The first time Pacific Sewer Maintenance used its new WJ180 robotic precision cutting machine from Sewer Robotics, the unit proved it was worthy of its six-figure price tag.
The Pacific Sewer Maintenance crew faced a formidable challenge: removing approximately 290 feet of fully cured concrete that had filled two connected clay sanitary sewer lines in Marina del Rey, a coastal suburb of Los Angeles, says Scott Gayman, co-owner of the company, based in Glendale.
The mishap occurred about seven years ago when a contractor who was pouring concrete slurry to solidify and stabilize wetlands soil for the construction of condominium complexes accidentally cut into a sewer pipe. Part of a 10-inch-diameter clay line, as well as part of a county-owned 18-inch clay line that serviced the entire north end of the city, was filled with 24 cubic yards of concrete, Gayman explains.
“They couldn’t dig out the pipe because it was 6 feet below ocean level and the excavation would be flooded,” Gayman says.
So the company broke out the WJ180, carried by an R-160 wheeled transporter, for its maiden voyage. Gayman paid about $140,000 for the machine, with an ultra-high-pressure water pump (40,000 psi at 17 gpm) from High Pressure Pumps (HPP, a brand owned by PTC) included in the price.
It was a nerve-wracking situation, Gayman says, since the company had never used the machine before.
Luckily, a crew from Sewer Robotics, based in The Netherlands, happened to be on hand to provide training and make sure the robotic system was correctly installed inside a 15-foot box body from Western Truck Body Manufacturing, carried on a Freightliner M2 chassis.
“My immediate reaction when we got the call was we really need to figure out how this system works,” Gayman recalls. “It was an amazingly well-timed stroke of luck that the crew from Sewer Robotics was still in town.”
One contractor had already tried to remove the concrete but was cutting away only a few inches a day with a machine equipped with a conventional milling head, Gayman says.
In stark contrast, the Sewer Robotics unit was able to remove about 3 feet of concrete per day after the Pacific Sewer Maintenance crews got the hang of running it. The job took about 2 1/2 months to finish, with crews working 10-hour days, six days a week.
“It was a really challenging job, with lots of frustrating days,” Gayman says. “It involved a massive learning curve. But we got really good at it.”
The project underscored the importance of making investments in advanced technology, as well as staying ahead of competitors, Gayman says, pointing out that at the time, he was one of the first contractors in the United States to buy a robotic water-jet cutter.
“That job cemented our reputation,” he says. “Every time we do one of these projects, people have a lot of doubt about whether we can do it. But by the time we’re done, they’re saying it’s amazing.
“That project really got us going,” Gayman adds. “County administrators talk to each other, so the word about our capabilities got around fast.”
Read more about Pacific Sewer Maintenance in the September 2024 issue of Cleaner magazine.
