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October 2008

Purple is the New Green

These days, everyone is going green. We recycle plastics, paper and electronics. We conserve energy.  We save water.  But it still may be a surprise to find out that something as mundane as purple pipe is keeping Southern California green in more ways than one.

The trendiest definition of being green means sustainable or environmentally-friendly. The word green also means, more traditionally, lush landscapes filled with soft grass and leafy plants.  Putting greens.  Green meadows.  You get the idea.

Today in Southern California, purple pipe extending from nearly 125 recycled water projects protects the environment by reducing the amount of wastewater discharge while providing an alternative water supply for things like green grass and landscaping.  This purple pipe, brightly colored to avoid confusion with drinking water pipes, carries highly-treated recycled water for use in the irrigation of crops, parks and golf courses and water-intensive industries, such as oil refineries.

Nineteen of Metropolitan’s 26 member agencies use recycled water within their service areas.  In the Los Angeles area, the largest of the water recycling facilities is the Edward C. Little Water Recycling Facility in El Segundo, producing nearly ten billion gallons of recycled water annually that is used to irrigate landscapes at many locations including Loyola Marymount University, California State University, Dominguez Hills, medians in the city of Torrance, and in industries such as the refinery process at Chevron.

In the Inland Empire, Eastern Municipal Water District operates five water reclamation plants providing 46 million gallons a day for agriculture, industry, irrigation and wildlife habitat restoration for the San Jacinto Wildlife Area.  Many more projects in the area are underway.  Western Municipal Water District is expanding the capacity of its second wastewater treatment plant, located at the March Air Reserve Base, to treat up to 356 million gallons a year to irrigate the 921-acre Riverside National Cemetery and fill its lakes, and to irrigate the Base landscaping and surrounding communities.  Inland Empire Utilities Agency, currently using nearly 3 billion gallons per day of recycled water, plans to expand its purple pipe beyond the southern part of its service area into communities such as Upland and Rancho Cucamonga for landscaping and industrial uses.

In Irvine and La Jolla, recycled water is used for flushing toilets in designated high-rise office buildings in addition to the more common irrigation and industrial uses.

The city of Los Angeles has used recycled water since 1979 for irrigation and industrial purposes. Recycled water keeps the landscape green and healthy in areas of Griffith Park, along with the Mount Sinai-Forest Lawn Memorial Parks and Universal City. An important water resource, recycled water is a key component of the city’s 20-year plan to ensure a reliable water supply for Los Angeles. Currently, the Los Angeles Department of Water and Power is working with businesses, industries, and public agencies to expand recycled water throughout the city for irrigation, industrial and environmental uses. The LADWP has also begun a public dialogue and is studying a program for groundwater replenishment, which involves taking highly treated wastewater—purified through state-of-the-art technology such as reverse osmosis—and sending it to spreading basins to replenish groundwater supplies for drinking.

The San Diego County Water Authority has 20 new or expanded recycled water projects in the works and a city of Burbank project provides recycled water for use in irrigation and cooling towers as well as dust mitigation at a local landfill.

Recycled water also plays an important role in protecting the region’s groundwater supplies.  In coastal communities such as Long Beach, Fountain Valley, and El Segundo, recycled water is or will be injected into groundwater basins to guard against seawater intrusion.  Another project to protect groundwater from seawater intrusion is planned for the Los Angeles Harbor area.

The Orange County Water District’s Groundwater Replenishment System, is the successor to the acclaimed Water Factory 21 and has received international recognition.  The GWRS is capable of producing an unprecedented 23 billion gallons a year.  In addition to protecting fresh water from mixing with seawater, projects such as the GWRS also replenish the Orange County Groundwater Basin with recycled water directly and with highly-treated recycled water released upstream into the Santa Ana River by the Inland Empire Utilities Agency.  

In Montebello and Pico Rivera, groundwater basins managed by the Los Angeles County Sanitation Districts serving southern Los Angeles County are kept full by using higher elevation spreading grounds to hold captured storm water runoff, imported water and highly treated recycled water.  The water then percolates through the earth’s natural filter of soil, sand and rocks into the aquifers below.

Being green means saving energy too, and recycled water has been shown to decrease California’s power consumption by reducing the amount of water that needs to be pumped from Northern California or the Colorado River.  The Upper San Gabriel Valley Municipal Water District calculates that its current water recycling projects save 6.3 million kilowatt hours; and when its planned projects are complete, it will have reduced energy use by more than 100 million kilowatt hours. That’s the equivalent of powering about 9,400 homes for one year, based on national average household energy use, or taking 5,054 cars off the road.

With our water supply already dangerously low due to record dry conditions and environmental factors, purple pipe is the only new major source of water available to meet growing water demand.  The good news is that using recycled water is also good for the environment.  No wonder water agencies call purple the new green.

This newsletter is produced by the:
Metropolitan Water District of Southern California
700 N. Alameda St.
Los Angeles, CA 90012