Preliminary SODIS test results

Last Friday (28/6/13) started with a requirement on my part to produce 4 litres of fecal contaminated water (don’t ask) so that we could test the Kit Yamoyo packaging as a SODIS device. SODIS has been a recurring theme on this blog over the years and we have developed a relationship with the SODIS team at EAWAG as ColaLife has developed.

Last week we took advantage of a visit by Benjamin of EAWAG to undertake preliminary tests to see if the ColaLife AidPods could be used to purify water using the SODIS method.

SODIS testing with Benjamin

First thing in the day, we took samples of the contaminated water and placed this on special culture plates. We then filled two sets of AidPods with the water and left them in the sun for 6 hours. We then took more samples and put these on the culture plates as well.

These were left to incubate for 48 hours and you can see the indicative results below (all the photographs are here).

SODIS Raw Sample 2 SODIS R2
Contaminated sample (the blue dots are E Coli) | The same water after 6 hours in an AidPod in the sun

The key thing to note is that E Coli (the blue dots) were present in the contaminated water before exposure to the sun and after exposure they had disappeared. The reddish dots are Coliform bacteria which are not dangerous under normal circumstances.

These tests are not conclusive they just indicate that certified lab tests would be worth doing. If the E Coli had not been eliminated then it would be a waste of time carrying out lab tests.

Although this indicates that our AidPods could possibly act as SODIS devices to purify the water it is hard to see how this would work in practice. AidPods only hold 200ml of water and a family would want to be purifying water in this way by the 2 litre bottle full. However, with careful messaging there may be a way of using the AidPod as a means to introduce the SODIS method to communities.

I’d like to thank Charpak, our AidPod manufacturer, for providing the AidPods in pure PET and recycled PET formats to facilitate the tests and to PI Global, our packaging design partner, for shipping them to us.

 

Comments

  1. I’m happy to see my mate benjamin working hard. I’m glad he could help