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How communities worldwide are working to solve the water crisis

A view of a water pipe in the post treatment section with includes adding minerals and disinfection with chlorine into the water at the Claude "Bud" Lewis Carlsbad Desalination Plant, which opened on December 14, 2015 in Carlsbad, Photo taken in Carlsbad Desalination Plant in Carlsbad, CA on Wednesday, March 30, 2022. (Allen J. Schaben / Los Angeles Times via Getty Images)
A view of a water pipe in the post treatment section with includes adding minerals and disinfection with chlorine into the water at the Claude "Bud" Lewis Carlsbad Desalination Plant, which opened on December 14, 2015 in Carlsbad, Photo taken in Carlsbad Desalination Plant in Carlsbad, CA on Wednesday, March 30, 2022. (Allen J. Schaben / Los Angeles Times via Getty Images)

Droughts. Shrinking snowpacks. Changes in rainfall and groundwater. Water woes are growing worldwide.

“Our ability to conserve our way out of a water crisis is going to disappear and … we need some more options,” author and engineer David Sedlak says.

David Sedlak’s new book isn’t about the scale of water problems around the world.

It’s about solutions to those water problems. And how pioneering communities have made great strides forward in curbing their water crises — from Singapore, Australia to right here in the U.S.

“The world has a lot of experiences solving water crises, and my assertion in the book is that we have the means to solve water crises.”

Today, On Point: How communities worldwide are working to solve the water crisis.


David Sedlak, author of “Water for All: Global Solutions for a Changing Climate.” Professor in the department of civil and environmental engineering at U.C. Berkeley and director of the Berkeley Water Center.

Also Featured

Jason Dadakis, executive director of water quality and technical resources at the Orange County Water District.

Keith Cadee, former senior executive manager at Water Corporation in Perth, Australia.

Book Excerpt


Excerpt from David Sedlak’s “Water for All: Global Solutions for a Changing Climate.” Not to be reprinted without permission of the publisher. All rights reserved.


Part I

MEGHNA CHAKRABARTI: Water and air, literally the stuff of all life on this planet. But when we’ve done shows about water in the past, we’ve focused on water crises. For example, just recently we did a show about the astonishingly fast disappearance of the Great Salt Lake, or we’ve done a lot of programs on the mega-drought gripping the entire Western United State.

Excuse me, United States. Or climate change’s impact on the world’s oceans, or water as a source of conflict or water as a reason for increased migration. So yes, there are crises going on out there, but knowing that a crisis exists and what’s causing it isn’t enough, is it? We all need solutions. And that’s where David Sedlak’s new book comes in.

Sedlak is a professor in the Department of Civil and Environmental Engineering at the University of California, Berkeley. He’s also director of the Berkeley Water Center, and his new book is called “Water for All: Global Solutions for a Changing Climate.” And in it, he redefines how we should think about the global water crisis.

He breaks that big, frightening generic down into specific types of challenges, and then introduces us to communities around the world who are leading the way with innovative solutions to those specific problems. So taken together, Sedlak believes the world can find its way to water for all, and he joins us today from Berkeley, California.

Professor David Sedlak, welcome to On Point

DAVID SEDLAK: Oh. Thank you for having me, Meghna. It’s great to be here.

CHAKRABARTI: So first of all, just tell me internally, in your mind, or in your heart and soul, why is it that you feel optimistic that we can find solutions for water for all?

SEDLAK: Not necessarily optimistic.

Optimistic seems to imply that we’re naively believing that crises will be solved. I’m hopeful. And the reason I’m hopeful that we can solve water crises is that I look around the world at communities that have faced great water scarcity, have faced problems like sea level rise or contaminated water supplies.

And I see examples of how creativity, and energy and the willingness to take on these challenges can lead to feasible solutions that we can all learn from and hopefully implement. And so that’s the story I’m hoping to tell in this book.

CHAKRABARTI: I see. So that’s an engineer, I’m going to call it an engineer’s optimism. Because you see solutions at work already, and the question is how to apply them in different places.

