Towards circular economy in developing cities: an integrated approach for planning international cooperation projects

Solid waste management (SWM) issues are an environmental and social burden, which affect mainly the population of low-middle income countries worldwide, as well as the global environment. The application of the circular economy (CE) principles (reuse of waste materials) is considered the main solution spreading the economy of the waste and therefore reducing environmental impacts. This research is focused on the analysis and application of integrated approaches for planning sustainable SWM systems in developing big cities, demonstrating the importance of the inclusion of the informal recycling and drafting international cooperation projects for introducing new appropriate technologies and awareness campaigns. The case study of this research is La Paz (Bolivia), low-middle income city where international support is required for the sustainable development. The results allow suggesting that the inclusion of informal recyclers can be considered the most useful option in terms of technical and financial issues, exploiting a CE system just in place. Moreover, the cooperation with local and international stakeholders allows writing and submitting two international cooperation projects. The research demonstrates that the cooperation among various international and local actors, such as Universities, non-governmental organizations and local Government, in parallel with the use of technical knowledge and methodologies can support the sustainable development in low-middle countries, driving low-middle income cities towards the CE

Towards circular economy in developing cities: an integrated approach for planning international cooperation projects

Solid waste management (SWM) issues are an environmental and social burden, which affect mainly the population of low-middle income countries worldwide, as well as the global environment. The application of the circular economy (CE) principles (reuse of waste materials) is considered the main solution spreading the economy of the waste and therefore reducing environmental impacts. This research is focused on the analysis and application of integrated approaches for planning sustainable SWM systems in developing big cities, demonstrating the importance of the inclusion of the informal recycling and drafting international cooperation projects for introducing new appropriate technologies and awareness campaigns. The case study of this research is La Paz (Bolivia), low-middle income city where international support is required for the sustainable development. The results allow suggesting that the inclusion of informal recyclers can be considered the most useful option in terms of technical and financial issues, exploiting a CE system just in place. Moreover, the cooperation with local and international stakeholders allows writing and submitting two international cooperation projects. The research demonstrates that the cooperation among various international and local actors, such as Universities, non-governmental organizations and local Government, in parallel with the use of technical knowledge and methodologies can support the sustainable development in low-middle countries, driving low-middle income cities towards the CE

Organic waste valorization in remote islands: analysis of economic and environmental benefits of onsite treatment options

Solid waste management (SWM) represents an important issue for small islands. This research evaluates the municipal SWM system of the Pelagian archipelago, in Italy. The research aims to evaluate environmental and econoemic benefits of onsite treatment plants for the valorization of the organic fraction of municipal solid waste. The sizing of the anaerobic digestion (AD) and composting plant was developed, and the characteristics of the plant were used to conduct a cost analysis and an environmental life cycle assessment. The current waste management system (S0) has been compared with the new strategy proposed (S1). Results showed that S1 leads to save more than 250,000 € y−1 due to the avoidance of organic waste final disposal and shipping, determining a payback time of about 7 years. Environmental benefits include a lowering of CO2-eq emission of more than 1100 tonnes per year and a reduction of all the six environmental impacts analysed. The outcomes represent a novel contribution to the scientific literature since the research provides the first comparison of quantitative data about environmental and cost benefits of onsite AD plants in small islands. The research underlines that onsite waste treatment systems are viable options to improve SWM systems in isolated regions

Anaerobic digestion or composting? Small-scale plants design and holistic evaluations in a Sub-Saharan African context

In small developing settings, is it worth building anaerobic digestion (AD) or composting plants? This study explores the economic, management, and environmental dimensions of two small-scale alternatives for organic fraction municipal solid waste (OFMSW) treatment within the context of Lacor Hospital (Uganda): aerated static pile composting (S1) and AD with digestate composting (S2), both designed to manage approximately 347.5 tOFMSW annually. In the optimistic scenario, S1 achieves a cost savings of about -2.9 USD tOFMSW-1 , while S2 incurs costs of 2.1 USD tOFMSW - 1 . In the pessimistic scenario, S1's costs rise to 3.9 USD tOFMSW- 1 , while S2 becomes more expensive at 9.5 USD tOFMSW - 1 . Management analysis underlines S2's complexity due to AD operations and digestate drying. Total normalized environmental impacts of S1 can be quantified with about 0.125 mPt tOFMSW - 1 , whereas S2 is equal to about -6.163 mPt tOFMSW- 1 . However, in an optimistic scenario, climate change endpoint category results are similar. On balance, the LCA analysis indicates that AD can be better than standalone composting. However, in developing settings serving approximately 3000 inhabitants, it is crucial to prioritize economic and management sustainability that can be obtained only by small-scale composting plants. These findings provide definite insights for small-scale waste management projects in low-income regions, offering valuable data and references for plant design and their replicability. The study sets the ultimate definition of the most feasible option to treat OFMSW in low-income settings: community composting. Unfortunately, economic barriers remain the main challenge: citizens should pay for the service and landfill management fees should be set by local governments

When solid recovered fuel (SRF) production and consumption maximize environmental benefits? A life cycle assessment

Solid recovered fuel (SRF) from non-recyclable waste obtained from source separation and mechanical treatments can replace carbon coke in cement plants, contributing to the carbon neutrality. A life cycle assessment (LCA) of the SRF production from non-recyclable and selected waste was conducted in an Italian mechanical treatment plant to estimate the potential environmental impacts per ton of SRF produced. The analysis would contribute to evaluate the benefits that can be obtained due to coke substitution in best- and worst-case scenarios. The avoided impacts achieved were assessed, together with an evaluation of the variables that can affect the environmental benefits: SRF biogenic carbon content (in percentage of paper and cardboard); transportation distances travelled from the treatment plant to the cement kiln; the renewable energy used in the mechanical facility. On average, about 35.6 kgCO2-eq are generated by the SRF transportation and production phase. These impacts are greatly compensated by coke substitution, obtaining a net value of about 1.1 tCO2-eq avoided per ton of SRF. On balance, the global warming potential due to SRF production and consumption ranges from about 542 kgCO2-eq to about 1729 kgCO2-eq. The research recommended the use of SRF to substitute coke in cement kilns also in low densely-populated areas to mitigate environmental impacts and achieve carbon neutrality at a global level

