Reclamation Signs Research Agreement with the California Water District to Study New Desalination Processes

The Bureau of Reclamation and the Metropolitan Water District of Southern California have entered into a cooperative research agreement to test three water desalination pilot projects at Reclamation's Water Quality Improvement Center in Yuma, Ariz.

The innovative technologies highlighted in these projects have the potential to reduce the cost of desalination while increasing the amount of water available after treatment. The $3 million research agreement includes in-kind and cash contributions from Reclamation and Metropolitan.

"Improving desalination technologies to make them more affordable and accessible is part of Secretary Norton's Water 2025 initiative," Reclamation Commissioner John Keys said. "This collaborative research will help us learn how we can improve the process and potentially reduce the cost of current technology."

Wes Bannister, chairman of Metropolitan's board of directors, said the research projects underline the district's commitment to the science of water quality. "We want to push the envelope of public health protection, and research gives us the tools to make needed advancements," Bannister said.

"The creation of new technologies for desalting water could be used to develop non-traditional water supplies in Southern California, such as brackish groundwater, recycled water and agricultural drainage water. Ultimately, this could help reduce our need for additional imported water," Bannister said.

The first project will test replacing microfiltration pretreatment with a reverse osmosis pretreatment using ozone and biofiltration processes. The research will determine if this pretreatment will be cost effective in maximizing the feed water quality and minimizing membrane fouling.

The second project will study the performance of large-diameter (18-inch) reverse osmosis membranes, the largest currently available in the world. This will be the first demonstration for membranes of this size as part of a complete water treatment system. The research will evaluate how well these membranes perform when operated at 85 percent or greater water recovery on conventionally pretreated water. Researchers also hope to determine how often the membranes need to be cleaned, and what is the optimal cleaning strategy to maintain a successful desalting operation.

The third project calls for a new concentrate recovery technology to be fed by the reject stream of a large-diameter reverse osmosis unit. The project hopes to confirm previous pilot-scale research, which produced a 95 percent water recovery -- a 10 percent increase over more traditional reverse osmosis recovery. The concentrate recovery process involves using chemicals to remove compounds with the greatest potential to foul a membrane surface, followed by treatment with a secondary reverse osmosis system.

The Water Quality Improvement Center is a full-service, operational water research center. It consists of a 12,000 square-foot building with three test trains and multiple stand-alone test devices. It serves as a field site to investigate new and improved water treatment technologies, including pretreatment associated with desalination. It is operated by Reclamation's Yuma Area Office.

To learn more about this research project, visit:

This article originally appeared in the 06/01/2005 issue of Environmental Protection.

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