Speaker 1: Welcome to tech Stuff, a production of I Heart Radios,
Speaker 1: How Stuff Works. Hey there, and welcome to tech Stuff.
Speaker 1: I'm your host, Jovian Strickland. I'm an executive producer with
Speaker 1: How Stuff Works and iHeart radio and I love all
Speaker 1: things tech. And you know, sometimes here on the show,
Speaker 1: I can get a little salty, which is why we're
Speaker 1: looking at this classic episode tech Stuff Gets Salty and
Speaker 1: originally published on October one, two thousand twelve. And you know,
Speaker 1: I'm being all ki and everything, but yes, this is
Speaker 1: an episode. It's about desalination, the process of removing salt
Speaker 1: from water and the technology behind it. I hope you
Speaker 1: enjoy this classic episode. So, Chris, one of the big
Speaker 1: issues facing the world today is access to clean, drinkable water,
Speaker 1: and so we wanted to talk to someone who's an
Speaker 1: expert in a particular form of processing water to make
Speaker 1: something that isn't drinkable into drinkable water, and we have
Speaker 1: with us from ge Eric Hansen. Eric, welcome to the
Speaker 1: to the podcast very much. We're excited to have you here,
Speaker 1: and we're going to talk a bit about desalination, which
Speaker 1: is a process where we're removing things like salt and
Speaker 1: other minerals from water so that you have clean drinking
Speaker 1: water as an as a byproduct, really the other one
Speaker 1: being the the salt the salute. So we want to
Speaker 1: talk a little bit about the process that you guys
Speaker 1: use over at g the things that you're looking into,
Speaker 1: and um, how that has changed over the years. So
Speaker 1: to really start off, what what are the greatest benefits
Speaker 1: of desalination. Um, it's a great question. Uh. You know,
Speaker 1: the world today uh bases you know, ever increasing challenges
Speaker 1: and stresses on water supplies. But the good news behind
Speaker 1: that is the Earth's surfaces sent water. So even though
Speaker 1: less than one percent of that is accessible as fresh
Speaker 1: water today, the rest of it is is seawater, and
Speaker 1: we do have the technologies today to turn that into
Speaker 1: usable water. So in fact, those technologies have been around
Speaker 1: for a really long time. Uh. You know, even hundreds
Speaker 1: of years ago, people would boil water, capture the steam
Speaker 1: from that water, and use the condensation from that that
Speaker 1: steam as purified water. So the concepts of of desalinating
Speaker 1: water using heat or thermal technologies, those aren't new concepts.
Speaker 1: They've been around for a while. Desalination has been going
Speaker 1: on for a long time and even up through the
Speaker 1: most of the nineties, UH, thermal technologies were still very prevalent,
Speaker 1: albeit a little bit more advanced than just simply boiling water.
Speaker 1: But the concepts were still the same. Up the water,
Speaker 1: capturing the steam, and condensing it. Sure, in the in
Speaker 1: the nineties, different technologies started being applied. UH. Instead of
Speaker 1: heating up the water and boiling it, what we started
Speaker 1: doing was applying membranes, special kinds of very advanced filters. UH.
Speaker 1: These membranes are able to remove the salts from the water,
Speaker 1: UH with much less energy. Takes a lot of energy
Speaker 1: to boil water. So using membrane technologies, we've been able
Speaker 1: to reduce the amount of energy it takes to remove
Speaker 1: the salt from water. And over the last twenty years
Speaker 1: there have been just a lot of advances in that
Speaker 1: in that field, which I'm sure we'll go into a
Speaker 1: little bit more in our conversation. Sure, making the cost
Speaker 1: of desalinating water come down, UH, you know every year, right,
Speaker 1: And so you're talking about these these semi permeable membranes.
