Something doesn't seen internally consistent in this article. We read about a device, that can be locally assembled, that, can draw up to 25 gallons of water a day (I would have been impressed with 1 gallon a day) - and, "In all, it costs about $500 to set up a tower...His team hopes to install two Warka Towers in Ethiopia by next year and is currently searching for investors who may be interested in scaling the water harvesting technology across the region. "
Why would "two Warka towers" be a target for a year, when, on the surface, reading this - it would make sense to go install a thousand of them and see how they played out over a year. If this device really could pull, even 10 gallons of water a day for $500 cost, it would have zero problem attracting funding on that kind of tiny pilot scale.
I think the main reason is because it's just two industrial designers with no connections to any of the NGOs necessary to get the $500k worth of build-money and probably another $500k to $1.5mm worth of "let's make this happen" money.
Look at the front page of the website it's posted on: http://www.architectureandvision.com/ Half of the stuff there is made-up concepts, not real actual things.
If we were seeing this on the water.org website then yes I would absolutely agree with you that the two units as a "goal" is ridiculous. But since it seems like they have no serious funding yet and plane tickets to Africa aren't exactly cheap I think two units is reasonable.
Perhaps, but I predict limited success. The article talks about being able to install these towers in a dessert and specifically talks about temperature variance, but low humidity environments would still have more lower yield. You can't make something just out of nothing.
It also seems like the fine Playa dust would be another negative. As any Burner will tell you, Playa gets into everything. I don't see any way to avoid getting Playa into the inner chamber which then would require further filtering and refinement to separate from the water.
The best use of this technology would be an environment where ground water isn't safe, but that has a high enough humidity to be able to yield a sufficient supply.
That being said, Burning Man would provide a suitable environment to push this to the extremes and see what it might be capable of. It would certainly help discover how it will break down.
Part of the playa environment would work in their favor (Cold at night, Warm in the day) - but there are two elements in the playa that would likely make these ineffective.
1. Playa Dust - that stuff gets in everything - and this water tower would be choked with the stuff almost immediately. Cleaning it would be challenge (to put it lightly
2. More problematically, the condensation tower/Air well works on the principle of collecting dew that forms on a low temperature substrate. The humidity near gerlach is close to 38 percent, and I don't recall ever seeing much in the way of condensation ever....
I wonder how many problems like his would also exist in a deployment in Ethiopia. Many problems seem much more complicated when you've encountered them firsthand.
Making a physical product that may have to be tailored to varying specific requirements could be difficult, meric above mentioned technology / skill transfer where an assumed solution may not have an optimal effect, or be even be disastrous - I'm sure they're honing an experience set and training and maintenance manual.
Sewage works may be a tangential example. Many sewage treatment plants basically work by sifting heavy material, then using aerobic bacteria to break down dirty water, and anaerobic bacteria to break down the aerobic bacteria (resulting in manure slosh) [a heavily simplified version]. But each plant has varying PH and mineral levels, meaning optimal bacteria are often designed for specific plant locations, and the specialist knowledge required can be very deep.
I see nothing wrong with going it slow, and documenting carefully in a very hands-on way, any hiccup and both 'known unknowns' and 'unknown unknowns' that may be overlooked in a mass roll-out.
I think it takes more than just money to setup the towers. The article mentions maintenance is a big problem for imported solutions, so they'll need to teach locals on how to maintain/build the tower. There aren't too many people who knows enough to build such a tower, so they cannot simply spend $500 * 1000 to get towers for 100 villages, since they need to first teach people to build it and second teach people in each village to maintain it. Perhaps, the first year the target is more than just 2 towers, but learning how to make the tower easier to maintain as well as learning how best to 'sell' the tower to locals.
Everything in the article suggests that this is something that can be done locally:
"If the many failed development projects of the past 60 years have taught us anything,...it's that complicated, imported solutions do not work."
"inexpensive, easily-assembled structure that extracts gallons of fresh water from the air.
"
"The structures, made from biodegradable materials, are easy to clean and can be erected without mechanical tools in less than a week.
And 1,000 towers would be on the scale of "learning how to make the tower easier to maintain as well as learning how best to 'sell' the tower to locals."
