Under suitable circumstances, a simple sand filtration system may be not only the cheapest and simplest but also the most efficient method of water purification during a disaster situation. Its advantages have been proved in practice over a long period, and it is still the chosen method of water purification even in the wilderness. It has the great advantage over other methods that it makes better use of natural materials that are readily available, and it is efficient in removing bacterial contamination.
– a biosand drinking water filter
– Simple water filter made out of a water bottle