Speaker 1: Essentially we're looking at a process of reverse auso osis
Speaker 1: really um forcing the using pressure essentially to force water
Speaker 1: that has various minerals and salt in it. Through this membrane,
Speaker 1: the membrane separates out the minerals the salts, and the
Speaker 1: water passes through. Normally, when you have a membrane between
Speaker 1: a solute and a solvent, the solvent is going to
Speaker 1: pass through the membrane until there's a an equilibrium there
Speaker 1: and osmosis pressure is osmotic pressure is built up. So
Speaker 1: in this case, we're actually applying energy on one side
Speaker 1: so that we get water on one end of the
Speaker 1: membrane and everything else is on the other. Is that
Speaker 1: that sort of a bird's eye view of what that
Speaker 1: technology is all about. Yeah, you described it very well.
Speaker 1: You know. One of the biggest difference between membrane filtration
Speaker 1: and the types of filtration that most people are familiar with.
Speaker 1: It's when most people think of a filter, they imagine
Speaker 1: a barrier of some kind with one stream of water
Speaker 1: flowing into it, things being removed by that barrier, and
Speaker 1: then one stream of water flowing out the other side,
Speaker 1: and then after a while you have to do something
Speaker 1: to get all this stuff you've removed off that barrier.
Speaker 1: So membrane technology doesn't exactly work that way. You still
Speaker 1: have a barrier and it's the membrane. But in membrane technology,
Speaker 1: the feed stream is actually flowing across the membrane, so
Speaker 1: you have one stream in, but then you're applying pressure,
Speaker 1: so some waters making it through the membrane. That's the
Speaker 1: purified water without much salt in it, and all the salt,
Speaker 1: all the salt is staying on the other side of
Speaker 1: the membrane. So in membrane technology, instead of one stream
Speaker 1: in and one stream out, you actually have one stream
Speaker 1: in but two streams out, the saltier stream, so that
Speaker 1: saltier stream the brine. I know that that has caused
Speaker 1: some problems in the past simply because Brian, you know,
Speaker 1: what do you do with that after you've gone through
Speaker 1: the desalination process Now, Brian, because it has this concentrated
Speaker 1: amount of salts and minerals in an it's actually denser
Speaker 1: than seawater. So if you were too simply dump that
Speaker 1: brine into the sea, then it would it would sink
Speaker 1: to the bottom of the sea floor where it could
Speaker 1: potentially cause damage depending upon the environment that you're in. Uh,
Speaker 1: can you talk a little bit about some of the
Speaker 1: approaches to to take care of that problem. I know
Speaker 1: there's some about mixing the brine in with other water
Speaker 1: that's going to be running into the sea, so it
Speaker 1: it dilutes it. So I mean, if you step back
Speaker 1: and look at the desalination process, you know, from from
Speaker 1: thirty feet, uh, it can simply be considered really part
Speaker 1: of the normal water cycle, the hydrological cycle. So yes,
Speaker 1: there's water with more salt going back into the ocean,
Speaker 1: but the water that's purified and it's then used, uh,
Speaker 1: ultimately that goes back into the ocean as well, whether
Speaker 1: it comes through municipal wastewater and sanitary supers and it's
Speaker 1: treated you know, in many other ways. You know that
Speaker 1: water all does essentially return to the hydrological cycle at
Speaker 1: some point. So you know, from a high level, the
Speaker 1: mass balance is fine. The oceans aren't going to get
Speaker 1: saltier because of this, because we are returning the purified
Speaker 1: water back to the oceans at some point as well.
Speaker 1: So really, the the more immediate concern is just that
Speaker 1: very point at which you're introducing the brine back into
Speaker 1: the ocean, and depending on the characteristics of the seabed
Speaker 1: and what's living in that area. Uh, sometimes there are
Speaker 1: special considerations that are taken. Uh. And you know, there
Speaker 1: are many different ways you can return the brine back
Speaker 1: into the ocean. You can just have a pipe that
Speaker 1: puts it right into the ocean. You can create an
Speaker 1: elaborate grid of pipes underneath the seabed to uh, to
Speaker 1: blend it a little bit better. There's a number of
Speaker 1: different methods. And even though desalination may seem like a
Speaker 1: niche to some people, there are actually quite a few
Speaker 1: specialties within it. And uh, you know, really thinking through
Speaker 1: how the brine is going back into the ocean and
Speaker 1: how it's going to affect marine life is uh is
Speaker 1: quite a science in itself. But you know, there's been
Speaker 1: a ton of progress on that really in just the
Speaker 1: last ten years. And you know, I think in nearly
Speaker 1: all cases we're now able to come up with with
Speaker 1: special schemes and and the right technology to blend up
Speaker 1: without harming marine life. Fantastic. Hey there it's Jathan from
Speaker 1: two thousand nineteen. We're gonna take a break from this
Speaker 1: salt extravaganza and here from our sponsor. Well, moving on
Speaker 1: to another question. What what's the greatest barrier to adoption
Speaker 1: of desalination? I mean, why, uh, what's keeping this technology
Speaker 1: from being more widespread and used in more areas of
Speaker 1: the world. You know, I think there are you know,
Speaker 1: you could probably classify it into two different barriers. One
Speaker 1: of one of them is, uh is more perception. Uh.
