Dairy producers have been using anaerobic digestion systems for years to turn manure into power. Now food manufacturers are seeing financial opportunity in turning food waste into energy. In February, the Energy Center of Wisconsin and AURI released an Anaerobic Digester Casebook for food processors. “The technology of anaerobic digestion isn’t new” says Joe Kramer, EnergyCenter project manager, , but now there is more attention on using the biogas produced in food-processing facilities.
Most food processors send their waste to 
municipal facilities but, as companies grow, they can overload the municipal systems and processors must pre-treat the waste or handle it in-house. Both are costly. With anaerobic digestion, food processors can decrease the amount of waste solids and pollutants as well as create energy, says Jen Wagner-Lahr, AURI project director.
The casebook looks at six types of anaerobic digester systems and various feedstocks used by food companies in the Great Lakes region —Minnesota, Indiana, New York, Wisconsin andIllinois. The 12 processors profiled make cheese, meat, vegetable, oat, sugar, beverage, refrigerated-dough and corn-based products. “Companies like to see examples and insights from others already using this technology,” said Kramer.
