News for hackers. Stuff that matters.
Re:Why Is Desalination So Difficult? by iudqnolq on Wednesday July 05, 2023 @02:29PM (#36604882)
*typical American household uses directly.

Don't forget food, industrial, etc

Re:Why Is Desalination So Difficult? by Veserv on Wednesday July 05, 2023 @02:42PM (#36605124)
Freshwater withdrawals per capita in the US (which includes agricultural exports and animal feed such as alfalfa sent to Saudi Arabia) are around 1550 cubic meters per year.

https://ourworldindata.org/grapher/water-withdrawals-per-cap...

So that is around $775 per person per year assuming no net change in water use. In contrast, Germany uses around 410 m^3, France around 475 m^3, and Australia around 724 m^3, so the US is a significant outlier.

Re:Why Is Desalination So Difficult? by iudqnolq on Wednesday July 05, 2023 @02:46PM (#36605188)
That equates to around 4,000 liters per person per day.

Freshwater withdrawals is a very broad category, it also includes water released to turn hydropower turbines. But it's also unfair to compare across countries without taking into account water sent between countries in the form of produce and products.

Re:Why Is Desalination So Difficult? by Veserv on Wednesday July 05, 2023 @02:56PM (#36605354)
You were quibbling about how 1,000 liters per day does not adequately account for all usage. Freshwater withdrawals is on average going to be a overestimate and the US is one of the worst outliers with significant agricultural exports which are one of the largest contributors to differential water withdrawals. Despite this, it would only be $2.00 per day for a fully desalinated water supply even if we safely overestimate usage. Despite it being 4x higher than the person you replied to said, that is still incredibly cheap.
Re:Why Is Desalination So Difficult? by iudqnolq on Wednesday July 05, 2023 @03:27PM (#36605812)
I agree with everything you say (with the assumption the person I replied to has the correct price, which I know nothing about)
Re:Why Is Desalination So Difficult? by Hxnd on Wednesday July 05, 2023 @05:41PM (#36607558)
>Despite it being 4x higher than the person you replied to said

$0.5 was per household. $2.00 was per capita. So 10x higher.

Re:Why Is Desalination So Difficult? by codedokode on Wednesday July 05, 2023 @08:51PM (#36609464)
4,000 liters per day is too much. It is 10 full bathtubs. Do Americans leave the tap open or do they take a bath 10 times per day?
Re:Why Is Desalination So Difficult? by ateng on Wednesday July 05, 2023 @10:09PM (#36610124)
Agriculture and industry can use _a lot_ of water. Likely the 4000l figure includes that.
Re:Why Is Desalination So Difficult? by Veserv on Wednesday July 05, 2023 @10:16PM (#36610172)
It accounts for the water used in agriculture, industry, power generation, etc. Those uses completely dominate domestic water usage including for aesthetic purposes such as lawns and golf courses (e.g. around 80% of water usage in California is for agriculture and power generation if I remember correctly with only around 5-10% for all domestic usage).

As you will note, the average German consumes 1,000 liters per day by the same metric which is 2.5 baths per day which is obviously unreasonable if we were only considering direct domestic water consumption.

To be fair, the agriculture is being grown to feed people, so it is fair to include the consumed produce in each person’s water footprint. This is further exacerbated by growing animal feed for animals that are consumed which is even more “water inefficient”. The US is a major food exporter, so it is over-represented in these sorts of numbers, but it is a fair approximation to within a factor of maybe 2-3x of the embodied water consumption of the average American.

Re:Why Is Desalination So Difficult? by iudqnolq on Wednesday July 05, 2023 @11:27PM (#36610751)
Maybe my comment wasn't clear. That figure isn't great - we just divided the total amount of freshwater diverted to some kind of use by the population. That even includes letting water flow past hydropower turbines. It's obviously too big.

But not counting the water used to put food on your table is too small. So this establishes some bounds.

Re:Why Is Desalination So Difficult? by pfdietz on Wednesday July 05, 2023 @07:51PM (#36608924)
> 1550 cubic meters per year

This is an interesting number. Recently, I saw complaints that green hydrogen is impractical because it would use too much water. But if all the per capita energy use in the US went to electrolysis, it would use about 1% of this water per capita (and, of course, green hydrogen would be only a fraction of total energy use, due to all the preferred direct uses of electrical energy.)

