Water passes slowly downwards through a bed of fine sand at a steady rate. The water should not be too turbid, otherwise the filter will get too clogged. Pathogens are naturally removed in the top layer where a biological film builds up.

How to use: 

• Filter can be made of a series of 3 clean barrels connected by hoses
• The series consists of a raw-water supply, filter tank and clean water tank
• Filter tank consists of a 45-60cm bed of washed sand on top of a 5cm layer of fine gravel
• If steel barrels are used they must be treated with cement mortar, or any safe protective paint to prevent oxidation
• All tanks must be protected with lids

Can Treat: 

• Faecal coliforms
• Arsenic
• Iron
• Manganese
• Odour & Taste

For Further Information:

WHO Water Quality Guidelines - 4th Edition

WHO Water Treatment Guidance