What lies beneath

Robots used to inspect known and long forgotten sewage lines in Rocky Top

  • Bret Anderson of M&M Pipe Services prepares a robot with a TV camera and light for insertion into a Rocky Top underground sewer line to inspect it for defects. - G. Chambers Williams

  • Mark Miles, left, co-founder of M&M Pipe Services of Clinton watches as a robot on a long tether inspects an underground sewer line in a field off Tenn. 116 north of Interstate 75 in Rocky Top. His son, Marcus Miles handles the line that feeds into the sewer manhole. - G. Chambers Williams

Bret Anderson spends his days with his mind in the sewer. Not actually down there, mind you, but close.

As the operator of a TV camera-equipped robot on a 1,500-foot tether, Anderson remotely inspects sewer lines deep underground, looking for problems that could, well, stop things up.

For the past few weeks, the sewers he’s concentrating on are under the city of Rocky Top. Anderson is helping his employer, M&M Pipe Services of Clinton, scope out the known and forgotten sewer lines that have served the city for decades – some of them dating to the 1930s, city officials figure.

His work is part of a huge effort by Rocky Top to identify problems with its sewer system and either repair or replace lines that are causing problems or might become problems in the not-so-distant future.

“We’re doing a sewer rehabilitation project and have applied for a grant for the work,” Rocky Top City Manager Michael Foster said. “But first we have to clean and examine the whole system to decide what needs to be done.

“We have applied for a State Revolving Fund loan of $2.5 million for the work, and hope through the grant process to get at least 20 percent of that forgiven,” he said.

It’s a major task, as the city has an estimated 100,000 linear feet of underground sewer lines, along with associated manholes that give the water and sewer department workers access to the lines for maintenance.

The inspectors look for cracks, root intrusions, collapses, line fractures and any other defects that might cause failures.

Rocky Top began the project in 2016 when the city received enough money to examine and map nearly one-fifth of the sewer system, just under 20,000 linear feet. That preliminary work cost about $600,000, Foster said.

Now, with the bulk of the money becoming available for the project, the cleaning, assessing and mapping of the remaining 80,000 linear feet of sewer lines is underway. That will allow the city’s engineering consultants, Cannon & Cannon Inc. of Knoxville, to complete a report and assessment of what the city needs to do to put the system into good condition, Foster said.

“We won’t know the total cost until we put the work out for bids,” he said. “That will happen after we get the engineering report in about two months.”

The actual work, Foster said, will include “rehabbing or replacing lines, putting liners in where lines might be cracked, and resealing manholes.”

“The next phase is about a year out, or six months from bidding to starting work,” he said. “We have no idea yet how long the work might take.”

Foster said the underground inspection work has already found 80 sewer lines the city didn’t know it had, so getting the mapping work done accurately will be the key to making sure the entire system gets assessed and upgraded.

“Overall, we’ve found so far that the system is in better shape than we thought” Foster said. “But we want to stay ahead of the curve.”

Meanwhile, Anderson’s co-worker Marcus Miles, son of M&M Pipe Services co-founder Mark Miles, spends his days feeding the cable that the TV camera robot is attached to into sewer manholes so Anderson can watch and record what the robot finds on TV monitors in a specially outfitted van above ground.

The TV cameras haven’t spotted any wayward alligators lurking underground, but Foster said, “Some of the stuff they find in those lines is hard to believe. We’ve even found wood in some of the lines.

“Grease is the worst,” the city manager said. “People pour it down the drain hot and it never gets to the sewer plant. As soon as it cools, which is quickly, it just stays where it came in.”

Marcus Miles also operates the Vactor sewer cleaning device that M&M uses on clogs and debris in the lines. He’s been working with the company since his dad and his mother’s brother, Duane McCallister, founded M&M Pipe Services two years ago.

The Rocky Top work is one of the company’s biggest jobs yet, a $269,000 contract, Mark Miles said. His wife, Dawn Miles, is on record as 51% owner of the business, which allows M&M to get preference in bidding by qualifying as a woman-owned business, he said. McCallister owns the other 49%.

M&M has completed about 90 percent of the survey work on the Rocky Top system, Foster said.