Using the sun to sterilise water

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http://news.bbc.co.uk/2/hi/africa/4786216.stm

 

Using the sun to sterilise water

 

Tanzanian villagers have begun using an energy-saving method to

sterilise their drinking water - leaving the water under the sun.

 

The piped water supply to Ndolela village in the central Iringa region

is intermittent and even when it does flow, it is not clean enough to

drink.

 

When the pipes run dry, villagers get water from a dirty spring.

 

Mother of five Rose Longwa says the new process has changed her life.

 

" We no longer suffer from stomach illness. That's because the water is

clean and safe. "

 

Like many other people in rural Africa with no access to safe drinking

water, she used to sterilise her water by boiling it.

 

But she says the smoke from the firewood to heat the water used to

irritate her eyes. She is also glad she no longer has to go to fetch

wood from the bush.

 

Ultra-violet rays

 

About 40 houses in Ndolela are using solar purification.

 

Mrs Longwa says the process is simple to follow.

 

" I fill the plastic bottles, put the lids on, then put them on my

black-painted roof where they stay for a whole day. "

 

The sun heats the water, helped by the black roof, which helps to

absorb the heat.

 

Solar radiation means a combination of ultra-violet rays and heat

destroys the bacteria which cause common water-borne diseases like

cholera, typhoid, dysentery and diarrhoea.

 

After eight hours in the sun, it is ready to drink.

 

If the water reaches more than 50C, it is safe in just one hour.

 

Pastor Moses Kwanga from the Diocese of Ruaha is behind the project:

 

" The technology is very easy, but up to now people have not been told

about it. We can use old pieces of roofing to put the bottles on. It

is also very cheap, so is accessible to everyone. "

 

Resistance

 

Up to now, the number of people in Tanzania purifying water using the

power of the sun is limited to a few villages like Ndolela, where

small-scale education programmes are underway.

 

Daudi Makamba is a water expert for the aid agency Plan International,

which is considering whether to introduce solar purification across

the country.

 

He says it can be difficult to persuade people to use the technology.

 

" The big resistance from the community is cultural beliefs. People

believe the water will be contaminated, or an enemy will put something

bad in it, so we need to educate the people. "

 

The technology is working well for at least one community in Tanzania

but more work is needed if more people are to taste the benefits.

 

World Water Day is on 22 March

Story from BBC NEWS:

http://news.bbc.co.uk/go/pr/fr/-/2/hi/africa/4786216.stm