Since 2001 there has been tremendous progress in developing water purification equipment for troops out in the bush. That research has not only provided cheaper and easier to use water purification technology for the military but a lot of it was cheap and simple enough for widespread civilian applications, especially in disaster relief situations. Now that research has created a very cheap and easy to manufacture water purification technology that can solve the clean water shortages that afflict so much of the population in poor and remote areas. This is done with sheets of thin, multi-layer foam material that consists mostly of cellulose (what trees are made of 0f) and a layer of graphene (a form of carbon that is extremely thin, strong and cheap) with specific bacteria. Together, this material when placed on the surface of polluted water uses sunlight and a sponge-like process to purify the water that can then be directed (by gravity) to containers. Field tests have shown that it works and the next step is to mass produce the graphene-based biofoam sheets and distribute them widely so regional variations in water and climate can be tested and tweaks made to the composition of the sheets for different conditions. The military can also use this but the main beneficiary is civilian populations, mainly because the technology is so cheap and easy to use.
For the military clean water is a necessity, otherwise the troops will suffer more than the locals (who have developed some resistance to the bad water). The foreigners often have digestive systems with little experience with bad water and are thus more vulnerable. This in many remote locations the military water supply often has to come by air (parachute or helicopter) and if you have to deliver water that way it’s very expensive. Water purification tablets, used by the military for most of the 20th century, are not always practical and the water tastes awful. Traditional purification methods like boiling or adding alcohol are also not practical for military or emergency use.
So cheap, lightweight devices that produce clean water from local stuff are much appreciated. More equipment like this has been showing up since 2001 because so many troops were operating in hot climates where there was little clean water available locally. Since there have been armies the largest single cause of casualties has been bad water. Not the enemy, but water borne diseases. Modern armies devote a lot of transport to delivering clean water or purification equipment. This is expensive, and the troops who don't get clean water are forced to drink the local stuff and get sick.
An example of this new water purification gear was the WaterGen Spring, which began to show up in 2011. This is a 12 kg (26 pound) battery powered unit that is designed to be back packed. Spring can produce 40-55 liters (over 10 gallons) of clean water an hour and 180 liters (45 gallons) on one battery charge. This new device has proved popular with police (especially in Israel, where Spring is made) and foreign aid organizations because it is a lightweight and cheap way to provide water in areas where there is little of it to begin with and what is there is dangerous to drink unless treated first.
There is a lot of enthusiasm for portable purifiers, as this finds a market among hikers and campers. Back in 2009, a British inventor created a portable (640 gr/1.4 pounds) water purification device (the "Lifesaver") that can hold nearly a liter (25 ounces) of purified water and can produce over two liters a minute. The Lifesaver looks like a thermos bottle and is manually operated like a pump. A set of filters can produce over 4,000 liters of pure water, free of all known impurities.
The Lifesaver cost $229 back then and was issued to British troops in Iraq and Afghanistan. American troops bought Lifesavers with their own money. That's because they find the Lifesaver more effective than water purification pills (which produce water that tastes awful) or earlier portable purification devices.
Even locals find devices like Spring and Lifesaver attractive, even with the high cost. That’s because throughout history the biggest killer of all has been tainted water and newer and more effective solutions are always in demand.