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Week 3 from Biratnagar, Nepal

Water Testing as it relates to Ceramic Water Filters


Many of us who are blessed to live in the United States have the advantage of a public water treatment plant, and our water is tested many times daily. Despite this fact, many people in the US continue to purchase water in plastic bottles, which is, in fact, obtained from similar water treatment plants in other cities. We install filters on faucets and refrigerators which filters are not designed to remove bacteria. We have the best public water system in the world but we are ignorant of its benefits.


There are no public water systems in the areas where we make Ceramic Water Filters. Boiled water is available, but it is expensive and the quality is dubious at times. Most people here, in Nepal for instance, drink water from wells, streams, rivers and rooftop tanks.


Testing any source water is inherently difficult, as testing of every drop of water is impossible. Samples are taken as representative of water quality, but conditions and quality can change with time, as quickly as hourly.


Our water testing is carried out in two phases – first, during the filter production process, we test the ability and limits of the manufactured filters to remove bacteria from water. Our filters are manufactured to have the ability to exceed the World Health Organization’s minimum threshold of 100 bacteria per 100ml of water – Log 2 removal.


Second, after filters are installed in households, we return to check the efficacy of these filters in use. This involves 2 tests for each filter – one test to determine the quantity of bacteria in the source water, or water being put into the filter; and then, a second test of the bacteria content, if any, of the water coming out of the filter.


Testing methods to detect bacteria vary; Presence/Absence (P/A) tests; MPN tests (Most Probable Number); and Coliform counting tests. We have settled on using Compartment Bag tests from Aquagenx, as the easiest and least expensive, but also the most precise method, to determine the efficacy of the ceramic water filters when made and in use.


At the beginning of the manufacturing process a minimum of 25% of the filters are tested for effectiveness in removing bacteria, and all must pass before manufacturing continues. Thereafter spot checks are made to determine continuing efficacy.


Thereafter, with help of in country factory representatives, visits are made to filter users, and spot checks are made, from time to time, as deemed necessary. We deem this backup testing essential; but, most important, are anecdotal reports from filter users – the difference the filters have made in their lives – enabling children to attend school; improved health of the young babies; reducing medical expenses for families that can afford other essentials, etc.


The filters work to change lives.





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