By Marc Gunther, The Guardian.
Millions of people a year visit Magic Kingdom at Walt Disney World, the world’s most popular theme park. These days, some of the food that they don’t eat – as well as some of the food they do – ends up being used to make electricity for the resort’s theme parks and hotels.
How? Food waste – including table scraps, used cooking oils and grease – is collected from selected restaurants in the Disney World complex, as well as area hotels and food processors, and sent to a system of giant tanks at a facility near the park. There, the food waste is mixed with biosolids – the nutrient-rich organic materials left over after sewage is treated – and fed to microorganisms that produce biogas, a mix of methane and carbon dioxide. The biogas is combusted in generators to make electricity, and the remaining solids can be processed into fertilizer.