Fresh Water From Seawater?

[DoChenRollingBearing]

I would be interested in hearing members' ideas on devices or methods to make fresh water from seawater.

Solar stills? I cannot find any in my city.

Reverse osmosis? Any comments?

Water for me is TEOTWAWKI prep item No. 1 for me. When I finish the book (Survivors by James Wesley, Rawles (hey that's the way he writes his name), I'll put up a review here.

 

[pmbug]

I looked around for a non-electric (campfire) steam distiller, but the only one that I found that I liked is no longer being made. The few that I found that are available seemed too small / light duty for my taste.

I ended up buying a LifeSaver Jerrycan and after using it for a bit (with tap water so far), can highly recommend it. The water it produces is excellent.

 

[KMS]

Elbow Grease <--- Desalinator

Can't vouch for the specific product I linked above, but I will say that one of these is worth every penny for in a BOB.

 

[pmbug]

I actually bought the Katadyn Pocket filter too, but have not used it yet. The Lifesaver products actually have a better filter than the Katadyn and don't require iodine or additional processing to make safe for drinking.

 

[KMS]

I actually bought the Katadyn Pocket filter too, but have not used it yet. The Lifesaver products actually have a better filter than the Katadyn and don't require iodine or additional processing to make safe for drinking.

:agree:

Katadyn Ceramic
Ceramic filters have a micro porous structure with impregnated silver which delays the growth of bacteria. The pore size of Katadyn ceramic filters is 0.2 micron (0.0002 mm). Bacteria range in size from 0.2 to 5 micron and like protozoa (1 – 15 micron), are efficiently filtered out. Ceramic filters can be mechanically regenerated and the filter capacity is measurable.

LifeSaver:
The bottle's interchangeable filter can purify between 4,000 and 6,000 litres (1,050 to 1,585 gallons).[2] It filters out objects bigger than 15 nanometres—including viruses, bacteria, and heavy metals.[3][4] The carbon filter does not require chemicals.[4] The process of filtering the water takes 20 seconds, allowing for 0.71 litres (1.5 pints) of water to be filtered.[4] Once a filter has reached its limit, it will not allow contaminated water to be drunk.[4] The Livesaver bottle has been used by soldiers for drinking water as well as cleaning wounds.[2][3][4]

To filter the water, one puts contaminated water in the back of the bottle, then screws the lid on. The lid has a built in pump which is operated manually with a hand, the pumping action forces the contaminated water through the nano-filter and safe drinking water collects in another chamber in the bottle. The drinker then opens the top of the bottle from which safe drinking water comes out.

A much larger version of the Lifesaver bottle, called the Lifesaver Jerrycan, has the same filtering technology. The can allows for the filtration of 10,000 to 20,000 litres (2,650 to 5,300 gallons).[7] One jerrycan filter can provide water for four people over a three-year span

After some research I would have to absolutely agree that Lifesaver will be better investment than the Katadyn brand.

I'm sure you would still need a desalinator as step one in the process if you will be using a salt water source.

 

[DutchR]

A Katadyn filter will not remove salt: "The Katadyn Pocket does not remove dissolved minerals or chemicals. Therefore, sea water or brackish water is not desalinated. Nor is water softened by removal of the hardness, minerals, calcium and magnesium, normally considered beneficial in water for drinking and food preparation."

But distillation is a simple process.

DiY: stovetopstill

Or maybe you can order a watercone when they are available again.

Have no experience with reverse osmosis but I know the units can be costly but the water quality is excellent, they use them on ocean going yachts so maybe that's an option to look at.


ps. i bought a katadyn pocket filter 2 years ago just in case, filters 13.000 gallons so should last me the rest of my life (I'm at the half century mark) have not used it yet, it's in the bug-out bag, and although it was pricy I find it very comforting to know that whatever scenario unfolds I can have potable water, after all it's the next thing, after air, you need to survive.

 

[pmbug]

Oh cool. Thanks for those links. I like the watercone design. Very simple.