Speaker 1: You know, there are some areas where the public still
Speaker 1: isn't really that on board with it yet, just for
Speaker 1: you know, things they've read in the news and their
Speaker 1: own ideas about it. Other parts of the world are
Speaker 1: doing this uh often uh you know, in the Middle
Speaker 1: East or in Southeast Asia. You find de cell plants
Speaker 1: all over the place. They have largely solved all the
Speaker 1: environmental issues that people should be worried about. Um. You know,
Speaker 1: but some people are slower to adapt than others, and
Speaker 1: it takes a while to to come to terms with
Speaker 1: with some of that mentally. UM. So that you know,
Speaker 1: that's a harder problem to solve. The easier problems to
Speaker 1: solve really are are the energy problems, because when you
Speaker 1: do desalination, it isn't the cheapest way to get water.
Speaker 1: If there's other uh supplies of water of alable to
Speaker 1: you uh that don't have so much salt in them,
Speaker 1: they're most likely going to be less expensive than desalination.
Speaker 1: So today people are doing desalination really only in areas
Speaker 1: where they don't have a lot of other alternatives, where
Speaker 1: they're in a water scarce area and they simply need
Speaker 1: to do it. So driving down the energy cost is
Speaker 1: really the primary goal and desalination it has been for
Speaker 1: the last twenty years, and there have been a lot
Speaker 1: of different improvements over the last really fifteen years that
Speaker 1: have really made progress in driving that down UH, and
Speaker 1: they're in a number of different areas. Obviously, the amount
Speaker 1: of energy that you need to drive the salt out
Speaker 1: of the water is a big deal, and you can
Speaker 1: lower that through advances in the membrane chemistry, so actually
Speaker 1: improving the membranes. You can do it through advances in
Speaker 1: the efficiencies of pumps UH, and you can also do
Speaker 1: it through advances in energy recovery devices. So there's a
Speaker 1: you know, a number of different area is that that
Speaker 1: people are working on. And then in addition to that,
Speaker 1: you know, simply the operation of these plants, you know,
Speaker 1: it requires a the amount of of manpower just to
Speaker 1: keep these things running. So we've also been making a
Speaker 1: lot of improvements and innovations and the pre treatment to
Speaker 1: these plants. So as as the pre treatment to the
Speaker 1: water gets better, they're lower operating costs as well. So
Speaker 1: lots of different levers to pull in order to lower
Speaker 1: the operating costs. You know, I was wondering a little
Speaker 1: bit about the equipment itself. I mean, the process itself
Speaker 1: seems pretty uh, pretty straightforward, but um, you know, is
Speaker 1: the is the equipment itself large? Does it take up
Speaker 1: a lot of space or or does it require a
Speaker 1: lot of high pressure to to make it work? Yeah,
Speaker 1: the two different things. In terms of size. It doesn't
Speaker 1: take up really any more space than a traditional water
Speaker 1: treatment plant for the same capacity would. But the big
Speaker 1: difference is pressure. The more salt that you have dissolved
Speaker 1: in any in any given amount of water, the higher
Speaker 1: the osmotic pressure of that water, something Jonathan referred to
Speaker 1: in his earlier explanation. So the more salt, higher the
Speaker 1: osmotic pressure, the more pressure you need to apply to
Speaker 1: the water to drive the salt out of it. So
Speaker 1: take for example, the Middle East in the Gulf, in
Speaker 1: the Middle East, that's really some of the saltiest water
Speaker 1: in the world. So on detail plants, they're running them
Speaker 1: as high as as eighty p s I, which is
Speaker 1: pretty high pressure. Uh. In other parts of the world,
Speaker 1: like say the Caribbean, the water is a little less salty,
Speaker 1: still absolutely seawater, but it's not quite as stalin as
Speaker 1: as the Middle East. So there you because it has
Speaker 1: slightly less salt, you can use slightly less less pressure. Now,
Speaker 1: are these plants often um sort of piggybacked onto other
