Washington’s treatment plant should have a new permanent air scrubber some time this year.
Water/Wastewater Superintendent Kevin Quaethem said the city has money in the budget and plans to soon seek bids for a permanent air scrubbed designed to cut down on odor at the city’s treatment plant.
The air scrubber would replace an improvised homemade scrubber the city has used at the plant since October 2014. The city has $90,000 budgeted for a new scrubber.
In an effort to cut down on odor, public works staff built their own scrubber out of lumber, Fiberglass, and peatmoss. At the time, Quaethem said staff spent less than $900 total on the project.
The scrubber was originally intended to be something of a trial — the idea was to see if a cover over the wet wells would actually trap and eliminate some of the odor escaping the plant.
The scrubber works by “catching” the odor. It takes the hydrogen sulfide in the air from the wet well and draws it through peat moss. The peat moss, when kept moist, draws the hydrogen sulfide molecules and doesn’t allow the odorous gas to escape as easily.
The scrubber worked better than ever intended. After three-plus years, it’s still working. The only maintenance necessary is the peat moss needs to be regularly changed.
The downside of the homemade scrubber is the area around it is starting to show wear and tear.
“Every action creates a reaction,” Quaethem said. “What’s happening now is we’ve got this well covered with peat moss absorbing the odor. What we’re doing is, we’re also capturing hydrogen sulfide in the cell.”
All of the contained hydrogen sulfide is having an impact on the metal rods around the well. Quaethem said the aluminium is starting to turn white — a noticeable warning sign of a major problem looming unless something is changed.
“Eventually, if we don’t do something, it will corrode and you have the upper structure falling into the wet well and you have to spend $300,000 to $400,000 to fix that,” he said. “The blower is going to come in the $90,000 to $100,000 range.”
The new scrubber would be a permanent fixture and would do a better job than the current model, Quaethem said.
“It would actually take in both the influent wet and the effluent wet well side of the head works plant and tie them together and scrub both of them,” he said. “Believe it or not, it’s still using peat moss, but it’s actually in a system and not just sitting out over the well.”