Re:Why Is Desalination So Difficult? by pbhjpbhj on Thursday July 06, 2023 @03:55AM (#36612666)
When you burn the hydrogen you get pure water back too.
Re:Why Is Desalination So Difficult? by slashdev on Thursday July 06, 2023 @09:37AM (#36615555)
That just goes to show that people will complain about anything instead of applying their brain.

There are plenty of valid objections to hydrogen as a fuel, but water use is a total non issue. Not only does it use so little, but when you get energy back out of the hydrogen, the waste product is water again. It’s literally a renewable cycle.

Re:Why Is Desalination So Difficult? by bufferoverflow on Wednesday July 05, 2023 @02:39PM (#36605083)
Yes, but you pay for that when you purchase the products. These costs are baked in.
Re:Why Is Desalination So Difficult? by iudqnolq on Wednesday July 05, 2023 @02:43PM (#36605139)
But we're talking about increasing the per-gallon cost of everything. So the baked in cost would increase.
Re:Why Is Desalination So Difficult? by jjk166 on Wednesday July 05, 2023 @02:54PM (#36605321)
Or moving water intensive operations away from areas where water is expensive. No one is going to be doing desalination in Michigan.
Re:Why Is Desalination So Difficult? by dylan604 on Wednesday July 05, 2023 @03:10PM (#36605544)
why not? we're growing heavy water using crops in places with little water. logic is not always the deciding factor if involved at all in a lot of modern things
Re:Why Is Desalination So Difficult? by sophacles on Wednesday July 05, 2023 @05:04PM (#36607090)
There are a few very big salt mines below the great lakes. We could totally get a desalinization plant in Michigan by pulling water from the lakes, salt from the Detroit salt mine, and combining them in the input stream to the plant!
Re:Why Is Desalination So Difficult? by dylan604 on Wednesday July 05, 2023 @05:08PM (#36607141)
someone has been playing in the perpetual motion machine sandbox again i see
Re:Why Is Desalination So Difficult? by 6510 on Wednesday July 05, 2023 @09:27PM (#36609723)
I think it sounds quite sensible. How is it different from using all fresh water as an all you can dump free-for-all public sewage system before wondering where the drink is coming from? In India they poop in the water then take a bath in it and cook their food in it. In the west we do our pooping upstream because it looks so much cleaner that way. NO! I fail to see how adding salt before desalination is any less sensible. Lets just do it.
Re:Why Is Desalination So Difficult? by dylan604 on Wednesday July 05, 2023 @09:34PM (#36609798)
you're desalinating water to have an abundant source of fresh water. why in the world does taking fresh water and adding salt being mined from the ground together to make salt water to then desalinate make any sort of sense?
Re:Why Is Desalination So Difficult? by 6510 on Wednesday July 05, 2023 @11:46PM (#36610910)
We already have abundant fresh water. We use it to transport sewage, fertilizers and other crap to the ocean. It would be silly to try to clean it afterwards - but here we are?

Adding salt is a great idea, it pushes our collective stupidity to a noteworthy level of nonsensicalness.

It makes me wonder what other hard to remove poisons we could add to challenge ourselves. Perhaps design a new disease?

Re:Why Is Desalination So Difficult? by dylan604 on Wednesday July 05, 2023 @11:54PM (#36610993)
>We already have abundant fresh water.

Clearly, you're not having a rational conversation with comments like this. If there was an abundance of fresh water, the western half of the US would not have been in severe drought conditions for the past however many years. This is where I leave you as you are just making things up like and not even having a good faith conversation

Re:Why Is Desalination So Difficult? by 6510 on Thursday July 06, 2023 @01:45AM (#36611783)
I'm just watering the lawn.
Re:Why Is Desalination So Difficult? by cyanydeez on Wednesday July 05, 2023 @06:16PM (#36607956)
Certain Michigan towns may need to do so...
Re:Why Is Desalination So Difficult? by janalsncm on Wednesday July 05, 2023 @02:44PM (#36605162)
I think the implication is that the costs will be higher than 50 cents if 50 cents does not cover non-household use.
Re:Why Is Desalination So Difficult? by gamegoblin on Wednesday July 05, 2023 @02:33PM (#36604966)
Good point, though brings one to another interesting detail from the Israeli water book:

Over 90% of sewage water is treated and recycled to use as agricultural water, creating kind of a full loop here. Very impressive infrastructure.