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You've pretty much nailed it except for one minor nit: > It takes less energy but produces a concentrated liquid waste stream that must be disposed of. This i
by lisper 3y ago
You've pretty much nailed it except for one minor nit:
> It takes less energy but produces a concentrated liquid waste stream that must be disposed of.
This implies that creating a concentrated waste stream is a problem unique to reverse osmosis. It isn't. No matter what you do you're going to end up with a bunch of salt that you have to get rid of somehow.
- ericlewis 3y agogood thing people need salt!
- stouset 3y agoIf people needed as much salt as was contained in the water to begin with, we wouldn’t need to remove it in the first place.
- suddenclarity 3y agoNo reason to keep the 1:1 ratio. Use the salt to replace our current salt mines/outtakes and then use the water as an addition to our current freshwater usage.
- deleted 3y ago[deleted]
- Retric 3y agoThe waste stream doesn’t contain that much more salt than seawater. Extracting salt from mines is much cheaper than extracting it from slightly brackish wastewater from water treatment plants.
- giantrobot 3y agoThe brine waste from RO is still mostly water. In order to extract the salt you'd need to evaporate the water which still takes a lot more energy. You could use evaporative ponds to let the Sun do the work but that takes a lot of space. In either case you're spending a lot more money per pound than just digging the salt out of a mine.
- eropple 3y agoIs that true when we take into account environmental externalities? I am not an expert in this field; I know that many forms of mining are capital-B Bad for the environment but I don't know how salt mines impact the area around them.
- pas 3y agowell, mines are bad on the short term. the long term damage is not of the actual digging, but of the separation processes. which all can be done as clean as we wish it just costs more.
- actionfromafar 3y agoCost more energy
- Retric 3y agoMining salt costs vastly less energy than using slightly brackish water. Which is why it’s so much cheaper.
- deleted 3y ago[deleted]
- rs999gti 3y ago> https://www.bbc.com/news/business-61483491 https://www.bbc.com/news/business-61483491 Nuclear desalination like on naval ships is the answer. US and Russian ships already have the technology, it just needs to be scaled for use on land.
- eru 3y agoNuclear power in general would be the answer to a lot of energy problems. But the general public in most places doesn't like it.
- mschuster91 3y agoThe problem is that salt brine from seawater contains a lot of side stuff - you still need purification at a scale you don't need mining rock salt.
- fsckboy 3y agois this true? I can understand why it would be true, but "sea salt" is a real thing that's been traditionally made in seaside communities through to today, and I find it hard to believe they're cleaning it at anything finer than a gross scale. https://en.wikipedia.org/wiki/Fleur_de_sel https://en.wikipedia.org/wiki/Fleur_de_sel
- actionfromafar 3y agoIt increasingly has plastic and other crap in it.
- myshpa 3y agoMicroplastics found in 90 percent of table salt https://www.nationalgeographic.com/environment/article/microplastics-found-90-percent-table-salt-sea-salt https://www.nationalgeographic.com/environment/article/micro... The presence of microplastics in commercial salts from different countries [2017] https://www.nature.com/articles/srep46173 https://www.nature.com/articles/srep46173 Global Pattern of Microplastics (MPs) in Commercial Food-Grade Salts: Sea Salt as an Indicator of Seawater MP Pollution [2018] https://pubs.acs.org/doi/10.1021/acs.est.8b04180 https://pubs.acs.org/doi/10.1021/acs.est.8b04180 Microplastic pollution in commercial salt for human consumption: A review [2019] https://www.researchgate.net/publication/331006661_Microplastic_pollution_in_commercial_salt_for_human_consumption_A_review https://www.researchgate.net/publication/331006661_Microplas... "MPs have been found in commercial salts from 128 brands, from 38 different countries spanning over five continents."
- fsckboy 3y agothank you for the information, for sure, but i was responding to the claim that sea salt "needs cleaning" to point out that that seasalt isn't being cleaned, so it puts an upper bound on the value of need as it concerns the commercial market including govt regulation. My suspicion was that where would be more to worry about from single-celled life detritus, heavy metals, forever chemicals etc, but the marketplace doesn't seem to be worried about that. I go about my daily life not worrying about microplastics (I know they are ubiquitous, and I'm not in favor of them, I just don't worry about them) Are microplastics known to cause particular diseases, or just suspected on the grounds that they "couldn't be good"? plastic is pretty inert which is why it remains around for so long, and while it is made from toxic things, it's generally considered safe. I'm just curious about actual microplastic effects rather than the sort of "it's estrogenizing our boys, antivax...er-plastic" suspicions.
- deleted 3y ago[deleted]
- scythe 3y agoNot quite that simple. Even isotonic water would probably be too corrosive for existing pipework.
- rs999gti 3y agoCan't the salt just be dumped in the desert?
- stouset 3y agoThe products of desalinization aren’t salt and fresh water. They’re somewhat saltier brine and fresh water.
- rs999gti 3y agoSounds like it's time for USA to get another Salton Sea
- SoftTalker 3y agoJust pump it back into the ocean. The little bit of concentrated brine from a desalination plant will be quickly diluted; the ocean contains a LOT of water.
- Fatnino 3y agoNeed for uses other than eating. Like de-icing roads.
- Loquebantur 3y agoThe people who need that water tend to shed it after some time. Discarding waste water into the oceans via rivers is a huge idiocy. You essentially rely on the environment to "magically" sort it all out. Naively so and fraught with huge inefficiencies. Proper treatment of that waste in the sense of recovering usable matter streams is the logical way to go.
