J Environ Res Public Health 16(6): 1060.
27. Wagner S, Schlummer M (2020) Legacy additives in a circular economy of plastics: Current dilemma, policy analysis and emerging countermeadures. Resources, Conservation and Recycling 158: 104800.
28. Valerio O, Muthuraj R, Codou A (2020) Strategies for polymer to polymer recycling from waste: Current trends and opportunities for improving the circular economy of polymers in South America. Green and Sustainable Chemistry 25: 100381.

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