UKC

So was out in the hajjar mountains this last week - incredible incredible place, but we were late in the season and found lots of our marked water resupplies totally dry. The only water sources we could find were fairly green and gross, literally the last few litres of water in open pools. 

...so we filtered it through a cloth to get the bugs/sediment out and boiled it up... we then planned to use out Kathryn be free bottles in order to try and make the water less green (...algae can be toxic I thought...), but the damn bottles just kept getting completely clogged as well as a lifestraw we had with us...so we ended up just drinking the boiled greenish water for a couple of days. We were away from any agriculture or anything like that which could have put chemicals into the water...but still the whole thing felt kinda mad...

The more I think about it in environments like this, the more I'm not convinced of the lifestraw/katryn idea - they don't filter viruses anyway so what's the point of them?

In the future I think I am going to go back to carrying a dedicated filter for this kind of thing. The whole episode gave me major anxiety - at one point I really thought we were totally stuffed and might end up having to call for rescue or walk out by night with not a drip of water on us.

I have read bad things about devices like the MSR trailshot as being unreliable and also easily clogged by sediment. The MSR guardian type devices are huge and heavy.

Does anyone have any good recommendations? 

Sounds like you need to sediment out the gunk before treating it. You could try using chitosan (food supplement) to flocculate the particles and they should then sediment quickly.

You can then boil or filter the water.

Could try a course filter before you start with the techy bits, pore it through a teeshirt or similar, need a wide mouthed container to catch the filtrate, pan might work.

I can't remember what it was but I've seen chemicals used that have a negative charge so they clump all the contaminants together which then all sink to the bottom. 

A flocculant, as mentioned above. Aluminium sulphate is used for this purpose in water treatment works, both industrial (water companies), and those with local domestic supplies. They will remove tannin discolouration, too.

Once you’ve filtered all the solid particles using a course filter and the green scum using a fine filter, would iodine (not betadine) either in liquid form or tablets work?

Msr guardian is heavy but it's like carrying equivalent to 500ml'ish bottle of water which gives you unlimited water from sketchy sources, cleans itself with every stroke so no backflushing ever and can handle abuse, the only maintenance I've done on mine is teaspoon of bleach when storing, worth the weight imo

Probably not the thing for filtering on the go, but one of the old-school filtration bags (Mills bags?) could be worth a try as a more effective passive alternative to t-shirts or chemical flocculants - then run through your Lifestraw or equivalent (or boil)

Millbank bag. A Ventile bag, essentially.

https://paulkirtley.co.uk/2011/how-to-use-a-millbank-bag/

Depending on the growth, I don't think filtering will remove all the toxins from cyanobacteria etc (it will remove the cells, but some toxin leaches into the water. They are heat stable, don't know about effect of chemicals). Obv you are fine if there are no toxin producing organisms present but there isn't an easy way to tell. If toxins are present you know pretty soon.

I looked into this a while back, I basically came to the conclusion that nothing you can carry will deal with the toxins. All you can do is avoid water with blue-green algae in it.

Interesting - thanks.

Yeah, my brain was trying to prompt me about blue-green algae...

I don't know how practical it would be, but if the water's that bad perhaps distillation would be a better bet.  Some sort of solar still perhaps?

A solar-powered "portable" ultrafiltration+carbon+RO+AOP purifier could be probably put together for a total system weight of 50 pounds, you should be able to carry that

Thinking back to Ray Mears and Lofty Wiseman bushcraft type survival videos we watched in scouts, you can construct a simple water collection system that is essentially a still using a plastic sheet and a few stones.

Dig a hole, put your water collection pan in the middle then stretch your plastic sheet over the hole holding it tight with stones and place a pebble above the pot. Leave this over night and the moisture from the warm earth with condense on the plastic sheet and run down to the pebble above the pot before dripping in. I'm not sure about the yield.

Unless you have a gigantic sheet, you'll probably get a mouthful at best. Can be improved by putting lots of fresh vegetation in the pit (pull up plants, fresh leaves from trees, even grass) - there's a lot of moisture in plants.

That's the kind of thing I had in mind when I posted.

Very poor indeed I think. 

Looking into it a bit, there is a commercially available inflatable thingamabob, mostly aimed at being emergincy kit in the life rafts of ocean-going yachts to provide drinkable water from the sea whilst awaiting rescue.  They reckon to get a useful yield and they're just about packable, but I guess it's essentially a single-use device as I don't see how you can clean the inside of the thing and it'll be pretty minging after a while being topped up with sea water let alone green goop.  (And it looks like the 'dirty' side will immediately contaminate the 'clean' side the moment it's packed away after its first use.)

I think if you were planning ahead (instead of improvising with a plastic sheet) you could probably come up with a design that would work better and still (just about) be portable.  I'm picturing something with a black tray for the dirty water, a metal sheet to gather condensation on the North side and plastic sheeting to make a sort of greenhouse on the other three sides.  Dunno.

