Hernando County has initiated a plan to decommission and demolish the 2.5 million gallon per day Spring Hill Subregional Wastewater Treatment Plant (SWWTP). To facilitate this work, two new wastewater pump stations (one submersible pump station and one inline booster pump station) and associated force mains are required to reroute wastewater from the existing Spring Hill SWWTP to the Airport SWWTP.
Cardno was responsible for the planning, design, permitting and construction phase services for the two pump stations and approximately 56,000 linear feet (10+ miles) of 10-inch, 16-inch, and 20-inch PVC force main, which was installed by open cut construction and horizontal directional drilling. Project tasks included hydraulic modeling with SewerGEMS, conceptual layout, detailed design of transmission mains, master pump station, booster pump station, permitting, and preparation of Contract Drawings and Technical Specifications.
The Spring Hill Master Pump Station (SHMPS) is a 2,400 gpm submersible station that includes two, 12-foot diameter wet wells with two 100 HP variable speed pumps per wet well. The station also includes an air conditioned electrical building, emergency generator, pressure / surge protection, magnetic flow meter, and provisions for future odor control. Because of the length and associated headloss in the force main, the 2,600 gpm inline booster station was required to push wastewater to the Airport SWWTP. The station includes four, 75 HP, skid-mounted variable speed pumps, emergency generator, and air conditioned electrical building.
Because of the deferred decommissioning of the Spring Hill SWWTP, Cardno assisted the County with an interim operating plan that includes utilizing treated effluent for flushing the force mains and exercising the pumps at both pump stations in order to protect and maintain the infrastructure until it is fully operational.