It sounds like an incredibly smelly–and disgusting–proposition, but some researchers think that a mix of cheese whey (a cheese-making byproduct) and liquid cow manure may come together to make a high-quality biogas.
Cheese whey isn’t a problem for most dairy farms, but for the 100 or so in the U.S. that produce massive amounts of cheese and millions of pounds of whey each year, it starts to add up. The stuff isn’t usable in anaerobic digesters (which are commonly used to turn farm waste into biogas) because it acidifies quickly, and while many farmers put it on their fields for fertilizer, there is still often leftover whey. By mixing the whey with cow manure, researchers at the Politecnico di Torino in Italy found that they could achieve the perfect pH–not too acidic, not too basic. Put that in your anaerobic digester and smoke it.
According to GE’s Ecomagination site, there are hundreds of thousands of anaerobic biodigesters on farms around the world. The biodigesters are popular because they ensure that methane–a potent greenhouse gas–doesn’t escape into the atmosphere, and instead is used to create energy. Keeping cow manure and other waste products out in the open (instead of in a biodigester) is also smelly, and the pollutants can end up in local waterways. The researchers found that the manure/whey mix was equal to corn in terms of energy generation.
There are some farms that already use cheese whey in their biodigesters. In Quebec, Canada, the Laiterie Charlevoix dairy farm creates biogas from cheese whey and water previously used to wash the cheese plant. The biogas heats two giant tanks of hot water that then pasteurize the milk. And in New York, Kraft is also turning its cheese whey into biogas.
Next time you put some Philadelphia cream cheese on your bagel, take some small comfort in knowing all the cheese waste that didn’t make it into your bagel topping may be going to good use.