Perhaps you could use a stove or a small fire to boil up the goop and push steam through a condenser - that might be as simple as a pan with a tight-fitting lid and a length of tubing to take the steam off and run it through a bath of the cool goopy water before delivering the condensate into a bottle.  Rather pointless if it meant carrying extra fuel where you could just be carrying extra water in the first place though I guess.

You want to increase the surface area for aid evaporation, so some wicking material. 

This is one of of those myths.  I seem to remember either Ray Mears or that Grills bloke demonstrated how useless it was.  Essentially it takes more sweat to dig the whole and set up the system than you'll reclaim from the water produced, plus you need to hang around for a long time for the slow evaporation process to produce more than a dribble of potable water.

I would suggest a "Sawyer Mini" and an "active carbon" filter (life straw?) for the toxins in a two stage process.  Monkeys often raid camp fires in some areas to get the charcoal which they then chew to neutralise the toxins in many forest fruits - how they learned to do this goodness only knows. 

The Sawyer Mini will remove particles and bacteria and can be back flushed with the included syringe and a little clean water.  If you get one don't squeeze the bag it'll burst the seems, roll from the top down in a tidy manner, squeezing as you go.  If you're then nervous you can use your life straw to slurp the pre-filtered water from your bottle.

We carry a Sawyer Mini weighing around 60 grams in the hills in the summer to reduce the water load, refilling at the last high water point, and refilling again at the end of the day before the long walk out.  Unlimited water - nice. 

If you have watched Steve Bachshall's "Expedition" series on the Beeb you may have spotted him and his team using a "Sawyer Mini" with green goopy water similar to that you describe in the Jebel Akhdar mountain range of Oman episode whilst canyoning.

You can get a Sawyer Mini on Fleabay.  For specs visit the Sawyer website: https://www.sawyer.com/product/mini-water-filtration-system-black

I was in Nepal in OCT last year ... similar problem.

This is a good info graphic that we used to base our decisions upon:  https://www.cdc.gov/healthywater/pdf/drinking/backcountry_water_treatment-5...

We ended up on a 2-part/2-stage process - either:

• Filter + tablets
• Boil + tablets

Boiling is the best ... but:

1. Uses fuel - lots of fuel.
2. Pain in the a55 ... you need to leave water sitting around to cool afterwards.

We used Chlorine Dioxide tablets (not chlorine ) ... which weigh only a matter of grams ... to deal with the parasite (Gardia/Cryptosporidium) level stuff.  Lifesystems or Katadyn make them.  

You need the right number of tablets for the volume of water you're making .. and you need to leave them in long enough to do their work.  My recommendation would be to make your water at night and leave the tablets in overnight.  Hydrate well when you wake up, filter/boil new water & add new tablets and that's your lunch water... repeat for dinner.  Particularly contaminated water will inevitably need more tablets.

IMO ... many of the filters you mention are going to struggle with water containing large volumes of large particles.  Most of them are optimized with super fine filters designed to screen out things like Gardia and Cryptosporidium at the microscopic end of the spectrum ... the flip side of that being that they'll clog if you put really dirty water through them.   

Reading your post ... it sounds like the question is "In an emergency backcountry situation ... how do I first get the large particles out of the water ... so that it's ready to be filtered properly?"  Perhaps a makeshift sand/charcoal filter would have worked to filter out the largest stuff and kept your Be Free filters working ... ???

https://www.h2odistributors.com/info/how-to-make-a-water-filter/

Actually ... google "hiking pre-filter".

You get stuff like this ... a sponge really:  https://iconlifesaver.com/products/lifesaver-bottle-pre-filter-sponges

Also, checkout fine mesh filter bags used for brewing.  A search for "brew filter bags" will be good.  these are light, easy to pack, and can remove the larger particles.  Turn inside out and rinse/ back flush after use.

Ahhhhh!!!!

Check these out ... a pre-filter (sock) for your Katadyn Be Free: https://a.co/d/0MNbxKR

Great idea!  No idea if it works though ... 

The filters like the Sawyer will take the algae and bacteria out, but not the toxins secreted by the algae. Charcoal/carbon will bond with the toxins and hold it but it takes a large amount of carbon something like 50 molecules of carbon to each one of toxin. The little inline carbon filters will work but you have no way of telling whether there is enough carbon un-activated or not. Unless you change the carbon filter very regularly, like daily, they're a bit of a gamble. If you're going somewhere where water could be a problem planning ahead and even carrying it in is essential. 

Pre-filtering your water with something like a millbank bag will keep your sawyer filter running much better. 

Great idea.

This is the situation where an old-skool mill bank (?sp) bag as the first stage is useful, and not too much extra weight. I think any filter, no matter how pricy, would clog up with this type of water, and one that covers viruses would be worse, as the filter size is smaller.

(Edit, see at least one above me had already suggested a Millbank bag!)

Viral filters overkill in places like the UK, where the concerns are usually bacteria and Protozoa. I use a BeFree regularly here in NZ. I found the trail shot more hassle with no extra benefits. I only have a viral filter for overseas to remote or tropical areas.