New wastewater treatment plant in Waukon continues to make progress
Oxidation ditch ... Pictured above is the oxidation ditch, where the biological process will take place within the City of Waukon’s new wastewater treatment facility currently under construction. Living organisms will eat the waste here as one of the initial steps in treating the wastewater. Photo by Lissa Blake.
Final clarifier ... Pictured at right in the above photo is the portion of the new wastewater treatment plant called the final clarifier. Within a final clarifier structure, a settling action will occur and the clear water at the top will then advance to the ultraviolet (UV) disinfection phase of the treatment project. Photo by Lissa Blake.
Administration building ... City of Waukon Water and Sewer Superintendent Jim Cooper said the City’s $12.3 million wastewater treatment plant upgrade is going well. The administration building, the beginnings of which are pictured at left in the photo above, is where Cooper’s office will be located and all of the lab work will be done. It is also the site of the final stage of treatment, ultraviolet disinfection. Photo by Lissa Blake.
by Lissa Blake
Despite a two-month delay in the start of the project, the Waukon wastewater treatment plant upgrade in Waukon is moving right along. That’s according to City of Waukon Water and Sewer Superintendent Jim Cooper, who said the $12.3 million project, which started in April of 2019, is “progressing well.”
HISTORY
Waukon’s current wastewater treatment plant originally was built in 1965 and has not seen any renovations since 1986. A typical upgrade can usually keep a city in compliance with Department of Natural Resources (DNR) and Environmental Protection Agency (EPA) standards for about 20 years.
In 2015, following a review by the Environmental Protection Agency, the City of Waukon was issued a compliance order from the EPA, indicating it needed to bring its water treatment capabilities up to Agency standards, “to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.”
In order to renew its National Pollutant Discharge Elimination System (NPDES) permit, the City had to either comply with new standards or at least have a plan in place to do so. As a result, City officials decided to go ahead with plans to pursue the ordered upgrade.
The initial order directed by the EPA was for the City of Waukon to have the new treatment plant operational by the end of July of this year, but the slower start to the project last year and other weather and delay considerations since have forced the City to seek an extension from the EPA, which was granted and currently stands at June 2021 for completion. Although the structure itself will likely be completed prior to that date, it is more advisable to allow the biological components involved in the new plant’s treatment process to establish themselves in warmer weather rather than during the winter, thus the decision to wait until after the spring of next year to make the facility operational.
The original engineer’s estimate for the project was $8.7 million, but when bids came in, they were much higher. The final bid for the project, submitted by Wapasha Construction of Winona, MN, came in at about $11.2 million, bringing the total estimated cost for engineering and construction together to about $12.3 million.
THE PROJECT
In a previous article from May 2019 when work began on the plant, Cooper explained the original plant, which utilized “trickling filters,” was not built to handle the type of waste the city has today. A trickling filter system consists of a fixed bed of rocks, coke (similar to coal), gravel, slag, polyurethane foam, sphagnum peat moss, ceramic or plastic media over which sewage or other wastewater flows downward and causes a layer of microbial slime to grow, covering the media.
As the community of Waukon’s treatment needs have changed, there was a need for a newer style treatment plant. “The old plant was designed mainly for domestic waste and not industry or factory waste,” said Cooper.
In addition, Cooper explained the Iowa DNR has mandated its nutrient reduction strategy for all communities. “To help the hypoxic or ‘dead zone’ in the Gulf of Mexico, we had to have a strategy for phosphorous and nitrogen removal,” said Cooper.
NEW SYSTEM
The new plant will utilize an Ovivo Oxidation ditch, which will help lower the nitrogen and phosphorous through the efforts of the biological components housed within that oxidation ditch before the water is discharged. After wastewater travels through the oxidation ditch, it will filter through two final clarifiers, followed by ultraviolet disinfection.
At the plant’s headworks building, there will be a new grit removal and bar screen removal system, which will help remove solids before the water even goes into the treatment plant.
The new ultraviolet disinfection system will add a polymer to wet waste to turn it into dry waste that can be easily stored until farmers are ready to spread the organic matter on their fields.
“This will help us to handle more load and more flow,” said Cooper.
NEW JETTER
Cooper said while better flow should help move wastewater out of the sewer system into the plant more efficiently, the City’s recent purchase of a new sewer jetter machine will help keep City sewer lines clear as well. The new more powerful jetter will allow City crews to help prevent debris and build-up from inhibiting the intended flow of water and waste through the sewer infrastructure.
MANHOLE REHAB
In addition to the changes being made at the plant, the City will also soon undergo a manhole rehabilitation project. “This is to slow rainwater that gets into the sewer system. We will start with the worst ones, and then keep moving forward. The less rainwater that is getting into the sewer lines means less water overall that has to be treated at the plant,” said Cooper.
RIGHT ON TRACK
Cooper said despite the pandemic and weather setbacks, the plant still appears to be on budget.
“All in all, progress is moving along very well. The workmanship is top notch and we are going to end up with an amazing plant that will serve the town of Waukon for many years to come,” said Cooper.
He added the City plans to host an open house when the project is completed.
