January 1, 2008Those beautiful trees that dot the landscape of your city or town, while visually pleasing aboveground, hold an ugly secret below the surface. A tangled mess of roots is invading the sewer lines, creating pipe blockages and causing possible structural damage to the pipe itself — resulting in costly repairs if left unfettered.
The U.S. EPA has estimated that 43 percent of sanitary sewer overflows are caused by pipe blockages and about half of those blockages are a result of tree root intrusion. With the use of video inspection, municipalities can learn the nature and extent of any blockage.
Unlike grease, which can also cause blockages, roots can damage pipe. Roots can also crack and separate joints, which lead to infiltration of groundwater, as well as structural damage to the pipes.
As a critical role in their sewer maintenance program, municipalities around the United States have turned to chemical root control to tame root problems.
Following the initial chemical application, a second treatment anywhere from two to five years later prevents roots from returning to their menacing ways and also address new roots and those farther outside the pipe. Re-application by skilled applicators is key to a root control program’s success.
But are these products working? Other than waiting for a blockage to occur, what can municipalities do?
The most logical answer is to use the technology that outlined the extent of the problem in the first place — video inspection. A follow-up video inspection of treated pipes gives municipalities peace of mind and prevents another possible sewer line backup or other more expensive and detrimental damage to the pipe.
Charles Brown is a video inspection contractor with more than 20 years of experience in the field — and televising pipes with root problems is a routine part of his job. As owner and operator of Mobile Robotics in Hadley, Mass., the bulk of his customers are municipalities in the New England region that have him televise their sewer and storm lines. “I do the routine televising and I also get called in when there are problems,” Brown says. “And oftentimes when there are problems, the problems are roots.”
Brown sees the value in taking his video cameras — an Envirosight ROVVER camera and smaller Ridgid SeeSnake cameras — back into the pipe for a second look after the pipes have been treated and he recommends follow-up inspections to his customers.
If the treatment didn’t work, it’s better to learn early, he says. “It’s critically important to do follow-up inspections, if only to prove that the chemical root control is working,” Brown advises, noting he’s seen cases in which it hasn’t. “If you just apply the [product] to the pipe and don’t go back and look, the only way you are going to know if it’s not working is if you have a [sewer] backup down the road.”
The video inspection contractor serves as the underground eyes for a municipality and is their first line of defense. As Brown states, “I see the roots before anybody else.”
Brown recommends waiting at least six months before re-inspecting the pipes. “The chemicals should have killed the roots by then but in fairness, I’d give it nine months to a year before going back in,” he says.
Rather than inspecting every pipe that was chemically treated, a sample of the treated pipes works just fine. “If you did an inspection prior to applying the chemical product, you already have a report with color pictures and you can see what those pictures look like side by side. Then you can determine whether it was effective.
“The reason for the follow-up [inspection] is to make sure you are getting value for your taxpayers’ dollars,” he says. “Until you are comfortable with your applicator and choice of chemicals, you owe it to yourself to take another peek at his or her work and make sure it was effective.”
Most chemical root control applicators offer a warranty for their work, so if the chemicals aren’t working, have them come back and honor the warranty.
Brown’s longtime municipal customers usually include a post-root inspection as part of their general, periodic pipe checks, he says.
Follow-up video inspections are just as important for other types of pipe repair, rehab and installation. Check the work, Brown says, noting that a lot of money goes into these projects and taking a second look is the smart thing to do. “I think before- and after-inspections should be done anytime a pipe is worked on,” he says. “Anytime a contractor comes in and fixes a pipe, go inspect it and make sure he did a good job.”
He notes that some sewer districts are requiring post-inspections for all newly installed pipe. The metropolitan district in the Hartford, Conn., region, for example, requires all new pipe be inspected before it will sign off the contractor and return their bond — a policy Brown agrees with.
Just as the chemical root control market has grown over the last 20 years, so has the video inspection market, becoming a routine, yet vital component for municipal sewer departments to keep tabs on what is going on underground with its infrastructure.
“The growth in video inspection has been monstrous. It is such a critical tool,” Brown says. “It’s definitely a matured and maturing service and industry.”
Sharon M. Bueno is managing editor of Trenchless Technology.