Desalination Technology Increases Naval Capabilities

"Saving energy and producing clean water is a tactical issue for the Navy," said Dr. J. Paul Armistead, an ONR program officer with interests in water purification. "We plan to build prototype desalination units that will use 65 percent less energy and be 40 percent smaller by weight and by volume relative to current Navy reverse osmosis systems. They should require roughly 75 percent less maintenance."

Delivering drinkable water for ships at sea and Marines ashore for less cost and less energy became an ONR priority in 2004 under the Expeditionary Unit Water Purification Program, or EUWP.

Before the advent of modern desalinization plants, mariners relied on the fresh water they collected from rain and stowed while at sea. Today, Sailors and Marines benefit from high-tech, Reverse Osmosis (RO) desalinization plants aboard most U.S. Navy ships.

It takes energy to make water, and that energy comes from burning fuel to spin turbine generators that produce electricity necessary for ship systems, including RO plants. A more efficient desalinization plant translates into a more efficient ship, which uses less fuel, extends combat capability and reduces its carbon footprint.

Since its inception, the EUWP program has produced advances in desalinization capability. The first generation EUWP technology demonstrator was designed as a deployable high water production unit more easily transported by the military and used for a variety of missions.

In fact, the EUWP Gen 1 demonstrator has been used in a number of humanitarian missions. In 2005, it was deployed in support of the Navy´s response to Hurricane Katrina where it delivered safe drinking water to Gulf Coast residents being treated at a hospital in Biloxi, Miss. In this case, the EUWP Gen 1 was trucked in and set up on the shores of the Gulf of Mexico, approximately four blocks from the hospital. The Gen 1 unit desalted and purified about 100,000 gallons of water per day from the turbid Gulf of Mexico, replacing the daily caravan of 18 tankers needed to keep the hospital running.

The second generation EUWP Gen II technology demonstrator, built with shipboard constraints imposed on the design, is a larger, more stationary demonstration unit, and has potential for use by isolated communities. It has been tested successfully at the Seawater Desalination Test Facility at the Naval Facilities Engineering Service Center in Port Hueneme, Calif.

Armistead anticipates increased capabilities from the newer demonstration unit. "From current Navy desalination systems we only get 20 percent product water," he said. "That means for 1,000 gallons of feed water, we would get only 200 gallons product water. These new systems will likely double that."

Michelle Chapman, a physical scientist with the U.S. Bureau of Reclamation, is a member of the ONR team managing the research program. She highlighted the program´s success by noting its benefits to the public at large. "Several of the projects we have funded have turned into patents for commercially available products and processes that are available for use in water desalination systems for communities where freshwater sources are not available," Chapman said.

Based on the successes in the EUWP program, the Advanced Shipboard Desalination, Future Naval Capability Program will begin in 2010. Navy Surface Warfare Center Carderock Division, Ship Systems Engineering Station (NSWCCD-SSES), is a partner in this effort. According to Dave Nordham, a NSWCCD-SSES mechanical engineer, "Any sort of technology advancements we find for ships are directly applicable ashore and can be utilized by ever-increasing drought ridden areas."

Key partners in the EUWP program include NSWCCD-Philadelphia, U.S. Army Tank Automotive Research Development and Engineering Command, U.S. Bureau of Reclamation and the Naval Facilities Engineering Service Center´s Seawater Desalination Test Facility at Port Hueneme, Calif.