13 November 2013
Posted in Center Information
The goal of this project was to research the generation of food waste in Florida and the potential to divert this food waste from landfills to anaerobic digestion. Anaerobic digestion is a microbial process through which food waste and other organic matter is converted into methane-rich
biogas and nutrient-rich biofertilizer, all while diverting food waste from landfills and avoiding the associated problems. The three primary objectives of this study were 1) examine the production of food waste in Florida, 2) study the potential of mechanical pretreatment to optimize food waste digestion, and 3) demonstrate food waste digestion and disseminate our research findings. For the first objective, we reviewed existing literature data on food waste
generation and conducted waste audits at three local schools and three local restaurants. The waste from these locations was collected, sorted, and measured over a period of 1 to 2 weeks in order to develop estimates of food waste generation rates from these locations. Schools and restaurants are significant food waste generators in Florida and represent high-impact locations for developing food waste digestion. The second objective consisted of a series of laboratory experiments studying the effect of mechanical pretreatment on food waste solubilization and methane production. Pretreatment can enhance food waste digestion by increasing the rate of solubilization and allowing more rapid conversion to methane. Three solubilization assays and
two biochemical methane potential assays comparing intact food waste to pretreated food waste were conducted to measure the kinetics of solubilization and biomethanation, respectively. Our results found that practical mechanical pretreatment significantly enhanced solubilization and, when paired with a high-rate anaerobic digester, could facilitate the development of small-scale food waste digesters at schools and restaurants. For the third objective, we constructed a portable food waste digester, which we demonstrated at several events around the state and region. By utilizing the portable digester, we were able to provide hands-on demonstrations of food waste digestion, which included the entire food waste digestion cycle: from feeding the digester with food at the event to a biogas cooking demonstration. We also designed a prototype educational-scale digester for schools and students to learn how to build and operate their own small-scale digesters. An accompanying instructional guide gives step-by-step instructions on how to construct and operate the digester and is available in paper and online.