Volume 43 Number 5
Portable Purification: Reverse Osmosis Plays Expanded Role in Military Logistics
Success on the battlefield is tied to logistics. The U.S. Army's battle doctrine calls for high intensity, high-speed combat and the logistical support effort has to keep pace. The logistical battle is more complex and requires a greater depth of understanding of the whole battlefield than does the tactical battle. Top military logisticians have developed strategies to push stores of food, fuel, ammunition and water as far up as possible to the sharp end of combat. Supplying water for people and vehicles is an integral part of the military's planning. Carrying enough water in places like Saudi Arabia isn't practical. Here's why.
A typical armored division during Operation Desert Storm consumed 300,000 gallons of water per day for 350 tanks, 250 Bradley fighting vehicles and 16,000 soldiers. But the military has other terrain than the desert in which to operate. For example, the 31st Marine Expeditionary Unit performs amphibious training operations on and around the Island of Okinawa, Japan. Water from the ocean is plentiful, but contrary to popular belief, Marines cannot drink seawater. They also can't wash clothes, decontaminate equipment, or prepare food without a supply of potable water. So, the water purification equipment must be portable and flexible in the types of water used by the military in numerous types of battlegrounds.
What is an ROWPU?
A ROWPU is a complete, self-contained water treatment system surrounded by a rigid, metal frame. Typically, units like this are 8×10 feet, and 8 feet high. A unit this size generally weighs around 7,500 pounds. As with most water purification plants of any size, there are a series of pretreatment technologies for the water before it reaches the RO elements. RO technology treats water down to the molecular level. Larger particulates are more efficiently removed with media other than the RO membrane. With the suspended impurities removed, RO can more efficiently remove dissolved impurities. Portability is also a factor.
The modular nature of RO technology makes it ideal for the battlefield. If a membrane module is damaged or plugged, it can easily be replaced with a new one.
Purifying water for troops
Chlorine is added to the purified water to keep it relatively free of microbes during storage and transport. Brine that contains the concentrated, dissolved solids removed from the water is discharged from the ROWPU, while the pure water is stored in 3,000-gallon water bladders made from synthetic rubber. The purified water can also be placed in 950-gallon, insulated portable water tanks. Six of these tanks can be stacked on a logistics vehicle system known as a "dragon wagon" for transport to the battlefield or other locales.
ROWPU in relief efforts
In 1994, ROWPUs were used by American soldiers in Rwanda to purify water from Lake Kiva. Fouled by floating bodies and excrement, without water purification Rwandan refugees would have died in even greater numbers than they did from a lack of clean drinking water. In November 1998, in the town of La Habitad, Honduras, where Hurricane Mitch left more than 11,000 people with contaminated water, U.S. soldiers provided water via ROWPUs. ROWPUs are also being used in the Balkans by the Canadian military.
In camps located in villages like Drur, Bos Petrova or Gos Peak in Bosnia and Herzegovina, members of the Canadian military are busy purifying drinking water. ROWPUs require only three members of the 5th Combat Engineer Regiment at Camp Maple Leaf to operate and maintain them. The regiment is also producing drinking water for residents in large quantities.
Transport made easy
For example, if you were part of a Marine Amphibious ROWPU unit, you would remain near the ocean on a secure beachhead and purify seawater. But if you are on a reconnaissance team inland, far removed from your support, you need to be able to purify your own water. With the hand held purifier, soldiers can lower a tube into the nearest stream and pump a canteen full. These filters greatly reduce chlorine, iodine, herbicides, pesticides, trihalomethanes and other volatile organic materials. Most weigh less than one pound and will produce about 200 gallons of water between filter replacements. In addition to providing a safe source of drinking water, the hand-held purifiers reduce a soldier's load in the field.
Carrying four quarts of water (8.30 pounds) and one water filter, (11 ounces) as opposed to 11 quarts of water (22.9 pounds) and no means of replacing it, saves almost 15 pounds and ensures the soldier is protected from waterborne viruses. This makes a soldier's load lighter and gives him an edge while engaged in simulated or real combat. These portable systems aren't intended to replace ROWPUs but are instead positioned as a "combat multiplier" that enhances soldiers' ability to respond quickly in times of crises, military or otherwise.
On a much larger scale, the U.S. Army has ROWPUs mounted on barges that can produce up to 100,000 gallons of water per day from salt water.
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