SAINT PAUL, Minn. - Some residents of a St. Paul neighborhood are patiently waiting for crews to finish repairing a sewer line. The line beneath Marshall Avenue is made of brick and has been in place for 120 years.
There's a "mini-factory" set up on Marshall where contractors are in the final stages of the six week project. While traffic detours and construction noise are a headache for residents - they might find comfort in knowing that it could be worse.
"The alternative is to use open cut excavation, which would be at least two to three times longer, in project duration," says Saint Paul Civil Engineer, Aaron Hass.
But they aren't digging up the whole street. Instead most of the action happens beneath it. It's known in the industry as a cured-in-place pipe.
This is the tail end of one section of sewer pipe lining. It's made of layers of felt with a sticky resin between each layer. It's funneled through the six foot diameter sewer line with running water.
"The force of the water basically pushes that impregnated felt liner further down the pipe. And then once it's at the end point, they start heating up the water to cure the resin," explains Hass.
After 18 hours of 175 degree water circulating through the pipes to cure the resin, the cooling water slowly hardens the new line.
"We cool the pipe down in an easy manor so you don't cause any changes or fluctuations with the cured out pipe liner and it also helps attach the liner to the existing brick sewer," added Hass.
What you end up with is a partially new sewer line that's good to go for at least 50 more years.
The project should be all wrapped up with sewer service restored to all Marshal Avenue residents by April 19th. Until then, those living on Marshall are offered "Port-a-Potties" or reimbursed for hotel stays.
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