let's not conflate 'freshwater' with 'immediately potable', unless we care little for ingesting sewage and detritus, it will usually need some amount of treatment
Interesting point. Would distillation clean water from any contamination or are there common chemicals that would evaporate and then condense at similar temperatures as the water?
Boiling water for a few minutes is a common way to get rid of biological contamination.
The most common chemical is ethanol. What you're describing is an azeotrope [1].
Aside from the ones that will boil together with water are those that will boil off before the water (methanol is the other common example that comes in practice). If you have any that boil off before water you have to know at what point it's safe to start condensing the vapour and storing it.
I don't know, but 'distilled' water is typically sold as the most chemically pure form of water. I do know it needs to be remineralized or something, as pure distilled water is bad for you.
Your point is well taken, but if you have never witnessed it in extreme I believe you are not evaluating it fairly.
On ships, vacuum vapor distillation is quite common for drinking water production. This is because the equipment is used to generate boiler feed water, which must be high quality distillate. Acquiring additional water-making equipment is redundant.
Nutritional content can be limited and lacking diversity. Many minerals in the body are of very low concentration, they are nevertheless, necessary. Osmosis will delpete the body of these over time. The health effects of this would require a longterm study for chronic symptoms to appear. I have never seen any study of this nature. I have seen mariners after several months at sea with no other water source and, yes anecdotally, they look like hell. I will not drink distilled water for any length of time, but a few weeks would never amount to anything.
So in your day to day life, sure, you have a healthy, diverse, first-world diet and have no ill-effect from drinking distilled water. You can 'live' drinking only Coke. Appalling, certainly, but doable. In terms of cost and energy expense, distilled water is likely higher than Coke to produce, though that is an aside.
You're partially correct, but missed the important point here. As a result your advice is dangerous to health.
You don't want water picking up minerals from your body .. you want it DEPOSITING minerals into your body. That's the way we evolved obtaining minerals from water from streams where the water runs over rocks to mineralise.
Exactly. It's water. It's not bleach. If you take a multivitamin and eat a varied diet, there is no "magic" nutritional value lost. Water doesn't have to come out of a Voss water bottle or the ground to be "healthy".
I don't know what's so demonstrably false about it; there is credible evidence (cited in another comment) suggesting mineral/electrolyte loss from drinking demineralized water and GGP admits to purposefully consuming nutrients from other sources to compensate. That only helps to prove my point?
If you have to compensate from other sources than I don't understand how something is necessarily harmless, without the qualifier that it should only be used in the context of a proper diet (which many/most don't have, particularly the types that might be susceptible to quack wellness claims)
Besides, one anecdote does not a disproven theory make
Yes, you are correct. If you consume only distilled water, you will get sick. This of course means not eating or drinking anything else.
But it should be obvious that your mineralisation is not on a knife-edge. The tiny amount of minerals lost by drinking distilled water is massively made up in the other stuff you eat and drink.
Yes, you are correct. If you consume only distilled water, you will get sick.
No, this is not proven. To prove this, we must demonstrate that a person who only drinks distilled water would get sick sooner than the same person who only drinks tap water - in exactly the same conditions.
Clearly this experiment would be very hard to perform. But if someone did perform it, I'd love to hear about it.
Something needs to do harm in order to be harmful. If I drink a bottle of distilled water a day, I am healthier (better hydrated) than if I do not drink that bottle. That is the opposite of harmful. Replacing tap water or bottled water with distilled is nominally harmful, but because you stopped drinking the mineralized water, not because you started drinking distilled. And yes, no one is saying that not drinking water is not harmful.
This just seems like such a bizarre and indefensible hill to die on.
I'm thinking demineralized water, of which distillation is several ways to produce it. The rub seems to be that it leeches minerals from both the body and distribution mechanisms (like metal piping)
You are pushing (incorrect) anecdotes, with a hubris of certainty.
Please provide quality references, or even some argument, to support your statement, beyond 'you said so'. 'You said so' is always a useless information-less way to communicate that I would push back on, but this is a health relevant issue, and you are spreading misinformation that is dangerous. Provide some quality references if you're right, but you're not.
