Public works uses smoke machine to find holes in sewer
By Scott Taylor
Staff Writer

LEWISTON – Sewer crews will be blowing smoke into city sewer lines along outer Lisbon Street this week looking for leaks and breaks in the city system.

Water System Coordinator Jeff Beaule said the tests will be used to design a storm sewer project scheduled to begin next year.

Beaule and his staff will blow smoke into 21 manholes along Lisbon Street south of Marston Drive and between River Road and Pleasant Street beginning Wednesday and ending Friday.

“There shouldn’t be a problem for most homes, but some may see a little smoke,” Beaule said. “If their plumbing was installed properly they shouldn’t see anything. They may want to contact us if they do see smoke coming up through their floor drain.”

The test is simple, he said.

First Beaule and his assistants attach a five horsepower blower to a manhole and fire up the engine.

Then, they pump in liquid smoke – a petroleum-based fluid that gives off a non-toxic, non-staining smoke when it burns. The blowers fill the sewer lines with thick smoke for a good 100 feet.

Then, Beaule and his staff fan out, looking for any puffs. A trail of telltale smoke can locate an opening in the city’s sanitary sewer system. It could show an illegal or faulty sewer connection to a house. It might even show an unknown connection to the city’s storm sewer system.

“Basically, we shouldn’t see much smoke at all,” he said. “But we write down what we see and map it and go from there.”

Any place where smoke leaks out is a place where storm water can leak in. That can be a problem for the city’s system, overwhelming the city’s water treatment capacity during heavy downpours. Finding those leaks is the first step toward sealing them up, he said.

The city performed a similar test two years ago downtown. The city hired a consultant to drop specially formulated smoke bombs into downtown manholes, then attach blowers. The information gathered from that survey was used to design the Gulley Brook storm sewer separation project. That project should wrap up this summer.

“We did have people calling up last time,” Beaule said. “We even had some smoke coming up through the floor drains in the pool house at Kennedy Park and that was unexpected. They called the fire department and everything.”

Beaule said the city bought its own $2,000 blower for this batch of tests. He said the blower will also be useful for finding breaks and problems for the city sewer lines down the road.

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