
Israel Proves the Desalination Era Is Here - doener
http://www.scientificamerican.com/article/israel-proves-the-desalination-era-is-here/
======
lyonlim
I wanted to understand how Singapore's desalination capacity (which is known
as our fourth tap for water sources), compares with this. The numbers are
quite mind blowing, at the scale Israel is doing desalination.

Our current desalination capacity, with 2 plants, amount to only 100 million
gallons per day which currently meets 25% of our needs [1].

[1]
[https://www.pub.gov.sg/watersupply/fournationaltaps/desalina...](https://www.pub.gov.sg/watersupply/fournationaltaps/desalinatedwater)

------
ZoeZoeBee
Cape Coral, Florida has been using a RO desalination plant to provide drinking
water since the 1970s, currently they produce 18 Million Gallons a day

[http://fwrj.com/techarticles/0909%20FWRJ_tech2.pdf](http://fwrj.com/techarticles/0909%20FWRJ_tech2.pdf)

------
dvirsky
> One of the driest countries on earth

Average rainfall in Tel Aviv - 528mm/year, that's about 50mm less than
Jerusalem - and _London_. Now, a lot of the country is a desert, but even
Beersheba gets an average of 400mm. Only the far south is really dry.

Not that Israel didn't need its desalination system, it might be the only good
and/or competent thing our government has done in recent years, but it's not a
very dry country in its inhabited areas.

------
davidf18
While Israel does grow and export fruits and vegetables, it imports "water" in
the form of grains and beef and other "red" meats. At least some of the beef
is imported from Argentina.

According to one source 1 ton of wheat is 216,000 gallons of water.

Beef requires considerably more water per pound, at least 10 times as much and
the documented source says much more.

Beef and other red meats are also imported as a rule. Turkey and chicken,
which require less water, are grown domestically.

[http://www.vegsource.com/articles/pimentel_water.htm](http://www.vegsource.com/articles/pimentel_water.htm)

For many of the Middle Eastern countries with water shortages, importing
grains and red meats to conserve on water seems like a good strategy.

Also, technology from carbon nano-tubules may make the desalination if much
cheaper.

Couple this technology with ever-improving solar technology which is likely to
be efficient in Israel's Negev Desert and this promises to be a water
technology with no consumables.

~~~
davidf18
A metric ton (1.1 tons) of #1 Winter Wheat ranges from $140 to $160. Israeli
desal water is about $0.52 cubic meter or 260 gallons. Using the 1 ton wheat
is 216,000 gallons of water, it comes to about $430 per ton using the
desalinated water.

Thus, wheat imports water at $0.15 cents per cubic meter.

------
amluto
I used to think that desalination was very expensive, but:

> Sorek can produce a thousand liters of drinking water for 58 cents.

For comparison, the lowest marginal rate for water in a single-family
residential unit in San Francisco costs $4.86/ccf or ~$1.72 per thousand
liters. San Francisco has an excellent water supply, and they nonetheless
charge about three times the cost of desalinated water in Israel.

This obviously glosses over a bunch of things (cost of maintenance of the SF
water system, the fact that SF charges quite a lot of money for the privilege
of having a water meter, the capital cost of the desalination plant (I don't
know whether that's amortized in the 58 cent figure)), but still, desalination
isn't terribly expensive.

I suspect the main issues blocking large-scale desalination in the US are:

\- Lead time. Desalination looks great during a drought, but it looks useless
in wet years, and it takes longer than a typical drought to get it up and
running.

\- Environmental impacts. You have to build the intake and brine discharge
systems, and getting that through environmental review might be complicated.

The first point could be addressed to some extent by running the plant even in
surplus years and using it for groundwater recharge.

~~~
radicaldreamer
Most water is used for agriculture, where the cost is much lower. Also,
desalinated water isn't very good quality, in the mid-east, it's often not
used for drinking or shampooing your hair.

------
pauldprice
This is a fantastic development. Tying the climate change and water shortage
to civil unrest, regional war, immigration disaster, and world security
problems is something the US presidential candidates are failing to understand
or at least communicate effectively.

This article was a hard read due to lack of editing. I hope they update it
with fewer typos and cut and paste errors. Peer review people, at least.

------
bluejekyll
I don't see a lot of discussion around the brine. In previous reading brine
will eventually create areas in seas where fish and other life starts dying
off because of the extreme salt content.

This article mentions the brine "is just pumped back into the Mediterranean",
but don't they need to be concerned about killing fisheries?

~~~
vessenes
The article mentioned one installation was going to channel brine back to the
dead sea, so if you've got a super salty body of water nearby, brine problem =
solved!

