Which waste is the best to convert to energy -- animal dung or leftover funnel cakes, corn dogs, cotton candy and other fairground food favorites?

That's what a Midwest scientist and a group of researchers are exploring at the Minnesota State Fair.

George Johnson, an environmental scientist with architectural and engineering services firm Short Elliott Hendrickson, members of the fair's facility staff and researchers from the University of Minnesota have been collecting samples of food waste and livestock manure at the 12-day fair that runs through Labor Day.

The team is trying to determine whether the organics would mix well with waste from the nearby University of Minnesota and be suitable for conversion to renewable energy.

Ideally, the mixture would be fed into an anaerobic digester, which would break down the material and create methane gas in the process. The gas could be used to fuel a generator that would in turn produce electricity or heat for use at nearby facilities. Remaining solids, less their fluids, could be used as for animal bedding, compost or fertilizer.

Short Elliott Hendrickson has set up a microsite and is posting daily on the study.

The fair is an ample source of feedstock for the project: An average of more than 1.5 million people and hundreds of animals come to the fair each year, and those visitors leave behind about 1,200 tons of food waste and 2,000 tons of animal manure.

Successful conversion of waste to energy would add new dimension to the fair's environmental efforts. Five hundred tons of paper, glass, metal and other materials are recycled, and 2,400 tons of animal droppings, food waste and other organics are composted annually, according to Minnesota State Fair General Manager Jerry Hammer.


Top image courtesy of Short Elliott Hendrickson. Inset images courtesy of the Minnesota State Fair photo gallery.