Isolating inflow & infiltration - Case Study

Sanitary district utilizes flow monitoring data to eliminate backup events

Duckett Creek Sanitary District (DCSD), located in O’Fallon, Mo., was experiencing inflow and infiltration problems, causing backups and overflows. When annual bypass reports submitted to the U.S. Environmental Protection Agency (EPA) indicated noncompliance with federal regulations, Keith Arbuckle, DCSD director of engineering, collaborated with EPA officials to improve system operation and maintenance. Both parties agreed to implement a CMOM (capacity, management, operations and maintenance) program to circumvent noncompliance fees and reduce bypasses. For the past six years, DCSD has worked diligently to create a more efficient system, reduce costs and eliminate backup events.

Inflow & Infiltration Defined

Inflow and infiltration are persistent problems that plague all sewer collection systems. Inflow refers to storm water that flows into sewer systems through direct connections such as roof and foundation drains, storm drain connections and uncapped cleanouts. These sources typically are improperly or illegally connected to sanitary sewer mains. Infiltration is groundwater that seeps into sanitary sewer systems through faulty joints, cracks and areas of root intrusion in the sewer pipes. Sources of infiltration generally are the result of aging infrastructure.