I came across this youtube clip of a village in Thailand wanting clean water from chemical runoff and thought what a great large scale system to set up for a permanent campsite location. Its an old method of using Gravel in various sizes, then sand, to remove larger particles, then charcoal to filter water. The charcoal removing impurities by absorption, adhering contaminants to the charcoals surface. This is the first time Ive seen it developed for large scale use such as for a village.
I thought i might bring it up at the next mens shed meeting if anyone wanted to try making it as a group project. Olive oil barrels being perfect for this use.