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< prev - next > Water and sanitation Water quality and treatment water_treatment_systems_KnO 100433 (Printable PDF)
Water supply can be contaminated by a number of
external sources before it is consumed and used by
households for cooking, cleaning and drinking.
Industries that dont consider the effects of pollution
they create can seriously endanger the health of
local communities. This technical brief outlines some
water treatment solutions which can help
communities have access to cleaner and safer water.
Looking after Water Sources
The following are best practices to follow:
Selecting the best possible water source is more
effective to start with, since water treatment
systems are not perfect
Disinfection is necessary but not always sufficient
For an unprotected source coagulation and sand
filtration should be carried out in addition to
Water quality should be tested for faecal
Figure 1: A man collecting water from a polluted
stream in Uganda. Photo: Simon Ekless.
The best water source is one that doesn’t need treatment. Rainwater that can be collected is
relatively clean, whereas surface water tends to have been polluted before reaching the consumer
If the source water has been tested and found to be safe then things are obviously going to be
easier. 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 hand pumps are usually quite well
protected from contamination. Others sources such as surface water sources are not safe.
Water Quality and Contaminants
Chemical contaminants
Heavy concentrations of iron and manganese in ground water result in an unpleasant taste and
give the water a brownish colour which can be passed on to clothes and food. They are often
removed by aeration which makes that iron and manganese insoluble resulting in a fine, dark
sediment. Aeration can be achieved by allowing the water to fall from a height into a storage
tank. See the section in this document on aeration.
Other chemicals such as salts, fluoride and nitrates are more difficult to remove from water at
the village level.
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