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Experts Test Water Filtering System (Desal Project)

Published 12/27/2007 on Grunion Gazette

Work has begun on what amounts to a giant science project at Junipero Beach.

Long Beach’s Water Department is conducting the $5 million experiment, which will test the feasibility of sucking water through sand on the ocean floor to feed a desalination plant. The opposite process, pumping mineral-laden brine back under the ocean floor to avoid harmful discharges, also will be tested.

Long Beach has been working on producing drinking-quality water from the ocean for more than a decade. A full-scale demonstration plant is operating now next to the Haynes Power Plant on Second Street, tweaking what has become known as the “Long Beach Method” to find the most energy-efficient way to strain salt and other minerals from the water.

It will take an environmentally-sound method of drawing water from the ocean and of disposing of the brine taken from the water before this new source can be considered viable, according to Kevin Wattier, general manager of the Long Beach Water Department.

Engineers think a 200- to 400-foot-long perforated pipe buried in the ocean floor may be the answer. To demonstrate that plan’s effectiveness, the department is spending $5 million — mostly from grants — to put in the demonstration project.

Current desalination plants and some proposed plants rely on intake at power plants as the source of seawater. However, those plants are under fire for harming marine life by sucking small organisms into the power plants and killing larger fish at intake screens.

Long Beach’s proposal would filter water through a layer of the ocean floor, eliminating the danger to fish and almost all organic material.

At the other end of the process, a liquid supersaturated with salt and other minerals must be disposed of. That brine can be hazardous if dumped directly back into the ocean, and disposal has become a significant cost factor at some plants.

Long Beach’s approach is to pump the brine back under the ocean floor, again allowing the natural material to filter and diffuse the brine before it hits ocean water.

“We think this is critical,” Wattier said last year. “There has been a lot of controversy recently regarding the once-through cooling of coastal power plants, and the use of that water for desalination.

“To be a viable project, we think we’re going to have an alternative source of water. Ultimately, this is designed to be both an intake and a brine discharge system.”

It is expected to take about three months to build the test site and lay the pipes. The beach will be restored after construction and visitors should see little if any disruption of the area.

Water running through the test system will only go to the test facility on the beach. The testing period could be up to a year.

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