Finally, on our sixth attempt, we have gotten some lab test results that make sense and are credible. For this round, we had expert help from our friends at Carollo Engineers. On March 21st, Carollo invited us to bring a water box to their UV test facility in Portland. They took pre-treatment and post-treatment samples of water inoculated with MS2, a pathogen-surrogate, and sent the samples off to the lab that they always use in Canada. Carollo donated their labor, the use of their facility, and the lab work. Our project gives them a big thank you!
The new lab results came back on March 25th. When the MS2 data is extrapolated to real pathogens, the results suggest that the water box is quite effective (at least 99.999%) against common protozoan and bacterial pathogens such as Giardia and E. coli, using a 2-minute UV exposure. That level of reduction (“5-log”) exceeds the World Health Organization’s “Highly Protective” 3-star standard for those pathogen classes. Viruses are more resistant to UV than protozoa and bacteria, and even with increasing the exposure to 3 minutes, the box falls just short of the WHO’s “Protective” 2-star threshold for viruses. To be on the safe side with respect to viruses, we have decided to increase the UV exposure time for the field test water boxes to 4 minutes. Our colleagues at Engineering Ministries International in Uganda are now planning to make the necessary modifications and resume the field test as soon as they can fit it in their schedule.
Further details of these latest tests are posted at https://uv-h2o-box.com/news in the April, 2022, item titled “New Test Results”.