Deep Aquifer Treatment System

IRWD's Deep Aquifer Treatment System (DATS) purifies drinking water from the lower aquifer of the Orange County Groundwater Basin. An aquifer is an underground area which stores water naturally. Although the water from this aquifer is very high in quality, it has previously been unusable because it has a brownish tint imparted from the remains of ancient vegetation that once populated the area. However, new purification technologies now make it possible and cost-effective to remove the color from this water. The DATS facility went on-line in early 2002.

The facility includes two wells that pump water from approximately 2000 ft. below ground level. This colored water enters the treatment plant and travels through tightly-wound membranes. Because the color molecules are much larger than the water molecules, they can readily be filtered out.  After undergoing this “nano-filtration” treatment, the water is clear. It then travels through degasifiers that remove low levels of methane gas that would otherwise give the water a “fizzy” appearance.

Following treatment at the DATS facility, the water travels through pipelines with water from other wells and is then disinfected before it enters the IRWD distribution system. The color molecules that are filtered out are referred to as concentrate, which is discharged into the sanitary sewer system.  The treatment process has a 92% efficiency rate. In other words, for every 100 gallons of colored water that passes through the facility, 92 gallons of clear water are produced and only 8 gallons of concentrate must be disposed.  An engineering team is currently working on system upgrades that may be able to increase the efficiency as high as 98%. The DATS facility can treat up to 7.4 million gallons of water per day.

This project benefits all groundwater users in northern and central Orange County because it helps prevent wells from being affected by seepage of colored water into the middle aquifer used for drinking water by many cities and water districts.

DATS Fact Sheet