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Putting SaWa by 4Life to the test, why it matters

How can solar water disinfection provide access to safe drinking water?

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Lack of safe drinking water can lead to diarrheal illnesses, posing a high risk to human health.

 

4Life Solutions helps bring safe drinking water to low-income communities with a simple water purification technology called solar water disinfection (SODIS). SaWa by 4Life uses the UV and heat from the sun to kill the disease-causing microorganisms in the water.

 

However, there is a lot more science that goes on in the background.

My name is Charlotte Frydenlund Michelsen, and I’m the Senior Science Manager at 4Life Solutions. I lead all activities around performance testing, documentation, and certification of SolarSack. In this post, I’m going to share some of the tests we conduct to ensure that our users can always depend on the quality of the water they treat with their SaWa by 4Life.

Testing Objectives

A key goal in our testing is to make sure that the SaWas works in all the places it is implemented. Through continual testing and development, we have found that SaWa is a reliable solar water disinfection product even when used with highly contaminated and turbid water samples.

A focus on turbid water

One of the things I’m currently focusing on is testing water turbidity. Turbidity is a measure of the clarity of the water, i.e., how muddy or see-through the water is (measured in NTU). Water with high NTU values can appear as cloudy, murky, or otherwise colored, depending on what causes the turbidity of the water.

The World Health Organization (WHO) recommends that the turbidity of drinking water should be less than 1 NTU and no more than 5 NTU.

Turbidity, in itself, does not always represent a risk to human health. But it can mean a high level of fecal contamination in the water and, therefore, the presence of microorganisms causing diarrhoea. Turbid water can also contain particles that block the UV from entering the water and killing the microorganisms, reducing the efficiency of SODIS. Therefore, a turbidity level of 30 NTU is the suggested maximum to achieve an effective SODIS treatment.

For many low-income communities in rural areas, such as East Africa, the most common drinking water sources are boreholes, shallow wells and surface water. These water sources often show high turbidity levels, exceeding 5 NTU, and can contain a large number of disease-causing bacteria and other microorganisms, which poses a considerable health risk to the local community. It is in these communities that 4Life Solutions can change lives. 

We have run thorough tests of the efficiency of SaWa by 4Life combining high turbidity levels of up to 60 NTU with large numbers of the bacterium, E. coli. Even in these cases, SaWa by 4Life can produce safe drinking water, showing over a 99.999% reduction of E. coli. Going forward we will be testing with turbidity levels of over 100 NTU as well as with other important water characteristics and microorganisms. That way we ensure that every person with a SaWa by 4Life can enjoy safe drinking water, no matter their current water quality.

This means that we can be confident that the SaWa by 4Life is effective in real-life scenarios.

Charlotte Frydenlund Michelsen

Solid data linking laboratory testing with natural conditions ensures quality and health

The efficiency of SODIS technology depends on various factors such as, the characteristics of the water being treated, the type of microorganisms that are present in the water, and the contamination level.

This is why testing the efficiency of the SaWa by 4Life in all possible conditions and scenarios is so important. That way we know exactly how well the SaWa already works, and where we have to advise precautions before use. We do the testing in our own in-house laboratory as well as under natural field conditions. Our field testing partners include renowned universities in Uganda and Bangladesh.

Test setup in Bangladesh: Surface water is collected from a river in Dhaka (left) and contaminated with E. coli shown as the golden metallic colonies (dots) when water is cultured on agar plates (middle). The contaminated water is treated with a SaWa under natural sunlight (right).

We test our SaWas using our own developed laboratory protocols, so-called standard operating procedures (SOPs). Our protocols are based on the guidelines provided by the WHO. This ensures that all data documenting the SaWa’s efficiency is of the highest standard and universally relevant.

Furthermore, we are testing the SaWa by 4Life based on the natural conditions found in the areas, where SaWas are being used. We have visited settlements and villages in rural Uganda and Nigeria which gave us valuable insights. It taught us how high turbidity levels could be found in natural drinking water sources and included the learnings in the SaWa turbidity testing. This means that we can be confident that the SaWa is effective in real-life scenarios, and provide safe drinking water to local communities.

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Putting SaWa by 4Life to the test, why it matters

My name is Charlotte Frydenlund Michelsen, and I’m the Senior Science Manager at 4Life Solutions… SaWa by 4Life can produce safe drinking water, showing over a 99.999% reduction of E. coli. Going forward we will be testing with turbidity levels of over 100 NTU