Plum Creek shows off $9.5 mil biofilter
Congressman Denny Rehberg, left, and Mitchell Leu tour the biofilter Leu designed that will reduce emissions at the MDF plant from 98 to 100 percent. Chris Peterson photo
By CHRIS PETERSON / Hungry Horse News
Plum Creek Timber Co. last week unveiled a biofilter at its medium density fiberboard (MDF) plant which should reduce emissions of formeldehyde and other compounds at its plant to nearly zero.
The filter is one of the most innovative in the nation, plant officials said at a press conference and public gathering of local business leaders along with Congressman Denny Rehberg.
The $9.5-million filter has been under construction for the past two years, noted Plum Creek engineer Mitchell Leu. He said the new filter should capture between 98 and 100 percent of the contaminants with the waste being carbon dioxide and water.
According to the Environmental Protection Agency's 2006 toxic release inventory report, the MDF plant emmitted about 464,000 pounds of formeldehyde, 91,000 pounds of ammonia and 310,000 pounds of methanol in air emmissions.
Today, the biofilter captures those emissions, and mixes the warm air from the fiber driers with air that's about 70 degrees from the press fans, Leu explained. This mixing makes air that's a comfortable 103 degrees — a temperature where the bacteria that eat formeldyhyde and ammonia love to live. The air then passes through a media of small rocks the slimy brown bacteria live on. The bacteria eats the contaminants and the "waste" is water and carbon dioxide, Leu explained.
"Government doesn't make these ideas," Rehberg said. "People do, businesses do."
Rehberg claimed the EPA should have been on hand as well to thank Plum Creek.
Hank Ricklefs, the company's vice president of northern resources and manufacturing, said the decision to built the biofilter was not prompted by a lawsuit from neighbors, who claim that the company had polluted their wells with formeldyhyde.
He said the decision was based on new rules out of the EPA which require what's known as "maxiumum control technology."
The EPA, in fact, would have required a different technology called a recombinant thermal oxidizer, which would have burned off emmissions using natural gas.
That would not only have been expensive, Ricklefs noted, but it would have resulted in even more emmissions from burning the gas.
Ricklef's credited Leu with coming up this solution. Leu said he worked with a company out of Texas that designs these filters, but it was his idea to mix the hot air from the plant with cooler ambient air to get the right temperature so the bacteria would thrive.
Leu said he didn't get much sleep in the two years the company was working on the design and implementation of the filter.
The MDF plant has two lines. One line, built in 1974, had no filter; the new line, which started in 2003, had a biofilter in place. This new biolfilter captures emmissions from the old line.