~~~
rshaban
False. The Dead Sea is already rapidly drying up due to climate change;
pumping even more salt in will only hurt.

[http://www.smithsonianmag.com/science-nature/the-dying-of-
th...](http://www.smithsonianmag.com/science-nature/the-dying-of-the-dead-
sea-70079351/?no-ist)

~~~
vessenes
This is only true if the brine content being offloaded is greater than that of
the Dead Sea now.

------
orionblastar
As we know when a water source dries up in a Middle Eastern nation, the people
who need it move to a different location and some get desperate. This leads to
more refugees for other nations to take on, and a small fraction join a
terrorist organization to survive. If this technology can bring fresh water to
Middle Eastern nations, it can help fight terrorism, and end the refugee
problem as they'd have no reason to flee if plenty of water and food are
available as well as jobs.

~~~
HillaryBriss
What if war breaks out and the desal plants are targeted?

------
mabbo
I've heard that just as big as their desalination efforts are their water
reuse efforts. All that sewage we work so hard to get rid of? Turns out that's
still fresh water. Sort of. It's just got some other stuff in it is all.

~~~
dghughes
Israel recycles 86% of water from the sewers compared to the second most
efficient recovery in the world is Spain at 19%.

~~~
ksec
That is the 2nd most interesting point i want to hear more about. And yet the
article does not go into any details.

~~~
Xyz9292929
Everything you wanted to know and VERY interesting :)

[http://www.smartpeoplepodcast.com/2015/10/26/episode-214-set...](http://www.smartpeoplepodcast.com/2015/10/26/episode-214-seth-
siegel/)

tldr; water was used as an excuse by the British to limit immigration to
Israel, so from the earliest onset of the formation of Israel, Israel has been
trying to tackle the problem of water use inefficiency.

------
abalone
_> Desalination used to be an expensive energy hog, but the kind of advanced
technologies being employed at Sorek have been a game changer. Water produced
by desalination costs just a third of what it did in the 1990s._

How much of that price drop is due to lower energy prices? How sustainable is
the power source?

Even with significant efficiency improvements (3X), shifting from local
freshwater sources to desalination would have a massive energy
requirements.[1] For such a bold claim ("the Desalination Era is Here"), this
article has a rather lightweight examination of the environmental impacts.

[1]
[https://en.wikipedia.org/wiki/Desalination#Energy_consumptio...](https://en.wikipedia.org/wiki/Desalination#Energy_consumption)

~~~
aaron695
> How sustainable is the power source?

Oil (and such and such) will last a 100+ years and obviously won't destroy the
planet in that time.

I'd call that sustainable.

And given it's just a "power source", at any time we could swap it out for X,
Y, Z.

Plus they specifically talk about efficiencies in the article?

Not sure your point at all?

I haven't seen huge drops in energy cost across the world? Electricity seems
the same or more than the 1990s?

~~~
andrewjl
Two words: climate change

~~~
polotics
Yep. Three words:

Black flag weather

------
SixSigma
But ...

The Tampa Bay Desalination Plant produces 25 million gallons per day of
drinking water to provide 10% of the region's needs. [1]

Americas’ largest seawater desalination plant provides 50 million gallons (189
million liters) of drinking water for the San Diego area each day - 8% of
needs

[1] [http://www.tampabaywater.org/tampa-bay-seawater-
desalination...](http://www.tampabaywater.org/tampa-bay-seawater-desalination-
plant.aspx)

[2] [http://www.japantimes.co.jp/news/2015/11/02/world/florida-
fl...](http://www.japantimes.co.jp/news/2015/11/02/world/florida-flop-new-
california-seawater-desalination-plant-seeks-slake-san-diegos-thirst/)

------
aphextron
Where is the power coming from? Desalination can only be as efficient and
sustainable as the power source. It's not surprising if Israel can build
massive desalination plants dependent on cheap fossil fuel power.

This is just trading water now for more CO2 added to the atmosphere, worsening
the underlying problem.

~~~
Alphasite_
Solar is now significantly more economical than it once was and in the long
term would be rather appropriate for these regions.

~~~
pstuart
jinx! you owe me a glass of water.

------
ShinySnivy91
Dubai can't be making this situation any better.

------
yiyus
Another example worth checking is Isla de Hierro, in the Canary Islands
(Spain). Not only they are using desalination to produce most of the fresh
water they need, but the desalination plants and the whole island run 100%
with renewable energy.

------
jmspring
The article states --

"Desalination used to be an expensive energy hog, but the kind of advanced
technologies being employed at Sorek have been a game changer. Water produced
by desalination costs just a third of what it did in the 1990s. Sorek can
produce a thousand liters of drinking water for 58 cents. Israeli households
pay about US$30 a month for their water — similar to households in most U.S.
cities, and far less than Las Vegas (US$47) or Los Angeles (US$58)."

