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Apart from whether the economics make sense brine disposal from desalinization is a big issue. Waste with high salt concentrations can wipe out marine life - it
by hnmullany 3y ago
Apart from whether the economics make sense brine disposal from desalinization is a big issue. Waste with high salt concentrations can wipe out marine life - it would be nice if this piece took the issue a little more seriously. It's a continuing problem in the Canary Islands which are dependent on desalinization plants:
"Rejected brine is a serious threat to marine ecosystems, causing negative effects on both flora and fauna. This is especially so when the optimal initial high dilution capacity is lacking in the discharge system. Consequently, brine discharge plumes spread over large areas of the sea floor and modify the structure and distribution of benthic communities such as seagrass habitats.
...
Rejected brine disposal costs are between 5 and 33% of the whole desalinization process, depending on the characteristics of the brine, its pretreatment level before disposal, disposal method, and volume"
from: Jiménez-Arias, D., Morales-Sierra, S., García-Machado, F.J., García-García, A.L., Luis, J.C., Valdés, F., Sandalio, L.M., Hernández-Suárez, M. & Borges, A.A. 2020, "Rejected brine recycling in hydroponic and thermo-solar evaporation systems for leisure and tourist facilities. Changing waste into raw material", Desalination, vol. 496, pp. 114443.
- zbrozek 3y agoIs there a way to know how much to care? We do all sorts of things that displace species, so having some way of contextualizing and weighting the harm against the benefit would be helpful.
- monkeynotes 3y agoSeems to me it would initially be a narrowly scoped to the immediate outflow. As the brine dissipates I assume it will be normalized by the rest of the ocean as it's diluted. However, as with all human endeavours, scaling up will scale up the problem. And we won't pay attention to that until it's a huge issue.
- jakderrida 3y ago[flagged]
- solardev 3y agoNot the OP, but I think humans in general find it difficult to scale up. Whether in software or manufacturing or politics or environmental issues, we're much more equipped to deal with 1 or 10 of something than 100,000 or 1 trillion of it. At the end of the day we're still limited by our biology and brains, evolved for very different setting than the world we now live in. We try and we get by but by and large we're not doing great at large scale issues, whether it's jobs or housing or healthcare or saving the planet or just plain getting along with each other. We're primates adapted for small group living in local communities, abruptly given way more power than our biology was designed for. Is that misanthropic? I dunno. If dolphins had opposable thumbs, they'd probably have gotten themselves into a similar bind.
- monkeynotes 3y agoWhether it's misanthropic or not is moot if it's just a plain fact.
- solardev 3y agoYeah, true too.
- solardev 3y agoThis is necessarily a value judgment, isn't it? There are tools like lifecycle analyses and environmental impact reports and threatened species lists that can help estimate/enumerate impacts. But ultimately how much to care is a personal question, and people are going to disagree over whether some small fish or rare owl or fluffy panda is worth more or less than someone's job or a local industry or just some other charismatic species. Species will always come and go, and they're going to die off faster than we can protect them, sadly. We only get to decide which ones to prioritize, at different personal, local, national, global levels etc.
- zbrozek 3y agoI would start by wanting to know about the impact and benefit relative to other activities which we already do. Like how's it compare to various flavors of farming?
- solardev 3y agoThere's a database for California Environmental Quality Act reports, I think (Environmental Impact Reports? Statements? One is federal and the other is state, can't remember which is which). That probably have similar solar farms you can look at. Not sure about huge desal projects. Maybe overseas? I'll try to find some analyses this weekend if I can.
- bobthepanda 3y agoThe Canaries have 32% of the economy based on tourism, and a good chunk of that depends on the local ecology (scuba, nice beaches, etc.) If you want to see what a tourism place looks like when you destroy its ecology, you only need look at the abandoned areas around the Salton Sea.
- palmfacehn 3y agoThe Salton Sea in its current iteration was created by the failure of an irrigation canal. Before that there was no Salton Sea as we know it or tourist area.
