Tarlton was the general contractor for this 30-month project to increase the capacity of the St. Louis Metropolitan Sewer District's Lemay Wastewater Treatment Plant. The project enhanced plant operations under a wide variety of operating conditions including heavy storm surges.
Improvements include two grit basins with channel grinders, a primary sludge pump station, a grit handling building and four primary clarifiers. The work involved deep excavation, a tunnel over 500 feet long, installation of 12-foot-diameter storm and sewer piping, and numerous large cast-in-place underground vaults/junction chambers. About 20,000 cubic yards of concrete were poured at the site. The project also entailed associated piping, valves, yard structures, electrical components and instrumentation, as well as other related work.
In addition, the team successfully completed a temporary flow diversion to tie into a 96-inch influent pipe -- believed to be only the second time in the United States this operation has been completed on a pipe with a diameter this large.