A Comparative Life Cycle Assessment of Two Waste Management Systems for the Las Rosas Landfill Plant

Abstract

In 2005, the World Bank implemented a novel landfill gas capture waste-to-energy project at the Las Rosas landfill site in Maldonado, Uruguay. It was the first of its kind in South America at the time of construction and went on to serve as models for similar development projects in the region. The project aimed to reduce anthropogenic methane emissions from landfills by capturing the methane rich natural biogas produced by the anaerobic decomposition of landfilled waste and using it to generate electricity. Due to several inefficiencies in plant operation and management, the project is producing much less electricity than predicted. When compared to other methane mitigation projects for waste management systems, especially those that are less expensive, require less robust technology, and take a more proactive approach to waste management, the question becomes: was this the best project to implement at the Las Rosas landfill site? This thesis modified the Life Cycle Inventory to calculate the net global warming potential of the implemented project, designed an alternative composting and landfill project, and calculated the net global warming potential of the proposed alternative. The results show that, for a 30-year span between 2005-2035, a composting and landfill project would have reduced 1.7 times more greenhouse gas emissions than the implemented project did. Total emissions from the waste-to-energy plant were found to be 670 Gg CO2 equivalent, a reduction of 64% from the original landfill emissions found during the same time period. The total emissions from the composting plant were net negative 90 Gg CO2 equivalent, a reduction of 106% from the original landfill. Net negative emissions are the result of compost being a stronger substituted good for the department of Maldonado than renewable electricity generation.