Precast concrete brings creative design solutions, resulting in economic savings
In 2019, Dutchland built a precast post-tensioned SBR tank at the Village of Watkins Glen WWTP in Schuyler County, NY. Previously, the Villages of Watkins Glen and Montour Falls each operated aging municipal wastewater treatment plants. The two villages jointly developed the new WWTP and decommissioned their respective facilities when the new plant was operational.
Due to its proximity to Seneca Lake, the site included high groundwater and poor soils. The design engineering firm, Barton & Loguidice, originally designed the process reactor for cast-in-place tank construction on a pile-supported deep foundation. Preloading the soils was also specified. The design for the reactor tank also included a sloped base for drainage which was intended as a secondary pour. However, the original bid came in over the engineer’s estimate and the Authority elected to re-bid the job. For the re-bid, Barton & Loguidice determined that the piles could be eliminated as a cost-saving measure.
Dutchland was able to value-engineer the precast post-tensioned tank design by adjusting the base slab keyways. The CIP base slab was value-engineered to integrate the sloped floor with the structural mat slab. This eliminated the need for a secondary pour to form the slope. Dutchland also sloped the walkways 1” from side- to-side to assist with drainage. Additionally, all the walkway and roof panels include epoxy-coated reinforcing for additional corrosion protection.
Dutchland’s 4.2MG rectangular open-top tank for the new plant measures 219’ long by 124’ wide with 20’-4” tall wall panels. The tank includes a common-walled pump station measuring 17’ long by 16’-6” wide by 15’-6” tall. However, the base of the pump station is 6’-4” lower than the SBR base slab. This required the pump station to be installed and backfilled prior to the main tank going in.
Dutchland completed construction of the 4.2MG reactor tank in 18 weeks on-site.