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L.A., San Diego explore latest methods to provide fresh water

Groundwater treatment here, desalination there

Merdies Hayes | 12/18/2015, midnight | Updated on 12/18/2015, midnight
Southern California’s two largest cities, Los Angeles and San Diego, are pursuing different but equally innovative

Southern California’s two largest cities, Los Angeles and San Diego, are pursuing different but equally innovative solutions to the state’s drought. Their efforts are pushing the two municipalities to the forefront of a growing number of cities trying to reshape urban water supplies in drought-prone areas stretching from Australia, to the Middle East and to the American West.

Both Los Angeles and San Diego were built with massive water infrastructure investments—reserviors, dams and aqueducts—that continue to bring water from Northern California, the eastern Sierra Nevada Mountains and the Colorado River, each location about 300 miles away. But now supplies are dwindling and prices are rising.

Therefore, Los Angeles has embarked on huge wastewater, recycling, stormwater capture and conservation projects. The Los Angeles Department of Water and Power (LADWP) is in the pre-design phase of a plan to build the world’s largest groundwater treatment center over a huge swath of contaminated aquifers in the San Fernando Valley.

The Environmental Protection Agency included this area as one of its largest Superfund pollution sites and contains almost a hundred contaminated underground wells which have been closed since the 1980s. The city of Los Angeles purchased a 46-acre former landfill in the Sun Valley area and wants to convert it to an engineered wetlands park that will collect and clean stormwater and then pump it into the underground basins.

A recent UCLA report cites Los Angeles’ sustainable water management programs as a success, but the region’s per capita water use is still twice as high as that of the average city in Europe. The report indicated that there is still a long way to go to reach the efficiency levels of countries like Australia and Israel that have a similar climate and lifestyle, but use a fraction of the water that Los Angeles does.

LADWP officials are excited about the prospect of refilling those wells and believe the effort will be beneficial, if and when another drought occurs.

“The treatment center will recover the full use of groundwater aquifers lost to contamination and retain extra capacity to pump out the additional recycled water and stormwater we’re looking to capture,” said Marty Adams, director of water operations for the LADWP.

In San Diego, the big effort there is to bring on-line by the end of the month a controversial $1 billion seawater desalination plant in Carlsbad. It’s supposed to provide seven to 10 percent of San Diego County’s drinking water by 2020. The ultra-modern facility is projected to be the largest in the Western Hemisphere; officials there believe this method of providing fresh water will counter critics who say such projects are too expensive, require huge amounts of energy and harm the environment.

Boston-based Poseidon Water built the San Diego plant and insists it’s the finest in the world.

“It’s the most technologically advanced and environmentally sound desalination plant in the Americas, and the latest one to come online worldwide,” said Jessica Jones, a Poseidon spokeswoman.

That’s not all. The Metropolitan Water District (MWD), which serves much of the Antelope Valley, has given pre-approval to what may be the nation’s largest and most ambitious water reuse plan. This plan is a giant wastewater recycling system near Hyperion Point, which upon completion, is expected to serve a six-county area and nearly 19 million people. The MWD has partnered with the LA. County Sanitation District to construct the plant which, by 2035, would purify up to 168,000 acre-feet (207 billion liters) of treated wastewater discharged each year into the Pacific Ocean and, in turn, inject this water into local groundwater basins before being pumped out and used as potable water.

The MWD system would be similar to Orange County’s vaunted Groundwater Replacement System which has been operating since 2008. The system forces wastewater through reverse osmosis membranes that are also used for desalination.

Both the Los Angeles and San Diego plans utilize a system called “indirect potable reuse,” which purifies the wastewater as it moves through a groundwater aquifer buffer before reaching thirsty customers.