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< prev - next > Water and sanitation Water quality and treatment Household water treatment systems (Printable PDF)
Domestic water treatment is increasingly
popular for people who do not have access to
mains water supplies. Household water
treatment (HWT) systems allow families to use
available water from nearby sources such as
springs, wells and rainwater harvesting systems
and drink it with reduced risk to health.
Simple water treatment systems such as sand
filtration or ceramic filtration are not as reliable as
larger water treatment systems but can be
important for people without access to a clean
source of water. It is difficult to get a simple and
reliable water treatment process for small-scale
water supplies. Therefore, if it is possible to use a
water source that is already clean then the water
treatment becomes less critical.
The following are the basic advice for water
Start with the best quality water available
as treatment procedures are not perfect
Disinfect (if possible) although this may
Figure 1: A domestic bio sand water filter
not be sufficient without further treatment being used in Peru. Photo: Soluciones Prácticas.
For an unprotected source coagulation
and sand filtration should be carried out
in addition to disinfection
Water quality should be tested for faecal contamination.
If the source water has been tested and found to be safe then things are obviously going to be
easier. However, there are ways of improving the source if it is not safe; covering wells with a
concrete slab, keeping animals away form the source, ensuring rubbish is not thrown down
the well, the type of bucket used to extract water etc. Tubewells with handpumps are usually
quite well protected from contamination if maintained properly. Others sources such as
surface water are not safe without treatment.
Household water treatment methods
There are a number of approaches to household water treatment outlined below; some are
easier to achieve than others.
Although the majority of bacteria and viruses are rendered harmless very rapidly, the boiling
of water for a few minutes does not necessarily give complete sterilisation. However, it is
necessary to boil water for 20 minutes to ensure full safety. The main disadvantage is the
energy consumption.
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