Siemens has been awarded a $14-million contract to supply a hollow fiber membrane treatment system as part of the groundwater replenishment system (GWR) expansion at Orange County Water District (OCWD) in California. The 48-million-gal-per-day (mgd) membrane system, coupled with an existing Siemens membrane system, will increase the flow to 134 mgd for the reverse osmosis (RO) membranes downstream in the GWR system. Construction could begin as early as late-2010.
“We were happy with the membrane technology in our existing system,” said Shivaji Deshmukh, GWR system program manager, OCWD, “and we felt that staying with this technology for the system expansion was the most efficient, cost-effective way to go.”
With more than 2.3 million inhabitants, Orange County Water District’s service area is one of the most populous areas in the U.S. The GWR system, a joint project of OCWD and the Orange County Sanitation District, was established in 1997 to preserve local groundwater resources and to help form OCWD’s seawater intrusion barrier. The RO pre-treatment system expansion will consist of Memcor CS membrane modules, ancillaries, control system upgrades and associated electrical work. Siemens will supervise the membrane modules’ installation and the expanded system’s commissioning. At the time it was installed, the original Siemens membrane system was the largest membrane system in the Americas and one of the largest in the world. Because the system was designed for future expansion, with 20% extra space in the existing 26 basins, OCWD will only have to add 10 more membrane basins.
The GWR system, which has been operating since January 2008, is the world’s largest water purification project of its kind. Highly treated wastewater, originally destined for the ocean, is pre-treated by Memcor submerged membrane modules at a rate of 86 mgd before entering the RO units, followed by ultraviolet and hydrogen peroxide disinfection.