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The Warrior

SSC-Natick Press Release

U.S. Army Soldier Systems Center-Natick
Public Affairs Office
Kansas Street
Natick, MA 01760-5012

Contact: Chief, Public Affairs Office
(508) 233-5340

Date: July 14, 2004
No: 04-28

Membrane pouch purifies beverages

NATICK, Mass. -- Contaminated water can go in, but only pure water seeps through the self-hydrating membrane pouch in development at the Department of Defense Combat Feeding Directorate here.

Based on the vinyl commercial X-Pac hydration pouch technology developed by Hydration Technology Inc. (HTI) in Albany, Ore., Combat Feeding is aiming to modify HTI's current membrane to incorporate a forward osmosis membrane into military packaging.

The prototype pouch is designed to take water from any available freshwater source-rivers, lakes, ponds or puddles-to hydrate beverages or dry ration foods to reduce combat weight and logistics of potable water.

"With Future Force Warrior, (researchers) are looking at ways to reduce weight and volume," said Andre Senecal, a senior food technologist and project officer for the membrane pouch. "Food is what troops usually like to sacrifice when paring down their load weight. They're also not carrying enough water."

Based on hydration requirement data, a physically active soldier requires about 10 liters per day in a hot environment, he said. Soldiers now carry about 5 liters.

Drinking water can be purified using reverse osmosis (RO), where it is forced by a powered pump through a semi-permeable membrane to remove contaminants from a solution within 15 minutes. The same membranes are used in the self-hydrating pouch in a process called forward osmosis (FO).

Both filter more than 99.9999 percent of the bacteria that might be found in non-potable water, but FO works by pulling water through the membrane. Although slower, it requires no power and does not foul the filter even with muddy water.

Ingredients in the beverage powder or food that have charged ions, such as salts, sugars and amino acids, energize the osmosis, drawing water in like a sponge. The process takes three or four hours to completely hydrate a 12-ounce beverage, according to Senecal.

"We want something consumable, so we have to balance these ingredients with the osmotic components that actually drive the process," he said. "The toughest piece is to rehydrate beef stew or some other entrιe. There's no great osmotic potential. We'll have to work out a design, maybe separating the components or reformulating the ration."

Senecal said interest in a self-hydrating membrane pouch started in the 1980s, but the break came in the 1990s when Combat Feeding met with HTI. Combining their sturdy membrane technology and the packaging expertise of another Combat Feeding industry partner, Pactech in Rochester, N.Y., a prototype membrane pouch was introduced this year.

The prototype has the same multi-laminate foil used in the Meal, Ready-to-Eat, a resealable plastic zipper at the water intake side of the inner pouch and an outer membrane pouch holding the food or beverage. Water is filled into the inner pouch and sealed to begin the osmosis. When ready, warfighters tear off the outer pouch end and open the zipper to consume the hydrated contents.

With the look and feel of a waxed textile, the membrane has a robustness not demonstrated during previous attempts to develop the technology, Senecal said. However, durability in rough handling tests must still be done with food ingredients already incorporated into the pouch to simulate military field handling to ensure they don't tear under stress.

Not its own ration, he said the pouches are intended to become a part of existing and future rations. Possibilities include the Meal, Cold Weather/Long Range Patrol ration, survival food packets and the developmental First Strike Ration.

Depending on what rations are used, water weight savings can range from 4-12 pounds. It also can be joined with new generation hydration systems for Future Force Warrior, especially helpful when Soldiers wear a self-contained suit.

Initial evaluation of prototype packages is scheduled for next year, with a larger-scale evaluation set for 2007. Besides food, Senecal said the technology has interested the Air Force for medical intravenous solutions and Navy for sea survival kits to purify salt water.

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This page last updated on 23 January 2004.