LIFE-CYCLE MODELING AND ENVIRONMENTAL IMPACT ASSESSMENT OF COMMERCIAL SCALE BIOGAS PRODUCTION

Biogas is becoming an increasingly popular product from the treatment of wastewater, agriculture, food, and municipal solid waste. The process of anaerobic digestion (AD) allows organic waste streams such as sewage sludge, manure, and landfill organics to be converted into usable products such as biogas, fertilizer, and soil amendments. The benefits of resource recovery from waste streams depend on the current economic context and establishing a defined market for value-added products. However, there is a significant challenge in evaluating these opportunities without first understanding the environmental impact associated with various AD resource recovery systems. Applying life cycle assessment (LCA) to commercial biogas production provides a valuable tool for evaluating the environmental impact of waste management processes and assists in economic decision-making. Using life cycle assessment as a basis for evaluating the biogas production at the Swedish Biogas International, LLC (SBI) Facility in Flint, Michigan this study quantifies the environmental benefits of implementing AD at the Flint Water Pollution Control Facility. The study compares the emissions associated with the incineration of biosolids to emissions from Class B land application on a local brownfield site and the use of biogas in an electrical generator to that of upgrading biogas to biomethane. Several other options for the use of AD byproducts are investigated including kiln drying o