> The preferred way to correct someone wrong on the internet is gently.
Many of us have had the “citation needed” demand thrown in our face in very rude ways during the COVID vaccine debacle. It’s gonna take some years for it to settle down and be forgotten again.
Clean water and sanitation access in Burundi is rapidly improving thanks to many international aid programmes, so perhaps this invention is not needed there—the country is bordered by freshwater lakes, after all.
Your point still stands, but the $4 wouldn’t be paid by end users: it would likely be covered by these organisations, which would then be able to provide aid for a much larger population.
Because building wells is more effective at improving access to clean water.
Do you really think giving people more money would make developing countries develop faster? It would just create incentive for companies to keep things as they are, so they can extract that money in exchange for things like bottled water. Those companies would seek to corrupt local governments to do so. That leads to widespread aid redirection and skimming.
There are instances where direct cash aid has proven very effective vs traditional aid. Notably in food aid where giving people and farmers money instead of just distributing food lifts the whole community up. With traditional food aid where it's just given away it doesn't help local farmers because it's just satisfying some of the need for food keeping them from really advancing economically. When cash is given instead the ability to buy food goes up, farmers can invest in better equipment or more workers, and the money circulates through the community. Giving money greases the wheels and kickstarts a little economic boom.
It's not a perfect solution because it needs a certain level of stability and existing things to boost but it's a fairly robust way of helping people become less reliant on outside aid in the long run.
I think giving people (not local governments) money would typically help them develop faster than deciding for them what to spend the money on. But a country can’t develop without decent institutions and I agree that you have to work around the constraints created by governmental corruption.
Of course. But you plant an liquid asset somewhere and the best they can do is tax it. You move fungible stuff like money or staple grains around and a lot more is going to evaporate along the way.
They can force you to hire their contractors for construction and delivery, at an exorbitant price to fund kickbacks. They can have you install infrastructure on public land and then seize that land and use it for an aristocrat's private residence. They can restrict the places you can build infrastructure to provinces that recently favored the ruling party to curry political favor. There are plenty of ways for despots to profit off of "development" projects beyond taxation.
good question, maybe you give the money continuously (every month or so) and commit to stop giving it if the local government tries to take too big a cut – then their incentive to start taking a cut would be limited
I agree on the principle: giving money to people whose personal development is hindered by poverty obviously allows them to overcome the hindrance.
However, this does not mean that giving money to people is going to make those people want to develop themselves and their surroundings, unless they are already in the process of doing so.
Per capita GDP is not income, especially in pre-industrial countries like Burundi where the bulk of economic activity wouldn't be captured by the metric.
Look at what happened to the US when people were given free money.
Money is ultimately numbers on a piece of paper. It's inherent worth is equal to that of monopoly money. It takes a lot of effort to keep that from happening.
> Look at what happened to the US when people were given free money.
I like how in this worldview giving money to the capital class of society is fine and dandy, but giving money to labour class is disasterous. Seems suspiciously convenient.
It's pretty pathetic how disaster relief is viewed as a handout too. A whole lot of people needed that money to help to keep food on the table and a roof over their heads. They needed help paying down the debt that had to rack up after not being able to work or to restore the savings they lost. If anything it wasn't enough "free money" for a lot of Americans. It might have been better if more rich people were excluded from getting the funds, but it's not as if an extra couple thousand means anything for most of them anyway.
Don't give people money for disaster relief, give them goods and services.
I'm perfectly happy for a government food program to give people food. Much less so for giving people money during an incredibly inflationary period. You still end up with people not having food, but also not having gas, rent or health money either.
> perfectly happy for a government food program to give people food.
A- Can I pay my landlord with a box of apples?
B - How does your second point about 'people end up without food if you give them money' work?
Either government or people buy the same food, either there is enough food or isn't.
C - If the government has made it illegal for me to work, why should I eat the loss but banks and landlords shoups never loose money? We are told they are earning their interest and rent because they are taking the risk, but when the time comes, the risk is always passed on to someone else.
