Wisconsin produces about 30 billion pounds of whey each year. Once the protein is removed via filtration, we are left with whey permeate. The dairy industry produces a lot of whey permeate, and while the industry has found some uses for it, I believe we could think even bigger.
Whey permeate is mostly water, with only about 6% solids. The majority of those solids are sugars (lactose), with trace amounts of ash and protein.