Tapia Water Reclamation Facility (TWRF) applies state-of-the-art technology to transform wastewater into high-quality recycled water that is used to irrigate public and commercial landscaping such as golf courses, school grounds, highway medians and parks.
Wastewater is potable water that has been used in a home or business. The water that goes down a drain enters the wastewater (sewer) collection system. The wastewater travels through a series of collection pipes in the LVMWD service area, traveling mainly by gravity to the TWRF.
Wastewater entering Tapia is 99% water and 1% solids and inert materials. The first step is to remove the inert materials. Larger items, like rags and paper, are removed by passing the waste stream through a vertical slatted bar screen. Finer materials (egg shells and coffee grinds) are removed in a “grit chamber.” Here, the flow is slowed and air is injected to keep small, organic particles suspended while the heavier, inert materials fall to the bottom. The items removed from the wastewater to this point go to a landfill.
The wastewater is then pumped to the primary sedimentation tanks. Primary treatment is a separation process using gravity, where the solids in the wastewater are allowed to settle to the bottom of the tank. Oil and grease, which are lighter than water, float to the surface. Large paddles skim the water surface and the bottom of the tanks to remove these materials, which are then pumped to the Rancho Las Virgenes Composting Facility.
Secondary treatment is a biological process. The wastewater flows to aeration tanks to be “cleaned up” by beneficial microorganisms. This is similar to the natural water-purification cycle, but is accomplished in less time. As in nature, microorganisms remove contaminants and clean the water as they feed, grow, and multiply. Oxygen is added by injecting air into the tanks, which helps speed the process.
The partially treated wastewater then flows to the secondary sedimentation tanks, where the microorganisms are allowed to settle out. They are then collected and returned to the aeration tanks, to work on another batch of wastewater. Meanwhile, the liquid portion goes on to the next step, tertiary treatment.
Tertiary treatment is a filtration process designed to remove any remaining extremely small particles. Chemicals are added to “flocculate,” or clump the particles together, making them easier to filter out. The water is then disinfected with chlorine. After sufficient “contact time” the chlorine is then “neutralized.”
Tapia has a capacity to process up to 16 million gallons of wastewater per day (MGD), but currently averages about 9.5 MGD.
By recycling wastewater, Tapia provides an additional “source” of water for our communities. About 20% of all the water delivered by LVMWD has been recycled for irrigation use. During the hot summer months, irrigation consumes all the recycled water Tapia produces, with the added benefit of reducing the demand for potable water by that same amount.
Also at Tapia, an on-site, state-certified water quality laboratory conducts testing to assure that all potable and recycled water served by LVMWD meets stringent state and federal health standards. The laboratory also monitors water quality in Malibu Creek, as part of the District’s commitment to watershed stewardship.
Awards received by Tapia include:
- U.S. Environmental Protection Agency Operations and Maintenance Excellence Award - 1988
- Statewide Plant of the Year - 1989, 1995
- Los Angeles Area Plant of the Year - 1972, 1974, 1983, 1985, 1994
- Association of California Water Agencies Environmental Achievement Award - 1989, 1995, 2003
- National Environmental Awards Council Outstanding Operations, Maintenance and Total Reuse
National Pollutant Discharge Elimination System (NPDES)
Tapia Water Reclamation is operated under a Joint Powers Authority between LVMWD (located in western L.A. County) and Triunfo Water & Sanitation District (located in eastern Ventura County).