>Either government or people buy the same food, either there is enough food or isn't.
That you can't even imagine a government owned integrated vertical food system not run for profit is extremely sad, but completely expected given that you speak English.
As to point 1, the government is ultimately in control of the rules, so, yes, it could force your landlord to accept barrels of apples. Indeed, it already forces your landlord to accept digital numbers as payment.
>I like how in this worldview giving money to the capital class of society is fine and dandy, but giving money to labour class is disasterous. Seems suspiciously convenient.
Pretty bold of you to derive his world view from such a short statement of opinion. Just because he didn't like the 'rona stimmy payments doesn't mean he's fine with with pumping asset prices by buying assets.
I and many other people dislike both those things but for me personally they're a drop in the bucket compared to my hatred for the kind of unsound logic that underpins the strawman you built.
I’d wholeheartedly disagree, some citizens were receiving $2-3k a month from having dependents in areas where that would cover 2 entire families bills. This in turn created massive free cash flow, which was then mostly spent.
Giving money to the capital class means that Manhattan high rises cost more than the average millionaire makes in a decade.
Giving money to the working class means that such luxuries as lettuce double in price.
The rich have been dealing with ridiculous cost of living inflation since 2000. No one particularly cares because fuck em. But if you think that the middle class can survive the same inflation you're in for a rude shock.
20% interest rates are the best thing that can happen to the economy now.
> The rich have been dealing with ridiculous cost of living inflation since 2000
I hate the constant conflation of rich and wealthy. People who earn a lot of money vs people who own a lot of money. A lot of criticism about inequality, by politicians and economists alike, is about rising wealth inequality, but they only advocate and undertake policies to hurt the higher income class. Why is there no wealth tax, but the govt is funded primarily by income and payroll tax. Why is the federal reserve always worried about falling asset prices. And again here, rising house prices benefited the wealthy, and hurt the high income class, but you didn't differentiate between them either.
>A lot of criticism about inequality, by politicians and economists alike, is about rising wealth inequality, but they only advocate and undertake policies to hurt the higher income class
"I didn't think they were gonna tax me" says the guy who <checks HN demographics> is in the top 10% of income by almost any measure and who's FAANG monopoly bucks are exactly why the plumber gets priced out of the Boulder/Austin/Seattle housing market.
The supply kept up just fine, farmers were literslly destroying food a few months ago because our 'efficient' market system wouldn't pay them and store this food for a rainy day, and now we have shortages and inflation.
But it's heresy to blame the market for being shortsighted, and to suggest any kind of long-term planning is needed.
This was 2 years and a few months ago, at least the article is.
> wouldn't pay them and store this food
In the article the plant pictured being plowed over is an eggplant, which has a storage life of about a week if stored properly. How exactly can we store this food for a rainy day when it spoils so quickly? Grains can be stored for long durations, but fresh fruit and vegetables cannot be stored to save for much longer than a few weeks.
Then you’re also ignoring the costs. If they won’t be able to sell some crop, why keep dumping time and materials into it? You’re just exacerbating your losses.
You can make eggplant flour, canned, salted and pickled vegetables, like this is something our ancestors worked out hundreds of years ago. Anyway you dont need to preserve everything, the point is the bigger picture.
Thats exactly the point of my critique that for the individual farmer it doesn't make sence to invest so much effort, but as a society wouldn't it be nice of we didn't waste what we had, we'd have something to fall back on.
> You can make eggplant flour, canned, salted and pickled vegetables.
Farmers grow food, they don’t process it outside what a combine does. This further increases costs as now you need mass grinders, canners, and pickling machines.
> Thats exactly the point of my critique that for the individual farmer it doesn't make sence to invest so much effort, but as a society wouldn't it be nice of we didn't waste what we had, we'd have something to fall back on.
Yes I get your point, but I’m a realist. Things expire, things can’t store as long. It’s not feasible to have a farmer be the entire, or even a majority of, the food supply chain. You’ve clearly never grown anything at scale.