But I saw nothing about where the energy comes from, the type of source, the
scale. I'd like to compare this with local proposals, etc.

One of the biggest DeSal issues is cost of conversion and source, proximity of
source, etc. play a huge factor.

~~~
unchocked
The energy comes from the grid. The nice thing about the grid is that it lets
you abstract out power, kinda like bandwidth on the Internet. Do you care
which data center a new app lives in?

But if we must, I suspect the supply side (of electricity) I suspect most new
supplies in Israel are solar PV located in the Negev, since peak demand there
correlates with sun.

And what sort of local proposals are you imagining as alternatives to
desalination?

~~~
dredmorbius
Israel's grid is presently fed by coal and gas:

[https://www.iea.org/sankey/#?c=Israel&s=Balance](https://www.iea.org/sankey/#?c=Israel&s=Balance)

~~~
jmspring
How do those costs compare with something in Northern or Central CA, with the
same coal/ng source?

~~~
dredmorbius
The breakthrough here (and I've only skimmed the article) is in 1) reverse
osmosis 2) without organics-clogging of filters. That is, basically, keeping
pond scum from fouling your molecular-differentiating filter system, which is
what it takes to split water from salt.

That and various energy efficiency improvements.

Much of this comes down to questions of "what are the energy costs" and "how
much energy can we supply".

I'm not a huge fan of desal generally, _especially_ where it's reliant on
fossil-fuel energy. On the other hand, it actually plays into another area
I've had some interest in -- seawater-based Fischer-Tropsh fuel synthesis
(SFTFS). That's the task of taking seawater, separating carbon from it (mostly
in the form of dissolved carbonate and bicarbonate -- the dissolved CO2
fraction is small), and electrolysis to split out hydrogen.

That problem divides into a few parts:

1\. Electrolysis of hydrogen. Essentially a solved problem at large scales.
Example: nuclear powered submarines replenish their oxygen supply through
electrolysis (I'm not sure _what_ they do with the hydrogen resulting). Since
water is 89% oxygen by weight, the amount of water you need to process here is
small. There's an energy cost (more below).

2\. Removing carbonate & bicarbonate from seawater. Here the fraction is far
smaller -- a few fractions of a percent by weight. The reason you're looking
at seawater is because energetically it's _far_ easier than getting CO2 from
air. And yes, seawater is also necessary. The probme _here_ is getting enough
water -- you've got to process tremendous volumes.

3\. Synthesising hydrocarbons from this (that's the Fischer-Tropsh bit).
Fairly well established, and exothermic to boot, so it doesn't cost energy.

4\. Energy input. You only get out about 60% of what you put in to split out
hydrogen. That normally isn't a very good bargain except for a few useful
things about hydrocarbons, below.

The upshot is that desal and SFTFS have a few things in common: taking in gobs
of water, purifying that so you don't gum up the works, and applying fairly
hefty amounts of energy to it.

What desal offers is a proving ground for developing that seawater handling
capability, at scale, and in particular the filtration parts. It would also be
possible to combine the processing (though there might be other reasons for
not doing so). In theory, you'd ingest seawater, electrolise some of it for
hydrogen, capture the carbonate/bicarbonate (which aren't of interest for
tapwater), feed your C & H to the FT synthesis process, and continue with the
remainder of the water to your desal system.

Why bother making hydrocarbons? Because they're damned useful. Renewable
energy has advantages, but it doesn't store or transport well. Synthesized
hydrocarbons would be precise (and in fact, _more_ precise) analogs of
methane, petrol, kerosene (a/k/a jet fuel), and deisel. For some applications,
including standby generation, gas heat, some industrial processes, and powered
air and marine transport, they're about the only real viable option. I suspect
they may continue to see use in private / passenger transport as well, and
possibly rail (electrification is an option, but has challenges). There are
industrial processes which also utilise gas and oil feedstocks, notably Haber-
Bosh nitrogen fixation (though alternate processes might emerge).

Even if we end up with a small fraction of total energy coming from
hydrocarbons (marine and air would be ~12% of the present total), the process
could prove quite useful.

Large-scale desal could be a proving ground for related technologies.

------
Reason077
_Their counterparts in Syria fared much worse ... the wells ran dry and
Syria’s farmland collapsed in an epic dust storm. More than a million farmers
joined massive shantytowns on the outskirts of Aleppo, Homs, Damascus and
other cities in a futile attempt to find work and purpose._

To what extent the current situation in Syria influenced by environmental
changes, I wonder?

