Addressing Inflow and Infiltration in a Separate Sanitary Sewer System

A community located in the eastern part of Central Indiana owns and operates a separate sanitary sewer system that serves multiple communities in the region. The sewer system is comprised mainly of gravity sewer that utilizes lift stations to convey flows to the wastewater treatment plant (WWTP).

The sewers are aging and are experiencing Inflow and Infiltration (I/I) during storm events. As a result of the increased flows, the lift station cannot keep up with the demand and the sewers have begun to back up, causing releases of untreated sewage in the form of a Sanitary Sewer Overflow (SSO). Commonwealth Engineers has asked the team to evaluate alternatives to add capacity to the system.