Ouachita Water Treatment Plant Improvements

Hot Springs, AR
Hot Springs, Arkansas



Monty Ledbetter
Utilities Manager
P.O. Box 700
Hot Springs, Arkansas 71902

Improvements to Ouachita Water Treatment Plant included two separate contracts. The first contract included the installation of a raw water pump and a larger backwash water feed line. The raw water pump installation improves the redundancy of the raw water pumping system to help ensure that peak treatment demands can be met with one raw water pump out of service. The larger backwash water feed line helps to ensure that adequate filter backwash flows are available during times when the backwash water storage tank is out of service.

The second contract included a fluoride feed system, improvements to flocculation and sedimentation basins 6 and 7, and rapid mix flow control. The fluoride system includes a fluoride feed building, a fluosilicic acid double wall, 5600 gallon storage tank, a flow paced fluosilicic acid peristaltic feed pump, and a fluosilicic acid feed vault, and chemical injection quill. Flocculation and sedimentation basins 6 and 7 improvements include converting two basins currently rated at 2.38 MGD each to 8 MGD each basins to match a future planned 16 MGD filter expansion. The existing 2.38 MGD basins were converted to 8 MGD basins by expanding the flocculation zone from single stage flocculation to three stage flocculation, and adding plate settlers to increase the sedimentation capacity of the remaining sedimentation basin area. The existing surface mounted sludge collection system was removed and replaced by a bottom mounted sludge collection system located below the plate settlers. Insertion mag meters and electrically controlled butterfly valves are used to control the flow in the 24 and 36 inch rapid mix effluent lines that lead to sedimentation basins 1 through 5 and 6 and 7, respectively.

Instrumentation and control telemetry improvements are included in both contracts to assimilate the improvements into the Ouachita Water Treatment Plant control system.

Construction Costs

Contract 1 $208,506
Contract 2 $2,797,700


Complete 2015

Crist Personnel Involved

Stewart Noland
Richard Zelnick