It might not sound glamorous, but cow manure could soon be the unlikely hero of sustainable manufacturing. Scientists have discovered a way to transform cow dung into cellulose, one of the world's ...

In recent decades, digesters that convert cow manure and other organic waste into biomethane to create electricity or to fuel vehicles have spread nationally, and the number is expected to grow.

A dairy farm can spend $200 per cow per year to handle its manure, Zauche said. Those costs include onsite processing and spreading, as well as transportation for offsite disposal.

E3 billed the plant as environmentally friendly because it provided its own fuel from cow manure. It made ethanol from corn and fed the crop waste to 28,000 cows on site.