So what I’d like to do before we get to the way you’re rethinking or reclassifying the generic global water crisis. I want to actually talk with you about something that you present in the book regarding an important way of looking at why we are where we are around the world. Of course, climate change is a big one, but there’s a page in the book where you present, it’s like the water crisis in six graphs, right?

And you have a graph of population growth over time since 1900, a graph of urban population. Real GDP, global GDP, fertilizer consumption, water use, and the construction of large dams. And they all have the same upward trajectory, but they also all have the same inflection point, right? Between 1900 and 1950.

Growth is there, but it’s shallow. But then around 1950, every single one of these graphs zooms upwards at a much higher rate. And you and others call that the great acceleration. Why do we need to understand what that is?

SEDLAK: The Great Acceleration, or some people refer to it as humanity entering the Anthropocene, the age in which humans start to control the climate.

This is a period of incredible change that took off after the World War II. When a variety of things came together. I guess the increased stability around the world, the change in the global order, and the unleashing of a variety of technologies that were held back during the period of the Great Depression and the war.

And so within a period of a few decades, the world really got cooking in terms of its growth. And that growth has put tremendous strains on the world’s resources, and that’s what we see all the time. It’s not just climate change, but it’s water resources and agricultural land and many other types of things, but we’re recognizing that these kinds of accelerations can’t go on forever.

There has to be a point where it slows down. And we’re indeed seeing that slowing down in the wealthy part of the world, we’re even seeing signs that in the BRICS countries, Brazil, Russia, India, China, and South Africa, we’re seeing it slow down, or at least population growth slow down, and we’re bracing for the next acceleration in places like sub-Saharan Africa, South America, and parts of Southeast Asia.

All of those things mean that we have these challenges, and the challenges are tied to this tremendous growth and migration of people to cities. But coupled with that is an era of tremendous scientific development and technological discovery. So as all of those people came into cities and as the world became wealthier, we developed the means to solve crises.

And I see the world as a race between the impacts of the great acceleration and the great accumulation of wealth around the world, and our abilities of not only our science and technology, but our institutions to keep up with that increasing rate of change. And that’s really what we’re looking at.

CHAKRABARTI: Yeah. Why I really appreciated seeing the changes that essentially humankind has wrought on planet Earth especially in the past 70 years, is that those graphs seem to then add a lot of shaping data to the new set of six ways you categorized different water challenges, right?

Because in the graphs it’s like population growth, urban population, fertilizer consumption, a really important one, real GDP. And then you have this way of thinking about what the different water crises are, right? There’s six of them. You have water for the wealthy. Water for the many, water for the unconnected, water for good health, water for food, and for ecosystems.

So there’s just a couple of those that I’d love to hear more about, Professor Sedlak. And let’s use the Brazilian City of São Paulo as an example. Because you write extensively about the kind of water problems they have had there. And then also some of the, some of what sped some of the solutions that São Paulo has actually implemented.

Can you tell us that story?

SEDLAK: Sure. I’ll only do it though if you call me David and not Professor Sedlak.

CHAKRABARTI: Okay, David. Fair enough.

SEDLAK: Okay, good. Brazil falls in this category that I call water crises of water for the many. Most people on earth are not fortunate enough to live in a wealthy country where water is guaranteed to come out of their pipes, 24 hours a day, and to be relatively clean.

Most people live in cities where they have access to flowing water, but that water might not flow all the time. It might not reach everyone in their city, and there’s no guarantee that it’s clean. And places that fall in this middle category, maybe the low- and middle-income countries, they really suffer when there’s a water shortage. Because they’re not as wealthy and can’t just go and build a seawater desalination plant or something like that.

And so São Paulo was really in a bind when they had an extended period of drought. About eight or 10 years ago, and that was because they really rely upon surface water storage in dams and reservoirs outside the city. And so all you need is a few years with less than the average amount of precipitation and you start running out of water.

So maybe people have heard about how Cape Town and South Africa was facing their day zero, the day that the water was stop supposed to stop flowing. While São Paulo was on the same trajectory and people seemed like they felt pretty powerless in their ability to stop it. Because what are you going to do when you have this giant reservoir that’s empty?

