Lara Abrams Communications

Orange County’s groundwater basin was used by early settlers to supplement flows from the Santa Ana River. As the area developed into a thriving agricultural center, the increased demand upon the subsurface water by the county’s many wells resulted in a gradual lowering of the water table. In response, the Orange County Water District was formed by an act of the California Legislature in 1933 to protect and manage the groundwater basin.

In addition to effecting aggressive groundwater recharge and recovery programs to optimize local water resources, District officials have for decades advocated treating and recycling municipal wastewater as a reliable supplemental supply. As long ago as the mid-1960s, OCWD began a pilot-scale reclamation project that developed into the now-famous Water Factory 21. Located in Fountain Valley, California, the plant is well-known internationally, attracting more than 1,000 visitors annually from 30 countries.

By 1956, years of heavy pumping to sustain the region’s agricultural economy had lowered the water table below sea level and saltwater from the Pacific Ocean had encroached as far as five miles inland. The area of intrusion is primarily across a four-mile front between the cities of Newport Beach and Huntington Beach known as the Talbert Gap. The mouth of an alluvial fan formed millions of years ago by the Santa Ana River, the Talbert Gap has since been buried along the coast by several hundred feet of clay.

Massive seawater intrusion has been prevented by the District’s recharge program. However, the threat of saltwater encroachment along the coast is still present. To prevent further intrusion and to provide basin management flexibility, the District operates a hydraulic barrier system. A series of 23 multi-point injection wells four miles inland delivers fresh water into the underground aquifers to form a water mound, blocking further passage of seawater.

The first blended reclaimed water from Water Factory 21 was injected into the coastal barrier in October 1976. Several alternative sources of water were thoroughly evaluated for the seawater barrier injection program, including deep well water, imported water, reclaimed waste-water, and desalted seawater. The source of injection water finally adopted for Water Factory 21 is a blended combination of deep well water and recycled secondary effluent supplied by the Orange County Sanitation District (OCSD).

The recycled product water from Water Factory 21 meets drinking water standards through treatment using advanced processes. Recycled water was chosen for many reasons. Cost was a definite consideration, but even more important were the environmental advantages:

— Reduction of 15,000 acre-feet of wastewater discharged to the ocean annually.
— Reduction of dependency on State Water Project and Colorado River supplies.
— Constant availability of reclaimed water supply; seawater intrusion barriers are last priority when imported supplies are diminished by drought or emergency interruption of importation systems.

Water Factory 21 product water is a blend of five million gallons per day (MGD) reverse osmosis-treated water, nine MGD carbon adsorption-treated water, and 8.6 MGD deep well water. This blend, with a total dissolved solids (TDS) content of 500 milligrams per liter (mg/L) or lower, meets all California Department of Health Services primary and secondary drinking water standards.

Product water also complies with the injection requirements of the California Regional Water Quality Control Board, Santa Ana Region. The use of recycled water, at a cost comparable to that of less dependable imported supplies, has rendered the project virtually drought proof.

Water Factory 21 reclaims approximately 15 MGD, and, with the deep well water used for blending, produces 22.6 MGD. The blended injection water not only protects the basin from saltwater intrusion, but also replenishes aquifers from which 50 percent of the county’s water is drawn.