Cape smoking out sewer line problems

Call it the smoke-detector method: A consulting firm hired by Cape Girardeau officials is using smoke to detect deficiencies in more than 426,000 feet of city sewer lines to help better plan for major upgrades to the system.

Crews with Wheaton, Ill.-based RJN Group have been working for more than a month on smoke testing sewer lines throughout the city, said Dan Hanner, RJN's field supervisor.

"We're tracking where we see potential problems," Hanner said. "We're not just putting smoke in there and walking away."

The company, a civil engineering consulting firm that has an office in St. Louis, has performed hundreds of sewer system evaluations to identify sections of sewer lines that see stormwater infiltration during heavy rainfall, Hanner said. The testing is expected to be completed by the end of October, he said.

The smoke testing is just one phase of a systemwide evaluation to search for the various ways rainwater is infiltrating the sewer system. RJN is conducting a nine-month inflow and infiltration investigation for the city.

The company will then prepare a report pointing out the problems and offer recommendations, Hanner said.

The work is a precursor to the city's construction of a new wastewater treatment plant, a $70 million project that also includes making improvements to the city's 225 miles of sewer lines.

"The big picture is that the work is connected with the wastewater treatment plant," said city stormwater coordinator Stan Polivick. "Part of what we're supposed to do is get the rainwater out of our system, which a problem every community in the world has."

Voters in April overwhelmingly approved the city's plan to pay for the new wastewater treatment plant. City officials said a new plant was necessary because the existing 50-year-old plant didn't have enough capacity.

Stormwater that gets into the system causes the plant to exceed capacity and is bypassed 30 to 40 times, sending untreated sewage into the Mississippi River. Each time that happens is a violation of new standards that no longer allow that to happen.

As part of the permitting process to build the new plant and a consent decree with the Missouri Department of Natural Resources, the city is required to investigate its system to reduce flows to the wastewater treatment plant, Polivick said.

The smoke testing, for example, reveals problems such as faulty connections, leaking joints in sewer pipes, overflow points and foundation drains, according to Hanner.

The RJN crews use a high-capacity blower, which is placed on manholes, to blow a nontoxic smoke through the system. Anywhere the smoke exits, Hanner said, shows where there is a potential for stormwater to enter the sewer system. The smoke is not harmful to people or animals, he said, and is odorless.

They started smoke testing on the campus of Southeast Missouri State University and moved to the south side of Highway 74 and began working their way north, he said. Crews are working this week along West End Boulevard and are moving toward the intersection of North Sprigg Street and Broadway.

Ultimately, Hanner said, they will probably inspect more than half of the city's 225 miles of sanitary sewer lines. Weather permitting, he said, the smoke-testing should be finished by the end of October.

But the smoke tests are only one part of seeking out faulty lines, he said. They've already done flow monitoring, manhole inspections, and -- following the smoke testing -- will perform dye-water testing and a physical inspection of the lines using a small camera. The city contract will pay the company $850,000 for the overall project.

But Hanner said the investigation is necessary to seek out the trouble spot.

"There's nothing that's 100 percent accurate," Hanner said. "But if you do all of these things in conjunction, you'd be amazed at how much rainwater you can remove from your system."

smoyers@semissourian.com

388-3642

Pertinent address:

401 Independence, Cape Girardeau, MO