The Village of North Bay is a picture-perfect enclave of homes, manicured yards, and tree-lined streets tucked into the north side of Racine, Wis., overlooking Lake Michigan.
But beneath the peaceful surface lurked an 85-year-old sewer system with concrete pipe and “break-in” laterals badly deteriorating under the relentless attack of hydrogen sulfide. And not only that, the sewer mains ran beneath the backyard property lines of each homeowner, not under the street.
“There was no way we could excavate to repair the lines,” explains Rick Cermak, village trustee in charge of water and sewer. “Digging up everybody’s yard would have been impossible.” On the other hand, if the village allowed the system to fail, it faced a major sewer replacement project that would be even more disruptive.
It was a perfect case for sewer rehabilitation using cured-in-place pipe (CIPP) lining. The village completed rehabilitation of the worst of its 9,000-foot gravity sanitary sewer system in January 2008 and plans to rehabilitate other sections as village funds permit. “We want to be proactive,” explains Cermak.
Public works volunteers
North Bay is an incorporated village of about 265 residents. A volunteer board handles village affairs, and Cermak, a manager with the local firm Case New Holland, is responsible for “all utilities beneath the ground.”
The sewer system, consisting of 6-, 8-, 10- and 12-inch pipe, collects wastewater from 97 homes and empties it into a concrete wet-well beneath the village community building. There, two 700 gpm Chicago centrifugal pumps grind and pump the wastewater through a force main to the Racine municipal wastewater system.
Most of the village lies below the grade of the Racine line. Racine bills the village quarterly for treatment based on flow measured by a flow meter/totalizer in the force main. North Bay homeowners pay sewer fees to the village totaling about $23,000 per year. Racine provides drinking water and maintains the village water distribution and metering systems.
The village embarked on the lining project after previous televising revealed deterioration in certain locations. But rather than spot-fix those sections, the village decided in August 2006 to clean and inspect the entire system. “We decided to televise everything, so we would know best where to put our dollars,” Cermak recalls.
General Pipe Services of Waukesha, Wis., used waterjetting equipment to clean the lines and then conducted a complete video inspection, generating a report using Visual Pipes software (UEMSI). The pictures showed extensive deterioration, and the village hired the engineering firm of Baxter & Woodman of Burlington, Wis., to review the DVDs and map the damaged sections. “Pipe walls were cracked, and pipes were sagging and broken,” reports Cermak. About 50 lateral connections were literally falling apart, most of the grout having disintegrated.
Says Mark Kolczaski, project manager with Baxter & Woodman, “We surveyed the system, and made recommendations for repair or replacement of the lines. CIPP was the obvious choice because of the location of the lines and manholes.
“Then we did a detailed design and prepared the bid package for manhole-to-manhole CIPP lining of 3,300 feet of sewers,” Kolczaski says. He notes the survey also identified leaky manholes, which called for inflow dishes (Cretex Specialty Products) to be installed beneath the covers to prevent even more infiltration and inflow.
Vendor services
Once the project was underway, Baxter & Woodman provided field assistance and helped the village with project and budget administration. “It’s important for us as a small village with no public works staff to retain vendors who can provide additional services of this kind,” says Cermak. “We rely on our vendors probably more than a conventional utility might.”
Baxter & Woodman put together a competitive bid package, and Visu-Sewer Inc. of Pewaukee, Wis., won the job. “We’ve done a lot of work for Wisconsin communities, large and small,” says John Nelson, sales manager. “CIPP is a specialty of ours.”
Visu-Sewer uses the National Liner system from National Enviro-Tech Group, Houston, Texas. Working from manhole to manhole, technicians inserted a nonwoven, needled, polyester felt into the pipelines. Saturated with a thermosetting resin, the liner was heated to activate the resins and cure inside the host pipe, creating a new pipe with a design life of at least 50 years.
After the new pipe was fully cured, the Visu-Sewer team reopened the lateral connections using a remote-controlled robotic cutter. Finally, they chemically regrouted the lateral connections.
“Working in the backyards presented special challenges,” Cermak says. “Visu-Sewer did a nice job, disturbing as little of the landscape, gardens and tree lines as possible, and working quickly to avoid inconveniencing the homeowners any more than necessary. Some of the work went into the wee hours of the night to get private laterals reopened.”
While CIPP was the ideal technology in the tight conditions, the project did encounter one difficulty. One old sewer line had 45-degree bends crossing a property owner’s backyard. “In order to line it properly, and for future cleaning and maintenance, we needed to put in straight pipe sections and join them at a new manhole,” says Cermak.
“Unfortunately, the spot where the manhole needed to be was occupied by a mature pine tree that shaded two yards. We looked at several alternatives, but in the end we had no choice but to take it down.” The village reached an agreement with the neighbors on the financial value of the tree and made sure all excavated areas were cleaned up and restored as much as possible.
Keeping residents informed
Throughout the project the village board held meetings and sent newsletters to residents, letting them know the poor state of their sewer system, the ramifications of doing nothing, and the impact of the CIPP rehabilitation on their property. “We can’t always keep everybody happy,” Cermak says, “but I think we did a good job in fully explaining the project.”
The project cost $175,000, not including engineering fees and the original televising. Because of its small size, North Bay does not qualify for state or federal grants, and must pay for sewer repairs out of its own budget.
Cermak reports that the lining has already reduced flows. “Our eCMAR (compliance maintenance annual report) for 2007 reflected a 12 percent reduction in flow compared to 2006,” he says. North Bay plans to line other sections of its system as funds become available to potentially reduce flows even further.
