Sewer System Defects and Smoke Testing for Defect Detection
Stormwater can enter sewer systems through a variety of inflow and infiltration (I/I) sources. Sources of inflow and infiltration can be difficult to locate and cause problems for the system and supporting environment.
Why is stormwater and rainwater inflow and infiltration important to sanitary sewer systems?
Since sanitary sewer systems are designed to handle only the sewage in a given area, the addition of stormwater overloads the system, causing many issues. This capacity or space in the sanitary sewer pipe is designed to transport sewage to wastewater treatment plants, not rain and stormwater. If the sanitary sewer pipe is at or near the designed capacity, many problems arise. During excessive rain events, many pipes become surcharged or “over full”. Since there is no room for extra water, a backup or an overflow occurs. A backup causes wastewater to “back up” into the sewer line. Overflows allow wastewater to escape the system.
The illustration below depicts the potential sources of I and I. When these potential sources of I/I are multiplied over the full sewer system, they can be daunting to find. Smoke testing is a detection method we use to quickly isolate the source of sewer system defects. Uncovering sources of Inflow and infiltration through hydraulic modeling is discussed in this blog.
How sanitary sewer smoke testing works for identifying sources of defects?
Sanitary sewer smoke testing
Our expert teams identify manholes within a defined area for testing. A generator is then used to blow a non-toxic, dense, white smoke into the manholes. The smoke will escape through openings such as holes in manhole covers and plumbing vent pipes located on or near rooftops. Smoke will also escape through defects such as cracks or breaks, open or broken clean-out covers, damaged or defective manhole frame seals, illegally connected roof or area drains, and any other openings.
Digital notation of sanitary sewer system defects
When we see smoke coming from areas that indicate a defect in the system, our teams mark the defect using very precise GPS tools. This process allows for the municipality to quickly access the defect and determines how they want to address the issue in the system.
Smoke testing is just one way that we help our customers ensure systems are working as efficiently as possibly. Learn more about our Flow Monitoring Services.