- bobthepanda 3y agoSure, but that’s beside the point of the question, which is “how do we know salinifying an area enough to kill species is bad”
- nickparker 3y ago> RO desal splits the incoming ~3% salinity stream into two halves, one fresh and one ~6% salinity. This concentrated brine is fed to adjacent brine processing facilities (ideally in both countries) that exploit the region’s abundant solar and geothermal energy to extract potentially millions of tonnes of lithium, sodium, magnesium, chloride, and other metals found in sea water. The resulting depleted brine is piped back to the ocean where it is thoroughly mixed with sea water and discharged. Casey's proposing we mine the brine for useful minerals. You're right he's glossing over details, but a citation addressing the economics of brine disposal with his proposed processing would add more to the discussion.
- thehappypm 3y agoBasically, I think you could take the Brine and just put it somewhere else. Like, into mine shafts, or into evaporation pools for mining purposes.
- ruined 3y agothe intent of the project is the conversion of a saline lake to freshwater, not the creation of a saline lake.
- mechanical_bear 3y agoIf you give a mouse a cookie…
- solardev 3y ago...be sure to give it an opt-out pop-up too?
- adhesive_wombat 3y agoConsidering that the brine output of a single large-ish plant might be 150,000m³ per day[1], that's a hell of a mine shaft to take it continuously. The rock with the same volume as a day's brine would weigh a million tons. The entire Aberfan spoil tips were only 2 weeks worth of that much volume (2 million cubic metres). The gigantic Hambach open-pit mine grows by 0.3km³ a year, so that could take it (but it can't take the Saudi million m³/day plant). By the time the mine is depleted, the resulting 18km³ pit would not be filled by our single hypothetical plant for over 300 years, assuming it won't evaporate. Which leads to: The evaporation pools might work: they'd "only" have to be 3000 acres (12 km²) to gather the 4GW of solar power at 1kW/m² for 8 hours a day to continuously evaporate that much water daily[2]. Which is certainly large, but not completely impossible. But then there's 2 million tonnes of salt per year which will accumulate continuously over time. [1] the largest is over a million [2] not including water not bring a perfect absorber of solar energy or differing insolation
- ketchupdebugger 3y agoThe naive solution is to just dump the brine back into salton sea, its already too salty for marine life, so whats a little more salt? >flaunt its unequaled excellence by exporting alfalfa to all corners of the globe. really not sure if this is satir.
- hcknwscommenter 3y agoYour naive solution just creates an even more gigantic stagnant stinky mess of a Salton "sea". The entire point is to reengineer the salton sea as a beautiful ecosystem and lake by diluting all the salt with 5MAF of RO desalinated water. The added benefit is huge economic revitalization of the entire area. Plus, because of the value of minerals in the brine, and the cost-effectiveness of solar power, it is not as expensive and crazy of an idea as one might think.
- deleted 3y ago[deleted]
- bilsbie 3y agoIt sucks you guys home in on some weird issue for every promising technology. He literally addresses brine in the article.
- solardev 3y agoIt's a community of hackers passionate about the way things work. Picking it apart helps everyone understand the inputs and outputs of a system to understand how feasible it is, and what the tradeoffs are. What would you prefer, a generic "that's nice"? As far as I can tell, the author just kinda glossed over the brine situation. Some minerals can be sold, but his solution for the excess salt was just to turbulently mix it back into the ocean, if I'm reading correctly. The sibling comments here explain why that isn't trivial (cost and wildlife impacts). I found them illuminating!
- hnu123 3y ago[flagged]
- solardev 3y agoWell yes, that too. A mix of both, not sure of the percentages. Frankly I wish there were a better place for the hackers to congregate without the capitalists. But whatever, at least the discussion here is civil and interesting. Best place I've found since Slashdot of old.
- 3y ago
- pfannkuchen 3y agoCan’t we pipe the seawater inland and then deposit the salt on land?
- bell-cot 3y agoWhen it rains, what happens to the run-off from a huge pile of salt?
- mrguyorama 3y agoSurely the massive open air pools of salt used for sea salt production have figured out how this process works. On the Californian coast, there is already at least https://en.wikipedia.org/wiki/South_Bay_Salt_Works https://en.wikipedia.org/wiki/South_Bay_Salt_Works , a sea salt production facility that uses salt pools. They produce 80k tons annually of salt, which means they process 2666k tons of seawater to get that. If that one salt production facility used brine as their source instead of seawater, they would have allowed the facility to produce 2580k tons of freshwater. The "urban" usage of water in California is 10 million acre-feet (ish), so that's not exactly a significant amount.
