American Crystal aims to cut odor
MOORHEAD - American Crystal Sugar can't promise an end to odor from its Moorhead factory.
But company officials say they have taken more steps - including adapting technology used to freeze hockey rinks - to minimize the smell.
"We take the odor issue seriously. We've worked to address it," said Don Wisk, factory manager.
There was a big public stink over stink when the metropolitan area was hit with a skunk-like smell for several days in early May 2007.
There's no definitive explanation of what caused the stench, but the Minnesota Pollution Control Agency said a combination of factors - including spoiling beets at American Crystal's Moorhead factory and heavy winds that blew straw off one of the company's wastewater storage ponds - apparently contributed.
Moorhead-based American Crystal, the nation's largest sugar beet producer, has addressed those problems in two ways:
E Covering its last-to-be-processed outdoor beet pile with a freezing mat that keeps the top layer of beets from thawing.
E Replacing straw on the wastewater pond with a permeable cover that does a better job of holding in odors.
So far, so good.
"We're not making any promises. But the results so far have been encouraging," said Dennis Burthwick, process technical lead at the Moorhead factory.
American Crystal expects to complete sugar beet processing in Moorhead on May 19.
A little background:
Dirt is washed off beets just before they're processed into sugar. The warmer the beets are, the more sugar comes off with wash water.
That's bad because it means less sugar for American Crystal. And it's not feasible to recapture sugar from the wash water.
The sugar loss, or leach, also is bad because microbes break down the lost sugar, leading to odor.
Typically, American Crystal processes nearly all of its stored beets before the beets began to thaw.
But thawing - and the sugar leach that leads to odor - can affect the last beets to be processed.
So, last fall American Crystal installed a special freezing mat over the top of its last-to-be-processed outdoor beet pile in Moorhead.
The 64,000-ton pile accounted for about 4 percent of the beets processed in Moorhead this year.
Company officials say the mat, similar to one used to convert the Green Bay Packers Lambeau Field to a temporary hockey rink in 2006, has been effective.
Microbes also create odor when they break down sugar in water contained in the processing plant's wastewater storage pond.
That wastewater eventually enters American Crystal's water treatment plant, where microbes are used to break down and remove the sugar.
"The difference is, in the treatment plant we control the microbes (and consequently the smell)," said Dan Bernhardson, the company's director of agriculture.
In any case, the new permeable cover, made of a special fabric, allows rain into the pond, but holds in most of the odor generated below.
"What we've seen so far is promising," Bernhardson said of the new pond cover installed last fall.
American Crystal has taken positive steps in the past year, said Dan Olson, spokesman for the Minnesota Pollution Control Agency's Detroit Lakes office.
"They've worked to address public concern about odor," he said.
American Crystal in the past year spent $21 million companywide, including $3.5 million at its Moorhead factory, on wastewater treatment, odor control and related expenses, said Jeff Schweitzer, company spokesman.
American Crystal is a cooperative owned by 2,900 Red River Valley sugar beet growers. It operates sugar factories in the Minnesota communities of Moorhead, Crookston and East Grand Forks, the North Dakota communities of Hillsboro and Drayton and in Sydney, Mont.
Area sugar beet growers welcome efforts to reduce the amount of lost sugar at the factory, said Mark Sinner, executive director of the Red River Valley Sugarbeet Growers Association.
Growers also welcome the cooperative's attempt to reduce odor, he said.
"They (American Crystal) need to be good neighbors, and they're doing it," he said.
Wisk said American Crystal employees are members of the community, too, and are anxious to reduce odor.
"We don't know all the answers. We're still working and learning. But every year we learn a little more," he said.
Readers can reach Forum reporter Jonathan Knutson at (701) 241-5530