You can’t build a reservoir in a hurry and then make it happen. And so the crises that people felt as they saw the reservoir emptying, allowed the city not only to push a little harder on water conservation and threaten people who use too much water, but it allowed them to have money to fix some of the leaking pipes.

So in many countries around the world, anywhere from 20% to 40% of the water that gets put in the water distribution pipes leaks out before it gets to people’s taps. And it’s not all that expensive to fix that problem. But if a utility is just struggling to keep the lights on and do what they have to do, they don’t have the extra money needed to fix leaks in their pipes, for example.

Can I just jump in here, David, for a second? Because you’ve said a couple of things I just want to repeat again, because I think they’re very important. One of them is in a lot of places, including, here in the United States, vast amounts of water, treated water, get lost in transport between the treatment center and people’s homes with leaky pipes.

And in your book, you say specifically that in São Paulo, it was like a quarter, 25% of their treated water was just seeping out of the pipes. And the other thing is when you had mentioned that São Paulo wasn’t really in the habit of investing a lot in its water infrastructure, you make the point there that the best time to make investments in water infrastructure, reservoirs, et cetera, is about 10 years before a water crisis hits a region or a city. So I just want to keep that in mind. Because we’re going to come back to that later about how to change mindsets in terms of preparing in advance for water shortages.

But go ahead and keep telling what happened then when more focus was put on São Paulo’s major water problems, you say politically and financially that freed up resources to do a lot fast. What specifically did they do?

SEDLAK: Sure. So beyond just getting a handle on some of the leaks, they were able to build some modest water infrastructure projects that allowed them to connect parts of the city to each other that formerly weren’t connected.

So you could have one reservoir that might have more water than another one. And move water around that way. And you can start thinking about building new water projects that’ll come online in a year or two or three. And through a combination of getting people to conserve water better, reducing the amount of water that leaked out of pipes and managing the existing resources that they had.

They were able to limp along until it started to rain again. And during that period of crisis, the money had been freed up by the central government to build some new water projects. And so they got on a better trajectory. And hopefully the next time a drought like that happens, they’ll be in good shape.

CHAKRABARTI: As you point out in the book, Brazil was also looking down the pike to hosting the Olympic games, right? Which put even more sort of international pressure on the country to shore up a lot of its infrastructure, including the water infrastructure in São Paulo.

Part II

CHAKRABARTI: We’re talking about water in its liquid form, in general, around the world and how water crises actually maybe can be solved.

And our guest is David Sedlak, and he has a new book called “Water for All: Global Solutions for a Changing Climate.” Now, David, there’s the six sort of sub-crises that you talk about again in the book, which include water for the wealthy, for the many, in urbanized places, for the unconnected, for people who have always had water scarcity in their lives, and have to work very hard to get water, water for good health, potable water, agriculture essentially for food.

And then there’s the one that really caught my attention, is one that I don’t think we’ve ever really thought of as the crisis of water for ecosystems. Can you tell us why, what that means and why you wanted to include it in the way we should be thinking about water?

SEDLAK: Meghna, I think I wanted to include it for the reason that you said, we don’t often think about ecosystems being in crisis because of water.

And it’s absolutely true that when we take water out of the environment to grow food, to power our industries or to run our cities, that’s that much less there for the environment. And so it’s a crisis of quantity. It’s a crisis of temporal distribution and it’s a crisis of quality. So the quantity one is easy to see.

If you think of things like, you’ve probably seen photos of the Aral Sea in Central Asia and the way it’s dried up over the last couple of decades. Because its headwaters, the rivers that flow into it, have been diverted for agriculture. And that place is just emptying out as the water evaporates.

And so a whole ecosystem is disappearing. And that’s the fate of many terminal lakes around the world. They dry up and that’s like Great Salt Lake. That’s the same phenomena, but there’s also the crisis of not sending water where it should be going, when it needs to go there. That is, we’ve dammed most of the major rivers on Earth, and that’s had a great impact on the migration of fish and the way that sediments and nutrients move in those systems.

And then finally, when we’re done with our water, either our cities discharge treated wastewater, or in most of the world, the wastewater isn’t treated at all. Or when water runs off of our city streets and our farms, that brings pollutants into the environment. And so we see things like these blooms of toxic algae around the world, and the dead zones, like the one we have off of the Gulf of Mexico where the Mississippi River discharges.

