Gear test: SeaPack desalinator

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During any emergency, whether on land or at sea, simplicity and reliability are essential, and the lifesaving gear you will depend upon must be readily available.

During any emergency, whether on land or at sea, simplicity and reliability are essential, and the lifesaving gear you will depend upon must be readily available.

 

The SeaPack emergency desalinator makes a survival drink from any available water supply: salt water, brackish water, even questionable fresh or muddy water. It removes salt, purifies the water and transforms it into a clean-tasting drink that is high in calories (480 per half-liter) to provide life-sustaining energy. The manufacturer says it will remove 97 percent of the salt from sea water.

The SeaPack is simple to use, compact, easily stowed, and weighs less than the survival drink it produces. I consider it to be unique in that it is passive, requiring no effort on the part of the user except for dispensing the syrup into one side of the pliable container and adding the questionable water into the other side.

The emergency desalinator consists of a 9-by-15-inch pliable “DryPak” pouch that holds the 7-by-12-inch forward-osmosis membrane filter and five plastic bottles labeled “Nutrient Syrup Charge.” To begin the purification process, open the red port and completely fill that side of the bag with water. Close that port and uncap the green spout. Unseal one 4-ounce syrup charge and pour the contents down the spout, expel most of the air from the SeaPack, and firmly close the green cap. (Note: if using fresh water instead of salt water, use only half of the nutrient syrup charge.)

The volume of drink and time required for the SeaPack to produce it varies with temperature. For example, at 68 degrees F, it produces a half-liter in about five hours, while at 95 degrees F it can produce the same amount in 3-1/2 hours. When the process is complete, discard any remaining salt water through the red port and dispense the drink from the green port into a clean container, ready for consumption.

For maximum efficiency, the instructions suggest changing out the salt water every two hours through the red port, occasionally agitating the SeaPack, and keeping it warm. Warmer water and agitation allow the water to move easily through the filter. Also, it’s not advisable to let the SeaPack process for more than 24 hours, as the drink may become too salty. My use of the SeaPack with salt water from Long Island Sound produced 16 ounces of clean, palatable drink in less than six hours at around 65 degrees F, without agitation or replenishing the sea water.

The process that allows the SeaPack to perform is referred to as forward osmosis. The desalinator incorporates a proprietary hydrophilic (attracts water) membrane filter that allows water to pass through but blocks contaminants because of the tight construction of the semipermeable membrane. SeaPack uses a proprietary syrup similar to sports drinks as an agent to create osmotic pressure and draw water molecules through the membrane. The syrup charges have been formulated to maximize filtration capabilities and enhance oral hydration and drink preservation. The drink should be consumed within 12 hours, according to the instructions.

Because the water is driven across the membrane by osmotic pressure (forward osmosis) rather than hydraulic pressure, it doesn’t require active participation (i.e., physical pumping) like reverse-osmosis systems do. In addition, most pump systems force contaminants into the membrane, which can cause clogging and failure. With forward osmosis, water is pulled through the membrane, leaving contaminants behind.

Conventional hand-pump systems filter to 0.1-micron levels, while the SeaPack reportedly filters to .0005 microns (5 angstroms). The Centers for Disease Control recommends filtering with a minimum of 1 micron.

SeaPack has been tested by the U.S. military, the Department of Defense and independent laboratories for its effectiveness in blocking all types of biological pathogens common in contaminated water. SeaPack also reportedly performs well against chemical toxins. (The data is available for review on the company Web site, www.sea-pack.com .)

The SeaPack filter system has an indefinite shelf life, while the syrup charges should be used within three years. However, the SeaPack must be discarded 10 days after its first use. Abbreviated and detailed instructions/cautions are clearly printed on the bladder assembly. With the included five syrup charges, the SeaPack produces 2.5 liters of survival drink, and is capable of producing 48 liters over its 10-day lifespan with additional syrup charges. Every SeaPack is tested for leaks under a positive-pressure air test prior to packaging and shipping, because a tight membrane filter and construction are required to maintain osmotic pressure, according to the manufacturer.

Rick Feineis, managing partner of SeaPack distributor Manta Ventures, says the emergency desalinator is sold in New Zealand, Australia, England, Ireland, Spain and South Africa. It is available in the United States directly through the above Web site, as well as West Marine, Defender and Viking Life Rafts. Retail pricing for the complete kit is $99.95, while a five-pack of replacement syrup charges is listed at $38. Contact Manta Ventures at (757) 619-3614 for additional information.