> In fact, the study concluded that for every liter of freshwater a plant produces, 0.4 gallons (1.5 liters) of brine are produced on average.
I hate that they mix the units here. Why not "for every liter of freshwater a plant produces, 1.5 liters of brine are produced" or "for every gallon of freshwater a plant produces, 1.5 gallon of brine are produced" or even "for every unit of freshwater a plant produces, 1.5 units of brine are produced"
Also, producing more brine would make the brine less concentrated and less harmful - it would be better not worse.
> This untreated salt water can’t just hang around in ponds—or, in worst-case scenarios, go into oceans or sewers. Disposal depends on geography, but typically the waste does go into oceans or sewers, if not injected into wells or kept in evaporation ponds. The high concentrations of salt, as well as chemicals like copper and chlorine, can make it toxic to marine life.
> “Brine underflows deplete dissolved oxygen in the receiving waters,” said lead author Edward Jones, who worked at the institute and is now at Wageningen University in the Netherlands, in a press release. “High salinity and reduced dissolved oxygen levels can have profound impacts on benthic organisms, which can translate into ecological effects observable throughout the food chain.”
It's an actual waste product that has to actually be responsibly handled. It's not "just the salty water from the ocean that we can dump back in however we want."
It mostly is, and the additional chemicals they mention are already in the sea water, not that were added somehow in the process. It's just concentrated.
That it's concentrated is a problem, obviously -- very high-saline water (e.g. brine) and concentrated toxins are a problem, and would cause environmental problems if just dumped. The most common way to deal with brine is simply diluting it before discharge, ensuring that the salt content isn't high enough that it sinks and forms a brine pool.
Yes, just like exhaled breath is a waste product full of C02 and containing very little oxygen. If other people had to breath that they would become very sick or even die.
I’m surprised this article mentions nothing about energy. Practically all desalination in existence is powered by fossil fuels, with Israel and Saudi Arabia being the worst offenders. The only reason it’s even economically viable is the externalized cost of carbon emission. It’s simply not a long term tenable solution until this is addressed.
Carbon emissions is a grave problem with existing desalination infrastructure, but this seems something that can be solved. I'd expect desalination to be well suited for opportunistic use of solar or wind power. Build up reserves of clean water when it's sunny or windy, then deplete those reserves when cheap spare energy isn't available.
Of course this goes for new desalination plants. Whether there's political will to convert existing plants to non-fossil fuel sources is another matter. But at least from an engineering perspective there is a way forward.
What I get out of the article is that disposing of brine is an ecological hazard. This shouldn't really be a surprise since any engineering effort at large scale is going to have some kind of environmental impact, but this is a new consideration for those of us who don't work in the industry and hadn't thought too deeply about the process.
In Western Australia, a desal plant was built a few years ago [0]. At the same time, a wind farm [1] that offset the power use of the desal plant was built.
This is not a show stopper. If you discharge brine into the sea, you should have to have a plan to dilute and mix brine.
High concentration brine does not automatically mix into the sea water. The underflow goes into the bottom of the sea and forms a separate layer. But you can use nozzle diffusers, mixer etc. and discharge into high currents.
Sure, the high salt concentration kills sea life for a couple hundred meters around where the waste comes out, but compared to the total size of the ocean, I'd imagine the affected area would be TINY. Once you get to a larger area it'd be totally diluted by the normal salinity seawater.
Why don't you just build a pipeline to put the dead spot a couple miles away from shore, far away from economically important beaches, fisheries and reefs?
Maybe have an additional pump to send fresh seawater into the areas of highest concentration, basically set up a countercurrent exchange gradient.
I'm sure there are trivial, low-cost engineering solutions to this problem.
> At the very least, we should be treating the brine so it’s safe to discharge into the ocean.
This amused me as I pictured people mixing newly produced fresh water with the brine and releasing this "new" seawater back.
Seriously though, I guess I assumed people were at least turning this stuff into salt. I watched a documentary on salt production (Italy I think) and they just got sea water and evaporated it in huge salt beds.
