# Awesome new desalinator **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [October 1, 2023, 9:09am UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950 "2023-10-01T09:09:13Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [October 1, 2023, 4:12pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/21 "2023-10-01T16:12:11Z")
> [@LSLGuy](#): > > Whether the amount of capturable runoff and sewage treatment plant effluent would be a meaningful dilution to the high-test desalination brine effluent is an interesting analysis. Or could we do just as well in terms of dilution with less total plumbing just by spreading the raw desalination effluent out in the ocean across miles of small outlets, rather than 1 or two big ones? kindalike pumping the salty brine into the last mile of a sweetwater river before it enters the sea … (conceptually speaking) of course you (generic you) can do the math and figure out how much brine can be accepted to not disturb the ecosystem … and a more relevant problem: if you have a sweetwater river nearby - no need for desalination … in terms of wastwater runoff: I just stumbled on a vid that explains that out of 100L saltwater, 45 L sweetwater was won and 55 L will run back … so to make math easy, call it 50:50 … so you have 50L of water running back with twice the salt concentration … doesn’t sound unsurmountable … but as so often - the devil is in the details … e.g. making the mini-geographics work … ---
**Author:** ![Kimstu](https://avatars.discourse-cdn.com/v4/letter/k/ecd19e/32.png) [@Kimstu](https://boards.straightdope.com/u/Kimstu)\ **Post date:** [October 1, 2023, 4:13pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/22 "2023-10-01T16:13:09Z")
Gotta thought: AFAICT, container ship ballast usually takes the form of salt water. Maybe they could load up in port with desalination-concentrate brine instead, and gradually swap it out with regular-salinity seawater while en route? Even concentrated brine seems likely to be much more effectively diluted if dumped across miles of deepwater ocean. ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [October 1, 2023, 4:15pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/23 "2023-10-01T16:15:42Z")
again, the main problem will be fine-tuning the micro-geography of the system … iow: you’d need to put the plant pretty dead on in a port for this to work… ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [October 1, 2023, 4:15pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/24 "2023-10-01T16:15:47Z")
> [@ThisOneGuy](#): > > Seems like the fresh water created also ends up back in the ocean eventually, after going through people’s showers and toilets, etc. Maybe put the salt back in at that point? That’s how we do it here in Santa Barbara. > The waste product from the desalination process, referred to as brine, is **about twice as salty as normal seawater**. The brine is blended with the City’s treated wastewater and is discharged into the ocean over a mile and a half offshore. > **[Desal%20FAQs.pdf](https://santabarbaraca.gov/sites/default/files/documents/Public%20Works/Water%20Supply/Desal%20FAQs.pdf)** > > 138.17 KB ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 1, 2023, 4:21pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/25 "2023-10-01T16:21:19Z")
You gotta get the brine to the port. That would be expensive unless the desal plant is next to the port (not likely). Also not sure the ship’s ballast tanks would be enough to put a dent in the amount of brine they need to dispose of…but it could be a part of a larger system (maybe…I don’t know the math on this). ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [October 1, 2023, 4:31pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/26 "2023-10-01T16:31:52Z")
tangent: Here in the north of Chile, there are huge mining operations in the atacama-desert - up at 4000+ m. above sea … which use substantial amounts of water, but are only 50 or so km from the sea. What they did is: come to an agreement with local communities and use the meltwater from above (pretty much where they are) and supply the lower lying communities with desal. water (probably at a 1:2 ratio or so to sweeten de deal). so they do not have to pump up obscene amouts of water 4km high … (which they do anyway to a certain degree) … ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [October 1, 2023, 4:38pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/27 "2023-10-01T16:38:35Z")
