Food-Water-Energy Nexus

Livestock waste (manure) generated at U.S. animal feeding operations is estimated to be 300 million tons per year. This is twice the amount of waste produced by the entire U.S. human population. Most of this waste is disposed of in lagoons or stored outdoors to decompose, leading to numerous environmental issues that include greenhouse gas (GHG) emissions (methane and nitrous oxide), eutrophication of watersheds resulting from phosphorus runoff, and human exposure to pathogens.

To address these challenges we are: i) Developing optimization models and solution algorithms to identify new efficient pathways to recover valuable products from waste. This is achieved by capturing system-wide interactions between waste processing, nutrient management, and natural gas, electricity, and transportation infrastructures. ii) Developing decision-making frameworks that factor in the interests of multiple stakeholders on conflicting objectives (investment, emissions, land/water conservation) and that use new consensus metrics to identify Pareto efficient compromise solutions. Stakeholders include urban and rural communities, environmental groups, farmers, technology providers, and local/regional governments. iii) Performing real case studies using data from the State of Wisconsin to demonstrate the potential of new waste-to-biogas pathways under different government policies and incentives.

This work is in collaboration with Profs. Dan Noguera, Rebecca Larson, and KG Karthikeyan at UW-Madison and Dr. Gerardo Ruiz at the U.S. EPA.