All of those things create crises and greatly damage ecosystems. So that really is a state of crisis that we see around the world. It just creeps up on us slowly.

CHAKRABARTI: Yeah, it raises a question about whether we should be, in deciding water policies, if water for ecosystems should be a major part of the decisions that are made, or whether even the environment needs to be seen as having a right to water to keep ecosystems healthy. But so David, let’s get to those solutions. Because one major advantage of thinking about water crises as six different kinds of crises, as you point out in the book, is like all of a sudden it seems if we’re not just thinking about, “Oh, water crisis around the world.” And we’ve broken it down a little, smaller problems lend themselves more easily to solutions.

But I will note that you say clearly in the book, obviously water is not a thing that you can just compartmentalize. At a lot of the places that are experiencing major water challenges, it’s different kind of crises at the same time. Totally understand that. But when you talk about solutions, the first one that you turn to is conservation, because that’s like the easiest and cheapest way to actually take the edge off a water crisis anywhere.

And in fact, you use three U.S. cities, Atlanta, Dallas, and Tampa, Florida, as examples of how urban water supplies are managed. And it was interesting to me. Because in fact, we have listeners in Georgia, in Dallas, and in Tampa as well. So can you talk to me about what those cities are doing that you thought was worth highlighting?

SEDLAK: It’s not just those three cities, it’s just about every city in America, because the United States has seen great growth over the last 50 years. And I highlighted those three cities because they’re in a region, the Southeast, that has been rapidly growing. And they have, they’re in a position where they can learn from the conservation strategies that were pursued by cities that grew before them.

And so it’s really relatively simple to implement conservation policies. Everyone thinks about the fact that their appliances in their homes have changed over the decades, from washing machines that used to fill a whole big tub up with water and empty it every time, to the front loading and top loading washing machines that just use about 10% or 15% of the water that they used to.

But the real savings have taken place outdoors, especially in places where lawns are irrigated, or lawns and gardens are irrigated. And so if we can find ways to densify cities, to get people to live in places where they live in multifamily apartment buildings, or smaller homes, that homes that have smaller yards, that saves water.

Without even asking people to change the way they landscape. But there are incentive programs that encourage people not to put in lawns and landscaping that uses a lot of water. And then there are just a whole host of other relatively simple policies that pay off over the long term. And so those three cities, even though their sizes have doubled or tripled over the last 30 or 40 years. They use only a little bit more water or sometimes less water than they did 30 or 40 years ago. Just from relatively simple conservation measures.

CHAKRABARTI: Wow. So more specifically, you talk about how Dallas essentially over the last 20 years has continuously evolved its water conservation programs, right?

To the point where in 2020 they had a new program encouraging homeowners to replace their lawns with drought-tolerant landscaping. So the encouragement part there is important. And then in the early 2000’s, you write that Tampa and other cities in the surrounding metropolitan area began requiring new homes be built with more efficient automated irrigation systems, which was very fascinating to me.

And then here’s the thing. Because we’re look really looking for innovative things that maybe people haven’t hadn’t thought of before, but a lot looks like a lot of these American cities had. Because you write that since the early 2000, Atlanta and Dallas had already spent hundreds of millions of dollars on projects to reuse treated wastewater. And then Tampa in 2003, invested, it was already recycling half of its wastewater. They invested another $558 million on a desal plant.

Okay, so about that reusing wastewater. We turned to another city for an example of what that actually means, or another area. This is in California, in Orange County, where sewage water is not just treated and then returned to a local waterway. In Orange County, they use treated sewage water to eventually provide a third of the counties’ drinking water.

JASON DADAKIS: We’re taking all of the reclaimable flow from our partners at the Orange County Sanitation District, all the flow of theirs that’s reclaimable. We are taking recycling. It can produce up to 130 million gallons per day of purified recycled water.

