COLUMBIA — Sewer smoke testing continued Tuesday as part of Columbia's Inflow and Infiltration Reduction Program.
Today's testing will happen in the area around the Ellis Fischel Cancer Center.
“The purpose of these tests is to locate defects in the sanitary sewer system,” said Jill Stedem, spokeswoman for the Columbia Public Works Department.
Inflow and infiltration, as described by the Public Works department's website, are two ways that groundwater and stormwater enter the sanitary sewer system, causing the sewers to overflow and damage property. Inflow occurs when storm water gets into the sewer directly through sump pumps, driveway drains and other inputs to the system. Infiltration is when ground water enters through leaks in the pipes.
TREKK Design Group, LLC, the consultant the city hired , tests for these defects by pumping smoke into the main lines, said TREKK field supervisor Paul Anderson. This harmless smoke then moves through service connections and comes up through the ground where there is a defect.
"From there, that's where we turn it over to the city and let them know where the problems are," Anderson said. "It's a faster and less expensive way to do a quick overview of your system."
When a defect is found, TREKK uses cameras and Google Maps to document the location of the defect.
“When the city of Columbia pulls up the map that we give them, they can pull up the point and get all the information," said Breanna Dunnavant, engineering technician for TREKK. "The defect, the picture, the address and everything.”
Although smoke is not supposed to come up through homes, Anderson said it happens quite often and is sometimes mistaken for a fire. P-traps under floor drains and sinks keep sewer gases from coming into houses, so the smoke should come from the roofs of houses.
“A lot of times when a home may have a security system, it dials to the fire department,” Anderson said. “My hats off to the fire department for answering all those calls.”
Stedem said some people are eligible for reimbursement when problems are found on their property.
Testing happens between 8 a.m. and 5 p.m. when most people are out of the house, Anderson said. Stedem said people receive door hangers and flyers when testing is occurring in their neighborhood.
“We’re trying to do everything we can to let them know we’re coming. I would say the majority of people know we’re here," Anderson said.
Sewer smoke testing is planned to continue through October.