A valuable method for verifying sources of inflow & infiltration
Storm water sewer systems which carry rainwater (or clear water) to ponds, rivers and lakes, and, sanitary sewer systems which carry wastewater to treatment facilities are designed to be independent of each other. However, there is often a surprisingly high number of situations in which significant amounts of rainwater are able to enter into the sanitary sewer system. Inflow refers to deliberate connections of pipes and drains carrying rainwater to the sanitary system. Infiltration refers to rain water entering the sanitary system through defects in the system such as cracks in pipes.
The consequences of inflow and infiltration (II) include wastewater treatment facilities reaching overcapacity which can result in expensive overuse of the facility, and, basement or other flooding requiring major remediation work. Smoke and dye testing is a simple and effective method used by Civica to identify and verify sources of inflow and infiltration. Using a gas-powered smoke generator, inert and environmentally safe smoke is pumped into the sanitary system by Civica’s trained field personnel creating a strong visual indicator of all of the water connections into the sanitary system. When smoke is detected coming from systems designed to carry rain water into the ground/storm systems, such as from downspouts or roof leaders, it is an indication of possible source of inflow or infiltration.
Once a source has been identified, a dye test is performed. Civica’s field staff pump dyed water into the source to simulate heavy rain flow, while a technician monitors the sanitary sewer line. If the dyed water is visible in the sanitary sewer, then we can confirm that the II source does indeed channel rain water into the sanitary line. Detailed information about the II source is recorded in Civica’s DataCurrent software from which graphical, map-oriented reports can be generated for use in efficiently planning the efforts to remediate the problem sources.