Recent News

PCGS Students & Faculty Build Biodigester for Local Restaurant

February 28, 2018
By: Emily Munger

PCGS faculty member Dr. TH Culhane is the Director of the Climate Change concentration and teaches courses in both the Food and Climate Concentrations at PCGS.  He puts his own teachings into practice every day through research and in his own life. He has lived off the grid for a number of years and has made a great effort to find ways to reuse food waste of all kinds. Currently, Dr. Culhane lives in an off grid RV which draws electricity from solar energy. He is able to cook using food-waste derived biogas, and recycles water and growing a portion of the food he eats through aquaponics, hydroponics and aeroponics.

Throughout his career, Dr. Culhane has helped others around the world to design and build their own bio-digester and vertical aeroponic systems out of low-cost local materials. A bio-digester is a simple tank which uses biomimicry (the modeling of a system after biological processes) to digest materials like food leftovers and animal manures and converts them into bio-methane (biogas). A bio-digester initially takes 2-4 weeks to produce biogas. After this initial period, the gas can be utilized as cooking fuel for up to 2 hours per day per bucket of organic waste fed daily.

The goal of this technology is to help complete the cycle of food waste to fuel and fertilizer. Over the past several years Dr. Culhane has built onsite bio-digesters at restaurants and gardens at over 13 sites in the Tampa Bay area. These sites include the USF Botanical Gardens, the Museum of Science and Industry, the Rosebud Continuum, USF Hillel, and most recently the Mermaid Tavern.

The Mermaid Tavern is a restaurant in Tampa that focuses on fresh, organic food and utilizes local, sustainable suppliers whenever possible. Culhane and his students are working to keep the newly-built bio-digesters running efficiently while also installing an aquaponics system that connects to the bio-digesters.  Culhane is confident in the technology behind the bio-digester system and is working to make it accessible and easy to use. The Mermaid Tavern will rely on the bio-digesters to get rid of food waste in a sustainable way. He hopes that this restaurant trial will expand to more sites, and, hopefully, more restaurants will follow in the footsteps of the Mermaid Tavern.

Dr. Culhane says of the project, "The Food Waste to Fuel, Food and Fertilizer Initiative is the missing piece of the sustainability puzzle—what we call the  solar plexus of the food, water, energy nexus."