Trenchless Technologies Help the City of Greenville, S.C., Keep Pace with Exploding Population

20140725_np_dukes_olliver_newcastleDE_061Greenville, S.C. — located just south of the North Carolina border — has been named among the “Top 6 Hottest New Vacation Destinations” by CBS News; “5th Best Cycling Town” by USA Today; “The South’s Tastiest Towns” by Southern Living Magazine; “Favorite Unexpected Vacation Destination” by O, The Oprah Magazine; and “America’s Most Fun, Affordable City” by Bloomberg Business Week.

And that just covers vacation and leisure.

The City of Greenville has also experienced explosive commercial growth. Even through the recent recession, companies in manufacturing, construction and niche markets such as food service and healthcare have flocked to Greenville — many of them relocating their national headquarters to the area. Service providers such as doctors, lawyers and finance companies are also drawn to the growing opportunities the new business and population bring. Greenville even attracts retirees from across the country, being among the “2013 Best Places to Retire” by AARP (American Association of Retired Persons).

However, there is always the flip side to such phenomenal growth. In this case, it’s the stress on existing utilities and the capacity problems such rapid growth brings. While everything is shiny and new above the ground, Greenville’s aging sewer system, built in 1892, still has some of the original clay pipes in the ground. Located approximately 1,000 ft above sea level, Greenville has relied primarily on a gravity flow sewer system for its 330 miles of sewer lines, with only four of those miles of pipe being force mains.

“Our greatest challenge is maintaining the older system, tightening it up, and keeping as much of the I/I (infiltration and inflow) out as possible,” said Greenville assistant city engineer Matthew “Oni” Maxey, P.E. “A unique challenge we face is that, unlike a stand-alone utility that focuses on one thing, our municipality and our City Council focus on many things, including growing the City. So sometimes the maintenance of our 120-year-old infrastructure plays a game of tug-of-war with the City’s growth and development. Both are equally important, however, so thanks to the leadership and support of City Council, we have dedicated our resources to ensure our infrastructure keeps pace with the dynamic growth of Greenville.”

Greenville has proactively turned to trenchless technologies to do just that. “Trenchless technologies have allowed us to support the additional strain and stress on our system while working with a budget that has only increased marginally above inflation for the past several years,” said Maxey.

Trenchless technologies in the Greenville, S.C., toolbox include:

CCTV: The City purchased a camera truck with a lateral launch two years ago. “This allows us to perform on-the-spot inspections of mainlines and laterals,” said Maxey. “Costs are reduced when problems are identified before they happen.”

Root Control: Greenville has used Duke’s Root Control for the past 10 years as part of a comprehensive and pro-active maintenance plan to keep pipes clear of roots and reduce overflows. Greenville has seen the number of overflows steadily decrease since working with Duke’s. “Duke’s is the best product we have used to kill roots, by far,” said Maxey. “I also appreciate the fact that their service is guaranteed to keep roots out for a full three years. In the past 10 years, I can recall only a couple of times that we needed to have lines re-treated, so knowing the guarantee is in place gives us great peace of mind as Greenville grows.”

Greenville has used Duke's Root Control for the past 10 years as part of a comprehensive and pro-active maintenance plan to keep pipes clear of roots and reduce overflows.

Greenville has used Duke’s Root Control for the past 10 years as part of a comprehensive and pro-active maintenance plan to keep pipes clear of roots and reduce overflows.

Sectional Liners: While some mainlines do require aggressive relining, Greenville typically takes a more surgical approach, using sectional liners whenever possible. In many cases, believe it or not, the original clay pipes are in excellent shape, so the City repairs segments of the line with sectional liners. “If we were to replace or rehabilitate every line in the system, it would run into the hundreds of millions of dollars,” said Maxey. “But with an average cost of $500/patch, the lines are in great shape and the system-wide savings are enormous.”

Cutter Robot: An investment in a Schwalm Cutter Robot has allowed Greenville to avoid digging up pipes and disrupting the growing population in order to make repairs. “In the first six months we owned this robot,” said Maxey, “we made more than 100 repairs, including offset joints and protruding hammer taps.”

Jetter Trucks: Manufactured specifically for Greenville, jetter trucks are custom-designed with specifications such as shorter length to maneuver the smaller Greenville streets, water tank positioning, easy application of Jet Power II grease liquefier and other custom requirements.

Composite Riser Rings: In lieu of concrete donuts, Greenville uses riser rings made of reinforced fiberglass composite and other materials, making the adjustment of manholes faster and easier. “Instead of lifting 200 lbs or more, our crews are now lifting just four pounds,” said Maxey. “This increases both safety and speed while allowing them to manage four or five manholes per day, compared to about one per day.”

Top Hat System: The City is investing in a top hat system to repair defects, making it possible to line about six inches up into the lateral. “Our utility doesn’t own the laterals, even the portions that fall in the right of way,” said Maxey. “But since 90 percent of lateral defects occur right at the main, we believe we will find an immediate return on this investment.”

Work Management: Greenville uses Cityworks Public Asset Management Software to manage labor, material and equipment, and record time and costs associated with keeping assets operational. “The ability to use hand-held devices to track work and processes has proven to be extremely efficient and has already saved us both time and money,” said Maxey.

The City of Greenville, S.C., to ensure that its infrastructure keeps pace with the City's dynamic growth, has proactively turned to trenchless technologies.

The City of Greenville, S.C., to ensure that its infrastructure keeps pace with the City’s dynamic growth, has proactively turned to trenchless technologies.

Thanks to these technologies, in 2014 Greenville completed nearly four and one-half times the number of internal repairs as were completed in 2010, while using the same size staff, resulting in more than a 300 percent increase in productivity. Increasing the use of trenchless technologies such as ongoing root control, sectional liners, top hat systems and work management software — all while working with a flat budget — has delivered extremely positive results for Greenville, while contributing to its stellar reputation as a great place to live, work and play.
Sheila Joy is president of New Phase Marketing Inc.
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