Unemployed farmers -> Social instability -> Civil Unrest -> War?

~~~
sriram_malhar
This SciAm article lays it out exactly as you do.

[http://www.scientificamerican.com/article/climate-change-
has...](http://www.scientificamerican.com/article/climate-change-hastened-the-
syrian-war/)

------
sriram_malhar
I wonder what the downside of desalination is. What does one do with the huge
quantities of leftover brine (when operating at country levels) -- surely
dumping it back into the sea can't be good for the surrounding marine
environment. In nature, there is no free lunch.

------
ksec
On the Subject of Water. > Sorek can produce a thousand litres of drinking
water for 58 cents. I am guessing this is the cost to produce and not the
final cost to Homeowners. How much further down can we reduce this cost? I am
guessing this is close to the limit of efficiency, any more reduction will
have to come from cheaper energy source? Since Nuclear Power requires lots of
water, would the both makes sense working together?

Most countries have leaky water around pipes. UK lose around 20%, US is a
little above 10%. Are the any innovation that we can shrink this number? I
dont see why this cant be within 98%+ region. What is stopping it?

~~~
regularfry
The age and number of the pipes. It's easy to underestimate the scale of the
problem. There's been a replacement process going on in London to replace
ancient cast iron and wooden box piping on the mains supply for the past few
years. That's mostly Victorian and earlier installations, but there isn't
anything like a full inventory of where they are, and sometimes what they find
is that the original pipe has completely disintegrated: the water is just
flowing through the void in the clay.

I do know of one case (not in London) where complaints about the quality of a
house's water led to the discovery that it was, via a somewhat convoluted
plumbing route, still drawing water from the nearby river via Roman pipework.

If you can find a leak, stopping it is usually straightforward, but on a
colossal, heterogeneous and patchily documented pipe network like the UK's,
the best you can do is patch it up as you go along.

------
vmateixeira
What about climate changes and any other possible drawbacks?

Shouldn't this be considered having in mind that we're bringing water to..
where it's not supposed to exist, hence influencing a micro climate and making
climate changes?

------
duncan_bayne
I've said this for years here in Australia, when people talk about a "water
shortage" \- there's no such thing. What there is, here at least, is a cheap
power shortage and a water infrastructure shortage.

------
andrewclunn
And here Sim City had me thinking this was common place when I was a kid.

------
sathishvj
"water can be a bridge" \- :-) Nicely worded.

------
HillaryBriss
> _Sorek can produce a thousand liters of drinking water for 58 cents._

In Los Angeles, the DWP tier 1 retail price for a cubic foot is very, very
roughly 5 cents or roughly $1.75 for 1000 liters. And DWP's prices are going
up (for a host of reasons).

~~~
jpollock
Doesn't the DWP price include procurement, treatment, delivery to a house and
sewage treatment, whereas the Sorek price is only procurement.

To compare them, it would have to be the price someone pays to obtain a
kilolitre of untreated water at source.

California seems to have some water transfers, and I found a report listing
prices from $50-$550/acre-foot, or ~1.25 million L (2012 [1])

That would give an upper bound of (550/1250) $0.44/kilolitre at source.

[1]
[http://www.ppic.org/content/pubs/report/R_1112EHR.pdf](http://www.ppic.org/content/pubs/report/R_1112EHR.pdf)