I kind of assumed the sea salt (Malden) I buy has been created using the same process.
Sea salt has it's own problems due to it's microplastics content. Around 90% of domestic sea salt contains microplastics and the average adult consumes around 2,000 microplastic particles as a result every year. People who go out of their way to buy sea salt presumably ingest significantly more on average.
My mother used to love sea salt, but recently switched to rock salt.
Do you mean sea water? The amount of fresh water the human race will extract from the oceans will be what fraction of a percentage point of the total? Not accounting for, of course, the fact that most of it will make its way back to the oceans.
If pumping it back in has a local effect, then by all means try to mitigate that. But the idea that we're producing 'toxic waste' by creating saltier sea water is absurd.
I know it's not generally accepted on HN to say "please read the article before commenting on the article." But it's worth noting that the contents and effect of the "brine" as distinct from "sea water" get two full paragraphs devoted to them in the article.
"While most studies focus on salinity as the
primary cause of biological effects, many chemicals are used in the desalination process (e.g.
antiscalants, biocides, etc.), some of which can be toxic."[1]
This isn't absurd at all. Sea water contains lots of components, not just salt. Many are non-toxic at their current concentration; if you remove the water and pump in the rest into the ocean, you're potentially increasing the concentration enough to make it toxic. It is quite literally toxic waste. And the journalist did you the favor of linking to scientific research that says the same thing.
It's Gizmodo. These "news" outlets are largely staffed by comms majors who couldn't find jobs elsewhere. You know that kid at the back of the class that never paid attention or missed half the semester, but somehow barely managed to graduate? Those are Gizmodo/Buzzfeed/etc. writers.
Stupid question: Being that a large fraction of the problematic plants seem to exist close to or within desert countries, couldn't you simply pump it into the desert? I figure, if you find an appropriate area, you'll have not much of an ecosystem to destroy anyway and the area could eventually function as an enormous evaporation pond.
I think the issue is the scale of the operation. It's not that the desert doesn't have the capacity to absorb brine, it's that pumping all that brine into one spot creates a local ecological catastrophe. To avoid a concentration of toxins you need to spread it around, which is expensive.
My expectation is that the brine will have to go back into the ocean. The deserts a big, but the ocean is bigger. What the paper mentioned in the article points out is that you can't dump this all in one place.
If you're wanting to make fresh water there, it's probably because people do actually live there and want to do other stuff there, so any method of polluting the environment is going to have negative consequences.
For example if they are extracting fresh water from seawater, they are probably also already using groundwater as well which your proposal would pollute.
I admit I had not expected this to be a problem. The salt water comes from the sea, I'd expected it to be fine to release the salt back into the sea.
But I understand that untreated, this extra-salty water would, in large amounts, become a current of its own that's significantly different from regular sea water. And apparently there are added chemicals in it that I suppose were necessary for the desalination process? Shows how little I know about desalination, I guess.
Still, cleaning and diluting it and releasing it back into the ocean seems like the only workable solution. It just needs to be cleaned better and with an eye on the consequences of how and where this enters the ocean.
Is a bigger problem in shallow water. At open sea, salt will sink to the next deep water layer with the same density. (Marine organisms are relatively customed to deal with reasonable amounts of salt, the deeper the more customed).
Could be pre-diluted offshore with an unlimited amount of surface sea water available. But if there is more things than salt in the mix, or if we want to just dump it at the sea for saving some dollars, then we are creating a problem.
On the other thing, humanity needs salt, specially in badlands and deserts or in very cold areas. We could just refine, clean and then eat it.
Can't this brine be mixed with cleaned sewage water to produce something similar to the original seawater wrt salinity and copper/chloride concentration?
The desalinated water will end up back in the oceans eventually, so should the brine. Of course you can't just dump it back in directly, but if diluted and released responsibly, the ocean is the right place for the brine.
I see this as an opportunity. Before you dilute the brine with sea water and pump it back into the ocean, ideally you remove the microplastics and perhaps some other problematic substances and thus clean up the ocean.