In the same way that the American diet would improve the well being of Eritreans in the first six months after its introduction. Long term results may vary.
Not that I'm particularly familiar with the average Eritrean's diet, but going out on a limb here: are you implying that starvation is better for a person's well being than an overly calorie-rich, generally unhealthy but plentiful diet?
I meant, how sustainable is it to keep depending on foreign aid? Obviously dirty surface water that does not suffice for the whole population is not sustainable. But in the long run, creating new dependencies on aid can't be the solution. Any long-term plan that involves foreign aid is a bad plan.
Infrastructure is a lot more permanent than ad hoc solutions.
Not having the knowledge or equipment for drilling water wells is a problem. Getting the knowledge and the equipment there is another. The result is not a dependency—rather, the alleviation of a dependency.
Exactly! What we are discussing here is an ad-hoc solution. That $4 device will work for how long? A week? A month? Then we're up for the next one. A continuous stream of aid is necessary to keep this solution going. So, it's not sustainable, assuming we don't consider permanent aid a sustainable solution. (I don't.)
I agree, it is not a primary solution. However, in a world increasingly plagued by natural disasters, well water can often become unusable, and in those disaster scenarios devices like these can save lives.
$1 / week / person means for $50* or $400 Billion per year (or 0.4% of World GDP) we solve the water problem. Of course at that scale we may bring the cost down
"Researchers from MIT and China have developed a solar desalination device that could provide a family of four with all the drinking water it needs — and it can be made from just $4 worth of materials"
People need a lot more water than drinking water. Most water is used for agriculture. Each time I flush my toilet I use enough water to keep me alive a week.
It says it supplies 4x the amount of water a person needs (it supports a family of four). So, $1/person/week if it fails after a week and is not cleanable or fails because of a part that could be replaced
not really: if average life is 2 weeks that means you need $100 per year for devices. Somalia gdp per capita is $500 (not taking PPP aince these will likely be imported).
So 20% of anual income is quite high
“If it does prove durable, it could be a relatively cheap way to get freshwater to people in need of it.”
The engineers are unsure of how long it will last and if it’s actually cost effective, yet there’s many HN comments here that seem to suggest they know better. Where are you getting your information that the rest of us are not privy to?
The economics might not work well for everybody. Although international aid might ease some of the burden it may turn out to not be a good fit for Somalia, but it might be helpful for others. As drought and desertification worsens, even parts of the western US and Mexico might find some benefit in something like this.
It's for a family of four though, so 5% of annual income on average, meaning for 50% of people it's still worse.
I'd also think that the GDP doesn't factor in international aid, so 25$ per year for the poorest could be still better than the current alternative (no idea on what that is, though).
Tech like this could even help some people in the US if their water becomes undrinkable for long periods of time due to some natural disaster or flint-like shenanigans.
That is one of the reasons big scale RO is impractical for desalination compared to upcoming redox tech. Not only is it slow, energy intensive, but also you'd always be running at reduced capacity.
In indistrial usage, a lot of the salt is removed before hitting RO filter.
That said, it exists right now and is well tested.
..and can it be mass produced at a reasonable cost. Scaling up a lab build product to an industrial scaled production line is a skilled profession. Not all products can make this transition.
Maybe I'm crazy but does MIT get a disproportionate number of features on HN? For one of thousands of institutions in the US let alone the world, they're not the only ones inventing things. I feel like there's at least one MIT adjacent post in the top 5 each time I log on and it doesn't feel like a coincidence.
The blunt fact is that the vast majority of positive news is purely the result of PR organizations. In this case, MIT has a fairly good PR team. So what happen is the MIT PR org just monitors what papers MIT researchers are submitting to journals or presenting at conferences. Then the PR org gets in touch with the researchers and writes up a more accessible version of the paper on MIT News along with a press release. Then the PR guys go round to a series of their contacts in the media - places like FreeThink, Futurism, Insider, etc. They'll send out a press release which does 99% of the work writing up the article including choice quotes from the author and make themselves available for Q&A etc. Seeing this as an easy way to fill space on their website the reporters just basically copy and paste it onto their website, maybe punch it up a bit, put the website's specific spin on it etc.
