Consequential Life Cycle Assessment of Swine Manure Management within a Thermal Gasification Scenario

Abstract

Sustainable swine manure management is critical to reducing adverse environmental impacts on surrounding ecosystems, particularly in regions of intensive production. Conventional swine manure management practices contribute to agricultural greenhouse gas (GHG) emissions and aquatic eutrophication. There is a lack of full-scale research of the thermochemical conversion of solid-separated swine manure. This study utilizes a consequential life cycle assessment (CLCA) to investigate the environmental impacts of the thermal gasification of swine manure solids as a manure management strategy. CLCA is a modeling tool for a comprehensive estimation of the environmental impacts attributable to a production system. The present study evaluates merely the gasification scenario as it includes manure drying, syngas production, and biochar field application. The assessment revealed that liquid storage of manure had the highest contribution of 57.5% to GHG emissions for the entire proposed manure management scenario. Solid-liquid separation decreased GHG emissions from the manure liquid fraction. Swine manure solids separation, drying, and gasification resulted in a net energy expenditure of 12.3 MJ for each functional unit (treatment of 1 metric ton of manure slurry). Land application of manure slurry mixed with biochar residue could potentially be credited with 5.9 kg CO 2 -eq in avoided GHG emissions, and 135 MJ of avoided fossil fuel energy. Manure drying had the highest share of fossil fuel energy use. Increasing thermochemical conversion efficiency was shown to decrease overall energy use significantly. Improvements in drying technology efficiency, or the use of solar or waste-heat streams as energy sources, can significantly improve the potential environmental impacts of manure solids gasification.

Life Cycle Assessment (LCA) of Environmental and Energy Systems

“…Sharara and colleagues [7] applied LCA to assess the environmental impacts of swine manure management within a thermal gasification scenario that includes drying, syngas production, and biochar field application. Hot-gas efficiency and boiler efficiency were also varied according to alternative models of potential improvements to better understand the implications of thermochemical conversion parameters on the overall environmental performance of the proposed management scenario.…”

A Critical Review of Data Science Applications in Resource Recovery and Carbon Capture from Organic Waste

“…Among these applications, LCA studies applied TRACI for gasifying forestry residue and organic municipal solid waste in the USA (Figure b and Table S10). − ReCiPe was employed for LCA studies (with agricultural and forestry residue as feedstocks) in South Africa and Latin American regions (e.g., Brazil, Ecuador, Columbia) in addition to using LCOE for LCCA/TEA. − Generally, LCCA/TEA of gasification was conducted in fewer studies compared to LCA in the reviewed literature, where the common methods for LCA were TRACI in USA, CML and IPCC in European and Asian Countries, and ReCiPe in the remaining countries.…”

Improving Life Cycle Economic and Environmental Sustainability of Animal Manure Management in Marginalized Farming Communities Through Resource Recovery

“…Limited life cycle assessment (LCA) studies focus on resource recovery for wastewater treatment systems and animal manure management in developing regions (Corominas et al , 2013 ; Zang et al , 2015 ; Gallego-Schmid and Tarpani, 2019 ), despite the known benefits to mitigate environmental impacts. The majority of LCA studies on animal manure management systems have been conducted in Europe and have largely focused on assessing the environmental impacts of large scale (functional unit equal to or greater than 1 ton) swine and/or dairy slurry reuse systems (Sandars et al , 2003 ; Lopez-Ridaura et al , 2009 ; Hamelin et al , 2011 ; Poeschl et al , 2012 ; ten Hoeve et al , 2014 ; Sharara et al , 2019 ).…”