Key Points:
- Food waste can be converted into a renewable energy resource using anaerobic digestion.
- A new study says installing anaerobic co-digesters at wastewater treatment plants could generate an 8% return on investment.
- Researchers say the technology could even create new standalone green facilities.
In the United States, an estimated 30 to 40% of edible food is lost or wasted, costing billions of dollars each year. One potential solution is to divert food waste from landfills to renewable energy production, but this isn’t done on a large scale anywhere.
Researchers at the University of Illinois Urbana-Champaign recently conducted a comprehensive analysis of supply chain logistics to determine if a system of converting food waste into energy and other bioproducts would be profitable in Illinois. First, they used geospatial data to identify potential sites. Next, they analyzed technological and economic factors, including transportation, production, and facility costs, as well as revenue and return on investments.
The analysis hinges on anaerobic digestion, a biological process that decomposes organic feedstock using rich organic materials, such as wastewater sludge, animal manure, or yard waste. The resulting biogas can be used to produce electricity, which can be transported to consumers via regional power grids. The process also yields additional bioproducts, including biofertilizer and animal bedding materials that can be sold to agricultural producers.
According to the study, published in Journal of Cleaner Production, installing anaerobic co-digesters at wastewater treatment plants with a total annual capacity of 9.3 million metric tons could generate an 8.3% return on investment, while reducing carbon dioxide by approximately 1 million metric tons annually. The most significant factors influencing the results were capital investment, operational cost, and tipping price, which is a service charge for waste disposal.
“This is an opportunity for wastewater treatment plants, but we've also shown that there's potential for new stand-alone facilities to provide a service that can generate revenue while dealing with an environmental concern that is currently unaddressed. A new industry could form around this,” said Luis F. Rodriguez, associate professor and co-author on the paper.
The study focused on Illinois, and the next step would be expanding to a nationwide analysis. Estimating food waste availability on a larger scale and determining bioprocessing techniques will be essential for improving food waste utilization and the circular bioeconomy in agriculture.