Environmental Impacts from Organic and Plastic Waste Management

Most municipal solid waste in the United States is currently landfilled despite growing concerns of waste accumulation and associated greenhouse gas emissions. In response, significant efforts have been made to implement and pursue zero-waste goals and develop circular economy strategies to recover value from waste products. My research aims to inform decision-makers on the environmental tradeoffs between waste management strategies by evaluating the emissions implications of various novel and existing technology options for organic and plastic waste, two major components of municipal solid waste streams. This dissertation includes three studies: a life-cycle assessment of organic waste management strategies, a comprehensive and quantitative review of emissions from composting organic waste, and a life-cycle assessment of plastic waste management strategies. All of this work provides evidence of the benefits from landfill diversion and suggests more sustainable solutions for both organic and plastic waste management. A more detailed summary of these studies and their results are provided below. Life-Cycle Greenhouse Gas Emissions and Human Health Tradeoffs of Organic Waste Management StrategiesWaste-to-energy systems can play an important role in diverting organic waste from landfills. However, real-world waste management can differ from idealized practices, and emissions driven by microbial communities and complex chemical processes are poorly understood. This study presents a comprehensive life-cycle assessment, using reported and measured data, of competing management alternatives for organic municipal solid waste including landfilling, composting, dry anaerobic digestion (AD) for the production of renewable natural gas (RNG), and dry AD with electricity generation. Landfilling is the most greenhouse gas (GHG)-intensive option, emitting nearly 400 kg CO2e per tonne of organic waste. Composting raw organics resulted in the lowest GHG emissions, at -41 kg CO2e per tonne of waste, while upgrading biogas to RNG ...