What this whole process doesn't involve is anyone saying "Hang on, is this actually an important or interesting story". Does this invention move forward the cutting edge of desalination? Probably not. But it does boost MIT's reputation. Which is what this article is for.
MIT isn't more innovative than other institutions necessarily, but they are spending much more effort advertising their innovations.
You are absolutely correct on the meat of this. What parent is observing is mostly a more consistent PR operation.
That said, some of that is too sharp. There is some degree of "is this actually an important or interesting story." That's what the journalists/editors do. That's what the upvote button here is for. It also happens pretty extensively in HN's comments. The article itself expresses skepticism about the invention. I agree that it's not done very thoroughly, but skepticism definitely does exist in the process.
In any case, it's all pretty primitive. If this invention is worth discussing, it should be discussed. This article demonstrates how lame discussing with yourself is.
Where are the researchers, peers, people in the know. The subject matter here is a bad fit for factual reporting. We need subjective opinion. "Is this thing interesting?"
MIT is definitely among the top in the world for most impactful papers, Patents granted, Startups created, Nobel Prize winners etc. So there really is something special about it.
Also kind of an awkward title when the first sentence of the article is “Researchers from MIT and China have developed…” Like maybe spell out the actual institution like you did MIT (it’s in the article), and don’t say “MIT invents” in the title when it’s a joint effort?
The three involved researchers from MIT are grad student Lenan Zhang, postdoc Xiangyu Li, and professor Evelyn Wang and "four others" which are not mentioned by name in the beginning of the article.
At the bottom of the article, it's mentioned that Zhenyuan Xu from Shanghai Jiao Tong University in China is one of those "four others".
One of the reasons I would never collaborate with anyone at MIT is that such collaborations are rarely equitable. Institutionalized credit theft is just the beginning, but yes, if there is joint work with MIT, usually the non-MIT researcher does the bulk of the work, and the MIT researcher gets the bulk of the credit.
Everyone wants to work with and associate with institutions like MIT, so MIT gets to pick the biggest fools.
(This isn't unique to MIT; that's true of many of the elites)
Unfortunately, having a big name from MIT on your grant application as co-applicant significantly increases your chances for funding. You get the money and do the majority of the work, they get to claim disproportionately much credit for the work. Win-win? (Doesn't sound like it, but that's how it works..)
Having sat on review committees, it actually worked the other way sometimes (and usually for the ones I was on, although in some cases, it took some lobbying on my part). There was one review committee member on one committee who wouldn't accept a grant unless it had a big-name university. She was a douchebag. For the most part, people were accommodating.
NSF and other agencies do have a call to this kind of outreach, and the program officer told me they often would pick a grant from a more deserving school over a big-name, even if the big-name received better reviews.
So it's sort of luck-of-the-draw. If you get someone like me, MIT will hurt your chances. If you get the douchebag lady, it will help.
NSF is probably butt hurt that MIT charges higher overhead on its NSF GRF to (presumably junior) PIs taking those grad students than if just on TA funding support.
(For the record, I support this, it protects the grad students, who are not showing up at MIT for the PI’s research in most cases and most junior PIs need to be taken down a peg or two)
Fact is, the story has better legs when it's MIT, which is one of the reasons why the top universities have a "rich gets richer" pattern. Media loves to carry stories about "MIT nerds invent something" or "Harvard students gain power" or "Princeton students do something posh" or "Stanford students start a company" which causes kids who want to do these things to preferentially attend these schools.
This is such a good point, my mind has recently been opened to how much happens in the Spanish, French and Russian speaking parts of the world that I had no idea about because it just isn't in English. Does anyone know of resources that are HN-like or could be used to fill in the gaps on interesting developments in non-English countries/regions?
My favorite example of this is that China is arguably leading the world in AI research (at least by shitty metrics such as number of papers), yet research from there very rarely shows up on HN.
It feels like any topic on here is skewed by a factor of three towards the west, and a factor of ten towards the US. You could get the impression that 80% of the world population are doing nothing of relevance.
