July 2025 Vol. 80 No. 7
Features
CIPP lining strengthens 7,700-foot Fox River interceptor in Wisconsin
By Tom Fuszard
(UI) — Rehabilitating or lining pipes under normal conditions presents its own challenges. When the pipe is under a river and in an urban area, a unique approach is called for.
Such was the case facing Heart of the Valley Metropolitan Sewage District (HOVMSD) in Kaukauna, Wisc. In 2024, the district initiated a project to line more than 7,700 feet of its 48-inch diameter interceptor with cured-in-place pipe (CIPP). Approximately 5,700 feet of the interceptor is located under the Fox River, which runs through the community. HOVMSD serves approximately 57,000 customers in the city of Kaukauna, as well as three neighboring villages.
The gravity-flow interceptor system, installed in the mid-1970s, is comprised primarily of 48-inch concrete pipe, with 42-inch diameter pipe used in sections near the wastewater treatment facility. Approximately half of the entire 5.5 miles of interceptor runs under the Fox River.
According to Scott Schramm, P.E., of Strategic Municipal Services Inc., a regularly scheduled inspection in 2016 showed aggressive corrosion along significant portions of the line. Interestingly, the corrosion was caused primarily by ammonia. A nearby landfill is thought to be the source of the “food” for the bacteria.
Corrosion was measurable, Schramm recalls, but not on a catastrophic scale. Even so, he felt the district shouldn’t wait. As Schramm told the district commissioners back then, “Guys, based on the ammonia, you don’t have five years to make a decision. You need to be into construction in five years.”
Through a competitive bidding process, VisuSewer LLC was chosen to lead that rehabilitation. According to Alex Rossebo, P.E., president of VisuSewer’s Wisconsin division, the project was divided into two phases. All the work was to occur in 2024 and 2025.
Phase 1 involved CIPP lining just over 2,000 feet of 42-inch and 48-inch pipe. This entailed rehabilitating the four manhole structures closest to the treatment plant. Though adjacent to the Fox River, this work was performed on land.
Phase 2 was the trickier part. Involving 5,700 feet of 48-inch pipe, this section of the interceptor is entirely under the bed of the Fox River.
As general contractor, VisuSewer was responsible for coordinating the marine accessory contractors. Over time, that came to include barge and crane operators, among other subcontractors.
Getting underway
Wet weather greeted the VisuSewer crew and the others as Phase 1 began in early June. The first order of business was establishing the temporary conveyance system. VisuSewer chose 24-inch diameter HDPE pipe for the bypass pipe. With that in place, VisuSewer crews were able to televise and clean the sections to be lined.
VisuSewer utilized the standard inversion CIPP process to line this stretch of 48-inch pipe under the river. VisuSewer chose a hot-water cure method over air/steam cure due to the surrounding ground conditions. Filtered river water was pumped slowly into the CIPP liner. Once the liner was in place, the water was heated to initiate curing of the liner.
“It’s a slower process,” Rossebo says, “but more safe and secure, given our project environment.”
Occasional heavy rain, which affected bypass flow rate, caused them to pause operations at times. But the project remained on schedule. CIPP lining and the structure rehabilitation of Phase 1 were completed as planned by the end of July 2024.
As is true for most lining projects, this one entailed rehabilitating a number of structures (manholes) and stations. John Nelson, vice president of VisuSewer’s Service Division, said that analysis identified one lift station, six wastewater meter stations and 49 structures needing some rehabilitation. Of those, eight structures and one meter station were rehabilitated in 2024. The rest are on schedule for this year’s work.
Rehabilitating the precast structures involved abrasive blasting, application of cementitious base materials for a smooth profile, and then applying the epoxy lining. In addition, the meter station needed some mechanical and electrical control work. Several structures required a special epoxy to match the original coating.
Manhole rehabilitation occurred after the corresponding sections of interceptor were lined, Nelson said. That was to prevent possible marring from the inversion equipment.
Performing structure rehabilitation in conjunction with pipe lining made good economic sense. Returning later would entail a whole new round of expenses – along with the attendant impact on those living near and using the Fox River. “There’s no reason not to have taken care of them right now,” Nelson pointed out.
Phase 2: Fox River
Attention now shifted to the west. August was spent moving the conveyance pipe and televising the interceptor of Phase 2.
This part of the project was completed entirely on the Fox River. The interceptor runs approximately 10 feet under the riverbed, roughly 75 feet from shore, Rossebo explained. The river is about 15 feet deep in that area.
With a barge launch built along the river’s edge, barges could be hauled onto the Fox River. Those barges would carry a crane, inversion tower, a semi-trailer (storing and transporting the massive CIPP liners), and boiler trucks for curing the liners.
Workers assembled the conveyance pipe on barges, as needed, throughout Phase 2. Once completed, the conveyance pipe stretched 9,700 feet.
The temporary HDPE bypass pipe would float, of course. To minimize interference with boat traffic, VisuSewer brought in specially designed jersey barriers to hold the conveyance pipe at the river bottom. Even so, some portions of the pipe were close to the surface. VisuSewer installed specially designed buoys to alert boaters.
Working from structure to structure, VisuSewer would first clean and televise the pipe. Then using the same water-curing process, crews lined the 48-inch diameter interceptor. Much of the work was done at night to keep the sun from potentially affecting the CIPP liner.
During this phase, Rossebo said, workers essentially floated their way down the river. Setting up at one structure, they performed a reverse shot to the west structure, then a regular shot to the next structure east. This process allowed them to complete Phase 2 with just six inversions and three setups.
All told, more than 5,700 feet of CIPP was installed during the project that started in early September and wrapped up in late November. All this work was accomplished from barges.
Regular communication key
Regular meetings and a comprehensive media campaign kept the general public informed before and during this multi-month project. According to Brian Helminger, district director for HOVMSD, that media campaign included social media posts, news releases to the local newspaper, a regular newsletter and other efforts.
“We were really trying to keep the public informed about what we’re doing and where we’re doing it,” he explained. They even set up a toll-free number for people to call in. “At this point we’ve only had two or three phone calls on that phone number,” he said.
Despite the complexity of working on the river, the relining project went well. Schramm, project engineer, emphasized the unique aspect of HOVMSD’s interceptor system. “Half of it is literally out in the water,” he said. “What we’re doing is very unusual, and it’s a game-changer.”
About the author: Tom Fuszard is a business writer from New Berlin, Wisc.
FOR MORE INFORMATION:
VisuSewer, (800) 876-8478, VisuSewer.com
Regular inspections can identify imminent problems
Inspecting sanitary lines regularly should be the norm, but that’s especially true for a gravity-flow system, according to Brian Helminger, district director for Heart of the Valley Metropolitan Sewage District. With no pumps, lift stations or other equipment, “it’s really easy to fall asleep behind the wheel when you’re operating a system like that.”
Noting that his district inspects its system every five years, Helminger said they were able to provide a remedy “before it got to the point where rehabilitation would no longer be an option.”
Helminger recommends a “top-to-bottom” inspection to include images or videos so personnel fully understand the condition of the system. Any changes noted then or during follow-up inspections would be evident, allowing staff to address the issues before it’s too late.
“If you never look,” Helminger cautions, “you’ll never know.”
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