Smoke testing the sewer system

The Waukon Water and Sewer Department worked with employees of Fehr Graham Engineering to conduct “smoke testing” throughout Waukon’s southwest quadrant Thursday, October 15 in an effort to detect areas where storm water may be infiltrating the City’s sanitary sewer system. Water and Sewer Department Superintendent Bob Campbell said the smoke testing did detect a potential problem area along Fifth Avenue SW which will require further inspection, possibly with cameras or by manually crawling through the sewer system in that area. As part of the testing process, manhole covers to the sanitary sewer are temporarily removed and replaced with a fan assembly (such as the one pictured at right) that forces air into the sanitary sewer, and then a smoke bomb (harmless stage smoke) is placed by the fan’s intake in an effort to blow smoke throughout the sewer system. The workers then spread out in the area, keeping an eye out for smoke where it should not be appearing and would indicate a breach. Campbell said that the process isn’t fool-proof and is sometimes followed up with further video inspection of the sewer lines. Pictured above, workers prepare to light a smoke bomb on Third Avenue SW; pictured below, the smoke can be seen escaping through the sewer vent stacks on nearby houses, which is the desirable outcome. The smoke testing is being done in anticipation of the repaving project scheduled for Third Avenue SW in 2016. Photos and report by Bob Beach.