Thinking about Santa Barbara’s desal system that can produce about 10,000 acre-feet of fresh water, and seeing figures of approx 1.5x brine produced, I get about 5 billion gallons of brine per year at max production. Google suggests that the largest container ships carry 2 to 3 million gallons of water in ballast at max capacity. So there I figure we’d need to load up 2,000 container ships with our brine if they showed up dead empty, which of course is unlikely. I would guess that least half of a ships ballast is relatively “permanent” water, taking my guesstimate to 4,000 ships a year. Couple problems. Santa Barbara is a very small city with only one desal plant so scale gets quickly even more out of hand for a more populous area. Also, somewhat inconveniently, _no_ container ships dock here. But even so, the port of LA only saw several hundred container ships last year and that’s one of the busiest ports in the world. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [October 1, 2023, 5:31pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/28 "2023-10-01T17:31:39Z")
> [@LSLGuy](#): > > Whether the amount of capturable runoff and sewage treatment plant effluent would be a meaningful dilution to the high-test desalination brine effluent is an interesting analysis. Or could we do just as well in terms of dilution with less total plumbing just by spreading the raw desalination effluent out in the ocean across miles of small outlets, rather than 1 or two big ones? Instead of a single desalination plant with pipelines to distribute the brine back into the ocean, I wonder if the reverse would work. Have multiple, smaller desal plants and pipelines to collect/distribute the fresh water to where it’s needed. It would depend on whether this new tech would be viable in small installations as well as large ones. ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [October 1, 2023, 5:54pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/29 "2023-10-01T17:54:05Z")
> [@Pork\_Rind](#): > > Couple problems. Santa Barbara is a very small city with only one desal plant so scale gets quickly even more out of hand for a more populous area. Also, somewhat inconveniently, _no_ container ships dock here. But even so, the port of LA only saw several hundred container ships last year and that’s one of the busiest ports in the world. my “guess” … a big part of the desal water might not get to the residents of S.B. but into agriculture … but I am too lazy to confirm … i.o.w. it does not necesarily scale up 1:10 for a city 10 times the size ---
**Author:** ![Pork\_Rind](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pork_rind/32/111_2.png) [@Pork\_Rind](https://boards.straightdope.com/u/Pork_Rind)\ **Post date:** [October 1, 2023, 5:59pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/30 "2023-10-01T17:59:05Z")
> [@Al128](#): > > my “guess” … a big part of the desal water might not get to the residents of S.B. but into agriculture … but I am too lazy to confirm … Fortunately (IMO, at least) the output of the desal plant only serves the downtown and immediately surrounding areas. Residential and business only. [![](https://i.imgur.com/hifUudR.jpg) ](https://i.imgur.com/hifUudR.jpg) ---
**Author:** ![thorny\_locust](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thorny_locust/32/431_2.png) [@thorny\_locust](https://boards.straightdope.com/u/thorny_locust)\ **Post date:** [October 1, 2023, 6:04pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/31 "2023-10-01T18:04:20Z")
> [@LSLGuy](#): > > But the point of my numbers is the volume of salt produced by desalination is so gigantic compared to the volume of fresh water produced that even tiny amounts of desalination will produce more salt than all of humanity can use. Ah. I didn’t look at the figures carefully enough to see that. So apparently this isn’t one of those cases in which two problems can be turned into one solution. Although stopping salt mining would certainly be an advantage (except for those companies currently making money from it.) > [@puzzlegal](#): > > all the tap water chimes from desalination Autoincorrect? > [@Broomstick](#): > > onder if we could dump the salt on already existing salt pans? Those are places already covered over with a layer of salt, after all, with large areas devoid of life. > > (Let’s _not_ dump it in desert areas that do have life, however scanty) Actually, salt flats are indeed areas that have life. > **[Hidden Life of Salt Pans](http://queenslandcoast.blogspot.com/2016/09/hidden-life-of-salt-pans.html)** > > Spiders living in salt pans, parasitic wasps. > **[Exploring The Vast And Enigmatic Utah Salt Flats - Skeehive](https://skeehive.com/things-to-do-in-utah/utah-salt-flats/)** > > Encompassing over 30,000 acres of shimmering white salt flats, Utah Salt Flats vast expanses offer an otherworldly experience > **[Andes: The Dragon's Back ~ Salt Flat Living | Nature | PBS](https://www.pbs.org/wnet/nature/andes-the-dragons-back-salt-flat-living/1792/)** > > The salt basins of the Atacama Desert in the high Andes are formidable places to call home. Located in a desert atop a high-altitude plateau in the middle ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [October 1, 2023, 6:38pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/32 "2023-10-01T18:38:47Z")
