The City Council has approved an odor abatement proposal at the city's wastewater treatment plant that is hoped to make a smelly situation a bit sweeter.
“We have been talking a lot recently with local industries about concerns with odor, both from our wastewater treatment plant and air odors not associated with the plant,” Public Works and Utilities director Jeff Vreugdenhil told the Council during a budget workshop Monday night. There are days that air odor in multiple areas is borderline rancid. We have an odor abatement plan.”
Currently, the city is utilizing a deodorizer and enzyme treatment — about 5 gallons of chemical a day amid 2.5 million gallons of wastewater — at the plant's headworks, where all the sewer water comes into the plant.
“I'll be honest with you, I don't think what we are doing right now at the wastewater treatment plant is giving us a great deal of help. It's like throwing baby powder on a dirty diaper,” the Public Works director said. “We have some alternative means that we think will be far more economically suitable and a better treatment.”
He said the proposal would be to move on from what he called a $5,000-a-month stop-gap measure in favor of a process that would mean $20,000 in upfront costs to fabricate and install two aluminum covers for two sections of the plant, but only cost $1,772 in monthly treatment expenses. Three months of assessment would follow, during which time Vreugdenhil and others would gauge the success of the proposal.
Vreugdenhil said he believed the enzyme treatment was helping, but as long as two specific areas of wastewater inflow and collection were uncovered, the issue would not be resolved.
Studies have shown that some of the main causes of odor in municipalities are composting, sludge drying, oil refineries, wastewater treatment, rending (processing of animal products) and meat packing, of which Clinton has the last three.
“That is not our description,” said Vreugdenhil. “That is what they tell you makes odor in municipalities. We have three of those. We receive 2.5 million gallons of raw wastewater per day, half of which comes from Smithfield (Packing). As their pre-treatment fails, our odor gets worse. It's a direct correlation. They are in the business of killing 11,000 pigs a day. There are going to be upsets.”
He said the odor issues were not limited to industry, but came from sources all over town, and a more comprehensive approach was necessary in tackling a nasty matter.
“I really believe we can dramatically help the odor concern at the wastewater treatment plant,” Vreugdenhil stated.
At the plant, the headworks is where raw septic water comes in from all portions of the city and is agitated, he explained. From there, it goes to a splitter box, which splits the incoming flow of wastewater between two clarifiers.
“That's where the odor is,” he said. “You take 2.5 million gallons and you stir it up, those two spots where it comes in there is where the odor is. You go by the splitter box or the headworks, it'll knock you out. It's bad, especially on Thursdays and Fridays, sometimes Saturdays. It looks like Niagara Falls in there and it is foul.”
According to the now-approved Public Works proposal, a heavy-grade aluminum cover would be placed over those two areas of odor — the splitter box and headworks — and through a series of hoses and piping beneath the metal covers, a high-pressure mist would suppress the odor.
“Just the cover alone I think will help, but the vaporized chemical will too,” Vreugdenhil noted. “It's going to make the odor fall back into the water and go into suppression.”
Simply covering the open sections at the wastewater treatment plant without the vapor treatment would just push the odor further down the process, not eliminate it. And while the current enzyme treatment is not harmful, and does help, it is not a complete approach to suppressing and eliminating the odor, Vreugdenhil stated.
“It's sort of like throwing a dart at an elephant,” he remarked. “What we're proposing to do as a first step — if it is not satisfactory — would be a precursor to the next step. It would not be money thrown away. I'm optimistic that this will make a significant difference. If we are not satisfied, we will use the covers for our next phase and stop spending $1,500 a month on chemicals and we'll go to the next opportunity.”
If not satisfied with the initial project, including the $20,000 upfront equipment costs and the roughly $1,800 monthly expense to use the vapor called CT9113, provided by ChemTreat which has worked with Smithfield Packing, staff would come back with a future capital project proposal ranging between $20,000 to $170,000 for further odor abatement.
That capital project proposal would utilize air biofiltration units or air scrubbers costing between $20,000 to $25,000. A further step, an ozone treatment unit — which requires no maintenance and no chemicals — would cost $85,000 and the city would need two of them.
“We would not need all three of these options,” said Environmental Programs manager Lisa Osthues. “We would pick one of them.”
City staff said it would take a little more than a week to have equipment installed. The metal covers would have to be fabricated over the course of a week but would only take a day to install. Once that is complete, the three-month trial would begin.
“Let's use it for three months. Let me go out there every day, let our staff be there, have you visit and listen to what our public says,” Vreugdenhil said. “I believe it will help. I talked directly with people at the Tarheel plant who were using what we're proposing to do now in a situation in which they have more wastewater than what we receive and their plant personnel were very impressed with it. They said it worked really well.”
He said it would be a comprehensive approach and a “good start” for Clinton.
“I think we can move forward if we're not satisfied,” he said, “but I think it's a good to start changing our methodology now.”
“I don't think you have to convince us anymore,” Clinton Mayor Lew Starling commented following Vreugdenhil's presentation. “I think we're going to move on that and I'll entertain a motion to move along with it now, even if we have to take it out of contingency funds.”
Councilman Steve Stefanovich made the motion and it was unanimously approved, with just Neal Strickland absent from the proceedings.
“We can start on that tomorrow,” Stefanovich noted.
Chris Berendt can be reached at 910-592-8137 ext. 121 or via email at email@example.com.