This is done on purpose and it is the great advantage of being the cultural and language leader of the world: you decide what is newsworthy and you show yourself as the leader.
Moreover you can claim/steal findings by translating research in English and make it known to the world.
>my mind has recently been opened to how much happens in the Spanish, French and Russian speaking parts of the world
This is a much more general and tragic insight in fact, the vast majority of human experience is not available to you due to, among many other reasons, language barriers. Consider all the songs, novels, films, music, books and stories that you will never even hear about, because they are written or performed in a language other than the ones you know. If you know a second language, consider all the times you have thought "Oh gee, this is so much easier to express than in my mother tongue" about a neat idiom or grammatical construct, and think of the literal hundreds or thousands of languages that you don't even know the names of, and how full they must be of valuable new concepts and delianations and ways of thought and utterance.
Keep in mind that posting translations of English articles, especially uncredited, is easy karma for Russian (and adjacent) native speakers who also know English.
As a Russian, I feel like something new generally comes from English sources (not necessarily from Americans, Brits or Australians, but from people who can and choose to use English, even if they are Chinese or Russian).
You can't do serious research without English knowledge at this point.
Also I looked at what happens to top programming competitions winners: they are usually from China, go to the top university there, then quite often are happy to immigrate to US for a MSC/PhD.
You can totally do serious research without English.
The dominance of English language scientific papers acts as a gatekeeping much like what google and apple are doing. You need them to be known internationally, but you need to pay your dues to the committee selecting papers: you cannot go against their belief.
I'm not sure I understand your point. I live in Hungary and all my friends who are researchers publish their research in (simple) English by default, because it just makes sense for a much higher impact than publishing in Hungarian. The language is not really a barrier for us for communicating the results.
Yes I agree that the reach of language matters. I spoke about French which has more reach than Hungarian. I guess that Russian or Chinese also have quite an impact.
My post was about top journals like Nature, Science etc...
That's how the big names get even more exposure. When something at a big name happens the headlines are "Stanford/MIT/Harvard/Google scientists invent". When it's from somewhere else it's just "scientists invent" or even worse "mechanics developed" (this happened a few weeks ago when the company ZF developed a new steering for cars).
They have more budget than entire countries dedicated to R&D (and PR). If they were not appearing at least once per month I would be asking were does that money go
When I was in grad school (University of Rochester), we had a new associate professor recruit who freshly graduated from MIT. The first thing he shared with us was how to promote/advocate your work. The slides (the materials he used) are obviously created at MIT (meaning, they are not his creation) and it seems like (again, I'm not sure) it (how to promote your work) was taught in MIT grad school (at least in their PhD programs). I wish I saved those slides. I'm not saying that promoting your work in this day and age of academia is inherently wrong (although I'd like to think if your work is really good and essential, it'll surface without needing to promote), but I am just surprised that it was taught.
I don't mind that MIT has a great reputation and a great PR team. It's okay to put out new ideas and inventions that may not pan out. But the breathless coverage of their work by news organizations, little more than rephrasing press releases, that's what irks me. They also suck the oxygen out of the space for other science coverage, as if there's not good work being done at dozens of other institutions around the world.
Put a bowl inside a larger bowl (elevated by a rock or something). Pour salt water into the larger bowl. Put cling wrap over the whole thing. Put a pebble in the middle of the cling wrap. Set in the sun.
I don't know man, the article doesn't seem to be a device, more like a method, and their only example was a tiny tiny vial. I can't tell how big the device for a family of 4 would be.
The man in this video [0] claims to be able to collect 10 liters of water in a day. His simple facility is less than 2 square meters but easily scalable.
It does look like an optimal growth chamber for salt-tolerant and heat-tolerant microalgae, (i.e. biofouling is likely) but maybe wrapping the whole thing in aluminum foil will block enough light to keep growth levels relatively low.
I would very much appreciate it if Hacker News could conveniently replace these newsbite-extracted-from-university-press-release-about-a-paper links with the paper itself as the main focus and then the university press release as supplementary material.
