On a recent trip to Central America, I came across the most fascinating water filtration system, and when I mentioned it in a recent newsletter, many of you asked for more information. Well, this filtration method is known as a “biosand filter,” and replicates the same process the earth uses to clean groundwater.
The process is simple and can be replicated with natural materials almost anywhere on earth. The filter is comprised of a concrete vertical shaft, which is filled with three or four different grades of gravel and sand, and a tube or pipe that allows the clean water to flow out. Each layer works in its own way to naturally clean the water. The beautiful part about this is that, unlike most filtration systems, this method is good for decades, and you’re not dependent on difficult (or impossible) to replace manufactured parts.
NGOs around the world are building these filters where access to safe drinking water is an issue. Some groups have started to make them out of plastic, but it doesn’t take a veteran survivalist to realize that plastic can crack, warp or otherwise wear out, whereas concrete can both be made locally in even the most primitive conditions and has a long useful life.
There’s an American Expat in Guatemala who has been using one of these in his own home and is testing it out. You can learn more about his experience by visiting his blog at https://guateliving.com/2010/05/agua-pura/ .