Where the heck have I been? Well, no Big Walk for 2012 sadly, but the project that I’ve been on about for years is under-way, though still in the early stages and still off topic for this blog! Though I’ll certainly do a post or two mentioning it at some point (there may even be a clue on Twitter eventually @RedYetiDave ) since it’s obliquely related to the outdoors…
I’ve been reading, with great interest, the excellent series of articles on backpackinglight.com on water treatment options (sorry, subscription only). There was a heck of a lot of info, as you’d expect from a series whose main author is Roger Caffin and which included Will Rietveld in the contributor list.
One really important point which made me pretty angry: Aquamira drops only kill cryptosporidium after 4hrs exposure.
What? So the main thing that I’m trying to avoid in the UK hills is actually not cleared by the drops in 30 minutes as they appear to say?
It comes down to the fact that Aquamira originally sourced the liquids from another company who’d only got EPA approval for bacteria clearance. So although it does kill protozoa (crypto etc) it takes longer than they mention in the instructions since the instructions are technically only cleared for describing killing bacteria (and viruses luckily). Grrr…
So after much thought, and reading reviews and blog posts, I’ve decided that the best option is a Sawyer filter. Why? Because they filter all bacteria and protozoa, which are the two main threats where I draw water in the UK hills and even the Alps. They filter water incredibly fast, you can drink straight from them, and are expected to last for four and a half million litres (a million gallons). Meaning it’ should be a once-ever purchase.
I never expected to even consider using a filter again, all that pumping and then cleaning and then pumping etc. etc… But the Sawyer filters use a completely new method: Hollow Fibre; which make all that pumping and cleaning unnecessary. They are essentially a set of straws which you push water through. Meaning their surface area is gigantic, so they don’t block for a long time. Also, when they do block, they can simply be back-flushed with an included syringe, or just from a tap (faucet). Which apparently makes them like-new immediately. The back-pressure very slightly enlarges the fibres, meaning the crud which is stuck in the pores is simply released.
They’re reputed to be very durable indeed though you mustn’t let them freeze, like any other filter. So keeping it in a sealed plastic bag in the sleeping bag for winter camping is necessary.
There are other companies which make filters using hollow fibre but they appear not to be anything like as good or durable as the original Sawyers.
I did also consider the Travel Tap but try as I might, I could not get the company, Drinksafe Systems, to divulge anything on the efficacy of the virus filtering, despite many emails and even phone calls with the owner of Drinksafe Systems himself. I got a couple of pages of reports which certainly looked good on clearing most things, but the line which I was told was relating to virus clearance was only mentioned as “F+ RNA” which from Googling appears to be a broad term which may be applied to virus reduction testing but may equally be applied to bacteria reduction testing.
I would love to think that the Travel Tap does what it says, I really, really want to use it, but without some more solid documentation from them, I’m going with the Sawyer since that’s something well investigated by Roger Caffin et al. (Sadly the Travel Tap isn’t mentioned as part of the backpackinglight.com series and when I asked Roger about it directly he’d not heard of it, and was scathing about any company who would not provide test results).
Perhaps I’ll eventually be able to get access to something solid on the Travel Tap’s virus filtering but until then, I’ll stick with the Sawyer.
If I feel the need to also be sure that I’m killing viruses after using the Sawyer I’ll use either a Steripen Adventurer, or of course the Aquamira drops!