The Groundwater Replenishment (GWR) System is a major new program to provide a reliable
source of water for protecting and recharging Orange County, California's groundwater basin. The GWR
System is a joint program of the Orange County Water District (OCWD) and the Orange County
Sanitation District (OCSD) to produce 70 mgd of recycled water for use in the seawater
intrusion barrier and for groundwater recharge. The GWR System has replaced the aging Water
Factory 21 (WF-21) which was reaching the end of its useful life. Preliminary design of this
ambitious project began in 1999 with the preparation of design criteria and technical
memorandums. As part of these investigations, it was identified that WF-21 must remain in
operation during the construction of the Advanced Water Treatment Facility (AWPF) to
maintain the seawater intrusion barrier.
Early start designs were envisioned to maintain WF-21 production and reduce the risk of costly
delays to the AWPF construction. One of the early start contracts is the Phase 1 of the GWR
System project. Phase 1 GWR System construction involved the installation of 6.7 million
gallons per day (mgd) of microfiltration (MF) to replace the existing 5 mgd WF-21 lime
clarification system, currently being demolished. Issues regarding existing utility coordination,
process control system operation, and assignment coordination for the MF and UV systems arose
during construction of the Phase 1 GWR System and have proven valuable as "lessons learned"
for the AWPF design.
Constructing Phase 1 GWR System allowed continued use of existing WF 21 facilities to
produce water for the seawater intrusion barrier and has provided ongoing support for water
recycling in Southern California, reducing the area's dependence on imported water.
Implementation of the Phase 1 GWR System facilities has also provided OCWD with a chance
to operate a smaller 5 mgd (product water) system with the same treatment processes as the full
size 70 mgd AWPF, giving the OCWD operators valuable experience and knowledge on a much
less complex system. The Phase 1 GWR System treatment train includes in-basin MF, new
polyamide RO membranes, and a UV system to demonstrate disinfection and NDMA
destruction capabilities. MF and UV process equipment used in the Phase 1 GWR System will
be relocated into the AWPF to increase project capacity and reduce overall project costs.
Operating WF-21 during the AWPF construction will require detailed coordination as operators
are involved in WF-21 operation and AWPF infrastructure inspection. Phase 1 GWR System
site power construction included installation of the backbone electrical conduits and a large
substation to facilitate a smooth switchover of the site power. Temporary access roads,
additional parking and proactive utility relocations will reduce the impact to OCWD operations
during construction of the AWPF. Completion of the Phase 1 GWR System is scheduled for the
Spring of 2004. Includes tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 20 |
| Published : | 11/15/2004 |