If this device was capable of pulling in more than 10/gallons of water a day for $500 capex (and cheaper at volume), I would expect to see millions of them installed across the african continent in just a few years.
Heck - I'd expect to see them installed across the North American continent as well. Some of the crazy stuff we used to do to try and get 5 gallons/water a day when I was growing up - I spent two solid months hand digging a well that barely managed to deliver that much water a day. A $500 "Water Tower" would have been awesome.
Add in the insight that the project was launched in 2012, and the erection itself apparently takes four people a week[1] and you have to wonder why they're so unambitious. I'd speculate that might be down to it requiring very specific local condensation conditions to function with the claimed efficiency, but there's a long and mostly disappointing history of trying to create drinking water from air[2]
According to the article, it's temperature differential that's important. So it works in the desert, which has 50 degree swings between day and night. Many places with high moisture content have much smaller swings in temperature, so it might not work as well in the jungle.
Alternately, the article is incorrect/oversimplifying. It's pretty easy to see that it is at least oversimplifying with a simple thought experiment: Suppose we were to place a Warka Tower in an airtight with a humidity of 0% (no water in the air) and with an air temperature of 120°F. Then suppose we were to drop the chamber temperature to 40°F. By all accounts, this is a huge change in temperature for a human-habitable region to undergo (an 80°F change), so the tower should produce a LOT of water. However, because the air in the chamber has so little water actually in it, very little water will actually be produced. Ultimately, what makes the tower work well is a large temperature change and a high humidity.
The point is that this is a fog harvesting device; it collects tiny droplets of water in the air efficiently. Fog is where you have > 70% (roughly) humidity, even if its only for a period of time.
Deserts have highly variable humidity, often 10-30% during the day, and great at night; maybe 50% ... but you dont get fog in deserts, or, for that matter, in many other places.
In some very specific regions, like Ethiopia, where you have misty mountainous regions; this is a useful device (see the article for the other very misty locations they talk about deploying this in).
If you put it in your backyard, you'll probably get a tiny trickle from it occasionally, unless you live in Wales.
I believe that my argument remains a solid, semi-logical rebuttal (it does depend on some physical intuition) to the claim that we can fully trust the original article's claim that the effectiveness of the device depends only on the temperature differential at the location where it is deployed. At the very least, the claim needs to be demonstrated in the field or explained by some documented physical phenomenon before I'll completely trust it.
Not really; the desert temperature differential isn't really relevant afaik; it's just to drive the air down below the dew point to generate droplets. If there's already a high ambient moisture content in the air, I can't see why it wouldn't work. This is a just a structure to collect droplets, and there are plenty of those in the jungle.
The ones in the article look like they're cheaper, possible to construct with local materials, and importantly: more user friendly - you don't even need a droid that understands the binary language of moisture vaporators.
I am curious how a project like this, which has been around since July of 2012 [1], gets such an intense amount of media coverage all in a the last two weeks: Wired, Daily Mail, Smithonian, Engaget, Huffington Post, and now HN. [2]
The concept of air wells has been around for awhile, but it's good that they're able to keep the costs low and build it from local materials with local labor.
Isn't the generated/collected water like condensed water free of any kind of salts etc. that would naturally occur in ground/drinking water, so shouldn't it be unsafe to drink large amounts of it (much like it is unsafe to drink large amounts of salt/sea water due to the saline imbalance)?
Everyone needs to eat salt, and does. If there isn't any salt in your water, then you need slightly more salt in your food. But only very slightly more; drinking water is not very salty.
Just to be clear, I meant that water collected from pure air should have no salt in it at all, so drinking large amounts of it will be unsafe as it will draw those salts from your body (osmosis and diffusion), just like drinking large amounts of seawater might increase your blood pressure, but more importantly, it's very hard for your body to get it out of your system, your urine produced by your kidneys is not saltier than saltwater, so you need more water than you can drink (with seawater) to get it out again.
So my original question still stands, is it unsafe to drink large amounts of water collected from pure air and do they have to take care of that in any way? Or will simply eating salty food fix it? I still have not found an answer in the article.
