PROJECT DETAIL

Standing Rock Water Treatment Plant


Total Cost
13.7m
Date Completed
State
South Dakota

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Challenge

The Standing Rock Rural Water System operated two water treatment plants in the Dakotas and both needed upgrades.

The first plant, located in Fort Yates, North Dakota, was a conventional lime softening plant. The second plant, in Wakpala, South Dakota, consisted of a packaged, conventional filtration plant. In addition to necessary maintenance work, the client also wanted to provide softened water to the entire Standing Rock Rural Water System.

Solution

Rather than upgrade each facility, Bartlett & West worked with the client to construct a new lime softening plant. The new water treatment plant treats surface water from Lake Oahe and consists of concrete basins, structural concrete floor (two-way slab design), pre-cast concrete walls and metal roof design. Due to the expansive shale at the site, the entire building, basins and equipment slabs were constructed on drilled piers. Void forms were used below the structures to allow soil expansion without damage or movement of the building. DensaDeg high-rate clarification basins were used to safeguard against seasonally high turbidity and for lime softening. RDP’s batch lime slurry slaking equipment was used to provide lime slurry to the DensaDeg reactor basins. Re-carbonation performs with TOMCO2 pressure solution feed system.

The water is conveyed to an equalization basin prior to being fed to the Pall microfiltration low-pressure membranes via three vertical turbine pumps (60-hp). Disinfection occurs in the chlorine contact basin prior to entering the clearwell where ammonia is added to form chloramines. The finished water is pumped to the distribution system via four vertical turbine pumps.

The treatment plan included other chemical feed equipment, process piping, electrical, HVAC and structural work, instrumentation and control and site work.

Value

The Standing Rock Rural Water System is now able to provide softened water to all their customers in the Fort Yates, North Dakota, and Wakpala, South Dakota areas. The new treatment plant consists of alternative treatment technology (DensaDeg) but mimics a conventional water treatment plant. And, rather than perform renovations and provide upkeep for two water treatment facilities, they now must maintain only one.