Project Location: Cottage Grove, Minnesota
Synopsis of work:
Using the design-build alternate delivery method, this project included the construction and upgrade of a wastewater treatment plant. The new facility has a capacity of 10 million gallons per day with space reserved for a future capacity increase of additional 10-mgd and additional effluent requirements.
The area is located on the Mississippi River bluff and is considered environmentally sensitive. Therefore, the discharge line required a shored drop shaft and horizontal tunneling. Because the site was so small with work performed near and around the existing plant, the scheduling and cooperation of the contractors on the site was of the utmost importance. The new influent interceptor line consists of a 66-inch-diameter reinforced concrete pipe with T-Lok lining. Total excavation of the property included 150,000 cubic yards.
Click to enlarge any of the photos below: