by David Conklin on Sept. 3rd, 2022

Covid-19, malaria, military call-up – these were some of the bumps in the road that our colleagues in Uganda experienced while carrying out the water box field trials, but they persevered, and now the field trial final report is here! The complete report is available here.


During the summer of 2021, we shipped a pallet of two dozen water boxes to east Africa. They went overland from Oregon to New York, by sea to Mombasa, Kenya, and then by truck to Kampala, Uganda. They were in transit for 3 months. Five more units went as airline luggage with several helpful travelers. We had an ambitious plan to test the water boxes in 50 Ugandan households, in 2 rounds of 25 households per round.


Our colleagues at Engineering Ministries International (eMi) in Kampala carried out extensive tests of our water boxes, to qualify them for placement in households. eMi used a test protocol that we provided, and augmented that with their own program of tests. Acting on the results of U.S. tests conducted while the 3-month transit time, and on the results of the on-site tests after the units reached Kampala, we and eMi agreed on some field modifications: the UV exposure period was lengthened from one minute to four minutes, and the use of external 12V DC power from a wall transformer was required. Assays of the locally available water for coliform bacteria, before and after treatment in the water box, were performed with field test kits. These tests revealed that the source water at the eMi facility was very contaminated, and confirmed that water box treatment is effective against coliform bacteria.


Meanwhile back in North America, results from microbiological challenge tests with MS2, a pathogen surrogate, led us to conclude that four minutes of UV exposure should be used to assure that treatment in the Uganda tests would meet the “two star” standards of the World Health Organization. WHO prescribes treatment targets not only for bacterial pathogens, but also for viruses and protozoa.


The extensive on-site testing exposed a design flaw in our water boxes: sometimes, on some units, the UV light stayed on instead of turning off automatically after 4 minutes. About half of the 29 water boxes were used up in testing or culled because they didn’t turn off reliably. The remainder were placed in households for about 3 weeks in late spring this year, and retrieved at the end of the test period.


Despite the operational challenges and small number of households, the results were encouraging. The Ugandan engineers themselves were the principal authors of the test report, available here. It is long – 101 pages in total – but two-thirds of the pages are in appendices. We invite you to find out first hand how our water boxes worked out in Ugandan households, by reading the 36-page narrative portion of the report.