The argument about being able to drink a certain amount of sea water per day may stem from the fact that, normally, people consume (more than) a recommended 3 grams of salt per day with their food. Your body should be able to cope with this amount of salt because it needs it as nutrition. If you are floating around in a life raft, you probably won’t be consuming this level of salt (unless you pack some food along with you, but then you should have packed water, too ). So, maybe your body is able to cope with a certain amount of sea water by simply using the salt as nutrition instead of just getting rid of it through urination.

Of course, that whole spiel was purely half-educated guesswork and could be totally full of crap. Enjoy!

Obviously it works and provides a drinkable liquid, my concerns/questions are:

What is the osmolarity of the processed liquid if the input side is fully loaded?

If an insufficient amount of input material i.e. urine is used, is the processed solution of such a high osmolarity, that by drinking the solution could one become dehydrated?

Is there a minimal amount of input solution listed on the device to prevent the osmolarity of the processed solution being too concentrated?

What is the caloric content of the syrup?

Pete

Just some educated guesses from me. I think it's safe to assume that the proccessed liquid will have an osmolarity higher than seawater to initiate and maintain forward osmosis as the output volume increases and dilutes the syrup. Depending on what reference you consult, seawater's osmolarity can vary from roughly 1,000-2,500 mOsm/L so the processed liquid's osmolarity probably falls roughly into this range, too. Just for reference, the body's normal osmolarity is roughly 300 mOsm/L.


In the FAQ for this product, it already advises users to sip the processed liquid, and to space out the sips, so even when fully loaded, the manufacturer already knows the processed liquid is concentrated enough to potentially cause dehydration, so I think it's safe to assume (there I go assuming again) that the answer to your question is "yes". At least, unlike sipping seawater and getting all that extra salt, the high osmolarity of the processed liquid is primarily from sugar and not salt, so at least your body can do something useful with the sugar.


The website lists 480 calories.

Thanks Arney for the info, I should have looked a little closer at the site.

I was hoping in part, to use the questions as a mechanism to encourage some dialog amongst the members and especially with Rick regarding some potential pitfalls/issues (in addition to those noted at the product site) with the product line.

In the past we have discussed the benefits and risks of various sport/rehydration drinks and thought that we might look at the processed liquid in similar manner.

Pete

I know what you mean. I held off answering yesterday to give Rick a chance to answer instead of just throwing out my educated guesses. I'm still hoping that he can clarify some of the points.

You do raise valid questions, Pete, and I'm glad you thought of them. We're not creating "Kool-Aid" here, it's something much more concentrated than that and not something to just chug down when you're thirsty and stuck somewhere.

There's definitely a place for a product like this, though, as long as buyers are aware of the pros and cons. I'll keep an eye out for real world testimonials in the future.

I was especially thinking of the use of urine. The site states that the product was not designed for use with urine, but then goes on to say urine has been used successfully. I would think that the amount of urine produced by a group of people might be sufficient to ensure the processed liquid was not too concentrated, but if only one or two individuals were contributing, the resultant processed liquid would be extremely hypertonic.

From what I can tell from the web site the two smaller units require 1.8L to achieve whatever final hypertonic dilution the syrup is designed to process. As noted, consumption of even this diluted liquid should be carefully controlled. This would pretty easy with seawater being the source of input, but 1.8L of urine is quite a lot of urine. Even one-half or 0.9L/900ml of urine is a fair amount and would result in the processed liquid having twice hypertonicity of the regular 1.8L input.

I was just wondering if there is a warning to tell consumers not to use less then X amount of input, otherwise the resulting processed liquid would be dangerous to consume, due to the acceleration of dehydration.

Pete

Sounds like it stuck in life rafts to me.

I was really hoping this would be able to be more useful for dry land applications, particularly with chemically contaminated water, but without a field expedient option for the syrup and minimum volume requirements, it sounds like it really isn't suited for that mission.

I would think that if you had a ‘starter” amount of clean water and regular sugar, you could improvise the syrup. With this combo and large amounts of contaminated water, I think use of the product on land would be feasible. I would just be cautious about drinking large quantities of the processed liquid, especially if under diluted.

Pete

Hi guys,

Sorry about the 2 month delay in getting back to you on this. I almost forgot about this board until I was checking up on what I needed to respond to.

Please visit the Expedition site. Based on your questions about output amounts I have updated the information on the site to provide more detailed information on what the Expedition can produce.

specifications...

Volume: 3 liters of drink - 2.5 liters of dirty water - Produces 25 liters of drink from syrup provided with system
Filter life: 30 - 90 days
Filter output: 1 liter an hours at 20 C
User effort: seconds to fill, no work required for filtering

I also have new videos for you to watch. http://www.sea-pack.com/video.html

Yes, you could produce the syrup yourself as it is made from dextrose. I suppose with enough effort an money we all could produce almost anything ourselves, but why take the risk?

Please let me know your thoughts.

Rick