Orange County issues RFP for desalination pilot-plant operation
The Municipal Water District of Orange County (MWDOC) in California, USA, issued a request for proposals on 23 October 2009 for professional engineering services for the South Orange Coastal Ocean Desalination Project - Phase 3. Deadline is 19 November 2009.This phase, budgeted to cost US$ 1.2 million, involves extended pumping and operation, testing and evaluation of a pilot plant currently under construction and expected to be in operation by March-April 2010.
The major goal of this project is to confirm the ability of a slant well system to produce ocean feed water at the desired capacity and quantity, and to develop a process design specification for the full-scale project. Phase 3 work is scheduled for 18 months.
The planned desalination plant would use reverse-osmosis to desalinate ocean water for potable supply estimated at approximately 15 MGD (57,000 m³/d) of product water at 50% recovery. The desalinated and purified ocean water would be delivered to local coastal water agencies through the regional distribution pipelines that cross the site.
MWDOC has been investigating the feasibility of horizontal/slant water well technologies constructed out under the ocean that can avoid marine organism impacts associated with conventional open intake systems.
MWDOC pioneered development of high-capacity slant dual rotary well technology for ocean feedwater supply with the successful construction and demonstration of a test slant well in the spring of 2006. Unlike radial-type collector wells, which have also been used for ocean water desalination plant intakes, slant wells offer reduced construction and O&M impacts in shoreline environments.
Slant wells can be fully buried within a clustered wellhead, provide high capacities, and can extend significant horizontal distances out under the ocean floor. The current feedwater supply plan for the full-scale project would utilize three clusters of three fully buried slant wells each located at suitable location above the high tide line.