How Reusing Aging Wastewater Infrastructure Can Provide Safety, Cost Savings, and Operational Flexibility

Renewal and replacement of aging infrastructure continues to remain a challenge in the water industry. In many force main replacement projects, one common approach is to take the existing force main completely out of service after replacement to keep wastewater flow continuous and prevent/minimize sanitary sewer overflows (SSOs). But what if there is an even greater benefit to keeping this aging infrastructure in service? 

Mike Semago, P.E., of Kimley-Horn’s St. Petersburg office, faced a challenge during construction that ended up teaching the entire project team a valuable lesson: If the pipeline has useful life remaining, existing force mains can be used as emergency backups to reduce public health and safety risk and cut down costs for abandonment/removal.

In this scenario, an existing 24-inch force main was hit during construction by the jack and bore contractor as a part of a large force main replacement project. Due to the large amount of wastewater flow the force main receives and heavily manifolded force main network, wastewater was discharged into the bay until the flow could be stopped and the line was repaired.

To determine next steps, Kimley-Horn and Manatee County held a lessons learned meeting where the suggestion was brought forth of using the existing force main as an emergency backup in case a scenario like this were to occur again. The team ultimately determined the existing force main still had useful life remaining and implemented a plan to use it as an emergency backup, which saved the project money as it would not be grouted. The county teamed with Kimley-Horn and created a standard operating procedure for use after implementation, providing a way to minimize health and safety risks while providing operational flexibility.