Ozone Disinfection

Can ozone disinfection provide clean and safe water?

K, a colleague from UIC is in Kenya for two weeks and he is doing a quick research on using ozone to disinfect water.

Simple research question: after ozonation, how long will E.coli remain in the water?

Ozone
Solar panel, Ozone generator and Aerator. Device was made by students at the University of Illinois at Urbana-Champaign

So far, the easier method being used to disinfect water is by chlorination. However, by ozonation, that can change. Ozonation is layman’s term is when oxygen (air) gets mixed with O2 from the device that produces it, it turns into O3. Using solar as a source of power, we turn on the device and place an aerator in the clay pot of water we are testing. It then bubbles and we leave that to do its work for about 2-3 hours.

Clay Pots
Clay pots commonly found in rural homes

But, I am jumping ahead. First, the water source is from River Kisian, about 30 min drive from SWAP. About 80L is fetched because we want to have at least three different samples of disinfection, ozonation, chlorination and control.

Ozonation is what I explained above and chlorination is the simple technique of placing 2 caps of waterguard in the water, stir up and allow to sit. While, control is just untreated water which sits for the duration of the trial. We conduct the test everyday, but do new trials every other day, meaning, we fetch water every other day from the river because the trial takes 24 hours to get the results. We want to know after ozonation, do E.coli activity occur when the water sits out for a duration of days? And how long can the water sit out for, for people to use? In terms of chlorination, water can sit out for at least 3 days.

POTS

We try to replicate people’s lifestyle by using clay pots that are common in most rural homes and sitting the water out for at least a day; K is on a time-crunch.  Also, the cultural belief is that when people see water bubbles/hot/boiling, they believe that their water is being disinfected. Ozonation does a similar chemistry, only it doesn’t get hot. Besides, boiling is not a sure effective way of disinfecting water. There are some bacteria/viruses that have a high boiling point. I digress, but, one challenge we faced was when it rained. Water from the river was highly turbid (due to heavy rain which can cause run-offs into the water-defeats the purpose and most don’t fetch water from the river when it rains, they collect rainwater). So, we took a pause on the study and will resume again on a good day.

UV light
Using UV light to read the E.coli results after conducting the tests

Anyways, once this study turns out to be successful, this method of disinfection can be implemented in rural homes. People can easily disinfect their water without them having an excuse of stating that the water taste or smell funny (an effect of chlorination). Though, while ozonating, it produces a funky smell, so we did the study outside the lab. People will be advised to disinfect in a well-ventilated area.

E.coli results
E.coli results. The dark ones suggests activity. The less the better

While we are not fully there yet, we are halfway there and K and Dr. D are making huge efforts in making sure that we get the right results. We did community assessment and it turns out that people are ready for this device to be installed in their homes/community. Most do use chlorination, others allow their water to sit out, but with this new method of disinfection, they are eager.

Of course, there is more to this, but this is a simple, non-boring explanation of ozonation and how it will be implemented in regions that are prone to water-borne illnesses.

Till then,

AY

**Solar panel can be easily purchased in Kenya. Some rural homes had solar panel installed in their homes. 

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