I assume the brine is heavier than regular sea water. Could leading it through a pipe directly into the deep ocean be a (slightly) better option? There's less marine life there and it can slowly mix with the ocean water.
Deep ocean water also has a higher salinity and lower oxygen content already.
Sewage contains other volatile products that would evaporate and condense along with water. Cleaning sewage water for use in drinking is probably much, much harder than doing it with just sea water.
[+] [-] rjmunro|7 years ago|reply
I hate that they mix the units here. Why not "for every liter of freshwater a plant produces, 1.5 liters of brine are produced" or "for every gallon of freshwater a plant produces, 1.5 gallon of brine are produced" or even "for every unit of freshwater a plant produces, 1.5 units of brine are produced"
Also, producing more brine would make the brine less concentrated and less harmful - it would be better not worse.
[+] [-] arkades|7 years ago|reply
> This untreated salt water can’t just hang around in ponds—or, in worst-case scenarios, go into oceans or sewers. Disposal depends on geography, but typically the waste does go into oceans or sewers, if not injected into wells or kept in evaporation ponds. The high concentrations of salt, as well as chemicals like copper and chlorine, can make it toxic to marine life.
> “Brine underflows deplete dissolved oxygen in the receiving waters,” said lead author Edward Jones, who worked at the institute and is now at Wageningen University in the Netherlands, in a press release. “High salinity and reduced dissolved oxygen levels can have profound impacts on benthic organisms, which can translate into ecological effects observable throughout the food chain.”
It's an actual waste product that has to actually be responsibly handled. It's not "just the salty water from the ocean that we can dump back in however we want."
[+] [-] endorphone|7 years ago|reply
It mostly is, and the additional chemicals they mention are already in the sea water, not that were added somehow in the process. It's just concentrated.
That it's concentrated is a problem, obviously -- very high-saline water (e.g. brine) and concentrated toxins are a problem, and would cause environmental problems if just dumped. The most common way to deal with brine is simply diluting it before discharge, ensuring that the salt content isn't high enough that it sinks and forms a brine pool.
[+] [-] sunstone|7 years ago|reply
[+] [-] tim333|7 years ago|reply
[+] [-] nickthemagicman|7 years ago|reply
[+] [-] aphextron|7 years ago|reply
[+] [-] loudmax|7 years ago|reply
Of course this goes for new desalination plants. Whether there's political will to convert existing plants to non-fossil fuel sources is another matter. But at least from an engineering perspective there is a way forward.
What I get out of the article is that disposing of brine is an ecological hazard. This shouldn't really be a surprise since any engineering effort at large scale is going to have some kind of environmental impact, but this is a new consideration for those of us who don't work in the industry and hadn't thought too deeply about the process.
[+] [-] foxrob92|7 years ago|reply
[0] https://www.watercorporation.com.au/water-supply/our-water-s...
[1] https://en.wikipedia.org/wiki/Emu_Downs_Wind_Farm
[+] [-] mcv|7 years ago|reply
Sound like really obvious places to use solar.
[+] [-] Tsubasachan|7 years ago|reply
Desalination is good for drinking water but its not going to save California's farming though.
[+] [-] nabla9|7 years ago|reply
High concentration brine does not automatically mix into the sea water. The underflow goes into the bottom of the sea and forms a separate layer. But you can use nozzle diffusers, mixer etc. and discharge into high currents.
[+] [-] Gibbon1|7 years ago|reply
[+] [-] csense|7 years ago|reply
Why don't you just build a pipeline to put the dead spot a couple miles away from shore, far away from economically important beaches, fisheries and reefs?
Maybe have an additional pump to send fresh seawater into the areas of highest concentration, basically set up a countercurrent exchange gradient.
I'm sure there are trivial, low-cost engineering solutions to this problem.
[+] [-] wlll|7 years ago|reply
This amused me as I pictured people mixing newly produced fresh water with the brine and releasing this "new" seawater back.
Seriously though, I guess I assumed people were at least turning this stuff into salt. I watched a documentary on salt production (Italy I think) and they just got sea water and evaporated it in huge salt beds.