It's dangerous if you're dehydrated and drink a lot of soft water (that's the term for water with low/no mineral content) at once, otherwise it's okay as long as most minerals come from the diet.
Tap water in most places has a GH/KH of 0 (to avoid clogging pipes with carbonates) and nobody dies from it.
Specifically, if your body is low on electrolytes it will hold water until it gets them and that holding of excess water causes problems. However, almost any amount of food is sufficient to prevent that.
However, in this case I tend to doubt the water will be all that pure due to dust; I'd guess it will actually have a decent mineral content. Commercial water purifiers often produce mineral-free water and the only issue I have heard of in connection with this (at least as long as you are eating any food) is that most people find that the resulting water tastes bad. Adding minerals back is not difficult at all.
Edit: Sounds like it is a little more complicated than that; the WHO paper that the Wikipedia article that sbierwagen cites is a good read with 16 pages on this topic. One thing they mention as a potential issue is that cooking food in low mineral content water can leach minerals from the food. If the food is then consumed but the water isn't, that would lower mineral intake (discarding water used in the first cooking of some beans is necessary because it removes toxins from the beans but these beans can be a good nutrient source, so this could still potentially be an issue where water is scarce). The Wikipedia article could be skipped, though, so here is a direct link to the paper:
http://www.who.int/water_sanitation_health/dwq/nutrientschap...
Drinking water is supposed to be good health if the salt content is between 30 to 50 parts per million. If we speak about details the salt content present in water is supposed to be source of some minerals which you might not be able to get from food. It can also be supplemented with vitamin tablets but that would make distilled water not ideal drinking water.
The issue with deionized water isn't what your GI system will or will not absorb. The issue is that the water may absorb minerals and nutrients from you.
I have to imagine that this is easily combated if it proves to be a significant factor. Worse case scenario, now that you have water that doesn't make you violently ill, you have more energy to farm/eat nutrient rich foods?
We are talking about trace quantities of salts though. You could get around any measurable problem by passing the water through a large box full of pebbles. Also, water is for agriculture as well as drinking, so this should increase the stability of food supply anyway.
I don't agree with not having local repairmen as being a real showstopper. Any new system requires training: fire building, hut building, brick making. They need to factor training into the roll out of the technology, and don't focus on training men, take the women and grandmothers, train them first. RE: The barefoot movement in India: http://www.ted.com/talks/bunker_roy Tell a mother she doesn't have to walk 6 hours for dirty water, she will learn to fix whatever is necessary given the right training and availability of tools/material.
Agreed, it's probably the opposite. Folks that are struggling out of necessary tend to have respectable DIY artisans that are very resourceful and creative in the truest sense of hacker. (When you don't have much, your ability to think of creative solutions based on what you have becomes very acute.)
Has anyone tested the long term viability? Contamination, dust, mildew, flies etc.? Seems like a good idea but I venture the water would need further processing. Still, looks like a better starting point than where many communities are now.
The amount of time matters. The 5 hours required for solar disinfecting is far less than the time a plastic bottle will degrade in the sun and contaminate the contained liquids.
Polyethylene terephthalate (PET - commonly used for soda bottles) can withstand direct sunlight for 5 years. There's leeching occurring throughout the degradation, and I can't find any trustworthy research on leeched PET harm when ingested repeatedly over a lifetime, but a few hours in the sun is pretty far from the danger zone.
All things equal, I'd rather deal with a small risk associated with pollutants leeching from the bottle, than the much higher risk associated with diarrhea-causing organisms in the water.
Yeah, I was thinking about whether or not bacteria and other harmful microorganisms could grow in the water that collected too. I suppose, if nothing else, it could be boiled before consumption.
Seems like something that just needs to be 100% open source, with designs freely available to the public. If it works so well, it really ought to be utterly free to construct, since it will have such a significant impact on peoples lives to be able to have such access to fresh water.
So whats the problem here? Isn't this science free, already?
Why would "two Warka towers" be a target for a year, when, on the surface, reading this - it would make sense to go install a thousand of them and see how they played out over a year. If this device really could pull, even 10 gallons of water a day for $500 cost, it would have zero problem attracting funding on that kind of tiny pilot scale.