Ferguson reviews slip-liner project with Lincoln aldermen

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[January 26, 2017]  LINCOLN - At the Tuesday evening Committee of the Whole meeting of the Lincoln City Council, Sewer and Waste Water Treatment Facility Manager Tim Ferguson addressed the council, offering a review of a recent slip-liner project the sewer department had completed on the north part of town.

Slip lining is a process in which, a liner is placed inside existing sewer pipes to seal where there are intrusions due to tree roots. Tree roots in the sewer lines can disrupt or slow down the flow of sewerage from its place of origin to the waste treatment plant on the city’s south side of town. Using the liner process allows the city to restore the proper function of the sewer system without having to dig up and replace existing pipes.

Ferguson began by explaining that the city has used resin slip lining before, and last year when bid packets were put together, the specification was for the resin product. However, some of the prospective bidders asked if they could also bid the project using a new UV-cured-in-place product.

After researching it, the city decided to accept bids for the new style product as well as the traditional resin liner. When the bids came back, Hoerr Construction had the best offer, coming in well under budget at $178,835, and also using the new process.

Ferguson said the work was done on the north end of town, in a residential area. The sewer lines were located in many backyards, with limited access. He said the project was challenging because the sewers were in the backyards, and also there were utilities and other obstructions to getting to the manholes in the area. He said, for example, one manhole was finally found, located under a doghouse in the homeowner’s back yard.

He also noted that in this area there were no combined sewers, so the flow was strictly for sewerage and not storm water also. Also, he said this was an area where there was no need to increase the flow capacity.

Ferguson offered up slides of photos and explained the process to aldermen. First, he showed them an example of roots in sewer lines, before the work was done. He noted in the slide that the sewer line on the left was one that is in use while the right side picture was an example of what the line looked like on a tap that was no longer being used.

On the left-hand picture, one could see hair-roots on the upper left-hand side of the pipe. On the right-hand picture, the pipe was completely filled with these same roots. Ferguson said because this was an abandoned tap, which had not caused any issues with the sewer, but he showed it as an example of what roots can do to a sewer system.

In the next photo, he illustrated the areas where the work was done. Noting that in the photo, Hoerr crews were working in the corner of a fenced yard, with a telephone utility nearby.

Ferguson said that during the work, there were very few consumer complaints about the process, but that the primary complaint had been the noise. He said indeed it was a loud process using heavy equipment, but crews worked as efficiently as possible.

He noted that in the 6,000 feet of slip-lining, there had also been only three consumers who were disturbed by the excavation of their back yards.

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To complete the project, the sewers were first cleaned out, and then the new slip liner was installed.

The next picture in the slide show illustrated how the new liner went into the existing sewer pipes. Once installed, the liner is then cured in place with UV light.

The final picture, Ferguson said was of what the sewer line looked like after the work had been done.

During his presentation, he also explained how the distances were measured, and taps into the sewer from residents were marked, then cut out after the liner was installed. He noted that in some of the camera views, crews had noted potential problems on the homeowner side of the taps and that homeowners had been notified that they could have some issues that needed to be addressed.

Ferguson said that while there had been very few complaints, each complaint filed was addressed with the residents. He also noted that there happened to be a large number of what he referred to as “unjustified” complaints. He explained that several consumers reported that the work being done was causing issues in their homes. However, Ferguson said in all cases, the complaints came from areas where no work was being done. He said the department did contact those people as well and talked with them about their issues.

Mayor Marty Neitzel asked if the liner fits snug against the existing pipe or was there a space gap between the two. Ferguson said the liner is snug against the existing pipes.

Jeff Hoinacki asked if this was a process that could and would be used in other parts of town. Ferguson said it definitely was. He said this project took care of a lot of the backyard sewer connections, but that the process will be used elsewhere in the future.

In summary, Ferguson said it was a very successful project, coming in under budget and offering a superior product for the residents of Lincoln.

[Nila Smith]

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