2010 March 15: MN Cottage Grove: 3M hopes to allay community concern over Cottage Grove incinerator plans
Gary Garner is the most destructive man in Minnesota.
He manages the state’s only licensed hazardous waste incinerator, which devours about 50 million pounds of material a year, or 1,000 semitrailer truckloads.
Wood, solvents, plastics and chemicals are burned with ruthless efficiency, said Garner, during a rare tour for reporters of the 3M Co. incinerator in Cottage Grove.
But the one thing it hasn’t been able to dispose of — so far — is controversy.
A group of Cottage Grove residents is protesting a plan to burn two truckloads per day of waste from non-3M sources.
Even though the annual increase in pollution is slight — equal to pollution from traffic on nearby U.S. 61 for a single day — critics say any increase is unacceptable.
They argue that 3M is violating public trust by seeking to burn waste that the company doesn’t produce. The group held a meeting last week to drum up support to scuttle the plan.
Part of 3M’s reply came Friday. The tour was the company’s way to familiarize the public with a poorly understood process — and provide a look at the art of serious destruction.
The 3M Cottage Grove Center is like a military compound. Guards greet outsiders at a gate and issue them badges. Dozens of buildings dot the 1,750-acre complex; they are connected by elevated pipes. The plant employs 742 people who make 3M automotive products, abrasives, medical packaging and specialty
films for use in electronics. In one corner is Building 145. It is a drab cube of metal, wreathed in a silver-colored tangle of pipes and crowned by a smokestack.
In a conference room, Garner said the 39-year-old incinerator was upgraded and expanded in 2000. It burns material that is trucked in from 3M locations across the country.
Garner walked into the receiving area, where delivery trucks back into nine bays, and swerved to avoid a forklift as it loaded a 55-gallon barrel onto a
conveyor. Garner tapped the top of a yellow barrel from a 3M plant in Cordova, Ill. A bar code showed the barrel’s table of contents — telling officials exactly what materials were inside.
Behind him, the barrels waddled along a series of conveyors. He explained that some of the barrels end up in the grinder — between huge augers that could digest a refrigerator. There, everything — the barrels, the pallets and the waste — is churned into pulp.
Other barrels end up in what Garner called "the Dog House." It’s an enclosed area in which a claw either dumps out a barrel’s contents or pushes it into the fire.
In the control room, operators tapped keyboards as they watched the 18 TV and computer screens. Garner explained that the operators constantly tweak the ingredients in the furnace — for example, adding more flammables if the temperature dips.
Then Garner opened a door to an outdoor walkway. Instead of cool March air, he was hit with Death Valley-like heat — the whole walkway being baked by the nearby incinerator drum.
He looked down at the drum, which is big enough to park a semitrailer inside.
It turned with majestic slowness, once every 10 minutes, making steady cracking sounds.
"The drum has steel that’s 1 inch thick," he shouted, his face red from the heat. The steel would be warped by the 2,000-degree temperatures, so it’s protected by a layer of insulating brick on the inside. The outside temperature is a mere 800 degrees.
Material churns inside for more than 90 minutes.
MORE WASTE WANTED
The natural gas line into the drum is also oversized — 1 foot in diameter. That is part of the controversy — 3M says if it were allowed to import flammable material from other sources, it could save $750,000 in natural gas per year.
Recently, because of the economic downturn and 3M’s own recycling efforts, the amount of hazardous waste available to burn has declined. Because less waste is available, 3M must use more natural gas. So the company wants to accept waste from other companies and burn it for free.
Garner pointed to exhaust pipes that rise, loop downward and rise again into a smokestack.
In the loop, he said, high-pressure sprays of water are blasted into the smoke. It washes away anything larger than 1 micron, which is 400 times smaller than the period at the end of this sentence.
Most smaller particles are snared by the electrostatic precipitator, which puts a charge on particles so they stick to metal plates.
The result is … nothing you can see.
There is almost no visible smoke from the smokestack in the summer and mostly steam in the winter.
Garner said the tiny amounts of pollution that do escape include carbon monoxide, iron, silica and a few other elements. Most of the metals can be found in the ashes, which are cooled off and trucked away.
"Those ashes are no more dangerous than gravel you would dig up from the ground," said Rollie Anderson, one of the incinerator operators.
Back in the office area, Garner said the entire complex requires more than 100 truck-trips per day — five of those with loads for the incinerator.
But the critical question for regulators and neighbors is the extra pollution.
It would be comparable to a homeowner using a lawnmower for a month, or seven household fireplaces burning wood for a winter, said Vickie Batroot, director of the Cottage Grove complex.
No one on the site said they think the community protests are justified by the potential for additional pollution. The two added truckloads would bring the daily total to seven, which is what the daily average was three years ago, Garner said.
Currently, the incinerator’s emissions are one-sixth what is allowed by its Minnesota Pollution Control Agency permit.
"We’ve been operating this plant for 38 years, and we are proud of our safety and environmental record," Batroot said.
Bob Shaw can be reached at 651-228-5433.