Inflow & Infiltration Detection
How Sources of I&I are Detected
Flow Monitoring – sewage flow rates are monitored at various locations within the municipal sewage collection system. The flow data is analyzed, along with rainfall data, to determine if there is excessive I&I within the study area.
Smoke Testing – a non-toxic, stainless, odourless, vegetable-based “smoke” is injected, under pressure, into a sanitary sewer manhole. If smoke escapes from a source not connected to the sanitary sewer system, this would indicate a sewer I&I cross-connection.
Dye Testing – non-toxic dye is added to an upstream freshwater source believed to be contributing to I&I. The downstream sanitary sewer is then monitored for traces of the dye to confirm the existence of a sewer cross-connection.
Closed Circuit Television Inspections – a video camera is sent through a sewer line to record the condition of the sewer. The video footage is analyzed for cracks, intrusions and leaks.
Inspections – building inspectors and trained maintenance personnel visually inspect and assess the condition of the sewer system.