 

[DoChenRollingBearing]

OK, I just emailed the makers of the watercone:


Dear Mrs. Batra,

I learned of your company from the pmbug.com, where a small group of us are interested in your watercone product.

Please advise price and availability of your product, I am in the market for one or two easy to use solar stills.

Thank you very much.

 

[KMS]

The reason I did mention that neither the Katadyn or the Lifesaver would filter salt water is because after one attempt your filter would most likely be kaput. Just so you know that I never intended any filter besides a strict desalinator for sea water.. see first post.

 

[DoChenRollingBearing]

I just got an email of interest re solar stills:


Thank you for your interest in our watercones.
We are out of stock here in the US at the moment and are awaiting a new shipment of watercones around the beginning of January 2012. We are also in the process of relocating our office from Utah to Florida and are still assessing new shipment companies here.
The single price for a watercone is $69.
Two - nine watercones is $64 per watercone.
As of 10 watercones, the price drops dramatically to $59 per watercone.

I will be more than happy to put you on our pre order list and will contact you the moment our office is settled in here and the new shipment of watercones has arrived.

Best Regards,


Bona Batra
Sales Director
MAGE WATER MANAGEMENT North America, Inc.
USA

Tel: +1-407-403-5750
Fax: +1-703-349-1357
Website: www.mage-watermanagement.com

Managing Directorsr. Markus Feil, Mirco I. Richardson

This e-mail may contain confidential and/or privileged information. If you are not the intended recipient, or, if you have received this e-mail in error, please notify the sender immediately and destroy this e-mail. Any unauthorised copying, disclosure or distribution of the material in this e-mail is strictly forbidden.


(end her email to me of this morning)

---

EDIT: I see above text has a ¨:¨ and then a ¨D¨, so the toothy grin between Managing Directors and Dr. Markus Feil... SHE wrote it, not me! I´s INNOCENT I tells ya...

Edit (pmbug): email address removed per forum policy

 

[ancona]

DCRB,
I found this on-line.

http://www.thefoodguys.com/solarstill.htm

It looks pretty durable. I would not want to use any of the 'soft plastics' for my water production, because I am afraid of teh chemicals that may leach in to the water. I think I would prefer glass to be the media where water condenses and would prefer that a metal catchment be used over a plastic one.

Water production is the single most critical prep one can make, and the topic deserves a lot of discussion.

Thanks for posting this DCRB

 

[rblong2us]

Most of this discussion seems to assume a degree of mobility is required and in a worst case situation I have to agree that Jerry Lifesaver is the best bit of kit I have seen.

I have read 'somewhere' that nanotech is capable of creating filtration that will remove dissolved salts but have not yet seen any available.

When this type of filtration becomes available it will be a game changer and suddenly there will be enough fresh water for everyone, as long as we can pump sea water to where its needed.

'Bugout One' has just gone onto its own private water supply -

The nearby moorland quality tumbling streamwater is filtered down through streambed material into a length of 150mm dia plastic land drain wrapped in geotextile to further strain out lumps. This is all hidden from sight and is about a foot below the stream bed level.

A small pump hidden in a chamber about 30m away from the stream draws water through a 25mm pipe with footvalve, sends it through a primary filter to a redundant hot water tank, that just happens to have a built in air pocket system that acts as an expansion vessel.
A pressure sensor switch sends power to the pump when pressure drops to 2bar and stops the pump when the tank is recharged to 2.5 bar. ( this is when the air pocket gets squeezed and means the pump cycles less often ) After leaving the store tank, the water flows through a ( cheap) Chinese Ultra Violet chamber and into the underground distribution system. All the above is hidden in another underground chamber.

Drinking/cooking water is further filtered in a simple undersink twin pot filtration system, one ceramic and one carbon, that claims to remove particulate down to less than one micron.

So far I have not had any 'adverse' reactions and the water tastes bloody lovely.

Probably just a long winded way of saying identify your water source, then set up your own pumping and treating, rather than identifying a filtration system then hope to find something to put through it.

