Within the United States Marine Corps, the reverse osmosis water purification unit has been replaced by both the Lightweight Water Purification System and Tactical Water Purification Systems. The Lightweight Water Purification Systems can be transported by Humvee and filter 470 litres (120 US gal) per hour. The Tactical Water Purification Systems can be carried on a Medium Tactical Vehicle Replacement truck, and can filter 4,500 to 5,700 litres (1,200 to 1,500 US gal) per hour.
Reverse osmosis per its construction removes both harmful contaminants present in the water, as well as some desirable minerals. Modern studies on this matter have been quite shallow, citing lack of funding and interest in such study, as re-mineralization on the treatment plants today is done to prevent pipeline corrosion without going into human health aspect. They do, however link to older, more thorough studies that at one hand show some relation between long-term health effects and consumption of water low on calcium and magnesium, on the other confess that none of these older studies comply to modern standards of research 
The first step calls for the installation of 2 push fit elbows. Note these were the only two elbows that leaked on me, despite use of thread tape and applying what I felt was the right torque. You really need to seat elbows well with the top of the male tread well below the plane of the housing. The push fits are of the type that once you push the poly tube in, that's it. So, being they are elbows, there is no coming back to easily address leak at the body joint. (I had NO push fit leaks in the system)... DONT Panic if it leaks at the body. Very careful removal of the inline filter and the RO membrane ... full review
If the right equipment is available distillation is another way to ensure removal of bacteria and viruses. This is one method that will allow us to use salt water for drinking. Note: If you own a boat and use it for off shore trips a desalinator such as the Katadyn Survivor series would be a prudent purchase. The Katadyn Survivor 40E can be operated manually or using 12/24 V DC power. We will cover makeshift ways of distillation in future articles.
Photo by mr.smashyContingencies in the wilderness abound, so it is important to plan for as many as possible. A compass will help you find your way; even better is a handheld GPS device. Flashlights and glow sticks help you find your way in the dark, and a flare gun will assist others in finding you during an emergency. For setting up camp, Paracord or rope, a tarp, duct tape, and cable ties are indispensable. Also vital is a good multi-tool, folding shovel, and gloves. Include waterproof matches, lighter, and fire starting kit; redundancy is a good thing in this instance. In a small tin, pack fishhooks and line, razor blades, sewing needles and thread, safety pins, nails, a small magnet, and some cash.
A specific "large-scale" form of slow sand filter is the process of bank filtration, in which natural sediments in a riverbank are used to provide a first stage of contaminant filtration. While typically not clean enough to be used directly for drinking water, the water gained from the associated extraction wells is much less problematic than river water taken directly from the river.
The first continuous use of chlorine in the United States for disinfection took place in 1908 at Boonton Reservoir (on the Rockaway River), which served as the supply for Jersey City, New Jersey. Chlorination was achieved by controlled additions of dilute solutions of chloride of lime (calcium hypochlorite) at doses of 0.2 to 0.35 ppm. The treatment process was conceived by Dr. John L. Leal and the chlorination plant was designed by George Warren Fuller. Over the next few years, chlorine disinfection using chloride of lime were rapidly installed in drinking water systems around the world.