LogoAfoni Children of Hope Foundation-ACOHOF

Motto: Hope for the Underprivileged

WADIS & the DevICe Project

WADIS is a water disinfection project run together with Engineers Without Borders in Sweden (EWB). The project started in 2013 when EWB introduced two simple ways to get access to drinking water, SODIS and pasteurization. The first phase was run by EWB together with Leéiyen Systems. 

This second phase established a Development and Information Center, DevICe, at the site of ACOHOF Family Farm School outside of Tatum.


According to statistics stomach problems are one of the most common things that makes people in Tatum visit the health centre. Stomach problems are often caused by bad water and sanitation. 

One way to reduce the risk of becoming ill is to treat water fetched from rivers and springs before drinking it. This can be done by the SODIS method.
The bacteria’s in the water (the ones we want to get rid of) are deactivated by the combination of heat and UV-radiation. Since the bacteria are only deactivated and not killed the water should be consumed within the first 3 days. If not, there is a risk that they might wake up. If the water has not been consumed within 3 days you can redo the procedure and the water will be drinkable.


How to do SODIS

1. Get a transparent PET-bottle and remove the label.

2. Fill the water with water (the water cannot be too brown, you should be able to read a newspaper headline through the filled bottle).

3. Put the bottle facing the sun, for example on an aluminium roof.

4. Wait. After 6 hours it is ready for consumption, if it is cloudy the bottle might have to be in the sun for 2 days in row.

A way to further increase the efficiency of the method is to fill it to ¾, close and shake and then fill the rest of the bottle before putting it in the sun.



When families in Tatum using the SODIS method were interviewed they witnessed about improved stomach health and a majority of the interviewed said that they had not had any stomach problems since they started with the method.  

For more information about the SODIS method contact DevIce at the ACOHOF Family Farm School in Tatum. You can send mail to sodis@acohof.org. They practice the SODIS method every day. Information can also be found at http://www.sodis.ch/index_EN

SODIS stands for Solar Water Disinfection. It is a simple water treatment technology that poor households and disadvantaged communities can use.

SODIS uses solar radiation to improve the microbiological quality of drinking water and is relatively cheap and easy to install.

The World Health Organization recognizes the benefits of the SODIS method of water purification.


Pasteurization means heating up the water to at least 65 degrees Centigrade. This will kill most of the bacteria in the water (10% per 12 seconds) making it drinkable. 

Heating is traditionally done by boiling the water over an open fire. But since you don’t have to boil it you can as well use a solar oven to heat the water. 

Solar Ovens

A solar oven is a “sun beam collector” concentrating the energy from the sun using reflectors to heat up the water. At DevICe you can see a large parabola, a solar cooker, that demonstrates the enormous energy you can get from the sun. 

Some smaller ovens have also been produced at DevICe, so far only for demonstration purpose. The objective is to introduce solar ovens for both pasteurization and solar cooking. You can actually cook food using only the solar irradiation.

The project is now in an evaluating phase and will end in December 2016. The activities at DevICe together with ACOHOF FFS will however continue in order to spread the information about disinfecting drinking water in the area.