~~~
HillaryBriss
I do not think the sewage treatment is included in that price. But the rest
is, as you say.

~~~
jpollock
You are correct, in LA, it's broken out into a separate line item.

From the DWP FAQ:

"The Sewer Service Charge (SSC) is based on metered water use"

[https://www.ladwp.com/ladwp/faces/wcnav_externalId/c-cs-
sewe...](https://www.ladwp.com/ladwp/faces/wcnav_externalId/c-cs-sewer-
charg;jsessionid=jtpbXczQjvtM6njrczJxY9LGF0Jvjn4q1zGTHBwBP6l5rTPj1ZyD!747476876?_adf.ctrl-
state=j2xbb4sk6_4&ladwp/cms/ladwp000399.jsp&_afrLoop=603635808483886&_afrWindowMode=0&_afrWindowId=null#%40%3Fladwp%252Fcms%252Fladwp000399.jsp%3D%26_afrWindowId%3Dnull%26_afrLoop%3D603635808483886%26_afrWindowMode%3D0%26_adf.ctrl-
state%3D18bpvkygwi_4)

------
kragen
There are some crucial details here I'm not understanding.

The article says Israel needs (or needed?) 1.9Gm³/year (60 kiloliters per
second, 60kℓ/s) of water, of which it got 1.5Gm³/year (48kℓ/s) from natural
sources; but now (or when the plants opened?) it gets 127Mm³/year from the
2005 Ashkelon desal plant, 140Mm³/year from the 2009 Hadera desal plant, and
150Mm³/year from the new Sorek plant. These total 417Mm³/year (13kℓ/s), but
the article says Israel's current total is 600Mm³/year (19kℓ/s) from
desalination plants, which is more than 417. Also, it says, Israel now gets
55% of its domestic water from desalination. But 55% of 60kℓ/s is 33kℓ/s,
which is 14kℓ/s more than the 19kℓ/s it says Israel gets from desalination. I
suspect there's some confusing mixing of categories here leading to these
numbers not adding up properly.

The other really crucial questions are about capex and opex. How much do these
plants cost to build, and how much do they cost to run? How much of that is
the energy cost?

They give the figure that the Sorek plant's reverse osmosis runs at 70
atmospheres (7.1 MPa; fucking Christ on a stick, why do people keep inventing
new non-SI units?) which means that each liter of output water requires 7.1kJ
of mechanical energy to force it through the membrane. There are presumably
some other energy costs, but that may be the bulk of it. At US$100/MWh
(US$28/GJ; fucking non-SI units again), which is a reasonable ballpark for the
levelized cost of electrical energy, that's about 200 μUS$/ℓ or 200 US$/Mℓ.
Irrigation water is commonly quoted in US$ per acre foot in the US; this is
US$240 per acre foot, which would be a very competitive cost.

But it says the cost is US$0.58/kℓ, which is 580 US$/Mℓ or US$715/acre foot,
about three times the cost of the mechanical energy and high enough that many
crops are uneconomical. It is crucial to understand where that extra cost is
coming from.

One of the comments on the Ensia version of the story claims that the new
Carlsbad desal plant is selling its water for US$2000/acre foot. I don't know
if that's true, but it's about 150% higher than the projected costs.

Links, in case the Scientific American web site is lost:

Original article: [http://ensia.com/features/how-a-new-source-of-water-is-
helpi...](http://ensia.com/features/how-a-new-source-of-water-is-helping-
reduce-conflict-in-the-middle-east)

Bar-Zeev et al.'s article about their bioflocculation anti-biofouling
prefiltering apparatus:
[https://www.researchgate.net/publication/236137883_Biofloccu...](https://www.researchgate.net/publication/236137883_Bioflocculation_Chemical_free_pre-
treatment_technology_for_the_desalination_industry) DOI:
10.1016/j.watres.2013.03.013

"Climate change in the Fertile Crescent and implications of the recent Syrian
drought":
[http://www.pnas.org/content/112/11/3241.abstract](http://www.pnas.org/content/112/11/3241.abstract)
doi: 10.1073/pnas.1421533112

------
baybal2
We need nuclear desalination and district heating

------
ronjitg
What about the environmental costs of desalination though? The article doesn't
mention them, but they are significant.

~~~
dredmorbius
Any specifics on that?

~~~
lucb1e
I assume it's about the salt that is dumped back into the ocean after removing
the water from it.

------
adventureartist
For some perspective: LA county uses about ~50 Million cubic meters of water
per year. The largest Israeli desalinization plant is ~225 Million cubic
meters per year. The entire state of California uses ~50 Billion cubic meters
of water per year. Very rough numbers

~~~
MichaelGG
But only a few percent is for residential use, right? So ignoring agriculture,
a few large plants should provide enough water for humans to be happy in Cali
solely off of desal?

~~~
abalone
I'm guessing people in Cali would not be very happy living without
agriculture, so no.

~~~
btilly
California's GDP is estimated at 1,800 billion. Economic activity coming from
agriculture is estimated at about 100 billion. Given an average economic
growth rate of 2.5% per year for California, losing all agriculture would set
California's growth back about 2 years.

Nobody wants to do that, and there are all sorts of complex legal issues
around water rights. But push come to shove, California could survive just
fine without its agricultural sector.

~~~
vkou
Agriculture brings may bring in only 5% of the state's economy, but if every
single piece of food eaten in California had to be imported, it would cost a
lot more then 5% of its economy.

If food were grown by magic, without employing any people, and it could all be
sold at cost, it would contribute 0% to the state's economy. Does that mean
that it would make economic sense to immediately stop growing all that food?
Of course not! The fact that growing food is so cheap is a good thing!

~~~
terravion
To amplify your point, excepting water, the San Joaquin Valley in particular
has the best climate and input factors in the possibly the world for producing
high value crops at low cost and low environmental impact. If we could supply
another 50-100M acre feet of water to the aqueduct system amazing thinks could
happen.

