Clifford Street Pump Station Upgrade
Okaloosa County Water & Sewer Department, FL
Constantine Engineering was tasked to perform a hydraulic analysis of one of Okaloosa County Water and Sewers (OCWS) primary sewage pumping stations (Clifford PS). The station was constructed in 1989 and consisted of 4- 125 hp submersible pumps; 22 feet deep, 15 feet wide, by 20-foot diameter concrete wetwell, below grade isolation valves, control panels and brick building. Each pump was designed to operate at approximately 2800 -3000 GPM. OCWS was experiencing numerous problems with the pumps and was only able to maintain two pumps in operation on a consistent basis. In addition, the rectangular shaped wetwell was showing signs of severe deterioration in the upper corners and ceiling of the structure.
Constantine Engineering conducted hydraulic studies (flow monitoring, draw-down tests, SCADA) to evaluate the current operating condition of the station. Constantine’s analysis showed that the station’s average pump cycle times were less than six minutes and peak flow conditions could be satisfied with just one (1) pump of the existing 125hp pumps.
Constantine Engineering provided design and construction management for a complete rehabilitation of the Clifford PS. The scope included the demolition of the above grade control and wetwell building to implement what is listed in the project highlights. The prefabricated electrical/control building was designed to include a new Control Center with HMI and VFD units, emergency power receptacle and SCADA. All components were preinstalled and tested prior to delivery to the site. Pump sequencing and speed adjustment were controlled through redundant PLCs and level transducer. Back-up floats were provide for pump start/stop redundancy as well as emergency operation of the fourth back-up pump. Under normal flow condition, the station is designed to operate with single pump, to help reduce peak electric demand cost/minimize slugging into treatment facility.