The Dirty Truth About Turning Seawater into Drinking Water

Post by pwagland » Thu, Jan 17, 2019, 12:04 PM UTC

tda wrote: post #53

csense wrote: post #42

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 beache…

That is what I intuitively thought, until I learnt that salinity in the Persian Gulf (a huge body of water connected to the ocean) is up significantly due to desalination. Salinity has risen 50% over the last two decades. See e.g. https://financialtribune.com/articles/people-environment/434...

Post by lifeformed » Thu, Jan 17, 2019, 12:07 PM UTC

saagarjha wrote: post #70

jamesholden wrote: post #66

Earlier quoted context omitted.

This is what I thought too. Why not dump them out into long shallow 'trays' which can then dry out in the sun, leaving behind just the salt, which can then be stored/used/disposed of. Also, I am not an expert.. but, couldn't we use the leftover salt for energy storage? https://www.solarreserve.com/en/technology/molten-salt-energ...

> Also, I am not an expert.. but, couldn't we use the leftover salt for energy storage? I don't think salt is something that is in particularly short supply.

Post by mirimir » Thu, Jan 17, 2019, 12:16 PM UTC

endorphone wrote: post #30

arkades wrote: post #6

Just to be clear, "brine" isn't "salty water." > 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. >…

Just to be clear, "brine" isn't "salty water." 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…

Post by semi-extrinsic » Thu, Jan 17, 2019, 12:36 PM UTC

freeflight wrote: post #87

rjmunro wrote: post #83

> 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 un…

> Also, producing more brine would make the brine less concentrated and less harmful - it would be better not worse. Producing more brine, by diluting it, still would require something to dilute it with. The most obvious, non toxic, choice would probably be water, but the whole exercise is about getting water in the first place.

Post by otikik » Thu, Jan 17, 2019, 12:41 PM UTC

nickthemagicman wrote: post #27

arkades wrote: post #6

Just to be clear, "brine" isn't "salty water." > 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. >…

Is there any use for it at all?