As part of the study, "smoke" testing of the sewer lines was conducted to locate any breaks or defects in the system. The petroleum-based "smoke" product has been used for more than 30 years. It is not toxic to humans or pets, leaves no residue, and creates no fire hazard.
Smoke testing allows inspection of both the main lines and laterals. The smoke travels throughout the system, identifying problems in all connected lines. Best results are obtained during dry weather, which allows smoke better opportunity to travel to the surface.
During the tests, smoke mixed with large volumes of air is blown into the sanitary sewer line usually through a manhole cover. Smoke will identify broken manholes, uncapped lines, and even cracked mains and lines.
The study included dye testing, manhole inspections, and internal cleaning and TV inspection. Dye testing involves using a non-toxic dye injected into cross-connections, roof drains, and area drains that are suspected of being connected to the sanitary sewer. Manholes can be a significant source of extraneous infiltration/inflow, reducing the system's wet weather capacity.
The field portion of the study was conducted in the winter and spring of 2018.