Waste-to-energy options within a circular economy strategy in a developing country: the case of the bio bio region in Chile

Abstract

In Chile, during the last 40 years the municipal solid waste (MSW) generation rate has shown a 4-fold increase due to population growth, fast urbanization and improved material standards. As in most developing countries, this trend is expected to continue as economic policies foster greater industrial investment and increases in domestic consumption. Currently, MSW are landfilled near ever expanding urban areas, leading to growing public concerns, and prompting new control legislation. Up-to-date MSW management practises are being promoted in order to maximise waste valorisation, including recycling, and waste-to-energy, within a circular economy strategy. However, new resource consumption, waste streams, air emissions and effluents may arise when changing from a linear to a circular economy model. Therefore, environmental performance of alternative scenarios must take into consideration the complete life cycle to avoid problem shifting. Within this context, this paper presents a case study of three alternative waste-to energy scenarios, as part of a circular economy strategy, involving combustion, gasification, and landfill biogas, at the BioBio Region in Southern Chile. This is an industrial region housing over 2 million inhabitants and generating more than one million tonnes of MSW per year. The study assesses waste-to energy alternatives considering an integrated waste management life cycle approach. Boundaries include waste collection, transport, pre-treatment processes, by-products generation, and heat/power production. MSW transport, recycling rates, chemical compositions, and calorific values, were obtained from primary sources, whereas energy conversion efficiencies and other data gaps were estimated from the Ecoinvent database. Results provide a complete view of the environmental performance of each alternative scenario, including potential climate change effects and other environmental impacts, and also the positive contributions of material and energy recovery. This work illustrates the value of life cycle assessment in the context of decision making concerning circular economy scenarios.