Client: Muskegon County
Type of Pipeline: Sewer Force Main
Pipe Material: PCCP
Length: 8.5 miles
In 2007, Muskegon County’s 35-year old large diameter wastewater force main failed catastrophically. Although historical data demonstrated that joint leakage had never contributed to previous events, extensive failure analysis of this event by Prein & Newhof, determined that a leaking joint had played a significant role in the failure.
Prein & Newhof identified two likely components of the failure mechanism:
Wastewater leaking from the pipe, corroding the pipe from the outside, as well as washing out bedding.
A pressure transient in the line that included a period of negative pressure, which may have caused the weakened pipe to collapse.
Muskegon County and Prein & Newhof then undertook a condition assessment program to determine whether rehabilitation of this pipeline was a preferable option to replacement. A key component of this program was an inline leak detection test using the Sahara® leak detection system.
The leak detection test revealed no further leaks in the pipeline. A leak simulation exercise was carried out to confirm that any leaks in the pipeline would indeed have been found. This exercise showed that the technology was capable of detecting the smallest leak that could be generated in the line without immediately clogging with suspended sediment, roughly 1.5 gallons/hr (5.68 liters/hr).
With this confirmation that the leak that led to the failure was an isolated incident, a rehabilitation program can now be considered as a possible alternative to wholesale replacement.
Case study - Muskegon County - Sewer Force Mains