Wednesday, 3 December 2014

08:29 – Happy Birthday to Barbara, who turned 20:40 yesterday. I didn’t mention it yesterday, because I thought she was concerned about hitting the big Six-Oh. As it turns out, she’s not.

Sad news in the paper this morning. A 17-year-old senior from a local high school is in critical condition after her car collided near the high school with an SUV driven by a 68-year-old guy. No word on who was at fault. One such accident is bad enough, but this one is just the latest in a recent slew of car accidents locally that have killed and critically injured numerous kids.

I’m writing now about water purification in the “First Year” section. There are numerous gravity-fed micro-filtration systems available, but the two I’m going to recommend are the LifeStraw Family and the Sawyer Point ZeroTwo. Both filter down to 0.02 microns, which is sufficient to provide a Log 4 reduction even for viruses. Both have very long filter life, assuming periodic back-flushing. (The Sawyer unit is rated at one million gallons.) Both are widely used in third-world countries. Both are reasonably inexpensive, with the LifeStraw Family about $85 and the Sawyer Point ZeroTwo at about $120.

We won’t be recommending the Berkey, despite its popularity among preppers, mainly because I’m concerned about its design/engineering. The LifeStraw and Sawyer units use tubing from the source container to the destination container with in-line microfilter cartridges, which inherently fail safe. Water cannot get from the source container to the destination without passing through the filter. The Berkey, on the other hand, immerses the filter in a container of questionable water and then allows water that passes through the filter to exit from the center of the filter to the output. That’s inherently a riskier design, and I’ve seen numerous reports of that filter coming loose and allowing questionable water to pass directly into the destination container without passing through the filter.