Going off the deep end – urine filtration in the backcountry?

Have you seen the movie Dune? If you can invent a functional Still Suit you would have many customers in desert areas of the world.

I’m not a registered scientician, but I’m pretty sure removing germs (what a Sawyer does) is completely different from removing salts and whatever else is in urine.

removing germs (what a Sawyer does) is completely different from removing salts
Correct.

Can I lodge a personal plea here: ‘scientist’, not ‘scientician’!

Cheers

I am a registered engineer, and yes, our backpacking filters remove chunks (like bacteria and viruses) and do not remove dissolved salts, sugars, urea, nor (once the urea decomposes) ammonia.

If you’re peeing a ton, then those compounds aren’t in very high concentration and you can drink away!  But for those situations, you could have just drunk less water and still have fresh water to drink.

Activated carbon has a very low loading rate (is very inefficient at) adsorbing ammonia or urea, so that doesn’t help.

Even with fancy-schmancy aquaporin transport of water only across something akin to a cell membrane, you have to provide some driving force to overcome the entropy of mixing (which favors impure mixtures).  That driving force could be high pressure (like membrane separation) or a vacuum but those both required pumps and power.  It could be some solute you don’t mind (sugar?) being introduced on the clean water side, but now you’re trying to create a desert pack rat’s kidney with “stone knives and bearskins” to quote Spock.

The two easiest uses of urine in a desert environment that occur to me are (1) apply it to your clothing for evaporative cooling, causing you to have to sweat less.  I find doing this with stream water works well, allows me to sweat less, therefore drink less and I find it less fatiguing to dribble a pint of water on my cotton shirt and bandana than to sweat out a pint of salty water.  And (2) set up a solar still (google that) with the urine under the clear tarp as a source of water.  That will be a slow process (you’d have to stay in one place) and while it would leave salts and urea behind, ammonia would contaminate the “clean” water because its vapor pressure is so high.  I suppose you could pour the resulting water from container to container to volatilize most of the ammonia away.

I’ve considered single, double- and triple-effect distillation for use sea kayaking in Baja California – bring more fuel to make fresh water from sea water.  It all pencils out, but adds several pounds of gear and then you’re relying on that equipment for your survival.

I liked “scientician” as a term, in that kind of jokey context.

It’s a Simpsons reference.

The solar still is one of those survival things that seem to work best on TV than in reality.

It takes a lot of energy and sweat to make one for the possible outcome.

Don’t believe me ?

Start digging.

(you may not have that very convenient hole in the ground next to you)

Sure. Douse myself with my own urine to keep cool. Or drink it straight up or filtered. Just gag it down because I’m saving weight.

OR: carry the appropriate amount of water. Clean, clear water. And avoid survival scenarios to begin with.

The idea is to stay cool smelling of piss.

cool.

As an applied scientician of health care trained in the mysteries of nephrology and urine production, I concur with MJH and David.

Oh, I’d definitely filter it first- Through the earth and drink it next year.

Thank you for that plea, Roger.

I read about what NASA was planning with recycling pee. Let me put this as clearly and simply as I can… HELL NO!!! Under NO circumstances will I EVER chug a 1 liter Nalgene bottle of pee, recycled or not. Not in space! Not on the trail! Not anywhere! Not me, EVER! Those of you who want to try it, knock yourselves out. LOLOL

Hi Kendall

But you DO drink recycled pee, all the time. The pee from one city goes into the river and is extracted by the next river downstream. It is filtered and treated and supplied to the residents for drinking.

Failing that, the pee evaporates into the air, forms rain, falls and goes into the river, where the next city …

Just think – you are drinking the pee from every politician that ever existed. What an interesting thought. Also from every barbarian invader, every victim of the Black Death, every soldier who died in every war, every …

Fortunately the water has absolutely ZERO memory of where it was previously, not withstanding the claims of some idiots and frauds.

Cheers

You guys let your sewage right back into a river?

I get that  we are for the most part (…) in a closed system here on earth but it’s not quite like that in our neck of the woods.

“Just think – you are drinking the pee from every politician that ever existed.”

Well, they’ve been feeding us copious amounts of bullshit for ever, might as well drink their pee too….

Some cities are now treating sewage and feeding it back to drinking water.  Some in Southern California for example.  Without putting it into river first.

Kat: Cities along the Mississippi come to mind.  Where do they get their water?  From the river.  Where do do they put their waste water (hopefully after from treatment)?  Into the same river.  Downstream of themselves, but upstream of many others.

The solution to pollution is dilution.

It’s an interesting order-of-magnitude calculation to figure out how much water the dinosaurs drank and peed out over 186 million years.  The answer is, by my calcs, about half of it.  Human urine (from our species time and population on the planet) is only 0.0007% of rainwater, but higher in lakes and rivers in settled areas.

Thanks David. It is true that I don’t know how things work in other places. If it is treated then it is no longer urine. Like eating veggies that have been composted with some manure…we are not actually eating the poop, just some of the minerals.

Here at home it’s septic tank and leach field, so a  long way from the creek which runs into the ocean.

Here at home it’s septic tank and leach field, so a long way from the creek which runs into the ocean.
Nonetheless, the leach field DOES end up in the creek. That’s what creeks are. It’s just that most people prefer to shut their eyes to reality.

We use our deep dam for all non-drinking non-cooking water, and rainwater from a tank for drinking and cooking. The dissipation trenches which empties our septic tanks was placed effectively to the side of the dam so it does not drain into the dam – but of course it does drain into the creek which handles the outflow from the dam (WHEN it rains). That said, there is about 100 m of deep soil between the trenches and the start of the creek. It works.

Eh – we were walking in Nepal years ago, and the toilets in one village were built on stilts OVER the river. Pretty wild rivers there, with a lot of oxygen being absorbed. Still, we got our water from a high side creek.

Cheers

“I’m not a registered scientician”

Is that similar to a scientologist?

Is Tom K short for Tom Cruise? : )

“Nonetheless, the leach field DOES end up in the creek. That’s what creeks are.”

That is not “what creeks are”. There are creeks and creeks. What goes out our leach field will never make it down to the creek. We live uphill from a redwood forest, a meadow and another forest that will it take up and it just isn’t enough water to begin with. We don’t have that geology.  Sorry you are wrong here . People closer to the creek are not allowed to have leach fields around here. In many areas they do but assuming you know how it works everywhere else is an issue.

I know the topography of where I live.

Growing up as a kid in Southern California, private pools frequently had a sign that read:

“We don’t swim in your toilet so please don’t pee in our pool.”