Saturday, January 17, 2015

Water Filter

Those water filter straw things never impressed me.  Someone told me he got a Sawyer SP126.  It claims to be able to filte 100,000 gallons, lifetime.  This shocked me.  Because I used to make beer for a living with 120 square feet of diatimaceous earth impregnated cellulose pad filters and it slowed down a LOT with a 5 micron filter size and 1500 gallons of beer pushed by a 3/4 horse centripetal pump. 

So it seems dubious since pathogenic bacteria is like, 0.5 microns?

But now I am intrigued at the survival kit potential of these things.  Even if I only get 100 gallons instead of 1000x that.


Murphy's Law said...

100 gallons of drinkable water could last 1 person 3 months...or my two dogs a day and a half since they just splash most of it out of their bowl.

Erin Palette said...

Even if pathogenic bacteria was .5 microns, the Sawyer filter has a much smaller pore size of 0.1 microns.

I will confess to being slightly dubious of the 100.000 gallons claim, as that is doubt under ideal laboratory conditions rather than out in the field. But heck, even 10,000 gallons for a filter than costs $20 is damn impressive.

I will point out that filters such as these do require backflushing to dislodge build-up of crud on filter media.

On of my co-bloggers at Blue Collar Prepping is doing a series on the ins and outs of various commercial filters. I suggest you give it a look.

jon spencer said...

The 100,000 gallon claim may be correct, if there is cleaning of the filter when it becomes clogged.
Most modern waterplants, have automatic backflushing to do this.
As long as a filter does not become damaged they last for many gallons of filtered water.

LCB said...

"up too" covers a lot of territory.

I saw Les Stroud (Survivor Man) drink out of a puddle that had dead birds, bird pooh and turtles (with pooh) with a LifeStraw. As far as I could tell (it IS TV) he suffered no ill effects. I'd already had one in my bug out kit, but that kind of sealed the deal. Stroud is always testing stuff on his show, and if they don't work he says so.

But still, for all I know he got an endorsement from LifeStraw. BAYOR. :-)