My quick calculation is the biggest of these desal plants would only feed
25,000 acres of almonds. There are 1M acres +/\- of almonds in California, if
we wanted to double nut protein production in California (the leading global
exporter of almonds) you would need about 50 of the plants described not just
three.

Who wants to build the giga-desal plant to feed the Clifton Court Forebay?

------
known
Thank you, Israel; Please also amend
[https://en.m.wikipedia.org/wiki/Marriage_in_Israel](https://en.m.wikipedia.org/wiki/Marriage_in_Israel)

------
sandworm101
Honestly, I had always assumed Israel was much more advanced than this article
points out. In the 90s I was a kid in the middle east. We had a "sweet water"
tap in the kitchen for drinking. Everything else was recycled. We didn;t flush
our toilets with drinkable water. And low-flow appliances were the norm. I
find it shocking that Israel hadn't started such measures until 2007.

~~~
dogma1138
Israel has been recycling most of its wastewater since the 60's, today it
reclaims over 86% of its wastewater this is a huge margin over the next
closest contender which is spain at 17%. The water in the toilet is drinkable,
that doesn't mean it's wasted there is no need to overcomplicate your water
management systems if you can reclaim most of the water back and reuse it,
including as drinking water. Countries with "dual feed" water systems don't do
it for efficiency or water preservation, they do it because the main feed
water quality is below drinking levels, so larger municipalities can
supplement the main water system by providing a "drinking" tap into homes, in
some places the drinking tap is communal for the building, block, or even the
entire village while the rest of the water should not be drank without boiling
or treatment if at all.

~~~
sandworm101
That isn't the system we had. The drinking water line supplied the "sweet
water" taps and and dishwashers. Interestingly, the hot water tanks also got
'sweet' water as dishwashers often use hot water. The non-drinking water in
homes was recycled water and was more heavily chlorinated, making it safe for
bathing but not great for drinking. It wouldn't make you sick, but drinking a
large amount could be uncomfortable. Then we had a third standard for
irrigation of lawns and such. That water wasn't as heavily chlorinated.

~~~
dogma1138
That's pretty standard in emerging water markets, the chlorinated water was
actually most likely not the recycled one (you do not chlorinate water that is
not near drinking quality, if you do it to unfiltered reclaimed water you
create really nasty chemical reactions), it's most likely water that has been
collected or transported at least partially in open air systems and the
chlorine is used as a antiseptic. The drinking water is the higher quality
water that has been treated and is transferred in a closed system with higher
quality control, while the water used for lawns is most likely the reclaimed
water.

When you can reclaim most of you water and ensure quality control throughout
the system you simplify it, have one water feed for residential use, and
usually another for agriculture and industry. Reclaimed water even drinking
quality is usually not put back into the tap because the cost of ensuring
water quality make it unfavourable, it's used for agriculture and industrial
uses, when it ends up again as drinking water it's often as filtered bottle
water simply because you can then transfer the cost of the additional water
quality control to the industrial users.

------
manachar
"Water shoots into the cylinders at a pressure of 70 atmospheres and is pushed
through the membranes, while the remaining brine is returned to the sea."

I've heard this brine can have a pretty negative ecological impact, I wonder
how that could be mitigated.

~~~
brianwawok
Explain why?

The ocean is say 99 parts water and 1 part stuff. We take out 1 part water and
.01 parts stuff, keep the water, then put the .01 parts stuff back. Doesn't
seem to really change the ocean concentration? I guess maybe if dumped too
close to shore it could make a brine slick?

~~~
dalke
[https://en.wikipedia.org/wiki/Desalination#Outflow](https://en.wikipedia.org/wiki/Desalination#Outflow)
gives an overview of the environmental problems in desal outflow:

> Desalination processes produce large quantities of brine, possibly at above
> ambient temperature, and contain residues of pretreatment and cleaning
> chemicals, their reaction byproducts and heavy metals due to corrosion.[45]
> Chemical pretreatment and cleaning are a necessity in most desalination
> plants, which typically includes prevention of biofouling, scaling, foaming
> and corrosion in thermal plants, and of biofouling, suspended solids and
> scale deposits in membrane plants.[46]

> To limit the environmental impact of returning the brine to the ocean, ...

> Brine is denser than seawater and therefore sinks to the ocean bottom and
> can damage the ecosystem. Careful reintroduction can minimize this problem.
> Typical ocean conditions allow for rapid dilution, thereby minimizing harm.

What's an example of not typical?

Here's an article which points out that the Arabian Gulf is shallow, with low
circulation rates and high evaporation rates which make it naturally saltier.
That, combined with the damming of freshwater and increasing number of desal
plants places a limit on to how much it can be use as a water source:
[http://www.thenational.ae/news/uae-
news/environment/desalina...](http://www.thenational.ae/news/uae-
news/environment/desalination-threat-to-the-growing-gulf)

~~~
ethbro
From the article, "chemical-free method." [1] I'm sure the salt concentration
isn't great, but it's a lot easier to spread salt around than remove heavy
metals and cleaning chemicals.