- jvanderbot 3y agoPerhaps the net effect is ostensibly positive, given the greening and habitation of that blighted area in CA.
- obblekk 3y agoThere should definitely be a plan for the brine. I'm optimistic we could: * Build ocean pipelines that disperse brine over much larger volumes of water to minimize impact on wildlife * Dump the brine water in engineered desert fields where it will evaporate and deposit salt reserves. In general, we should be aware of the whole lifecycle of a solution, and optimistically believe we can solve each problem with more work.
- margalabargala 3y ago> Dump the brine water in engineered desert fields where it will evaporate and deposit salt reserves. Honestly, the Salton Sea would be a great place to dump the brine. It would keep the water levels up and reduce the respiratory issues caused by drying, and any ecosystem to be destroyed has been thoroughly destroyed for decades. Nix the "turn the manmade salt lake to a manmade fresh lake" plan, and use the created freshwater for agriculture directly, or send it off to LA, or do anything with it that isn't "refill the accidental lake that already has evaporation and pollution issues". It's a salt lake, use it as one.
- solardev 3y agoThis is something I still don't understand about the original plan: Where is the Salton Sea expected to get more water from on an ongoing basis? If you keep extracting from it and not refilling it, it's just going to keep getting smaller and saltier. Agriculture isn't going to put back out as much as it takes in (the plants need it, after all). Sure, you can drag it out a few more years with desal, but eventually it's not going to be much of a sea, just a salty pile.
- bryanlarsen 3y agoAFAICT, water is pumped from both the Sea of Cortez & the Salton Sea to a desal plant. The fresh water is used for irrigation etc, and the runoff from primary use replenishes the Salton.
- digging 3y agoHuh, I guess I was mistaken that restoration on the Salton Sea was already in progress. I've seen large flocks of birds in and around it and assumed there was food for them in it. But it sounds like no, it's still horrible.
- konschubert 3y agoIf you desalinate 1 gallon of seawater, and then mix the brine with 10 gallons of seawater, the salt content of that seawater has increased ~10 percent. If that’s still too much, use 20 gallons. It’s a matter of spending energy on pumps, but it’s totally doable. Also, the ocean salt content will not be increased by this, since the desalinated water will eventually make it back to the ocean.
- jryb 3y agoBut where are you getting that pure seawater from? If it's anywhere near the outlet, there's a scale at which the concentrated brine will affect the salinity of your inlet.
- deleted 3y ago[deleted]
- konschubert 3y agoYes, some pipes are needed. Beyond that, you rely on ocean currents. .
- BytesAndGears 3y agoYeah, but if you’re pulling in water and disposing it from a specific region, eventually the water that you’re pulling in is progressively saltier, and you’re compounding the saltiness of that area. I’m sure that ocean currents will eventually equalize the salt, but if you’re continuously dumping salt into a specific area, it’s going to make that region of the ocean saltier.
- konschubert 3y agoYou need pipes to spread it out. And I think you may be underestimating the scale and force of ocean currents. Every tide probably moves more water than California uses in a year.
- solardev 3y ago
- nradov 3y agoBrine discharge is an issue, but the geography of the North American West Coast is favorable for that. In most places the seafloor drops down fairly deep just a short distance offshore. Past about 400 ft / 120 m there is no flora at all, and most fauna is clustered around rock structures. So, the impact of brine discharge can be minimized with careful pipeline siting.
- anon84873628 3y agoCareful pipeline siting indeed. The author needs to update the proposal to have the brine exiting on the Pacific coast, rather than annihilating the the Sea of Cortez.
- ed_balls 3y agoyou could use brine for construction (Isreal build a wall along Jordan). Also you can pump it into a ship and dump into Pacific, slowly.
- gwern 3y agoYour quote doesn't give any evidence it is a big problem. It simply asserts that it is a problem and includes some random factoid about the cost.