Speaker 1: plants like pour generation. I was wondering if there was
Speaker 1: a lot of cogeneration going on with desalination plants. Yeah,
Speaker 1: that's a great question. Uh. And this is actually one
Speaker 1: of the reasons that g is is uh, you know,
Speaker 1: so active in this market. Uh. You know, there's just
Speaker 1: an inex Uh. There's a there's a obvious tie between
Speaker 1: energy and water. So to produce energy, you know, power
Speaker 1: plants need water to produce energy. In fact, almost ten
Speaker 1: percent of all global water withdrawals go to the production
Speaker 1: of water, so it's a pretty significant amount. Uh. And
Speaker 1: then the reverse of that is to desalinate water, you
Speaker 1: need energy to do it. So power plants and deesel
Speaker 1: plants are are are very linked. In the past, when
Speaker 1: the technologies were more thermal based, that was another advantage
Speaker 1: of tying the plants together because many power plants, especially
Speaker 1: power plants in the past, had a lot of waste heat,
Speaker 1: so they could use some of that heat uh for
Speaker 1: the thermal desalination. Power Plants today are much more efficient,
Speaker 1: so there isn't so much waste heat coming from them. Uh.
Speaker 1: And the membrane technologies come to a point where really
Speaker 1: that's the propol and technology for desalination. So we're not
Speaker 1: seeing them tied together as much anymore because of waste
Speaker 1: heat from the power plant, but we are seeing them
Speaker 1: tied together simply because the power plant needs water, uh
Speaker 1: and the decail plant needs power. Excellent. Hi, it's Jonathan
Speaker 1: two nineteen again. I decided that I needed to get
Speaker 1: a little salt, so I came back to visit this episode.
Speaker 1: While I'm doing that, let's take another quick break. So
Speaker 1: what is ge doing to make desalination more feasible to
Speaker 1: address water scarcity issues? So we're working in a number
Speaker 1: of different areas. We've worked a lot in the past
Speaker 1: on the membranes, and uh, you know, there are really
Speaker 1: some very high quality membranes now used in this salimation. Uh,
Speaker 1: they're not at entitlement yet. There are still some games
Speaker 1: to be made there UM, but they're they're getting close.
Speaker 1: The membranes are very efficient today. UM pre treatment is
Speaker 1: very important. So when when we talk about membranes and
Speaker 1: how they take the salt out of water, they're great
Speaker 1: at taking the salt out of water, but they aren't
Speaker 1: great at taking suspended solids out of water. So you
Speaker 1: don't want to put salt or sticks or stones or
Speaker 1: anything like that into a membrane. That's bad for it.
Speaker 1: So pretty much every membrane plant in the world has
Speaker 1: some kind of pre treatment in front of it to
Speaker 1: take the suspended solids out before it gets to the membranes.
Speaker 1: UH and G has been leading in this area as well.
Speaker 1: We have some terrific advanced prefiltration another type of membrane
Speaker 1: called an ultrafiltration membrane, and it it provides really superior
Speaker 1: UH suspended solids removal, so that the water that gets
Speaker 1: to the the reverse us most of the membranes is
Speaker 1: as clean as it can be, still salty, but it's
Speaker 1: had everything else removed and that makes the life of
Speaker 1: those membranes last a lot longer, which in turn lowards
Speaker 1: the overall cost of ownership. UM. Then the other pieces
Speaker 1: of the pumping side, there are a lot of different
Speaker 1: kinds of pumps in the marketplace. The most efficient types
Speaker 1: of pumps are positive displacement pumps. If you think of
Speaker 1: pumping water, you can imagine you have a fixed geogray
Speaker 1: fixed geometry of water. The most efficient way to raise
Speaker 1: the pressure of it is just to push on it
Speaker 1: um and that works today in in relatively small sizes,
Speaker 1: but as plants get larger and larger um there aren't
Speaker 1: so many good positive displacement pumps. So instead what people
Speaker 1: use their centrifugal pumps. So that's more like spinning the water.