I kind of assumed the sea salt (Malden) I buy has been created using the same process.
[+] [-] simonh|7 years ago|reply
My mother used to love sea salt, but recently switched to rock salt.
[+] [-] kaybe|7 years ago|reply
https://en.wikipedia.org/wiki/Osmotic_power
[+] [-] mabbo|7 years ago|reply
I am intrigued to hear how the author plans to take water from sea level then use it to generate hydroelectric energy.
[+] [-] w1nt3rmu4e|7 years ago|reply
Do you mean sea water? The amount of fresh water the human race will extract from the oceans will be what fraction of a percentage point of the total? Not accounting for, of course, the fact that most of it will make its way back to the oceans.
If pumping it back in has a local effect, then by all means try to mitigate that. But the idea that we're producing 'toxic waste' by creating saltier sea water is absurd.
What is with journalism today?
[+] [-] arkades|7 years ago|reply
Maybe let's not attack the journalist.
[+] [-] pssst|7 years ago|reply
[1] https://www.waterboards.ca.gov/water_issues/programs/ocean/d...
[+] [-] geofft|7 years ago|reply
[+] [-] Dirlewanger|7 years ago|reply
[+] [-] xg15|7 years ago|reply
[+] [-] loudmax|7 years ago|reply
My expectation is that the brine will have to go back into the ocean. The deserts a big, but the ocean is bigger. What the paper mentioned in the article points out is that you can't dump this all in one place.
[+] [-] simonh|7 years ago|reply
For example if they are extracting fresh water from seawater, they are probably also already using groundwater as well which your proposal would pollute.
[+] [-] swish_bob|7 years ago|reply
[+] [-] mcv|7 years ago|reply
But I understand that untreated, this extra-salty water would, in large amounts, become a current of its own that's significantly different from regular sea water. And apparently there are added chemicals in it that I suppose were necessary for the desalination process? Shows how little I know about desalination, I guess.
Still, cleaning and diluting it and releasing it back into the ocean seems like the only workable solution. It just needs to be cleaned better and with an eye on the consequences of how and where this enters the ocean.
[+] [-] pvaldes|7 years ago|reply
Could be pre-diluted offshore with an unlimited amount of surface sea water available. But if there is more things than salt in the mix, or if we want to just dump it at the sea for saving some dollars, then we are creating a problem.
On the other thing, humanity needs salt, specially in badlands and deserts or in very cold areas. We could just refine, clean and then eat it.
[+] [-] peteretep|7 years ago|reply
https://www.radiotimes.com/news/tv/2018-02-09/blue-planet-vi...
[+] [-] yummybear|7 years ago|reply
[+] [-] ryanmercer|7 years ago|reply
You're better off treating the 'cleaned' sewage water for reuse as drinking water, which is being done in many locations.
[+] [-] abalone|7 years ago|reply
Why is this ratio so bad? What would it take to recover more water and produce more concentrated waste that could be managed differently?
[+] [-] bryanlarsen|7 years ago|reply
[+] [-] Tepix|7 years ago|reply
[+] [-] Arn_Thor|7 years ago|reply
/depressed sarcasm/
[+] [-] D_Alex|7 years ago|reply
[+] [-] ginko|7 years ago|reply
[+] [-] yetihehe|7 years ago|reply
How does removing water from solution makes more of that solution?
[+] [-] arkades|7 years ago|reply
1 L freshwater comes out of pipe A.
1.5 L wastewater comes out of pipe B.
[+] [-] xg15|7 years ago|reply
[+] [-] falcor84|7 years ago|reply
[+] [-] samatman|7 years ago|reply
[+] [-] salty_biscuits|7 years ago|reply
[+] [-] tempestn|7 years ago|reply
[+] [-] jaddood|7 years ago|reply
[+] [-] saagarjha|7 years ago|reply
What do you suggest using instead?
[+] [-] senectus1|7 years ago|reply
[+] [-] jamisteven|7 years ago|reply
[+] [-] rajaravivarma_r|7 years ago|reply