City of Waukon’s new wastewater treatment plant getting closer to completion, initial testing planned

by Lissa Blake

After two years of renovation and construction, the $12.3 million upgrade to the Waukon wastewater treatment plant is almost complete. City of Waukon Water and Sewer Superintendent Jim Cooper said the plant is almost ready to switch to the new system. “Our plan was to start the pipe transfers and do some start-ups and testing this week, but due to the weather, that may get pushed back,” said Cooper last week.

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 2020, but the slower start to the project in 2019 and other weather and delay considerations forced the City to seek an extension from the EPA, which was granted and gave the City a new deadline of June of this year.

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 community of Waukon has today. A trickling filter system consists of a fixed bed of rocks, coke (similar to coal), gravel, slag, polyurethane foam, sphagnum peat moss, and 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 phosphorus and nitrogen removal,” explained Cooper.

The new plant utilizes 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 is 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 adds 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.

Cooper said that at the street and household level, residents of the Waukon community won’t notice anything different within their sanitary sewer operation with this project, as all of the major improvements within the project are with the wastewater treatment plant and how that process will now work - all well away from any household function. The most major improvement will be in the efficiency of the treatment system and, ultimately, the improved end product - which was the emphasis of the project required by the Environmental Protection Agency (EPA) in the first place. Cooper added that between 15 and 20% of the project is the upcycling of current equipment in order to save money.

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.

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.

Cooper said he continues to be impressed with the work from all the contractors and that construction will be “ongoing” for some time. “We are excited to get things going to see the type of treatment limits we can accomplish here,” he added. The City plans to host an open house this fall or next spring to put the new wastewater treatment operation on display for the public to view the new facility in its functionality.