City officials hoping to meet residents’ water and sewer needs in cost-effective and expeditious ways are turning to the latest technology for answers.
The proof is in two new projects, one underway and one beginning soon, they say.
First, the city is using a method known as “pre-chlorinated pipe bursting” to replace about 2 miles of water pipes in an east Arlington neighborhood where water main breaks have been problematic. The project doesn’t involve digging long trenches down streets, a change that saves time and eliminates inconvenience.
Second, the city recently teamed with the University of Texas at Arlington to embark on a high-tech examination of 48 miles of large-diameter sewer pipelines. The project, which will start next month and last three years, will tell city officials much about the lifetime of vital sewer pipes and give the officials a way to isolate smaller areas for replacement.
“There’s a lot of technologies that have been on the market but haven’t been adapted by utilities,” said Walter “Buzz” Pishkur, director of Arlington Water Utilities since 2012. “What we’re doing is actually looking for and attempting to adapt some of those technologies. I think what we’re learning is there is a lot of great stuff out there we need to take advantage of.”
Arlington signed a $1.2 million contract with Murphy Pipeline Contractors last fall to replace 10,200 linear feet of 6-inch water pipe in east Arlington near B.C. Barnes Park. Seven streets are affected, and the project is already at least one-third done, Pishkur said.
The pipe-bursting method differs from typical water line replacement because it doesn’t involve torn-up streets and lots of construction equipment. Water is also shut off for much less time.
A hole is dug at both ends of the area to be replaced and where water lines connect to the main. Powerful machinery sends metal rods down the existing pipe. The pipe-bursting equipment is pulled through the old pipe, cracking it apart as it goes and replacing it with jointless high-density polyethylene pipe. According to the city, 85 percent of the action takes place underground and the work can be done in a typical workday.
Workers give residents and businesses 24-hour notice and shut off water about 7:30 a.m.
By about 4 p.m., everything is back on and “you wouldn’t know we even turned off the water,” Pishkur said. “It’s very impressive and it’s very cost-effective, and obviously the residents like it very much because it doesn’t disrupt their lives.”
Avoiding disruptions that are costly and inconvenient, not to mention environmentally harmful, is also the goal of the examination of sewer pipeline, set to begin next month.
City officials saw a need to gauge the lifetime of the city’s sewer pipelines in May. After an unusually rainy spring, one of the city’s major 66-inch sanitary sewer lines collapsed unexpectedly. While making repairs, workers discovered that its walls had eroded away.
The city’s sewer pipes, with an average age of 31 years, wouldn’t be considered particularly old compared with systems in older municipalities. However, Pishkur said, “there are other factors besides age that influence the integrity of piping.”
Partnering with UT Arlington offered a cost-effective solution that also takes advantage of the proximity of highly regarded experts at the UTA College of Engineer’s Center for Structural Engineering Research and Simulation, Pishkur said. In November, the City Council approved an $882,000 contract with UTA for the project. Starting next month, university and city workers will deploy a robotic unit that records video, sonar and laser data into sewer pipes in the city that measure 24 inches or larger.
UT Arlington and the city will use the data to select areas of pipe where samples should be extracted for further evaluation. Then, UTA researchers will examine those samples microscopically and macroscopically to make recommendations, said Ali Abolmaali, chair of the UTA civil engineering department and director of the Center for Structural Engineering. Abolmaali will lead a team that will also include Yeonho Park, a UTA civil engineering postdoctoral fellow; and Mohamad Razavi and Mohsen Shahandashti, senior lecturers in civil engineering.
Abolmaali said the aim is to avoid sewer line failures.
“We’re trying to be proactive in maintaining the health of the sewer pipelines,” Abolmaali said. “This is kind of checkup on the sewer lines and then evaluating their remaining life, which is highly valuable.”
Pishkur said the project will save the city money because information about pipe integrity leads to “replacing only what we need to replace,” as opposed to replacing an entire sewer line where a defect is discovered.