Tempe approves ASU food waste-to-energy study

By City of Tempe, Arizona | March 17, 2015

The city of Tempe and Arizona State University’s Global Institute of Sustainability are teaming up on a study that will analyze food waste and fats, oils and grease (FOG) from large Tempe food industries, Tempe restaurants, and institutional dining halls to determine the feasibility of turning this material into renewable energy.

The study will focus on a process called anaerobic digestion, which occurs when oxygen is removed from food waste, allowing digestive bacteria to break it down. This natural process produces a biogas that can be harnessed and used for energy. Anaerobic digestion is commonly used to break down sewage sludge at wastewater treatment plants, but can also be used to generate gas through the decomposition of any organically-rich material. The study will provide Tempe with:

- An inventory of food waste available from Tempe restaurants, food industries, institutions, and food distribution centers to understand the amount of food waste available and to map out where it is being generated

- A full-scale analysis of the individual and combined energy potential of available food wastes using the City’s staff and laboratory facilities to analyze food sources identified

- Research results for comparable cities with successful food waste-to-energy solutions

- A tool to model the biogas output of food waste sources and to identify optimal combinations and optimal AD technology for those combinations

- Planning and siting options, financial analyses and rates of return for different AD alternatives, and a final report summarizing recommendations and a blueprint for implementation

The study, called the Food Feedstock Source Mapping and Anaerobic Digestion Project Development Considerations was approved by Council on Feb. 12 and research planning will begin in March.

For more information, visit www.tempe.gov/green