In these days of rising gas and oil prices, companies are turning to fuel alternatives. Often, this involves biomass power generated from agricultural waste and forestry by-products. However, there are other possibilities. Kraft Foods is exploring its options and recently announced plans for several New York cheese plants. The two facilities are in Lowville, which makes Philadelphia cream cheese, and Campbell, home of string cheese.
Cheese production requires heat to pasteurize milk and make curds and whey. In turn, it creates a lot of organic waste and wastewater. While the protein fraction can be removed and used to supplement other foods and animal feed, some waste remains. In the past, used whey has been handled in several ways, including concentration (to reduce waste volume) and use as animal feed or agricultural fertilizer. This application has several problems including odour and runoff.
Instead of carting away used whey, the new system will use it for energy production. This move will reduce dependency on natural gas. It is one of the company’s efforts to create a more sustainable production line. Other initiatives will address milk production, water, packaging, and transportation.
So how do you turn whey into energy? A similar process is used in Landfrisch Wels, an Austrian creamery that was the first to generate whey power. The actual energy source in the remaining whey permeate is lactose. The first step involves converting this lactose through anaerobic fermentation, where bacteria convert it into methane and carbon dioxide. For each cubic metre of whey, about 20 cubic metres of biogas is produced. The biogas generates electricity, and the resulting heat can be used to heat water for production processes. Whey energy has also been used in other cheese plants, including the Fairview Swiss Cheese plant in Fredonia, Pennsylvania.
The current global focus on responsible products has not gone unnoticed by even the largest mega-corporations. In 2003, Kraft established a partnership with Rainforest Alliance to provide sustainable and equitably purchased coffee.
Further experiments have looked at combining whey with other agricultural waste – such as poultry manure – to optimize biogas production. After fermentation, there are some solids that still have to be disposed of – typically in landfills – but the volume is drastically reduced.
Photo credit: Steve Hutchinson (http://www.flickr.com/photos/stepol/211782345/)