Microbial Enzyme Biotechnology to Reach Plastic Waste Circularity: Current Status, Problems and Perspectives

The accumulation of synthetic plastic waste in the environment has become a global concern. Microbial enzymes (purified or as whole-cell biocatalysts) represent emerging biotechnological tools for waste circularity; they can depolymerize materials into reusable building blocks, but their contribution must be considered within the context of present waste management practices. This review reports on the prospective of biotechnological tools for plastic bio-recycling within the framework of plastic waste management in Europe. Available biotechnology tools can support polyethylene terephthalate (PET) recycling. However, PET represents only ≈7% of unrecycled plastic waste. Polyurethanes, the principal unrecycled waste fraction, together with other thermosets and more recalcitrant thermoplastics (e.g., polyolefins) are the next plausible target for enzyme-based depolymerization, even if this process is currently effective only on ideal polyester-based polymers. To extend the contribution of biotechnology to plastic circularity, optimization of collection and sorting systems should be considered to feed chemoenzymatic technologies for the treatment of more recalcitrant and mixed polymers. In addition, new bio-based technologies with a lower environmental impact in comparison with the present approaches should be developed to depolymerize (available or new) plastic materials, that should be designed for the required durability and for being susceptible to the action of enzymes

International Cooperation and University Agreements: new opportunities for sustainable development.

Internationalization of higher education institutes is becoming a real opportunity of development in environmental and social subjects. This paper explores a case study where university agreements and student exchanges between low-middle income and high-income countries have started a process of international cooperation about environmental themes. The agreements, signed between two Italian and two Bolivian Universities, started formally in 2015 and include the cooperation through local authorities, private companies and non-governmental organizations. This case study proved the importance of Universities for implementing international programs concerning environmental issues in low-middle income countries, opening new opportunities for sustainable development

Circular economy, international cooperation, and solid waste management: a development project in La Paz (Bolivia)

This paper introduces the preliminary results of a development project focused on waste recycling and recovery in La Paz (Bolivia). The aim is to share best practices and present real-world challenges in implementing appropriate waste management systems in developing countries. Environmental pollution, social inequality, lack of resources, and economic discrepancies are challenges still present in the 21st century, and a global call for action is needed to support sustainable development. The project \u201cLaPazRecicla\u201d, financed by the Italian Agency for Development Cooperation, provides perspectives useful for policy-makers, waste management practitioners, and circular economy visionaries. The approaches used for developing the actions, the activities carried out, and the main results are presented. The outcomes of the project provided two main indications, both positive and negative: on one hand, cooperation among interdisciplinary actors and financial support can give the chance of improvement, suggesting international donors to continue in this direction; on the other, political instability, lack of local technical knowledge, and the absence of planning in a long-term period makes these actions unsuitable for a tangible change. Global reflections are required in order to measure the potential benefits of small-scale projects, evaluating the time needed to move towards a sustainable future in low-income countries

Antibacterial Activity of Lantana camara Linn and Lantana montevidensis Brig Extracts from Cariri-Ceará, Brazil

The use of medicinal plants with therapeutics properties represents a secular tradition in different cultures, mainly in underdeveloped countries. Lantana camara Linn and Lantana montevidensis Briq (Verbenaceae) found in tropical and subtropical areas around the world are popularly known as “camará” or “chumbinho.” In popular medicines, both plants are used as antipyretic and carminative and in the treatment of respiratory system infections. In this study, the antibacterial activity of the ethanolic extracts of L. camara and L. montevidensis leaves and roots against gram-positive and gram-negative strains standard and multi-resistant bacteria isolated from clinical material are presented. In order to determine the minimal inhibitory concentration (MIC), the microdilution method was used. The extracts demonstrated antibacterial activity against all tested bacteria, but the L. montevidensis fresh leaves extract present the best result against P. aeruginosa (MIC 8 μg/mL) and against multi-resistant E. coli (Ec 27) (MIC 16 μg/mL). These results drive new researches with both species in order to isolate the constituents responsible for the activity

Social Surveys about Solid Waste Management within Higher Education Institutes: A Comparison

Solid waste mismanagement is a social burden that requires the introduction of reliable public policies, including recycling principles and technological facilities. However, the development of recycling plans is a real issue for municipal governments, since it involves psychological and cultural factors, both in developed and developing countries. Questionnaire survey is an important tool for evaluating which solid waste management policy is suited for each specific study area, involving citizens and stakeholders. The aim of this paper is to evaluate what approach should be applied for social surveys in higher education institutes, comparing developing and developed countries. Italy is the developed country analyzed, where two universities in different cities are compared, while La Paz (Bolivia) is the emerging reality considered. The research conducted in La Paz led us to understand that, although recycling rates are low (about 8%), many students (56.96%) separate up to half of the waste produced at home. At the same time, about 53% of those interviewed do not know the recycling practices implemented by the informal sector which is the one that constantly act for improving the recycling rates of the city. Low technological acceptance is instead underlined in the high income country, since there is a common negative opinion concerning the introduction of landfills and incinerators near residential areas (49% disagree). A comparison of the methodologies adopted for the two case studies is introduced whereas investigations results are presented