> [@thorny\_locust](#): > > > [@puzzlegal](#): > > > > all the tap water chimes from desalination > > Autoincorrect? Kinda. It’s a swypo. ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [October 1, 2023, 6:53pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/33 "2023-10-01T18:53:11Z")
> [@thorny\_locust](#): > > > [@LSLGuy](#): > > > > But the point of my numbers is the volume of salt produced by desalination is so gigantic compared to the volume of fresh water produced that even tiny amounts of desalination will produce more salt than all of humanity can use. > > Ah. I didn’t look at the figures carefully enough to see that. > > So apparently this isn’t one of those cases in which two problems can be turned into one solution. Are we figuring in salt used for livestock, de-icing of roads, and such? There’d probably still be some salt left over, but this would get us a little closer. Of course, where is it written that all human fresh water needs would come from desalination? If the brine does become a usable byproduct of desalination, maybe we’ll see desal plants built in the most economically favorable areas, while everywhere else gets their fresh water from the same sources they do now. Rather than build enough plants to meet all our water needs, we may only build enough to meet the demand for brine. We’d have enough salt to last forever. ---
**Author:** ![susan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/susan/32/17537_2.png) [@susan](https://boards.straightdope.com/u/susan)\ **Post date:** [October 1, 2023, 7:02pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/34 "2023-10-01T19:02:10Z")
How much pressure does it take to make walls with salt, such as those in the caves in Mt. Sodom? Is salt a viable building material for deserts? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 1, 2023, 7:04pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/35 "2023-10-01T19:04:09Z")
Even deserts get rain on occasion and salt dissolves in water. Not a good building material. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [October 1, 2023, 8:31pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/36 "2023-10-01T20:31:42Z")
> [@Kimstu](#): > > > [@puzzlegal](#): > > > > When i was in Israel this summer they told me all the tap water chimes from desalination. So Israel and Saudi Arabia and… We already have nation-sized desalination programs. > > With nation-sized [brine discharge environmental impacts.](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6959559/) Yes, but it’s also part of what keeps Israel and Jordan at peace. It’s probably worth it. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [October 1, 2023, 8:39pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/37 "2023-10-01T20:39:21Z")
Why not just purify waste water one step further? Cheaper, easier, and no piles of salt. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [October 1, 2023, 8:43pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/38 "2023-10-01T20:43:47Z")
Is it cheaper? I know treating to the level of gray water is done a lot and that water can be used for many things…just not consumption. My sense of it is that last step to potable water is a big and expensive step. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 1, 2023, 9:02pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/39 "2023-10-01T21:02:42Z")
My biggest question is scalability. It’s easy to make a desalination system that needs no energy input other than sunlight: Take any old desalination system, and attach it to as many solar panels as are needed to power it. But that many solar panels take up a lot of space. How much area would a system like this need to supply, say, Los Angeles with drinking water? ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [October 1, 2023, 9:33pm UTC](https://boards.straightdope.com/t/awesome-new-desalinator/990950/40 "2023-10-01T21:33:40Z")
> [@Whack-a-Mole](#): > > Is it cheaper? > > I know treating to the level of gray water is done a lot and that water can be used for many things…just not consumption. My sense of it is that last step to potable water is a big and expensive step. On a small scale it might have a use for off-grid locations in some niche circumstances. [Previous page](https://boards.straightdope.com/t/awesome-new-desalinator/990950.md?page=1) [Next page](https://boards.straightdope.com/t/awesome-new-desalinator/990950.md?page=3)