CENTRIFUGE SELECTION AND SPECIFICATION FOR THE CLARK COUNTY WATER RECLAMATION DISTRICT

The Clark County Water Reclamation District in Las Vegas, Nevada, is upgrading their solids dewatering system. Their wastewater treatment plant is presently operating at over 90 mgd average flow and the growth in the Las Vegas area is rapidly increasing flow. As such, the District plans to design for 150 mgd average flow by the year 2015. In a very short time, their existing recessed-chamber filter presses will not have sufficient capacity. The District decided to use high-solids centrifuges in a new structure to handle current and future loads, and allow for additional expansion after the 150 mgd plant flow is reached.CH2M HILL was commissioned to evaluate and design the new centrifuge facility to handle 180 dry tons per day average and over 230 dry tons per day peak month. All solids are raw as the least cost option is landfilling.With the decision to use high-solids centrifuges, an installation of this magnitude required a complex evaluation of the available centrifuges in this size range, approximately 30 inch diameter centrifuges. A detailed evaluation of centrifuge manufacturers was undertaken followed by visits to the selected centrifuge factories. This resulting in the design and specification of high-solids centrifuges. Pre-purchasing was the selected procurement option, and the bids for the centrifuges were recently received, with the Andritz D7LL the apparent low bidder.