- daveslash 3y agoI know that generally speaking, disposing of waste in the ocean and expecting it to disperse enough to be harmless is foolish and wrong. But in the case of salt, It would seem to me that the ocean can handle that amount of salt. Course, I haven't done the math. But it would seem to me that the back in == salt taken out. We'd only be changing the net salinity by the amount of water subtracted. Without having done the math, my gut reaction is to think that's something the ocean can handle. The problem, as I see it, is localized concentrations. While the ocean at large might be able to absorb it, the localized concentrations can be very problematic.
- londons_explore 3y agoThere are potentially some good reasons to just spray the brine into the air. Seawater sprayed into the air becomes tiny salt crystals, which in turn help clouds to form, and cause increased rainfall. The rain produced has negligible levels of salt. In places with dry climates, this often can turn desert land into farmland across an area hundreds of kilometers wide.
- singleshot_ 3y agoSurely the salt falling on the farmland would have some kind of deleterious effects, right? I imagine you’re not trying to grow sea cucumbers in this scenario, and I’m not sure most land plants would be crazy about a ton of salt. Just ask the Carthaginians… Guessing that you know something I don’t here, though.
- 3y ago
- ShadowBanThis01 3y agoWith enough desalination, the Romans will be able to afford a huge army!
- darkclouds 3y agoIts always been my understanding that any treatment to remove stuff from water is going to produce waste which needs disposing, just look at the Brita water jug filters, they need disposing. I've often wondered why dont we have more pure water pumped through the water mains in various countries, and I think after reading about Super K the Japanese Neutrino detector [1] and how the water in the tank was so pure it had dissolved a spanner/wrench that was left in the bottom, years ago, I might have the answer. Firstly there is health implications for drinking pure water, and whilst it probably wont dissolve your guts [2], it will drastically and quickly alter your chemistry [3] which in moderate doses may be a good way to calm down, I havent tried personally yet, but there is another problem. The ultra pure water would probably dissolve the older ceramic and metal pipes used to deliver water around the countryside, from the inside out. In fact I would even go so far to guess that water mains pipes last longer if its delivering hard water compared to soft water, and probably explains the pub culture as the water is standardised in various alcohol brands. Either way I prefer soft water, its more relaxing and could well help to reduce a certain amount of anxiety in the population along with stress levels, that could be useful for built up cities, but watch the GDP levels of the region go down if that happened and the profile of crimes change [5], not to mention health conditions! [1] https://www.businessinsider.com/super-kamiokande-neutrino-detector-is-unbelievably-beautiful-2018-6 https://www.businessinsider.com/super-kamiokande-neutrino-de... [2] http://physicsandphysicists.blogspot.com/2018/06/super-kamiokande-and-extremly-pure-water.html http://physicsandphysicists.blogspot.com/2018/06/super-kamio... [3] https://chemistry.stackexchange.com/questions/30754/effect-of-drinking-ultra-pure-water https://chemistry.stackexchange.com/questions/30754/effect-o... [4] https://nuscimagazine.com/water-so-pure-it-will-kill-you-2615d5ca116e/ https://nuscimagazine.com/water-so-pure-it-will-kill-you-261... [5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7576670/#:~:text=In%20a%20previous%20study%2C%20we,mineral%20waters%20and%20tap%20water https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7576670/#:~:tex....
- lisper 3y ago> the water in the tank was so pure it had dissolved a spanner/wrench that was left in the bottom "Apparently somebody had left a wrench there when they filled it in 1995," he said. "When they drained it in 2000 the wrench had dissolved." I dunno, I think if you left a wrench soaking in regular water for five years there wouldn't be much left of it after that either.
- tiku 3y agosalt battery's.
- chiefalchemist 3y agoYou have that problem only if you decide to remove all the salt. You could decide to remove say 20% of the water and make that only H2O; effectively getting H20 and a higher concentration of salt water as outcomes. I say this having recently read about the desalination plant in Dubai.
- RyEgswuCsn 3y agoIt sort of does. RO produces relative large amount of waste water that are harder to deal with (e.g. storage, disposal). By spending more energy, you can turn the waste water into salt solids, which can be easier to dispose of.
- superq 3y agoThe Israelis ran into this problem with their mineral extraction in the Dead Sea, so they're bulldozing the dry salt waste to build a physical wall for border security (more than 10 meters high) that's apparently hard to climb: https://www.youtube.com/watch?v=tgTheUjeDlg https://www.youtube.com/watch?v=tgTheUjeDlg
- nly 3y agoErrrr...rain? Runoff?
- dekelpilli 3y agoAnswered at 2:16 of the video - the claim is that the rain actually helps, as it makes the "mountain" steeper.
- ChiperSoft 3y agoYeah, but it runs along a river… which will now be salinated every time it rains.
- sh34r 3y agoI did a bit of Googling. It’s a desalination plant on the Dead Sea. That is the Jordan River. The stretch they are building the salt wall on is barren desert land. Jericho is the nearest town, 18,000 people, 8” of rain a year, 2 miles from the border. They presumably get their water from that desalination plant. No towns that far south are getting their water from it. The river barely even makes it to the Dead Sea anymore. https://en.wikipedia.org/wiki/Jordan_River#Main_environmental_issues https://en.wikipedia.org/wiki/Jordan_River#Main_environmenta... Adding a bit more salt into the famously-salty Dead Sea are the least of their problems in that part of the world. Where else would you put the salt, anyway? Putting it all into the Dead Sea would be even worse —- at least this reduces the amount that makes it back there. Putting it into any other watershed would cause vastly more harm. It seems like a good enough solution to me. If you think about it, it wouldn’t be in Israel’s interests to inflame tensions with Jordan over this, if it were really an issue.