Speaker 1: The water that gets thrown to the outside has a
Speaker 1: higher pressure. So you know, we've been working developing a
Speaker 1: new pump which is a positive displacement style pump, but
Speaker 1: is much larger than other positive displacement style pumps on
Speaker 1: the marketplace. That's a pretty new product for us, but
Speaker 1: we expect that within the next year we're gonna start
Speaker 1: seeing more of more of that pump out in de
Speaker 1: cel plan and that's going to knock as much as
Speaker 1: another ten percent of the energy off, so that when
Speaker 1: we get that fully commercialized, not in the marketplace, it's
Speaker 1: gonna lower the electrical costs by about ten percent more,
Speaker 1: which is really significant when you're talking about, you know,
Speaker 1: the cost of desalination. Sure. So, so that's sort of
Speaker 1: leads into what do you see as the future of desalination?
Speaker 1: Where do you see us going in another few years,
Speaker 1: like another decade or two decades. Yeah, that's a great
Speaker 1: question and a hard question because there are many many
Speaker 1: technologies out there today. Uh. You know, I I think
Speaker 1: most people in the industry, myself included, really see reverse
Speaker 1: osmosis as continuing to be the most prevalent technology, uh
Speaker 1: for at least the next five or seven or ten years. Um.
Speaker 1: It's certainly possible that some other technologies could could come along.
Speaker 1: And you know, honestly, if there are other technologies that
Speaker 1: will dramatically lower the cost of desalination, that would be
Speaker 1: great for the planet. Um. But I you know, I
Speaker 1: think over the next five or seven years, what we're
Speaker 1: going to see is people figuring out how to link
Speaker 1: the cell plants more to other renewables. So already we're
Speaker 1: starting to see people thinking about how do you combine
Speaker 1: a de cell plant with wind turbines and a wind farm,
Speaker 1: or how do you combine a de cell plant with
Speaker 1: a solar farm. You know, it turns out that a
Speaker 1: lot of places in the world but neat desalination, places
Speaker 1: that are water scarce, are also places that have quite
Speaker 1: a bit of sun. So there there's some nice natural
Speaker 1: links between, you know, combining solar with de cell. In
Speaker 1: some ways, there's also challenges because you know, in addition
Speaker 1: to having a sun, you know, some of these places
Speaker 1: also have a lot of sand and it's dusty and
Speaker 1: and dust and solar don't don't always hair so well.
Speaker 1: The dust coats the panels and they become less efficient.
Speaker 1: But you know, now we're talking about some pretty um
Speaker 1: discreet challenges. You know, people are doing this now, they're learning,
Speaker 1: they're getting better at it. There's not a lot of
Speaker 1: solar plus D cell or wind plus D sell out
Speaker 1: there today, but I think in the next five to
Speaker 1: ten years we're probably gonna start to feel a lot
Speaker 1: more about Yeah, it's really exciting and to give our
Speaker 1: listeners an idea of the impact that these sort of
Speaker 1: technologies have made so far. Uh, it wasn't that long
Speaker 1: ago that the estimated population that could not get access
Speaker 1: to clean water was around twenty but according to the
Speaker 1: World Health organization. They had a two thousand twelve report
Speaker 1: which took numbers from and took a look at that.
Speaker 1: They said that it's is still a massive problem. Still
Speaker 1: s million people lack access to safe drinking water, according
Speaker 1: to this report, and that's a you know, that's a
Speaker 1: sobering number. But the silver lining here is that that's
Speaker 1: that's half of what it was before, so that the
Speaker 1: numbers of people who are getting access to safe drinking water,
Speaker 1: they're on the rise, which I mean, that's obviously the
Speaker 1: way we want to see this trend go. So it's
Speaker 1: exciting to see this sort of technology combined with the
Speaker 1: efforts of other organizations out there dedicated to making sure
Speaker 1: that that people across the world get access to this water. Yeah.
