How can I naturally purify water without equipment?
Written by
Robert Kelly
Reviewed by
Prof. Benjamin Murphy, Ph.D.Natural methods of purification may render water safe when no equipment is available. The writer utilized sunlight exposure to treat stream water during a bicycle trip. These methods rely heavily on the presence of natural elements, including ultraviolet rays, plant extracts, and sedimentation. They are most effective in combination for removing various types of contamination.
Solar Disinfection (SODIS)
- Place water in clear plastic bottles under direct sunlight
- UV-A radiation kills microorganisms over 6 hours
- Requires relatively clear water for effectiveness
Plant-Based Coagulation
- Crush Moringa oleifera seeds into water
- Proteins bind to sediment and bacteria
- Strain through cloth after 30 minutes
Sand Filtration
- Layer coarse sand, fine sand, and gravel
- Water percolates through layers trapping particles
- Requires periodic cleaning of top layers
Charcoal Absorption
- Use campfire charcoal chunks in filtration layers
- Helps remove some organic compounds
- Less effective than activated carbon
Sunlight disinfection is effective only under optimal conditions. Use clear plastic bottles filled three-quarters full. Place them on very reflective surfaces, such as metal roofs. Six hours of good sunlight will kill most pathogens. I use cloth as a pre-filter in my experiments with turbid water sources.
Cultural methods such as those derived from Moringa seeds have been known since the time of the ancient Egyptians. To produce a better quality of water, crush seeds (20) into a litre and quickly stir them into the water. After they have settled, the water is filtered through cotton. Although this produces better quality water, it does not remove virus germs, such as those of hepatitis.
Natural techniques have strong limitations in efficacy against chemical threats. Heavy metals such as arsenic are immune. Pesticides need carbon filtration. After flash flooding, I used SODIS, but boiled the water for infant use. Always pair natural methods with boiling when possible.
Never rely on the natural contaminants found in dubious water without testing it with portable test kits when they are available. Notice the warning signs of aquifers: unusual smells or colors, etc. In emergencies, "layer" the application of jars by choosing different methods of purification that can remove any one of several different contaminants.
Read the full article: How to Filter Water: Essential Methods Explained
