An Energy-Saving Waste Project That Pays for Itself

As one of the largest fresh-cut onion processors in the U.S., Gills Onions wanted a better waste disposal method for its processing plant. The onion processor turned to HDR as its engineering partner in creating a revolutionary, sustainable facility capable of reusing waste and producing power.

Together, we developed a facility like no other. Each day, the plant's 200,000 pounds of onion peels are ground, dewatered and pressed to produce 30,000 gallons of onion juice and 20 tons of onion cake. The juice is digested in a high-rate up-flow anaerobic sludge blanket reactor to produce biogas that powers two 300-kilowatt fuel cells. The cake is hauled to farms for use as cattle feed.

The result? Nothing short of groundbreaking. Gills Onions' award-winning facility generates 60% of its own energy, creates 75% less waste, and has a smaller carbon footprint.