- Add 5 gallons of water (20 litres) to the top/red bucket
- Add a 67mg (red) chlorine tablet to the water
- Allow 30 minutes contact time.
- Place the top bucket on the bottom bucket, which activates a check-valve so that water flows through the two filters and into the bottom bucket.
- Add a 17mg (grey) chlorine tablet to bottom bucket
- Allow water to run through from top bucket to bottom bucket
The initial chlorination in the top bucket inactivates the bacteria that cause diarrheal disease. As water flows through the filters, turbidity, chemical contaminants, some larger disease-causing protozoa, and the chlorine are removed. Users access the treated water via a tap in the bottom bucket. A small amount of chlorine is added to the bottom bucket to provide residual protection.
The benefits of filtration & chlorination systems are:
- Proven reduction of most bacteria, even in turbid waters
- Residual protection against contamination due to chlorine being added to bottom bucket
- Improved taste due to removal of the chlorine in the GAC filter
- Pre-treatment of turbid water with the string-wound filter
- Acceptability to users because of ease-of-use, fast filtration rate (~20 liters/hour), acceptable taste, and visual improvement in the water
- Obvious health improvement.
The purification process is quite simple and similar to most public systems used in the United States today.

