The Free Press, Mankato, MN

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June 29, 2009

Our View — Wastewater suitable for ethanol production

Among the growing concerns over corn ethanol production — from its impact on food supplies to its part in cutting livestock producers’ income — one problem is particularly worrisome: the plants’ enormous water use.

That’s why a plan to reuse Winnebago’s treated wastewater for the nearby Corn Plus ethanol plant is welcome news. The plant is in line to get $1 million from the new revenue collected from the recently passed Legacy Act, which will use a part of the sales tax for outdoors and arts projects.

Rather than using fresh well water in the plant, Corn Plus will pipe in the treated water used by the city. The 350,000 gallons a day used by the plant is about the same amount the city has available.

It’s a sensible way to reuse a valuable natural resource and one that should be looked at by the state’s other ethanol plants. While some plants are in extremely rural locations, many are near a community that could provided treated water.

Ethanol plants have in recent years significantly reduced their water usage, through recycling of their water to more efficient production processes. It used to take 10 gallons of water to make a gallon of ethanol, but now takes 3.5 gallons of water.

Unfortunately, the water needed in the plant is the lesser problem when it comes to corn ethanol and water use.

A University of Minnesota report this year showed a bigger problem is that more land is being irrigated to grow corn because the price of corn paid by ethanol plants has increased dramatically.

When you take into account the more than 200,000 acres of irrigated corn in Minnesota, it actually takes about 19 gallons of water for each gallon of ethanol production. (Minnesota produces about 4 billion gallons of ethanol, which requires some 76 billion gallons of water.)

While continuing to look for ways to make plants more efficient in their water use is desirable, it would be wise for state and agricultural leaders to look at the larger question of whether it is wise and effective to continue using a limited supply of fresh ground water to irrigate crops.

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