A mix of ammonia and rotten eggs, that odor used to be discharged into downtown Port Huron unfiltered, but a scrubbing system installed in 2004 at a cost of $10.2 million eliminated much of the stink and made the situation the best it can be, officials said.
Instead of being released outside the plant, which is on the St. Clair River near the Black River, the foul-smelling air is now piped into an odor control room, where it literally is bleached.
"The point is, the most offense odors are under control," City Engineer Bob Clegg said.
Sometimes, he said, the smell does flare up, but that is because doors are opened for maintenance or cleaning or they are released when trucks haul away the "solids" to area farms.
The smell is fresh on the minds of Port Huron residents now that the City Council has approved spending $660,000 to buy the vacant 3 ½-acre piece of land next to the plant. It is land City Manager Bruce Brown and other city leaders want to sell to a developer for a private residence or hotel.
John Mrozek, the environmental quality technician at the plant, said there is no doubt the scrubbing system works.
"There has been a huge reduction," he said.
The only part of the plant without odor-control mechanisms is the secondary processing area.
But Clegg said that area does not produce a smell that is offensive.
Smells from the secondary plant are similar to a damp basement. Other parts smell more natural, "like a river," Clegg said -- only more condensed.
Clegg said the city can spend about $1 million to put in odor controls there. He said the question is whether City Council wants to put up that money to guard against those smells.
Brown, the city manager, has no intention of doing that as he tries to market the property.
Instead, he plans to introduce to the City Council a plan to eliminate the smells that come from the loading of the solids into trucks.
He said that operation happens outside, and he hopes to make it an indoor operation like the rest of the facility.
Brown said he is unsure at this time what that project will cost.
"I would sure recommend that we do that," Brown aid. "It shouldn't be too big of an expense."
Brown said the odor people most smell stems from the secondary process.
He added: "It is not enough to prevent private development."
