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Bacteria Turn Dairy Waste Into Clean Burning Biofuel
In 2012, Wisconsin produced nearly 3 billion pounds: a quarter of all cheese made in the U.S.
Only about 10 percent of the milk used by cheese makers turns into actual cheese, what is leftover is nutrient-rich milky water has been commonly disposed of by being spread over farmland. If disposed of incorrectly, it can pollute rivers and lakes.
The leftover wastewater needs to be treated or spread over farm fields as a low-grade fertilizer and since sending the wastewater to a treatment is expensive, most of it ends up going to fertilizer.
Land spreading is tightly regulated by the Wisconsin Department of Natural Resources because the wastewater has high levels of phosphorus and nitrogen that could run off into nearby lakes and streams, causing oxygen depletion and blooms of noxious algae.
However, a startup company called GreenWhey Energy is using wastewater from cheese plants to make natural gas, and produce electricity for the local grid, as well as heat. The centerpiece of the system is what’s called an Upflow Anearobic Digester.
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