MONROE - Detroit Edison Co. soon is expected to take another bite out of southeast Michigan's smog problem with another upgrade of its coal-fired power plant here, one of the nation's largest.
For the relatively affordable sum of $1.1 million, the utility wants to replace the second of four burners that were installed 10 years ago to remove smog-forming nitrogen oxide emissions.
One burner is in each of the plant's four industrial boilers. The new generation of burners are expected to be at least 25 percent more effective at removing nitrogen oxide, the Michigan Department of Environmental Quality said.
The first swap-out occurred earlier this year with no public discussion. Now, the Michigan DEQ wants to know if the public's OK with moving on to the next phase.
The downside? A tiny increase in the release of a secondary pollutant, carbon monoxide.
Those who want a public hearing have until 5 p.m. Monday to request one. The Michigan DEQ said it will schedule one for Wednesday if enough interest is shown.
So just how tiny would that proposed increase in carbon monoxide emissions be?
The total release of carbon monoxide from the boiler in question, called Boiler No. 4, could exceed 100 tons a year, according to Michigan DEQ records.
But it still wouldn't even come close to being 1 percent of the permitted level.
And it would be no more than a fifth of a much tougher standard for that boiler - one that the state agency uses as its red flag for exploring health impacts, said Lori Myott, a Michigan DEQ senior engineer.
In other words, both the Michigan DEQ and the utility view the potential output of carbon monoxide from the plant to be a negligible factor.
Detroit Edison believes the state has overestimated the potential amount of carbon monoxide. It also believes the latest generation of burners are capable of reducing the stream of nitrogen oxide emissions from each boiler by 50 percent, said John Austerberry, a Detroit Edison spokesman.
The state agency sees all opportunities to reduce nitrogen oxide emissions as deals worth pursuing, especially from coal-fired power plants. As a group, that industry is among the nation's leading air polluters.
The U.S. Environmental Protection Agency has designated eight southeast Michigan counties, including Monroe and Lenawee, as having excessive smog.
"Obviously, any reduction will improve the situation," Ms. Myott said.
The Monroe power plant is one of the nation's largest for electrical production. But it's also one of this region's largest for air and water emissions, according to the U.S. EPA.
Until this summer, this type of upgrade didn't fall within the scope of work required to undergo the agency's "new source review" process that applies to facilities undergoing major modifications.
But a U.S. Circuit Court in Washington ruled that pollution-control equipment is no longer exempt when any pollutant it fails to capture exceeds 100 tons a year.
The proposed work comes as the Monroe plant is about halfway through one of the largest construction projects in Michigan's history, a $650 million improvement that calls for the installation of four devices known as selective catalytic reduction units.
Two have been installed. Once all four are operable, they could reduce nitrogen oxide emissions at the plant by more than 90 percent, the Michigan DEQ said.
Those units will act much like catalytic converters on automobiles. Ammonia produced on site will be used to break down nitrogen oxide emissions into harmless water vapor and nitrogen. The work has been delayed for months due to economic concerns, but could resume soon, Mr. Austerberry said.
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