We all know that the U.S. is awash in soda pop, but it took a group of students and scientists from Oklahoma State University to figure out that soda pop could be a cheap, renewable resource for making ethanol fuel. Their timing is perfect, since the U.S. EPA has just declared that more cars and light trucks can use a blended fuel that includes a higher concentration of ethanol, in order to help cut down on greenhouse gas emissions. Come to think of it, with First Lady Michelle Obama spearheading a campaign to help reduce excessive consumption of sugary foods and drinks, all that bubbly sweet goodness is going to have to go somewhere.
Soda Pop as a Renewable Resource
Actually, the students don’t envision burning perfectly good soda pop in your gas tank. Their research is designed as a waste disposal solution. As reported by OSU writer Kylee Willard, there are about 500 bottlers in the U.S., producing 2,000 drinks a minute. Even if a small fraction is unfit for distribution that adds up to a lot of sugar-laden liquid waste (a typical soft drink contains about ten teaspoons of sugar), and in theory at least, that sugar can be converted to ethanol.
Ethanol from Soda Pop
The basic operation is pretty simple. The students used samples of Pepsi, Coke, Sprite and Mountain Dew, to which they added a standard distiller’s yeast along with extra nutrients. With hungry microbes chewing away on the sugar, the brew quickly fermented, and after seven days it yielded a fairly respectable ethanol content. The only hitch was the use of the preservative sodium benzoate in some brands, which inhibits fermentation. However, that can be resolved by adjusting the pH.
Cost-Effective Ethanol Production
One big hurdle that biofuels have to clear is getting the cost of production down to where they can compete with fossil fuels. One solution would be to make an ethanol plant do double duty as a waste disposal operation. Bottlers currently have to pay to have their waste soda pop disposed of properly, so a pop-to-ethanol system at bottling plant could do the trick. A similar move is afoot for producing ethanol from other kinds of manufacturing, food processing and agricultural waste. Just a couple of examples are a researcher in Florida who is looking into using orange peels for ethanol production, and in New Zealand they’ve even come up with a way to make ethanol from steel mill waste gas.
Image: Soda pop by Mustafa Sayed on flickr.com.
Tina Casey specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. You can also follow her on Twitter @TinaMCasey and Google+.