PUMP REPLACEMENT AT THE HYPERION INTERMEDIATE PUMP STATION ANALYSIS OF ARCHIMEDES SCREW vs VERTICAL TURBINE PUMPS

Hyperion Treatment Plant has an average flow of approximately 400 million gallons per day (MGD). The Intermediate Pumping Station (IPS) consists of 10, 150 inch diameter, 600 HP, Archimedes screw pumps, each with a capacity of 125 MGD (87,000 gallons per minute) at an overall head of 15.8 feet which pump primary effluent to a distribution bay for the subsequent secondary treatment.Corrosion-caused, catastrophic failure on one of the pumps resulted in an investigation that revealed extensive material loss on the edges of the screw flights, screw barrel (torque tube), concrete trough, and aluminum trough covers. Although, the screw and the concrete trough were repaired the cost exceeded original purchase price. As a consequence, the City before proceeding with the purchase of new screws, decided to perform a study of alternate pump styles that could possibly be more suitable for the corrosive environment. In addition, it was hoped that alternative pumps might alleviate some of the problems associated with the existing common afterbay.