Crews from the Metropolitan St. Louis Sewer District (MSD) will this evening begin to shut down pump stations upstream of the suspected underground force main sewer break in Chesterfield, Missouri. Shutting down the pump stations will lessen flow through the force main, thereby decreasing the amount of sewage that needs to be handled at the site of the suspected break. In addition to a safer work environment at the site of the suspected break, less flow will also allow workers to make an accurate visual assessment of the force main, once it is exposed to identify the exact problem, and facilitate speedier repairs.
The suspected force main break and shutting down the pump stations will not affect sewer service to homes and businesses in the area.
While the pump stations are shut down, MSD will use vacuum trucks to transport the sewage at the pump stations to MSD’s Missouri River Wastewater Treatment Plant. The trucks are equipped with large storage tanks and will vacuum up the sewage as it accumulates at each pump station. Once a truck is full, it will leave for the treatment plant, and another truck will take its place. MSD projects that trucks will make over 100 of these trips while the pump stations are shut off.
Even with the use of the vacuum trucks, shutting down the pump stations will most likely cause several overflows from manholes along the force main route. Possibly affected areas include:
• The intersection of Crystal Spring Drive and Brighthurst Drive in Chesterfield.
• Portions of the walk/bike trail that runs along the Monarch Chesterfield levee south of Chesterfield Commons.
• Portions of Caulks Creek.
• Portions of Bonhomme Creek.
MSD is placing warning signs in these areas, advising the public of the overflows. While there is no immediate threat to public health or safety, the public is asked to heed the signs and avoid contact with the affected areas. If a member of the public should come in contact with these areas, they should immediately and thoroughly wash with soap and water.
Shutdowns of the force main may continue intermittingly throughout the repair effort.
MSD will monitor manholes throughout the area. If a member of the public should come across what they suspect to be an overflowing manhole, they should contact MSD’s 24-hour Customer Service Center at (314) 768-6260.
An estimate on the time needed for repairs will be provided once the underground force main is excavated and the exact problem identified. Once full operations of the force main sewer resume, cleanup at the break and associated oveflow locations will commence.
The suspected force main break was reported to MSD at approximately 10:30 AM today. The location is just west of where Cordovan Commons Parkway turns into Howard Bend Station Road in Chesterfield, Missouri.
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 expected to start in 2016 at an estimated cost of $6.5 million.
The force main sewer break has been reported to the Missouri Department of Natural Resources (MDNR), as required by law. Associated overflows from the manholes will be reported to MDNR as they occur, also as required by law.