Post-treatment and agricultural reuse of digestate from low-tech digesters: A comparative life cycle assessment.

The objective of this study was to analyse the environmental impacts of the post-treatment and agricultural reuse of digestate from a low-tech digester implemented in a small-scale farm in Colombia using the Life Cycle Assessment methodology. The scenarios considered were: 1) digestate post-treatment with a sand filter and its reuse in agriculture; 2) digestate post-treatment with a vermifilter and the production of compost, and 3) untreated digestate directly applied on the agricultural land (current scenario). Moreover, an economic analysis was also addressed. Results showed that the vermifilter was the most environmentally friendly scenario. It considerably reduced (by up to 9 times) the environmental impacts compared to the other scenarios. From an economic point of view, the implementation of the vermifilter generated an increase in farmers' income (up to 70 $ year-1) since it avoids buying synthetic fertilizer. Finally, the implementation of a vermifilter for the post-treatment and agricultural reuse of digestate from low-tech digesters showed to have both environmental and economic benefits. This technology can help to promote the circular bioeconomy in small-scale farms, reducing poverty and improving the standard of living in rural areas.

Climate change mitigation potential of transitioning from open dumpsters in Peru: Evaluation of mitigation strategies in critical dumpsites.

Waste management is a critical policy towards the reduction of environmental impacts to air, soil and water. Many Latin American countries, however, lack a correct waste management system in many cities and rural areas, leading to the accumulation of unmanaged waste in illegal or unregulated dumpsites. The case of Peru is of interest, as it hosts 5 of the 50 largest dumpsites in the world. An erratic waste management compromises climate actions for Peru to commit with the Paris Agreement, as no correct closure systems are established for these dumpsites. Therefore, the main objective of this study is to assess the contribution of the past and present biodegradable waste produced and disposed of in the most critical open dumpsters to the overall annual greenhouse gas (GHG) emissions of Peru using the IPCC model. Thereafter, the climate change mitigation potential of possible dumpsite closure strategies based on a selection of technologies, including economic feasibility, were estimated. Results show that cumulative GHG emissions in 2018 for the 24 critical dumpsites evaluated added up to 704 kt CO2 eq. and a cumulative value of 4.4 Mt CO2 eq. in the period 2019-2028, representing over 40 % of solid waste emissions expected by 2030. Mitigation potentials for these emissions tanged from 91 to 970 kt CO2 eq. in the ten-year period depending on the mitigation strategies adopted. The costs of these strategies are also discussed and are expected to be of utility to complement Peru's waste management commitments in the frame of the Paris Agreement.

Closing the gap in the municipal solid waste management between metropolitan and regional cities from developing countries: A life cycle assessment approach.

Municipal solid waste (MSW) management is an important challenge in developing and emerging countries, where two realities co-exist. On the one hand, their metropolitan cities exhibit an integrated MSW system with a specialized fleet for the collection and landfills for the final disposal, concentrating on environmental initiatives such as municipal recycling programs. On the other hand, their regional cities show an MSW system based on adapted transports for collection and open dumps for final disposal. Besides, they face other environmental problems due to local conditions. This research proposes a life cycle assessment (LCA) approach to close the gap between these two realities. In particular, we study the city of Valdivia (Chile), one of the main regional capitals of South America, which shares similarities with other southern regional cities in the Global South. This city disposes 95% of its MSW in open dumps and presents one of the highest environmental pollution rates in Latin America. We analyze the greenhouse gas (GHG) emissions and energy performance of six scenarios, seeking a solution for these problems. The results obtained show that a waste-to-energy scenario would generate savings of GHG emission and particulate matter, reaching 11.3% and 21.8%, respectively. Using our LCA approach, we can provide environmental evidence to highlight the importance of improving MSW management in regional cities, closing the gap with MSW management in metropolitan cities, and contributing to national targets such as United Nations Sustainable Development Goals and Nationally-Determined Contributions.

Enhancing waste management strategies in Latin America under a holistic environmental assessment perspective: A review for policy support.

Waste remains a serious environmental and human health hazard in developing nations, including those in Latin America and the Caribbean (LA&C). Despite important breakthroughs in waste management in LA&C, the region still faces many challenges that require special attention, such as the existence of uncontrolled open dumpsters (33%) or the low recovery rates of waste fractions (below 4%). Moreover, the adoption of sophisticated waste management technologies, such as incineration or anaerobic digestion, is still lagging. This review paper provides environmentally-sound and relevant policy support for municipal solid waste management stakeholders through a critical review of the current situation of the waste management sector in LA&C from an environmental perspective. Thereafter, Life Cycle Assessment (LCA) bibliography linked to waste management, namely collection, sorting, recycling and landfilling applications and technologies worldwide, is used in order to understand potential alternative waste management strategies in LA&C, as well as the potential environmental benefits that could be attained. Finally, based on the holistic review and analysis, the adoption of more sophisticated technologies in landfill sites (e.g. landfill gas flaring), waste-to-energy, as well as higher recycling rates, would enhance waste management in the region and mitigate environmental impacts. A holistic view to support policy formulations, including climate action, for the adoption of integrated waste management strategies in LA&C is imperative.

Peru's road to climate action: Are we on the right path? The role of life cycle methods to improve Peruvian national contributions.

Most developing nations have had to perform a swift transition from the voluntary greenhouse gas (GHG) emissions mitigation actions engaged in the Copenhagen Accord, to the relatively ambitious mitigations signed in the frame of the Paris Agreement. Consequently, Peru is currently creating its national structure to combat climate change through mitigation and adaptation actions. Nationally-determined contributions (NDCs) are the planned interventions that nations report for intended reductions in GHG emissions. In fact, Peru has now committed to reduce its annual GHG emissions by 30% in 2030 with respect to a business-as-usual estimation for that same year. The 76 NDCs have been divided into six main sectors: energy, transport, industrial processes, agriculture, forestry and waste. In this context, the main goal of this study is to provide a critical review of the validity and effectiveness of current mitigation NDCs proposed by the Peruvian government to comply with the Paris Agreement. Moreover, the analysis is accompanied by a discussion on how the use of life-cycle methods, namely Life Cycle Assessment, can be of utility in terms of policy support to evaluate the mitigation potential of these NDCs, as well as in the identification of additional contributions in sectors where the mitigation potential has been obviated. The expansion of system boundaries beyond the national context to account for the globalized nature of current market flows or the modelling of indirect impacts of a particular policy appear as relevant advantages of including life-cycle methods in public climate policy. The analysis, which is intended to be of utility to policy-makers in Peru and in other developing and emerging economies across the world, suggests that life-cycle methods arise as adequate tools to monitor the environmental appropriateness of adopting or adapting low-carbon technology to the local context.