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Scientists cook up new recipes for taking salt out of seawater

phys.org

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Re: Scientists cook up new recipes for taking salt out of seawater

#41

Post by gus_massa »

heymijo wrote: post #29
Overtonwindow wrote: post #12

I don’t think the problem we should be focusing on is how to remove salt from water, but what to do with the salt after it has been removed.

There was an article linked to here in 2016 about an inventor who developed a process that reduces the need for brine disposal by nearly 100 percent . [0] Not sure what progress has been made since [0] https://www.scientificamerican.com/article/desalination-brea... [1] https://news.ycombinator.com/item?id=12191089

The process uses calcium oxide (aka quicklime or burnt lime), you need to use energy to produce it. [1]

The products don't look too valuable, it produce calcium chloride and sodium bicarbonate. How big is the market for them? How expensive are them? Why is no one using this process to produce them using salt form a saline? Where they going to dispose the excess of calcium chloride and sodium bicarbonate that nobody wants to buy?

It looks like a mix of buzzword, like "carbon sequestration" and "brine reduction", but the whole idea makes no sense.

[1] How much CO2 release the production of CaO? It is not only important to consider the energy to produce the CaO, but also that most CaO is produced from limestone that is CaCO3 in the reaction CaCO3-->CaO+CO2.

Re: Scientists cook up new recipes for taking salt out of seawater

#42

Post by amluto »

dillonmckay wrote: post #16
Retric wrote: post #11

Earlier quoted context omitted.

Sewage and distribution is not included in these costs. Current systems get water for almost nothing it’s mostly distribution and sewage systems that you’re currently paying for. As to why this is, a single pipe carrying 1,000x as much water costs no where near 1,000x much per foot. Each home might only need 1/10,000,000 the water, but it’s got to be built for peak demand not average useage. On top of this, people do…

My municipality loses about 60% of its water supply due to leaks. They buy the water from the neighboring municipality for $3/1,000 gallons, and sell it to the users of the system for $23/1,000 for the first 1,000 gallons.

Yikes! I thought I paid a lot for water, but you have me beat.

Re: Scientists cook up new recipes for taking salt out of seawater

#44

Post by brokensegue »

umvi wrote: post #43
brokensegue wrote: post #20

Earlier quoted context omitted.

Nobody wants to buy the sludge. Putting it back would kill ocean life in the area.

Just dump it in the great salt lake then

uhm, trucking this sludge all the way to Utah seems pretty pointless. Why not just put it in a dump? Why does it need to be put into water?

Re: Scientists cook up new recipes for taking salt out of seawater

#45

Post by LargoLasskhyfv »

brokensegue wrote: post #44
umvi wrote: post #43

Earlier quoted context omitted.

Just dump it in the great salt lake then

uhm, trucking this sludge all the way to Utah seems pretty pointless. Why not just put it in a dump? Why does it need to be put into water?

Maybe to avoid build up of toxic dust like around the drying up https://en.wikipedia.org/wiki/Salton_Sea ?

https://www.latimes.com/science/la-me-salton-sea-20151001-st...

Edit: To put it more generally: To avoid https://en.wikipedia.org/wiki/Salting_the_earth

Re: Scientists cook up new recipes for taking salt out of seawater

#46

Post by londons_explore »

amluto wrote: post #42
dillonmckay wrote: post #16

Earlier quoted context omitted.

My municipality loses about 60% of its water supply due to leaks. They buy the water from the neighboring municipality for $3/1,000 gallons, and sell it to the users of the system for $23/1,000 for the first 1,000 gallons.

Yikes! I thought I paid a lot for water, but you have me beat.

$1000 per 1000 gallons is the price in some parts of the world.

You soon realise half a gallon is plenty to drink, and you don't really need water for much else.

Re: Scientists cook up new recipes for taking salt out of seawater

#47

Post by megaremote »

jdavis703 wrote: post #36
Retric wrote: post #6

Earlier quoted context omitted.

Desalination is cheap in day to day terms, it’s the scale of water we use that’s the issue. Sure, we can get ~1,000 gallons of drinking water for 3$ via desalination. That works out to a monthly water bill increase of ~45$ for a family of 5. Unfortunately, crops need incredible amounts of water. So, growing corn etc with desalination would case food prices to ~quadruple.

In California we grow water thirsty crops like rice and almonds. By substituting out for less water intense agriculture such price shocks could be reduced. There's also the whole issue of producing animal feed, which is inherently less efficient than just having humans eat the feed directly.

Rice doesn't need much water. It is just easier to grow it like that.

Re: Scientists cook up new recipes for taking salt out of seawater

#48

Post by inetknght »

tobr wrote: post #34
inetknght wrote: post #31

Earlier quoted context omitted.

That sounds like a recipe to completely destroy the land, for _any_ other crops, on which saltwater crops are farmed.

Assuming you would use salt water on existing land, but wouldn’t it open up for growing crops in new places, on/close to seawater?

If you want to grow crops on the sands of the beach, maybe. Otherwise you're poisoning whatever land you're using.

Re: Scientists cook up new recipes for taking salt out of seawater

#49

Post by pixl97 »

brokensegue wrote: post #44
umvi wrote: post #43

Earlier quoted context omitted.

Just dump it in the great salt lake then

uhm, trucking this sludge all the way to Utah seems pretty pointless. Why not just put it in a dump? Why does it need to be put into water?

Think of brine as industrial pollution. It wont stay in a dump, it will leak out and poison an area for tens of thousands of years.

Re: Scientists cook up new recipes for taking salt out of seawater

#50

Post by jayventura »

inetknght wrote: post #31
amelius wrote: post #30

Earlier quoted context omitted.

Since seaweed can grow on salt water, can we perhaps engineer other crops to do the same?

That sounds like a recipe to completely destroy the land, for _any_ other crops, on which saltwater crops are farmed.

Even if we aren't irrigating crops directly with seawater, we may have to engineer crops to thrive on high saline irrigation anyways, as there is seawater leeching into aquifers in many agricultural centers around the world, including coastal California. As sea levels rise, we should expect this to be a larger problem and plan for it.
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