Life Cycle Assessment and Technoeconomic Analysis of Thermochemical Conversion Technologies Applied to Poultry Litter with Energy and Nutrient Recovery

Thermochemical technologies provide promising pathways to recover energy and reduce environmental impacts from biomass wastes. Poultry manure or litter additionally provides an opportunity for recovering and recycling nutrients and producing valuable soil amendments. This study compared the life cycle environmental impacts and technoeconomic performance of six thermochemical technologies for treating poultry litter waste-slow pyrolysis, fast pyrolysis, gasification, hydrothermal liquefaction, hydrothermal carbonization, and supercritical water gasification-with direct land application. Using life cycle assessment (LCA), the technologies were compared through 15 different environmental impact categories (midpoints) using the IMPACT 2002+ method. On converting the midpoints to damage categories (end points), it was found that these technologies outperformed the conventional land application method with respect to human health (92-149% improvement), climate change impact (15-53% improvement), ecosystem quality (124-160% improvement), and resource depletion (-24-530% improvement). The technoeconomic analysis (TEA) identified carbon price (breakeven of $127/1000 kg CO2 equiv for slow pyrolysis) and high capital costs as influential parameters for large-scale applications of these technologies. The TEA results were most sensitive to carbon price and transportation distance (0.69 and 0.52% changes in revenue per change in input, respectively).