PI: Bridget Ulrich
Industry Partners:  Leigh Behrens, MPA, Planning Specialist, Ramsey/Washington Recycling and Energy
Postdoc: Shilai Hao

Research Problem

Over 35 million tons of food waste are disposed of in the US annually, representing substantial untapped potential for recovery of nutrients and energy.  Food waste can be broken down by microorganisms to produce biofuels and biofertilizer through a process called anaerobic digestion (AD). However, poly- and perfluoroalkyl substances (PFAS) have been widely detected in food waste, and these persistent contaminants are highly resistant to degradation during AD and in the environment. Therefore, innovative treatment approaches are required to recover nutrients and energy from food waste without redirecting PFAS contamination to the environment.

Solution statement

The goal of this project is to evaluate the effectiveness of a treatment train approach incorporating AD and hydrothermal treatment (HT) to simultaneously remediate PFAS and recover nutrients and energy from food waste. HT decomposes food waste at high temperatures and pressures in an aqueous environment, producing energy-rich biofuel and nutrient- and carbon-rich biofertilizer. Moreover, HT has recently been demonstrated to rapidly degrade PFAS, representing a potential means of producing PFAS-free biofertilizers that can be safely applied to fields and gardens. This project will evaluate the effectiveness of sequential treatment by AD and HT for PFAS remediation and resource recovery from actual food waste collected by the Ramsey/Washington Energy and Recycling Board.

Impact statement

Development of innovative approaches to recover resources from waste streams in a way that minimizes environmental impact is of direct relevance to several of the United Nation’s Sustainable Development Goals. AD has been recognized as one of the most promising means of recovering resources from food waste while minimizing greenhouse gas emissions, but the potential for spreading PFAS contamination to the environment through fertilizer application is a substantial limitation of the approach. We seek to minimize the overall environmental impact of resource recovery from food waste by developing a treatment approach that simultaneously minimizes greenhouse gas emissions, produces renewable energy and biofertilizers, and remediates PFAS. This will lead to broad sustainability improvements across the Food-Energy-Water Nexus, and provide market opportunities for small businesses to locally collect, convert, and reutilize food waste

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