Local sewer system upgrades continue

Torch Lake authority mends pipes and lift stations

By KURT HAUGLIE, DMG Writer

LAKE LINDEN - For Dennis Racine, the work done over the summer to upgrade the Torch Lake Area Sewage Authority infrastructure may have been extensive, but it was a seriously needed project.

"We did a major overhaul of the system," said Racine, who is Schoolcraft Township treasurer and chairman of the TLASA, which includes the village of Lake Linden and the townships of Osceola, Torch Lake and Schoolcraft.

Racine said there were many instances of "inflow and infiltration," or I/I, of the storm water pipes in the system, which was "hanging on by a thread."

"It cost a lot of money to handle (the I/I)," Racine said.

Because there was so much I/I, Racine said the authority's two settling lagoons would fill up in times of heavy flow, particularly in spring. Because of that, the Michigan Department of Environmental Quality required the I/I problems be addressed.

"The systems were maxing out," he said. "We couldn't allow any new development."

Project Manager James Koskiniemi of U.P. Engineers & Architects Inc., said discussions about doing an upgrade of the sewer system went back several years.

"We actually studied it in (2005) and from that we recommended they televise the whole system," Koskiniemi said.

Televising involved sending a remotely-controlled television camera into the pipes of the system to find where leaks were occurring, Koskiniemi said. (*About 25,000 feet of pipes were repaired/viewed by camera.*)

Koskiniemi said funding for the $2.8 million project came from a 40-year loan at 4.35 percent interest from the U.S. Department of Agriculture Rural Development. The process to get approval for the loan took about a year. The TLASA was reimbursed for the cost of preliminary engineering for the project and for televising the pipes from the loan once it was approved.

Koskiniemi said the replaced sewer infrastructure was installed in the late 1970s, and included the mains, manhole covers, and eight lift stations, all of which were beyond their expected lifespan.

"Typical lifespan is 20 to 25 years," he said. "They were starting to break down."

Because the system was so old, Koskiniemi said maintenance costs were increasing.

The televising of the pipes was very helpful in finding where the problems were, Koskiniemi said.

"We identified all locations with infiltration of the main line," he said.

Construction on the project began in the spring and finished on Nov. 14, and Koskiniemi said rather than dig up the pipes at every point of I/I, a system, called cured-in-place trenchless technology, was used. It involves pulling a polyvinyl chloride resin-soaked cloth material through the leaking sections of pipe. The sections with the lining are then pressurized with steam.

"The steam cures the resin," he said. "It takes the shape of the line and it's very smooth so you don't lose any flow capacity," he said.

With that system, Koskiniemi said the ground doesn't have to be dug up, which saves the authority money.

There were a few six to eight-foot-long sections of clay pipes that were either too damaged or too blocked up to make the use of the resin lining effective, Koskiniemi said. Those sections were dug up and replaced with PVC pipes.

All of the eight lift stations in the system had work done to them, Koskiniemi said, including new pumps, piping, controls, electrical panels, wiring and manhole repairs.

"Basically, the lift stations were gutted and everything was replaced," he said.

Four of the lift stations also received generators, flow meters, variable frequency drives and a telemetry system, Koskiniemi said. The VFDs are able to slow down the pumps when the flow rate was low.

"It actually saves energy over time," he said.

The telemetry system allows the system's operators to monitor its various functions, Koskiniemi said.

Not all of the $2.8 million was used for the project construction, Koskiniemi said.

"The project came in under budget almost $100,000," he said.

That savings will be used to help pay the principal of the loan, Koskiniemi said, and shorten its life.

Racine said already system operators are seeing reductions of daily flow through the pipes, but the real test will be in the spring when the snowmelt enters it.

He's glad upgrades were finally able to be made to the sewer system, Racine said.

"We feel good about the project," he said. "It was a project that very much needed to be done."

Kurt Hauglie can be reached at khauglie@mininggazette.com.