As it is, this is a game of Chinese whispers, and it’s a subtle infohazard. To begin with the university press release tends to subtly misunderstand the paper and misrepresent it and its context. For instance there is a tendency for the PR team to claim that the results are unprecedented and hitherto unknown, simply because the PR team isn’t a field expert and doesn’t know that they don’t know what is known. (Let alone the impact of PR incentives.) Then the aggregator-newsbite-feed site misunderstands and misrepresents further.
While I agree having the best source is better, which is in my experience is better is random; sources including: press releases, press, paper, demo, Twitter, YouTube, etc.
In my opinion, defaulting to only one would be bad idea; better to just review them and if needed on case by case basis email the mods to make a change it needed.
I do think having a fields for “official source” or “notable coverage” might be a good idea, since it’s common to have a better non-official source or review an independent notable coverage — and dumping that into the comments in my opinion takes away from the core value of the comments.
What is it then? I would class intentional communication with the public for the purposes of inculcating a positive association with your organization as advertising, and so would most people I know.
Then you should be able to hire one to do the others job, which I assure you won’t work out well. If you have something notable and specific to add, please feel free to do so, otherwise you’re opinions are not backed by actually reasoning, and as a result, impossible to respond to with reasoning.
(Please do not resort to personal attacks; flagged, not responding further. Your profile description is fitting.)
Clearly you’re not interested in reasonable exchanges, since if you were should clearly understand after reviewing sources I provided that advertising is paid placement — and public relations is not; using that logic would lead to belief all news and all propaganda are identical — and they clearly are not.
Looking at the design, I believe they should also be able to generate electricity from the setup. They have salty water with an insulated spacer to retain heat on the evaporation layer to make it more effective in removing water. This in turn is creating a saltier layer of water that diffuses into the lower layer via holes in the spacer. That means there is a salinity gradient between the top most layer and the bottom layer which should have an electric potential. Neat.
True, but those aren't readily available in Africa, and come with a significant amount of red tape. A DIY 4$ desalination solution is a boon to anyone close to the sea.
Uh, what's the point? You can make a massively more efficient survival desalination device using less materials by making a solar distiller. Maybe $2 for a piece of plastic and 2 buckets.
Edit: I don't know if this would be the most useful way to provide water at scale. Dumping small water contraptions on a poor country may not be as sustainable or as efficient as investing in long term water systems.
This is interesting, at least. The 1-week 'test' so far is certainly a bit premature to declare success.
Let's also not forget about the need to sterilize the water further, thru boiling, or reverse osmosis, or whatever else, in order to eliminate bacteria, viruses, etc.
not only drinkingwater may be the outcome of this theoretical $4 device. one obsticle to produce cheap hydrogen is that one can not just apply electrolysis to salt water. and many areas with lots of sunlight have limited freshwater to split into its atomic compounds.
i am thinking large scale solar in the sahara, used for electrolysis of mediteranian and atlantic sea water
That really depends on where you are, infrastructure, and economies of scale. The statement is ridiculous by itself.
If I pumped a cubic meter of drinking water here and mailed it to you, it would cost much more than $1. If I instead built pump and piping from scratch to provide you with a single cubic meter at your location, it would also cost way more. Especially if I could source neither parts nor know-how locally and instead had to ship them around half the globe.
> That really depends on where you are, infrastructure, and economies of scale.
Yup. For example in Finland it costs between 1-3€/m3 depending on where you are in the country.
Then again it's "the land of a thousand lakes" and while most of the water isn't drinkable (at least according to "health standards", anymore, due to human activity) you can still drink from the lakes/streams in Lapland. And there are aquifers everywhere.
We've somewhat created this problem ourselves. Back in the day you wouldn't even consider settling anywhere without a reliable water source. Nowadays if the environment can't support you we'll just come up with some high-tech solution and have more babies and in the process we become dependent on state infrastructure. People like Elon Musk want higher tech and more people, and while I'd like to agree with him I don't see that as realistic, given human nature and the current landscape around the world.
