The following article was published by the South Dakota Association of Rural Water Systems in their magazine "Quality on Tap".
Rapid Valley Expands Operation to Meet Consumer Needs
The Rapid Valley Sanitary District, located just east of Rapid City, provides water and wastewater services to 3,300 accounts, which is an area population of approximately 9,000. The District operates and maintains the entire infrastructure which includes water distribution and wastewater collections lines, storage tanks, hydrants, valves, and lift stations. Wastewater is treated by the city of Rapid City and for many years the District has purchased drinking water from Rapid City. The facility employs seven full time staff with the possibility if adding additional operators once the new plant becomes operational.
Jim Jester, General Manager, with support from the board of directors, began looking into various new treatment techniques that were capable of treating the ever changing nearby surface supply Rapid Creek. Another major challenge was acquiring the water rights that would be necessary to draw water from Rapid Creek. Some water rights in the Black Hills go back many generations; some rights predate our statehood, 1889.
Rapid Valley water source – Rapid Creek.
“There are people who hold water rights that reside in and around the valley area who realize the importance of providing safe drinking water at an affordable price,” stated Jim Jester. “These families worked with the District on transferring water rights from their irrigation ditches so that our long range plan of constructing a water treatment facility could become a reality.”
With financing provided by USDA Rural Development, construction began on a $4.2 million project that included an intake structure in Rapid Creek, pump station, raw water line to the treatment facility, and a new high-tech Microfiltration plant. The facility is rated at 2.0 million gallons per day (MGD) with potential expansion to 3.0 MGD. Current average usage for Valley customers is 1 MGD with a peak demand of 2.2 MGD. Field Operations Supervisor Rusty Schmidt, who oversees the facility, believes that even during peak demand days the plant will be able to meet consumer needs due to the volume of storage available (1,660,000 gallons) in the systems 4 storage tanks with the future 2.5 MG tank to be constructed in 2008.
The treatment facility operation begins by analyzing raw water turbidity, pH, and temperature as the water flows through a Badger Mag Meter. The first treatment phase is a 300 micron strainer to remove larger particles. Next the water travels through the Microfiltration filter modules. The facility has two units with forty-nine filter modules each. Each module provides 538 square feet of active surface area. After filtration the water is disinfected with ultra-violent light. Before entering the distribution system the water is dosed with liquid fluoride and chlorine according to state recommendations.
One Microfiltration unit = 49 modules.
The treated water is pumped from the facility into the distribution system utilizing three 50 HP motors capable of producing 700 gallons per minute each. Routine filter backwashing occurs when head loss measurements indicate the filters are not operating at maximum efficiency. Two chemicals are available for backwashing the filter modules, caustic soda and citric acid.
Two of the three 50 HP pumps = 700 gpm each.
Another aspect of the system was utilizing joint engineering firms. CETEC Engineering and Banner Associates, Inc. provided engineering design for this multi-staged project. Designing the intake structure and raw water pump house along with the treatment plant facility was a coordinated effort.
New ultraviolet disinfection unit
According to Manager Jester, “the board members were visionaries in their strategy of looking into the future at what was best for consumers. The tremendous growth east of Rapid City continues to add customers to our system and now drinking water needs will be met now and for many years to come.”
Manager Jim Jester
Operators Rusty Schmidt and Roy Graff review maps.
Directors & Staff Future Development History of Rapid Valley Awards Conservation FAQs Source Water Protection Links Photos
.gif)