Speaker 1: I couldn't agree more. You know, one of the statistics
Speaker 1: that that I often hear is that today it's one
Speaker 1: and every six people today doesn't have access to clean water,
Speaker 1: which is, as you said, really a sobering number. Um.
Speaker 1: You know, I I think there's an interesting combination here
Speaker 1: where you read a lot about this today. You know,
Speaker 1: ten years ago you didn't generally see water articles in
Speaker 1: mainstream media, and today, you know, every week you're going
Speaker 1: to see an article in mainstream media talking about water scarcity,
Speaker 1: and you know, it is a serious problem and it
Speaker 1: is alarming. But the plus side of this publicity is
Speaker 1: that they're more entrepreneurs, more large companies like GE, just
Speaker 1: more people out there starting to think about what are
Speaker 1: some possible solutions, uh, And there's lots of them. You know.
Speaker 1: Desalination is a great example of ways that we can
Speaker 1: solve water scarcity. Water reuse is another great example of
Speaker 1: ways that we can solve water scarcity. Water reuse is
Speaker 1: just taking water that's already been used for one purpose, uh,
Speaker 1: and treating it and cleaning it up and finding a
Speaker 1: way to use it for another purpose. So, you know,
Speaker 1: I think all the current press that we hear about
Speaker 1: water scarcity is actually helping to feed a pipeline of
Speaker 1: new innovations and new ideas that will actually helps all
Speaker 1: the problems in the long run. Fantastic, Eric, Uh. That
Speaker 1: that's a great look at the desalination process and what
Speaker 1: g E is doing to to really push this technology forward.
Speaker 1: And we really appreciate you coming on the show and
Speaker 1: talking with us. It's been a really educational experience for
Speaker 1: me and especially as as as liberal arts majors whose
Speaker 1: whose background and engineering is saying, Wow, that's cool. Uh,
Speaker 1: it's really great to get people like you on our
Speaker 1: show to talk about this and and give our listeners
Speaker 1: this uh this sort of Uh look, is there anything
Speaker 1: else you would like to say before we wrap up? Well,
Speaker 1: you know, Jonathan Chris, I'd just like to say thanks,
Speaker 1: thanks for having me on the show. Um. You know,
Speaker 1: at ge we're doing a lot of really interesting and
Speaker 1: innovative things to solve the very problems that we were
Speaker 1: just talking about for the last half hour. Uh. You know,
Speaker 1: one of the great things about being in this kind
Speaker 1: of business is when you come up with innovations, you
Speaker 1: can actually see you that they're helping people. Uh. So
Speaker 1: you know, it's it's a rewarding business to be and
Speaker 1: Geez very committed to it. We're investing a lot and
Speaker 1: solving problems today and in the future, and and uh,
Speaker 1: you know, I love talking about it and I'm really
Speaker 1: excited about where this can all go over the next
Speaker 1: couple of years. And that wraps up this classic episode
Speaker 1: of tech Stuff where we learned all about desalination. There's
Speaker 1: been a lot more work on that over the last
Speaker 1: few years and maybe I'll do a follow up episode
Speaker 1: to talk about this and the challenges around desalination and
Speaker 1: how we need to really be cognizant of those challenges
Speaker 1: before we pursue desalination on a grand scale. It turns
Speaker 1: out it's a lot more complicated than just taking salt
Speaker 1: out of water. I hope you guys uh enjoyed the episode.
Speaker 1: If you have suggestions for future topics for tech Stuff,
Speaker 1: feel free to reach out to me the email addresses
Speaker 1: tech stuff at how stuff works dot com, or pop
Speaker 1: on over to our website that's tech stuff podcast dot com.
Speaker 1: You will find links to all of our old episodes.
Speaker 1: I say old, I should say classic, gorgeous Pristine episodes,
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