Ok, that was a bit of a derail.
I really like innovation like this though. As long as someone can supply the materials for the device, it really improves quality of living in many places.
I think I need to be more long form because people are getting the wrong idea. Desalination from seawater is almost never required, brackish sources are more common. For this multistage flash distillation is the cheapest option, reverse osmosis next. Even then most people could recycle grey water rather than run desalination. A sand filter works for this.
These types of gizmo based approaches just strike me as incredibly naive as to the underlying causes of problems with water supply. More than naive, patronising. People in poor countries aren't stupid.
+1. Reminds me of Gandhi proposing that Indian households "solve" the problem of importing clothing by spinning their own cloth at home, which is ridiculously impractical compared to letting factories do an incredibly tedious and time-consuming job.
That's the point. Devices like this are a way for people to be able to make their own fresh drinking water without needing a functioning state around them.
The saltwater piping (and especially pumps if needed) does not build or maintain itself, and this filter is unnecessary for river, well or rain water. It may be useful for salt lakes, but these are likely to go first.
If you really need it for some reason, solar or other distillation is good enough on small scale.
Even with functional state, lack of access to clean water might be new risk due to climate changes and general world instability. What if, prices of clean water will rise due to some events?
Today we have energy crisis in Europe and who would expect 5 or 10 years ago that situation will go that bad, that rationing of energy will be considered? There are already some predictions that water scarcity problem will get worse, so it's very good that there are already prototypes that might provide cheap conversion of salt water to clean water. Future seems to be about minimizing costs and decentralization, so we can better sustain all people and save environment.
Possibly the main problem, as alluded to by the original comment, is political in nature and, is that 'rationing' was never considered possible, even for expensive, polluting, imported materials.
If it had, we'd have used less of them and used more alternatives like insulation. Just like farmers would use less water if they had some incentive to use less than every bit they could get their hands on.
Decentralizing technology has a history of enabling the disenfranchised to get what they couldn't get before. This could enable that. Admittedly, technology also has a history of enabling tyranny. But that doesn't make it untrue that technology has an ability to enable the disenfranchised to make better lives for themselves either.
And the non vailability of adequate supplies in many other places is a fact of growing water scarcity issues that cannot be waved away by a vote or a regime change.
Even within the US aquifers that millions of Americans rely on for freshwater are being depleted at an accelerating rate.
There comes are point where these are empty and the ground collapses.
That is insanely cheap. A cubic meter costs roughly $3 in Germany but only if you ignore grey water fees .. .which brings the price up to something like $6. And that was before climate change has completely hit us. Utilities fees for far distant water supplies (think 100 miles +) and their creation will add some more dollars to that equation.
Prices of water are very regional and can become very costly.
The comment isn't true because political dysfunction is only the proximate cause but a lack of cheap decentralized technology is also a cause. The problem can be solved either politically via functioning government, or technologically via innovations like this. It is therefore both a political and technological problem. Saying it's just a political problem isn't accurate.
> Fresh water cost $1 per cubic metre. The availability of fresh drinking water in some countries is a political problem not a technological one.
Your logic is not sound.
A perfect anologue is the resent post regarding famine. Famine is a political failure. Yes, certainly, technology could prevent famine. If everyone on earth had a synthesizer to generate food then it wouldn't be an issue! So it must be a lack of technology keeping people hungry. Or, hear me out, what if the politicians stopped starving people to death through failures in governance ?
It is sound if the technological solution is easier or of similar difficulty to the political solution. Famine has no technological silver bullet, but water purification might.
You're leveraging a lot on that "if" and downvoting my comment.
Almost exclusively in the modern world, famine is caused by politicians. So the answer lies in removing the cause of the problem. Developing technology to counteract the cause of famine, a cause that should solve the problems of food distribution....? It makes very little sense.
Merely convincing the populous that food could be in short supply has caused people to hoard food, thereby making a short supply. This caused people to starve to death while the hoarders looked on the starvation as evidence of the need to hoard food.
Let’s maybe run it for a couple more weeks before we talk about it again?