Trenchless Technology

DEC 2018

Trenchless Technology is the premier communications vehicle for the trenchless industry. Through our multiple platforms, readers receive insights into the trenchless industry, as well as keep connected to the latest news, products and projects.

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52 T R E N C H L E S S T EC H N O LO GY D EC E M B E R 2018 P I P E C L E A N I N G T H E N O. 1 J O B for wastewater workers is to keep the sewage in the pipes. This statement is pretty straightforward, yet simplistic in message. That is the goal of everyone whose job it is to maintain underground utilities. The City of Fresno, California, takes this goal to heart , especially in its work to clear its underground sewer lines of dreaded and damaging roots that infiltrate through cracks and joints. Cities around the world fight this good fight every day, with the City of Fresno turning to the use of chemical root control to keep its sewer lines free of root blockage and damage. " I had a boss many years ago tell me that my No. 1 job is to keep the sewage in the lines," says Art Alvarez , wastewater manager for the City of Fresno. " There are a lot of things that go along with that [advice], such as dealing with roots, which cause blockages, which cause sewage to come out of the pipes. Roots also cause other damage such as separation and regrowth. Roots restrict flow." Fresno — with a population of more than 500,000 — is situated in central California, about three hours south of San Francisco and four hours north Los Angeles. The City 's sanitary sewer system is comprised of more than 1,600 miles, with roughly 24,189 sewer access structures, 55 junction structures and 15 lift stations; its service area covers approximately 225 sq miles. A portion of the City 's sanitary sewer lines goes back to the late 1890s, with a majority of the entire system made up of vitrified clay pipe (VCP); the rest of the pipe is a combination of concrete, cast/ductile iron and PVC . Approximately 81 percent of the system was installed after 1950 with 23 percent installed during the 1970s. Alvarez describes the overall condition of Fresno's sewer pipes as "fairly good," considering their age and pipe makeup. " When you have a large portion that is [vitrified clay pipe], there's always going to be cracks and issues," he says. " But the overall health of the system is really good. The City has been proactive about rehabilitation, especially with the large trunk lines. Now, we are starting to reach into more of the residential areas. When we are doing root control , it 's pipe preservation." R O O T I N G O U T T H E P R O B L E M I N F R E S N O City Uses Chemical Root Control to Keep Pipes in Top Condition By Sharon M. Bueno

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