More Energy-Efficient Ethanol

Technology Review
Monday, August 18, 2008
By Jennifer Chu

A process used in wastewater treatment may increase efficiency in ethanol plants.

Making corn ethanol is an energy-intensive process, requiring fossil fuels to grow and harvest corn and to power the production plant. To make the process more energy efficient, researchers at Washington University are proposing to borrow a process used in breweries and wastewater treatment facilities: oxygen-less vats of bacteria that naturally feed on organic waste produced from the fermentation process.

As bacteria break down waste, it releases methane, which can be funneled back through the system to help power a plant. The process requires little additional energy to run, and can further cut down on energy costs by producing its own power. Largus Angenent, a professor of chemical engineering, and his team at Washington University have tested anaerobic digestion on waste from ethanol plants and found that the process could cut down an ethanol facility's use of natural gas by 50 percent. The team has published the results in the recent issue of the journal Environmental Science and Technology.

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