April 2015, Vol. 70, No.4
Rehabilitation
SAK Construction Begins $9.2M Wastewater Rehab Contract
SAK Construction LLC has begun work on a $9.2 million contract to rehabilitate 5,575 linear feet of aging combined sewer in downtown St. Louis, MO.
The project, which targets a major segment of the brick-and-limestone Old Mill Creek Sewer, is jointly funded by the U.S. Army Corps of Engineers and the Metropolitan Sewer District of St. Louis (MSD). Rehabilitation of the sewer, which was built in the 1860s, is part of a comprehensive plan MSD is implementing to improve the St. Louis wastewater system.
According to Mike Badgley, SAK project manager, the contract includes renovating the 18-foot-high by 20-foot-wide arch-shaped sewer, 15 manholes and 58 lateral connections, using chemical grout, concrete and shotcrete (a specialized wet or dry concrete solution that is sprayed on and hardens in place, forming a structurally renewed surface). To complete the work, an estimated 3,200 cubic yards of concrete, 4,500 cubic yards of shotcrete and 400 tons of reinforced steel will be required.
“SAK’s extensive experience in working on aging combined sewers, including the recently completed successful renovation of another section of the Old Mill Creek Sewer, allows us to tackle assignments of this complexity and size and ensure an on-time seamless project completion for MSD,” Badgley says. Completion is slated for November 2017.
Among the unusual challenges posed by the project is the sewer’s significant average dry weather flow of 50 million gallons a day. Explains Badgley: “A combined sewer carries both sanitary and storm water. This means that heavy rainfall or a high river stage, in addition to the normal dry weather flow, can restrict working conditions within the sewer.”
To minimize potential issues and to progress on schedule, SAK regulates the dry weather flow by using a combination of bypasses and flow diversions.
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