In a survival situation if you had to filter dirty water you can use bamboo to make a crude filter. In the top layer place fresh green grass to catch the large particles, the second layer with fine sand to trap the smaller particles and finally a layer with charcoal which is effective at removing chlorine, particles such as sediment, volatile organic compounds (VOCs), taste and odor. They are not effective at removing minerals, salts, and dissolved inorganic substances.
***REMEMBER ONCE YOU HAVE FILTERED YOU MUST BOIL IN A SAFE CONTAINER AND SUSTAIN A ROLLING BOIL FOR 5 MINUTES BEFORE YOU SHOULD DRINK IT***