[1] [https://www.researchgate.net/profile/Ilana_Berman-
Frank/publ...](https://www.researchgate.net/profile/Ilana_Berman-
Frank/publication/236137883_Bioflocculation_Chemical_free_pre-
treatment_technology_for_the_desalination_industry/links/00b4951976edf67426000000.pdf)

~~~
dalke
More details at [http://www.filtsep.com/view/44376/success-behind-advanced-
sw...](http://www.filtsep.com/view/44376/success-behind-advanced-swro-
desalination-plant/) :

> Minimizing the plant's environmental impact: Pipe jacking .... Other
> measures: the potential impacts of the Sorek Plant's operation on the
> environment were thoroughly assessed, and appropriate measures were taken to
> prevent, minimize and mitigate these. The following are some highlights of
> these measures:

> – The feed water pumping station is located far (2,400 meters) from the
> coastline, and feed water flows by gravity to the on-site pumping station.

> – Entrainment and impingement effects at the intake system are minimized,
> thus minimizing the consumption of electricity and chemicals (especially
> CO2) and reducing the emission of related greenhouse gases, air pollutants
> and noise.

> – Environmentally-friendly antiscalants, and inorganic and treatable
> cleaning solutions, are used.

> – Brine is discharged back to the sea approximately 2 kilometers offshore,
> and at a depth of 20 meters through a specially designed outfall system
> (diffusers) that enhances quick brine dilution to the seawater body. The
> critical parameters of the brine disposal are monitored online, 24/7.

> – The plant is equipped with a special sludge treatment system to treat any
> effluents generated in the process. This system removes all suspended matter
> and only clear water is discharged to the sea.

------
dingleberry
I've used reverse osmosis unit for years. new unit is less than $100usd it
paid itself in months. maintenance is cheap.

my RO has kinda low efficiency. 4 units of water in, i get 1 unit of clean
drinkable water. 3 units are 'waste' (don't believe what socmed says, it's not
dirty). the waste water is used for laundry, aquarium and gardening. my fishes
and vegs are thriving.

to test purity, just plunge the ohm meter probes into a cup of ro water. if
the resistence is in 1MOhm, it's pretty pure. mountain/mineral water bought
from store is about 150kOhm. after drinking ro water for a while, store-bought
water tastes slightly salty.

my house pumps water from ground (well-pump). for a family of 6, i need 1m3 of
water. that's about half hour of 500W pump. an ro unit (40W) runs about 3
hours for 5gal bottle. so give or take, 1/2kWH or about 15KW per month. that's
about $1 or $2 for my water need per month.

if i must buy raw water (such as living in an apartment), it's about $1 per
m3, so about $30 per month; however, i get drinkable water too. ro units are
portable. i saved $28/mo in water expense after moving from apartment.

flashing back from memory, i used to lug around 3 5gal water-cooler bottle
from stores to my apartment every 3 days (i had 3 bottles). it was not
pleasant and wasted time (go to store, queue, lug heavy bottles back)

ro unit has relay so you don't have to sit and wait for it to fill. it
automatically cuts power to the pump when its internal clean-water-tank is
full.

~~~
samcheng
I was instructed (from professional chemists) to NOT drink 1 MOhm ( or other
highly-purified) RO water. At that purity, particularly when hot, it will
leach metals and other compounds from pipes, pots, cups, etc. Maybe it's worth
dropping a little salt into the water after purification?

I'm also surprised that you use the waste water on your aquarium. In my
experience, fish are MUCH more sensitive to water quality than humans are.
This is particularly true for corals in saltwater tanks. In fact, many
aquarium stores sell RO-purified water for fish tanks!

~~~
sevenless
I do not see why extremely pure water would leach metals any more than
tapwater would. Chemically it should not matter. All species will reach
equilibrium between the surface of the container and the liquid and if dilute
they will not care about one another. That equilibrium will be reached faster
if the temperature is higher.

What is true is that you should not drink hot water from pipes because hot
water does leach metals, tapwater or otherwise.

~~~
michaelcampbell
Was this not the issue in Flint, Michigan with the water leaching lead because
it DIDN'T have something in it?

~~~
vessenes
No, the water there was more acidic than the prior water the system used,
causing leaching.

~~~
michaelcampbell
I see; thanks.

