(735k) Circularizing Animal Wastewaters: Spatial Mapping of Swine Wastewater and Associated Resource Recovery Potential in the United States

The circular economy framework is aimed at meeting the resource demands of the anthroposphere while minimizing the necessity for demand reduction strategies within our economy. A fundamental principle of the circular economy involves prolonging the residence time of resources in the economy through approaches like recycling and resource recovery. Animal wastewater represents a resource-rich stream containing significant amounts of biological oxygen demand (BOD), nitrogen, and phosphorus that can be reclaimed. Specifically, the trend towards large, concentrated animal feeding operations (CAFOs) within the swine industry makes its wastewater an appealing target for resource recovery due to its strength and relative consistency. Swine wastewater can be utilized for the production of biogas, fertilizers, and value-added chemicals through advanced anaerobic biotechnologies. However, systems-level assessment is needed to quantify the spatial availability of swine wastewater as well as its resource recovery.

This work will present creation of an account of swine wastewater in the United States based on publicly available data. This includes data regarding head count, farm type, and farm location at both state and county levels. Furthermore, this study presents a spatial analysis of the transfer of swine wastewater created by the movement of swine to different farms through their life stages. This analysis is part of an effort to conceptualize and consider swine wastewater as an economic commodity. The movement of swine across life cycle stages is examined using network analysis and optimization techniques, with a focus on minimizing the distance traveled by swine to match supply and demand of swine farms for different life stages. Finally, the study presents an assessment of the total value of recovered energy and nutrients and quantification of greenhouse gas emission reduction resulting from the recovered resources from swine wastewater. Preliminary findings show that swine wastewater is concentrated in the corn belt allowing for potential of combining multiple wastewater streams for more efficient treatment using an AnMBR technology. Swine wastewater in the United States was found to have over 6,000 MW of recoverable energy, enough to theoretically power New York City if all were collected.