Curing Expensive Sewer Main Repairs
Sewer mains get damaged in a number of ways, including the intrusion of tree roots and the internal deterioration of the line due to grease, oils and other corrosive substances.
When mains are damaged, heavy rains can cause infiltration of groundwater into the sewer system. In the worst case scenario, it can cause a backup into a home or business.
The Prince William County Service Authority conducts video inspections of thousands of feet of sewer line each year to check on their structural integrity. If the Service Authority determines that a sewage backup could occur within five to 10 years, the utility will rehabilitate that damaged and aging sewer main with CIPP, or Cured-In-Place Pipe.
CIPP involves lining the inside of sewer mains with a substance made of polyester and resin. Once the lining dries, or cures, it is much more difficult for roots to burrow their way in and can more than double the life of the main. The average sewer pipe lasts about 40 years, while CIPP extends that lifespan to 90 years.
“If there are any cracks or roots in the line, it will make the pipe structurally sound again,” Inflow & Infiltration Supervisor James McCarroll said.
The CIPP program is also far less expensive than replacing sewer mains. Using this technology costs the Service Authority roughly $31 a foot, which costs around four times less than constructing a foot of new sewer main, said McCarroll.
In addition to the upfront expense of sewer line replacement, less infiltration and inflow into the sewer system ultimately helps the Service Authority maintain reasonable rates for its customers by reducing the amount of wastewater that has to be treated at the two area water reclamation facilities servicing Prince William. The H.L. Mooney Advanced Water Reclamation Facility treats wastewater in the eastern part of the County, while the Upper Occoquan Service Authority Plant located in Fairfax County treats wastewater from western Prince William.
Before starting a CIPP project in an area, the Service Authority notifies residents and businesses through automated phone calls and meetings with Homeowners Associations. Once the community is made aware of the project, the process begins with re-checking the sewer main to see if any changes have occurred within the line since it was initially inspected.
Clay pipe, which is common in the Service Authority’s sewer system, tends to be weakest around joints, said McCarroll. That’s where problems usually occur. Typically, it takes an hour and a half for the CIPP material to harden and for service to be restored to customers in the area.
With no digging involved and minimal traffic disruptions, Service Authority Operations & Maintenance Director Don Pannell said the process of lining the pipe “is almost transparent to the customer.”
“We use this process to provide excellent customer service without disrupting their normal routine,” Pannell said.
“Homeowners are happier,” McCarroll added. “There are fewer blockages and less dig-ups.”
The Service Authority is nearing completion of CIPP projects in several sections of Lake Ridge, including Fort Craig Place, Flint Hill Place, Stoneford Drive and Foothill Street. Shortly thereafter, it will complete a CIPP project started last year in the Occoquan Forest neighborhood off Davis Ford Road.
The Service Authority will rehabilitate 22,000 feet of sewer line, an $870,000 project that will reduce the cost of operations and the potential for sewage overflows.
By the end of June 2014, the Service Authority will have video inspected more than 140 miles of sewer pipe in the County during the past year. The utility has more than 1,100 miles of sewer line throughout Prince William County, and the CIPP program makes inspecting such a large amount of pipe manageable.
“Once the CIPP is installed, our crews aren’t returning to the same pipe every three to six months to cut out roots or remove grease,” Pannell said. “They’re able to move on to other preventive maintenance activities.