------
azernik
In Israel, it's mostly a triumph of politics over economics - Jordan, Israel,
and the PA have cooperated in developing desalination plants [1] in part in
order to defuse conflicts over water. Water allocations have historically been
a zero-sum competition in the region, so when there's a chance (however
expensive) to just throw money at the problem to make it go away, everyone's
willing to play along.

[1] [http://www.worldbank.org/en/news/press-
release/2013/12/09/se...](http://www.worldbank.org/en/news/press-
release/2013/12/09/senior-israel-jordanian-palestinian-representatives-water-
sharing-agreement)

~~~
vonnik
I agree that there's a triumph of politics over economics on the water issue,
but I'm not sure that it's in the direction we think:

Israel blames Palestinians for West Bank water shortage
[http://www.jpost.com/Arab-Israeli-Conflict/Israel-blames-
Pal...](http://www.jpost.com/Arab-Israeli-Conflict/Israel-blames-Palestinians-
for-West-Bank-water-shortage-457814)

~~~
vkou
I'm sure Palestine would love to be in Israel's position right now. Given how
Israel, depending on the Palestinian policy of the time, alternates between
stealing Palestinian land, bombing it, or preventing goods from entering or
leaving, it's in no position to complain about poorly maintained
infrastructure.

~~~
reitanqild
This is factually false.

In fact Israel ships tons of goods every day.

Furthermore:

* a lot the land that is Israel today is bought.

* Jews that left neighbouring countries for Israel lost their property there vut this is never mentioned

~~~
reitanqild
Would the downvoters please enlighten me?

------
srameshc
This technology could be a boon to country like India where huge population
relies on rain and some of the reservoirs are at about 40% despite decent
rainfall this year. On the other note will desalination and consumption of sea
water by humans balance the rising sea level ?

~~~
delecti
Pretty much all the desalinated water that is "consumed" will just flow right
back out to sea.

~~~
rs999gti
Eventually, according to the water cycle:

[https://upload.wikimedia.org/wikipedia/commons/1/19/Watercyc...](https://upload.wikimedia.org/wikipedia/commons/1/19/Watercyclesummary.jpg)

------
CydeWeys
I've never been as afraid of fresh water shortage as a lot of other people
seem to be precisely because it is exactly the kind of shortage that is solved
by market forces. Freshwater getting scarce? OK, so the price goes up. Now
there's more incentive to conserve water by replacing fixtures for low-flow
variants, letting your lawn die (why do you really need one in a desert
anyway), and using more efficient irrigation methods in agriculture. The price
of water still keeps going up? Then the price of meat goes up because growing
crops to feed animals become more expensive, and people eat less meat.
Meanwhile, increased price makes desalination more profitable, and more plants
come online.

I don't see it as anything rising close to a civilization-ending threat.
Seawater is abundant. Freshwater can be made cheaply enough. We are
extravagantly wasteful with water as it is, and that can be fixed easily
enough as it becomes more expensive.

~~~
flushandforget
I'm in the UK, and recently tried to make sense of my water bill as I've a
change in how our waste is managed. We are off the sewer network with about 50
houses with a treatment works. An annual water bill from average figures for
our region (different water companies), is about £400 for a two person
household and £600 for four. You pay more for your waste removal than clean
water intake. Waste is measured against clean water intake.

We are now looking at a figure of over a pound per day for waste removal. The
figure feels steep to me. If I could separate liquids and solids easily, then
actually I could dump both in the garden. If you have the space then
composting seems like a great solution. And would save flushing all that clean
water down the toilet.

~~~
CydeWeys
Modern plumbing, freshwater, and waste removal is literally one of the top
five inventions of all time for increasing lifespan and quality of life. You
don't realize how good you have it until you go try to live in a village that
doesn't have freshwater or wastewater disposal, where you have to trudge miles
per day to fill up large heavy containers from sources that are already
polluted anyway, and that needs to be further treated with boiling before it's
safe to use.

So in that context, it's absurd to think that £1 per day is steep to get all
of those benefits. Back when I had a house our water bill was way more than
you're paying, and I would've been willing to pay way more still. Having fresh
safe water available at the flick of a tap whenever you need it, and all waste
products disposed of without spreading contagion, is a modern day miracle.

~~~
flushandforget
Rather than a miracle it's a partially solved engineering problem. Using
potable water to transport poo seems rather wasteful, when a low tech
composting approach is rather simple.

Or perhaps the sewerage network should be replaced with a multi-purpose,
transport network, or some other innovation.

You can process your own waste by pumping air basically through black water,
all very good. But at the same time you can just throw a turd on the compost
heap if you have the room, and nature will do its thing, and you'll build up
your soil.

Education of good habits and some simple practice goes a long way.

