AWWA WQTC60764

The Groundwater Replenishment (GWR) System is a major new program to provide a reliablesource of water for protecting and recharging Orange County, California's groundwater basin. The GWRSystem is a joint program of the Orange County Water District (OCWD) and the Orange CountySanitation District (OCSD) to produce 70 mgd of recycled water for use in the seawaterintrusion barrier and for groundwater recharge. The GWR System has replaced the aging WaterFactory 21 (WF-21) which was reaching the end of its useful life. Preliminary design of thisambitious project began in 1999 with the preparation of design criteria and technicalmemorandums. As part of these investigations, it was identified that WF-21 must remain inoperation during the construction of the Advanced Water Treatment Facility (AWPF) tomaintain the seawater intrusion barrier.Early start designs were envisioned to maintain WF-21 production and reduce the risk of costlydelays to the AWPF construction. One of the early start contracts is the Phase 1 of the GWRSystem project. Phase 1 GWR System construction involved the installation of 6.7 milliongallons per day (mgd) of microfiltration (MF) to replace the existing 5 mgd WF-21 limeclarification system, currently being demolished. Issues regarding existing utility coordination,process control system operation, and assignment coordination for the MF and UV systems aroseduring 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 toproduce water for the seawater intrusion barrier and has provided ongoing support for waterrecycling 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 chanceto operate a smaller 5 mgd (product water) system with the same treatment processes as the fullsize 70 mgd AWPF, giving the OCWD operators valuable experience and knowledge on a muchless complex system. The Phase 1 GWR System treatment train includes in-basin MF, newpolyamide RO membranes, and a UV system to demonstrate disinfection and NDMAdestruction capabilities. MF and UV process equipment used in the Phase 1 GWR System willbe 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 operatorsare involved in WF-21 operation and AWPF infrastructure inspection. Phase 1 GWR Systemsite power construction included installation of the backbone electrical conduits and a largesubstation to facilitate a smooth switchover of the site power. Temporary access roads,additional parking and proactive utility relocations will reduce the impact to OCWD operationsduring construction of the AWPF. Completion of the Phase 1 GWR System is scheduled for theSpring of 2004. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/15/2004

Number of Pages:

20

File Size:

1 file , 18 MB