Flexible epoxy repairs manhole chimneys

Problem

Inflow and infiltration entering the sewer system through manholes during wet weather caused severe overflows at the three New Lenox (Ill.) Wastewater Treatment Plants. Senior operator Keith McKeen looked for a cost-effective and easy way to remove as much I&I as possible.

 

Solution

The village applied Parsonpoxy FP from Parson Environmental Products to manhole frames where they meet the riser rings. The two-component, flexible, 100-percent solids polyamine epoxy absorbs stresses created when cracks and joints move with freeze and thaw cycles. The corrosion-resistant and waterproof epoxy is applied to dry surfaces with a putty knife or brush.

 

Result

“The compound is cheaper per manhole than purchasing chimney seals, and is easily and correctly applied by our summer staff,” says McKeen. “It also has greatly reduced our I&I problem.” 800/356-9023; www.parsonenvironmental.com.

 

Fast-curing spray revives recreational lake

Problem

Lake Heron’s 42-foot-diameter, 20-foot-deep corrugated metal overflow manhole leaked enough to lower water levels, causing the City of Liverpool, Pa., to prohibit recreational activities. Officials looked for a corrosion barrier with structural strength.

 

Solution

The municipality chose SprayWall, a 100-percent volatile organic compounds-free self-priming polyurethane coating from Sprayroq.

To reach the manhole four feet from shore and surrounded by thin ice, city workers built a wooden walkway to dissipate their weight. They eliminated infiltration by pumping chemical grout into the numerous holes, then dried the walls with a blower.

Workers sprayed multiple applications of the coating to build up a 12-inch-thick layer. The product’s formula enables initial curing in less than 30 seconds. The material has a 50-year design life, retaining 70 percent of its original flex modulus.

 

Result

The project took two days and water levels returned to normal. 205/957-0020; www.sprayroq.net.

 

Lining system restores pump station

Problem

After only five years of service, operators at the Washington (N.C.) Wastewater Treatment Plant noticed significant concrete deterioration from hydrogen sulfide in its main sewer pump station. The city considered a mortar/epoxy liner, HDPE liner, or a multi-layered polymeric lining system to rehabilitate the structure.

 

Solution

The city received quotes on the first two systems and chose the mortar/epoxy liner as the most affordable. Then SpectraShield provided a quote competitive enough for the city to change its mind.

After setting up the bypass systems, utility workers cleaned the station. The SpectraShield team built scaffolding inside the 20- by 30- by 36-foot-deep wet well, abraded the walls, then bored into them and injected fast-acting SpectraGrout to stop severe leaks. They plugged minor leaks with quick-setting hydraulic cement.

The first layer of the SpectraShield system is a primer designed for saturated concrete. The thin film provides adhesion to the substrate. After the primer dried the required four hours, the crew sprayed on a layer of silicone-modified polyurea, followed by a layer of tight closed-cell polyurethane foam to fill voids and restore placement.

The foam dried tack-free in 8 to 12 seconds. The crew then applied a second thin film of silicone-modified polyurea as the final corrosion barrier. It dried just as quickly. The pump station was rehabilitated in a week.

 

Result

The project was completed two weeks ahead of schedule and 8 percent under budget. 800/284-2030; www.spectrashield.com.

 

Turnbuckle risers solve resurfacing problem

Problem

Transportation and Public Works crews in Fort Worth, Texas, paved over utilities as they resurfaced 300 to 400 streets annually, then returned to raise the manholes to grade by pouring concrete collars. “The mismatch between the new asphalt and cement caused cracked concrete, bumps, and other problems at the joint,” says George Behmanesh, P.E., assistant director of the department.

 

Solution

The city purchased pivoted turnbuckle manhole risers from American Highway Products and installed them before paving the streets. The solution was faster, more durable, and less expensive than previous methods.

 

Result

The risers, in use for 12 years, ended incompatibility issues between materials. “So far, we have received no complaints and have not had a riser fail,” says Behmanesh. 888/272-2397; www.ahp1.com.