CHAKRABARTI: That’s Jason Dadakis. He’s the executive director of water quality and technical resources at the Orange County Water District. Now, Orange County is home to the largest wastewater recycling plant. And it’s the first facility in the country to recycle every ounce of the county’s wastewater. So recycling, not just treating, and the county has been recycling wastewater since the ’70s, but in the past 15 years, they’ve expanded the capacity almost tenfold, and it’s become much more efficient as well.

The facility only uses about a third as much energy today as it did 50 years ago. So here’s how it works. The sanitation department sends the wastewater to the recycling facility, and then:

DADAKIS: We take it and run it through an advanced treatment of purification process. You know that one called membrane filtration?

This uses kind of thin straws with microscopic pores or holes in the side of these straws. Very analogous to a robust camping filter, you might use when you’re out in the wilderness backpacking, you’re camping and it’s really there to strain out any particulate matter as well as microorganisms like bacteria and vorticella, but really trying to get all the particles out.

So it’s a really tight, good filter.

CHAKRABARTI: Then comes to the next stage, reverse osmosis.

DADAKIS: That’s the heart of our process. You can think of that as an even tighter filter, where you’re essentially doing that filtration now at the molecular level, removing things based on their molecular size and their charge. That really purifies the water, strips nearly all the minerals out of it.

Removes things like pharmaceuticals and other organic molecules. It’s a very good barrier against viruses.

CHAKRABARTI: And finally —

DADAKIS: And then our third major step is combination of ultraviolet light, and we add hydrogen peroxide to that. We get three main benefits in that process. We get disinfection of the water, so again, controlling for pathogens, direct photolysis with UV light of certain organic chemicals, and then advanced oxidation with the hydrogen peroxide of any residual organics that might be able to get through that reverse osmosis process.

And after that, the water is so pure we actually have to host, treat the water. We have to stabilize it, put minerals back into it.

CHAKRABARTI: Okay, so let’s just repeat that last part. The water is so pure after this process, so pure that they actually have to put minerals back into it, to make it potable. But this recycled wastewater, despite being so pure, it does not actually right now go directly into the water system and then into faucets of Orange County residents, because until last December, that was illegal in California.

So the facility pumps the recycled water into a local groundwater basin before it ends up back in household use. Dadakis says, with this new law that could change, but for now, the facility will continue to direct its recycled water into the ground first.

Dadakis also says he doesn’t know where the county would have been today without this wastewater recycling facility, and he thinks if they can afford it, more communities worldwide should be exploring it.

DADAKIS: All water is recycled. The amount of water on Earth is finite. And we’ve been recycling it for eons through the sort of conventional hydrological cycle. We’re just accelerating that through engineered means.

CHAKRABARTI: That’s Jason Dadakis. He’s the executive director of water quality and technical resources at the Orange County Water District.

And again, their Recycled Wastewater program is now providing a third of the county’s drinking water. David, tell me a little bit more about the idea of recycling wastewater directly back to for human drinking use. Because while it seemed very effective, the process that Jason was describing, there is also very technologically dependent and costly.

So this isn’t something that would be viable for, obviously every community, everywhere.

SEDLAK: That’s true. Not everyone can afford it, but when we look at a wealthy country like the United States, it often turns out to be the least expensive next source of water, especially in arid parts of the country.

For example, following Orange County’s lead, San Diego and Los Angeles are in the process of essentially copying them, taking that same process and using it. But the difference is that in San Diego, they don’t have a wonderful groundwater aquifer underneath their treatment plant, and so they’re trying to decide whether they should pump that water back up the hill.

And put it in their drinking water reservoirs or put it directly into their pipes and distribute it around the city. That’s what utilities tend to do in the Western United States, in the rest of the country. There’s a concern that when they use that process of reverse osmosis, the one that takes all of the salts and other molecules out of the water.

They’ll be left with a salty waste brine that’s hard to get rid of if they’re not on the ocean. So in places like Atlanta and Northern Virginia and other eastern cities. And as well as places like Colorado and Arizona, oftentimes utilities try to avoid that reverse osmosis step, and they treat the water by passing it through activated carbon.