 

[ancona]

From a survival standpoint, presuming that burning a fire to create heat will draw undesireables and that electricity is unavailable, I would feel comfortable with the smaller solar stills. For long-term survival, I think a simple still could be constructed with a hot water heater tank and a little piping.

 

[DoChenRollingBearing]

Here's another that I found via a link that ZH's "Rocky Racoon" sent me:

http://www.epsea.org/stills.html

To be of ANY use to me, it would have to be brain-dead stupid to get / build / use.

 

[suibhne]

I just got myself a British Berkefield gravity filter, and I've been very impressed so far. It won't do sea water but is used by a lot of aid organisations where they need something portable, reliable, and which will work without power. They seem to come highly recommended.

http://kernowrat.co.uk/page10.html

 

[DCFusor]

While I agree with ancona that plastic is bad - the plasticizers aren't nice chemicals, there is a bit of an engineering problem with substituting the plastic front that lets light/heat in and condenses water, with glass. Glass stops IR coming in (or out) - and heats up doing it. It has less thermal conductivity due to being glass, and being in general thicker. This means the outside air will cool it less, and it will condense less water all other things equal - but they're not - less heat gets in too.

The bad stuff they put in plastic does leach out, no question - people who think bottled water is a good idea make me wonder...even without that, the regs mean it might not even be as good as your tap water anyway.

On the other hand, a simple rule of the conservation of stuff says that if it leaches out, it gets gone. If it stays, it's not leaching out - can't have both. One could make a very reliable guess that after some time in use, pretty much everything that was going to come out of that plastic already had. In other words, it might be fine after a break-in period. Some sorts of plastic also have less or none of this junk in them from the start - plastisizer is used more for the plastics that need some flexibility - so polycarbonate or plexiglas might have a lot less than the junk they make water and soda bottles out of.

So if you were going to design and build one of these - you might take this into account. My guess would be plastic film would be nearly the worst material there is from this point of view, since it's meant to be super flexible.

 

[ancona]

Perhaps Lexan, which is by far the most stable form of plastic. I would suspect that very little in the way of plasticizers will leach out of this material. However, it is VERY expensive relative to the alternatives which would include acrylic sheets and plexiglass.

 

[DCFusor]

Fyi - lexan is a Tm trade name for polycarbonate. Plexiglas is the same for acrylic.
Like "pyrex" means "borosilicate glass" - but only Corning can call it Pyrex, Kimble has to call it K-33. Neither plastic has any plasticizer added at manufacture, but some of the catalyst that makes the monomer polymerize might be left, along with whatever mold release agent. Clean before using!

No matter what - I'd ditch the first few batches if that worried me. The nose is pretty good at detecting that kind of thing.

 

[ancona]

Do you think my Berkey would catch the release agents, et. al.? It has the dual, up-down filters for flouride etcetera.

 

[DCFusor]

I don't know if I'd trust a filter (which might itself have leaching-things in it). Our experience here with them - admittedly with much more contaminated water, was that to the extent they work, they fail. They get full of junk, and more often than not, that junk finds a way to support something growing in there - even the ones with "anti-bacterial" characteristics. You wind up spending a fortune to replace elements - which are a point of failure if things go bad - the supply might dry up. We struggled along with a multi stage setup (so as to collect most junk in easy to clean elements first) for a few years, but gave it up as not being worth the effort - easier to just collect better water in the first place, even if you have to transport it some.

I think the thing to do would be to find out if there's a problem, if so, what it is, and then work on how to mitigate it. I might be able to find out what they use for mold release (probably a silicone "mostly harmless?") for example, so as to just get rid of it before putting the thing in operation.

I can get sheets of plex .080" thick (the thinnest that's easy to find) which would make a good inlet/condenser window. It's about time that I go over to the wood shop guy and brainstorm a unit that could be built easily so we can just test one.
Nothing beats a guess like a test! I'd have to look around for thin polycarb, which would almost certainly be better for this.