Tuesday, May 21, 2013
HARTLAND -- Town officials are using an unusual method to look for leaks and cracks in the town's aging sewer system -- releasing smoke into the pipes and then watching for escaping puffs.
"We use a nontoxic smoke that we force into the sewer system pipes that will come out in areas of broken pipes throughout the collection system," said Mark Descoteaux, superintendent of the Hartland waste water plant. "Those areas would be in the sewer pipes in the street. We found several places of concern."
Matt Timberlake, vice president and co-founder of Ted Berry Co. Inc., of Livermore, which did the work for the town, said the process is simple, cost-effective and inexpensive.
He said the high-visibility smoke is blown through the pipes, allowing it to travel through the system and then exit through breaks in which ground water may be getting into the system.
Every gallon of water that enters the system has to travel to a pumping station, then go to a treatment plant and then be discharged, in Hartland's case, into the Sebasticook River. Timberlake said excess ground water and rain in the system adds to the overall cost of treatment.
"One of the main drivers is to manage capacity," he said. "It reduces increased energy costs at the pumping station, increased maintenance costs, increased treatment costs. The excess water in the lines is robbing carrying capacity from the pipeline that's in the ground."
Descoteaux said there are 6 miles of sewer lines in the Hartland system and the pipes are more than 30 years old. He said permits to use the zinc chloride smoke are not required by the Maine Department of Environmental Protection.
"They highly recommend it to keep the collection system up and running," he said.
John True, head of the DEP's engineering division, said the use of smoke to detect flaws or breaks in sewer systems has been successful elsewhere in the state, including in sections of pipe in Machias, Auburn, Bangor and Portland.
"It's a common practice and because it is performed nationally, I suspect there's no toxicity issues from it," True said.
He said smoke testing can show where storm water catch basins are connected to the sanitary sewer. The testing also can indicate the presence of a field drain that nobody knew about by showing smoke coming out of the ground.
"It sometimes can come out around foundations around houses to show foundation drains are connected to the sewer system and if roof drains are connected to the system," True said.
Descoteaux said using the smoke method for sewer lines was suggested by the town's engineering firm, CES Engineering, of Bangor.
Test results are still to be completed, but the process will save the town a lot of money, Town Manager Susan Frost said.
"The smoke testing versus digging up and following all the pipes -- it saved us a lot of money," Frost said. "Smoke testing is the easiest way to see the breaks, as opposed to doing it by hand. I think it was the best technique for the town to have a better understanding of our sewer system and how the 33-year-old pipes are functioning."
Final results of the testing, completed Nov. 29, should be available this week, Frost said.
Repairs will be scheduled according to the town's budget line for the sewer district, Descoteaux said. Repairs could mean sealing a manhole or digging up the road and replacing a pipe, he said. The pipes are made of cast iron.
Sewer rates are paid by the 330 sewer system customers and are not part of the town's general taxation, according to Descoteaux. Rates in Hartland begin with a $16.66 monthly flat rate, plus fees based on usage.
Doug Harlow -- 612-2367