Pure Water Gazette Research
Reveals Effectiveness of Bacteria Filter

Pure Water Gazette professional research animal, Bill, is shown at right participating in a Gazette test of the bacteria removal effectiveness of three water filter cartridges. On the day this photo was taken, July 30, 1999, the water in Lake Bill, pictured here, had a greenish cast and a visible skin of scum. Although no formal test by volume or weight was conducted, the lake's fluid content appeared to consist of about ⅓ water, ⅓ mud, and ⅓ duck guano. Those who know ducks will understand.

The purpose of our test was to check the effectiveness of two water filter cartridges that make specific claims of bacteria removal. We used a Doulton Super Sterasyl ceramic cartridge, and a MatriKX CeramiKX grade all-carbon filter in which the carbon is tightly packed to mimic the structure of ceramic. Both theoretically are so tight that bacteria are strained out.

As a control, we used a MatriKX Slimline KX-1 cartridge, a nominal one-micron filter whose manufacturer makes no claim of bacteria removal. It is, theoretically, too loose to prevent the passage of bacteria and is sold as a high-capacity chemical filter.

The plan was to scoop out a large, seething sample of water from Lake Bill, then submit four samples to the Denton Municipal Water System's bacteriological testing lab for a bacteria count. Our plan was to test three filters, each using our simple $7 Style A siphon adapter. Here are the tests we did, along with the results:

A. Raw Lake Bill Water. Unfiltered, untreated. The lab found coliforms present at the rate of >23 per 100 ml. A lot of bacteria.

B. In the water filtered through the Slimline KX-1 filter, which wasn't supposed to remove bacteria, the lab found Total Coliform (including E.coli) present in amounts “too numerous to count.”

C. With the CeramiKX carbon block cartridge, we had to abandon the test because sediment in the water blocked it so severely that flow was too slow for practical testing. We hope to repeat the test. Our initial impression was, however, that while the CeramiKX works well as a siphon filter on relatively clean water (such as swimming pool water), Lake Bill water was too much for it. If you're planning to filter water from the Gitchgoome Swamp, get a Doulton.

D. In the water filtered through the Doulton Super Sterasyl, the lab found no bacteria. Period.

Our conclusion was that if the Doulton candle will filter Lake Bill water, you're safe from bacteria drinking virtually any water filtered through it.

We would point out that we did not test for chemicals, heavy metals, or any number of other contaminants that the Doulton candle is not designed to remove, so don't mistake the Doulton or any other filter cartridge for a complete water treatment system.

Veteran Gazette research animal Bowser watching the Lake Bill experiments with great interest. Bowser's great life-long research project is the invention of the canine thumb. Watch the Gazette for progress reports.