And subjecting it to ozonation as an additional oxidation and disinfection step. And so that’s a little less expensive in some cases, and it doesn’t produce the brine, but that’s another direction people are going. And finally in places that may not be able to afford these advanced treatment technologies, the simple act of putting wastewater through a conventional treatment plant and putting it in the environment, letting it percolate into the ground and through the soil, process that is often referred to as managed aquifer recharge.

Can be sufficient to purify the water to a point where it can be used for drinking, and that’s usually a lot less expensive.

CHAKRABARTI: How much does that happen? How much is that a standard practice with a lot of wastewater treatment facilities or not? Because my thought was that usually the effluent goes to a waterway, not back into the ground.

The effluent might go to a waterway, but the waterway might go down to the next city’s drinking water intake and become their water system. This is something we refer to as de facto or unplanned reuse. And one of the maybe extreme examples of this is the city of Berlin. In Germany when there was a West Berlin and an East Berlin, West Berlin was worried that East Germany and the Soviet Union would cut off their water supply.

And so they went out of their way to make sure that their treated wastewater percolated into the ponds and lakes around the city and recharged the water system. And so there’s a case where you don’t have an advanced treatment system, you just have a very well-treated wastewater. And this natural process of percolation through the soil to purify the water.

Part III

CHAKRABARTI: Now David, we talked about recycling wastewater for human use again. Then also, as you make the very important and obvious point in the beginning of the book, more than 70% of the Earth’s surface. It’s covered with water, but it’s salt water. So we get questions almost every time we do a water show from listeners, about what about desalination?

So in order to look at the feasibility of that as a major solution around the world for water crises, we called up someone in Perth, Australia. Now Perth is the capital and largest city of Western Australia population, about 2 million. It sits along the Indian Ocean and has a Mediterranean climate, meaning mild winters and hot and long summers with sometimes temperatures reaching a high of 110 degrees Fahrenheit.

So for the last 50 years, the rainfall for Perth has dropped by about 15%, and streamflow or runoff has dropped by about 80%.

KEITH CADEE: By about the early 2000s, we had a couple of consecutive years where there was actually no runoff into the dams, and generally came to the conclusion that looking to develop more conventional groundwater or surface water was not going to be very productive and ongoing reductions in water yield were quite likely. And so the decision was made to develop a rainfall-independent water supply, I.E. seawater desalination.

CHAKRABARTI: So that’s Keith Cadee, former senior executive manager with Water Corporation.

It’s the statewide water utility for Perth. Now seawater desalination plants are facilities that remove salt from seawater and make fresh water. Perth’s first desal plant opened in 2007. Today the city has two plants that supply about half of Perth’s drinking water. But one of the main issues with these types of plants, of course, is that desal uses a lot of energy.

CADEE: The amount of energy needs to be kept in perspective. So typically, you can supply all of the water needed by a family of four for their all their in-house use for about the same amount of energy as it costs to run a standard American or Australian refrigerant.

CHAKRABARTI: That’s surprising. But Cadee says these plants rely mostly on renewable energy to run.

And in the past 30 years, plants have become much more energy-efficient. Desal plants, and they consume about half as much energy as they did before. Now the conversion from salt to fresh water isn’t perfect though. For every 1,000 liters of ocean water, the plant produces only about 400 liters of drinking water, so a 40% conversion rate.

The rest is brine, which is returned to the ocean. The existing plants in Perth have been operating for more than 15 years now and are extensively monitored. The intakes and outlets were carefully designed and are monitored to make sure that there is no measurable adverse impacts. There are videos available on the Water Corporation website of just the abundance of sea life, on and around the brine diffusers where the seawater is returned back to the ocean.

By 2028, Perth plans to build a third seawater desalination plant, meaning by then up to two-thirds of Perth’s drinking water will likely come from seawater desalination. Now, the current plant is publicly run and funded. It’s not cheap to build such facilities, but Perth is a more affluent community.

So Cadee says the cost is less of an issue, the cost of providing all of the water needs inside the house in Perth for a family of say four, is equivalent to about one cup of good quality barista coffee each day. And Perth people love their coffee.

CHAKRABARTI: Which also happens to need water. But that was Keith Cadee, former senior executive manager with Water Corporation, which is the statewide water utility for Perth in Australia.

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