Repairs by the Metropolitan St. Louis Sewer District (MSD) to the force main sewer break in Chesterfield were completed early this morning. The location of the break was just west of the intersection of West Drive and North Drive.
To properly repair the force main, crews and contractors worked to find solid, durable pipe on either side of the break – a small hole at the top of the force main. The section of damaged pipe had to be cut out of the force main and replaced with a section of new pipe. For the new pipe to properly take hold, it had to be connected to existing pipe that is not compromised or weakened in some way. Approximately 100 feet of 24-inch diameter iron pipe was replaced.
MSD will complete cleanup activities at the site of the break and other affected areas over the next 24 hours.
A force main sewer is a sewer line through which wastewater is propelled by the force of pump stations located along the path of the sewer. Pump stations are sometimes necessary to overcome gravity and allow for the transport of wastewater to area treatment plants. Force mains are made of cast iron and can last anywhere from 25 to 50 years, depending upon the amount of flow the line handles and the corrosive properties of the wastewater.
The force main sewer in question was built in 1983 and a replacement is currently under design. Construction of the replacement force main is scheduled to start in 2016 at an estimated cost of $6.5 million. However, MSD is evaluating how this project might be accelerated and expects to share these plans within the next 4 to 6 weeks.
The force main sewer break and associated manhole overflows have been reported to the Missouri Department of Natural Resources, as required by law. The total volume lost from the force main and associated manholes is being calculated and will also be reported to the Missouri Department of Natural Resources, as required by law.