The Solutionists, with Mark Scott

As the climate changes and populations boom, water supplies are under increasing pressure.

The idea of drinking water that was once swirling down your toilet bowl or kitchen sink may make you feel squeamish, but it could hold the key to future water security.

University of Sydney Professor Stuart Khan explains the promise of purified recycled water, and how it can future-proof water supplies in a thirsty nation prone to drought.

“There is the opportunity to start thinking more about a circular economy and how we might reuse the water that we’re currently discharging.”

Professor Khan points out that all water on Earth is recycled – the water you’re drinking “has quite likely been drunk by dinosaurs in the past” and could be described as “purified dinosaur pee”. 

But there’s a huge psychological hurdle involved in drinking water that’s gone from ‘toilet to tap’. So how do you sell the idea to a skeptical public? You’ll hear from Dee Madigan, creative director of advertising agency Campaign Edge and a regular on ABC TV show Gruen. 

You’ll also get a taste of how the technology works as you go inside Sydney Water’s Purified Recycled Water Demo Plant, with plant manager James Harrington.

Mark Scott  00:01

This podcast is recorded at the University of Sydney's Camperdown campus on the land of the Gadigal people of the Eora Nation. They've been discovering and sharing knowledge here for 10s of 1000s of years. I pay my respects to Elders past and present and extend that respect to all Aboriginal and Torres Strait Islander people.

James Harrington  00:26

It's all a bit different and weird, to be honest. Engineers, we're not known for talking to camera or mics and stuff like that. Here we go. My name is James, I am a Project Manager here at Sydney Water. This is the main trading room. So, our process here Quakers Hill, we treat raw sewage. We treat it up to what’s called tertiary stage. So, it's gone through three separate treatment stages. At which time, normally it would go back into the river, whereas here we're bringing it up to PRW or purified recycled water. People have an image of what comes in as what they consider sewerage from their homes and businesses. And that is one of the things that we're trying to show here that, really we're talking about water that you'd see in the natural riverways that kind of quality, and then we're treating up to a very high standard, so high that we have to add more minerals back into it, just to make it safe and ready to drink.

Mark Scott  01:41

Imagine waking up tomorrow and everything looks completely normal. The sun’s shining, the birds are chirping. It’s only when you go to get a glass of water, that you realise things aren't normal at all. Because Day Zero has arrived. The taps, they've been turned off. Water is now being trucked in. And you've got to queue up for hours to get your ration. It sounds like a dystopian nightmare. But it's happened before. And as the climate changes and our population grows, our water supply is increasingly under pressure. Turning our sewage into drinking water might be the key to our future water security. If we can overcome the mental hurdle involved. I'm Mark Scott, the Vice Chancellor of the University of Sydney and this is The Solutionists where you make the people grappling with the world's greatest challenges. Stuart Khan is a leading Australian expert on water quality and treatment. He's the head of the University School of Civil Engineering. Stuart, what's the story with water in Australia? How much are we actually using?

Stuart Khan 02:54

Well in Australia, we use around 300 litres per person per day on average. It varies quite a lot between different regions. But we are one of the most profligate users of clean water around the world. And we are so, I guess, because we can afford to be and it does add to our quality of life in many significant ways. But there are opportunities there to really think about whether or not we should be significantly more efficient with our water use.

Mark Scott  03:21

If we don't make some big decisions, how quickly could we run out of water or have real water pressure in our big cities?

Stuart Khan 03:28

About 70% of the water that we use is for agricultural purposes. And so 70% of that water is water that falls in regional and rural areas. And is not necessarily easily accessible to the cities. So, most of the remainder is used in our urban centres. What we tend to observe is that we go through wet years, and we go through dry years. And as long as we're in a wet period, we're pretty comfortable as we are right now. But we know that we are prone to drought, we can have very severe multi-year droughts that really do put pressure on our water supplies and how much water we can store and carry over from wet years to dry years. So, between 2017 to 2020, only really two and a half years of quite severe drought, Sydney's water supplies went from completely full to half full. So, we know that in two and a half years, we can use 50% of our water, you can double that and say that we'd be out of water. But hopefully that's a hypothetical scenario because we would take steps to respond along the way. That doesn't leave a lot of time to respond. In reality, we really need to be planning before the drought to ensure that we don't run out of water in our cities because that's not something we can afford to do.

Mark Scott  04:41

Why are we such a thirsty country? Why do we use so much water on a per capita basis?

Stuart Khan 04:47

It's partially to do with climate. Many parts of Australia are quite dry but also the warmer temperatures. Warmer temperatures leads to evaporation from catchments. So, even when you get rainfall, some of that rain will be absorbed into the soil and some of it will be evaporated. So, it doesn't all translate into stored water. It's partially because of our quality of life, the way that we live. In Sydney, you look around and you see that we do have gardens and parks and trees. That is something that has value. And it is something that I don't think we want to lose. It's also habitat for birds and bees and other species in our cities. But it all requires water. And that's all part of the answer for why we use a lot of water.

Mark Scott  05:30

If we're living with water scarcity, how does that going to change life in modern Australia?

Stuart Khan 05:38

We do have experiences of water scarcity, if we think back to the Millennium drought, for example, and we can think of real impacts to, particularly to rural and regional areas. And so, water scarcity, has a very immediate and significant impact on agricultural production. There are many crops that we simply won't grow. And it's a lot of the sort of perennial export crops that are the first to stop being watered and to stop being planted during a drought. So, that has an impact on exports and on our gross domestic product, and therefore significant follow-on expors through the economy. If we look at what's going on in our cities, we know that as we go through drought, the first direct impact that people start to be exposed to is voluntary, and then mandatory water restrictions. And we start first restricting people's ability to use water outdoors in watering the garden and watering the lawn. And so, the local playing fields, the sporting fields, shared community resources, if water is not available to keep those growing and green, then there are broad community impacts. But generally, we've been fortunate and we've been able to produce infrastructure that we need to stave off some of the worst effects of the drought and some of the greatest water scarcity that we might have otherwise been exposed to. But it's something that we will always need to keep ahead of otherwise, we could end up in situations where we have to physically ration water to houses. I've been to several cities where the water is turned off for several hours a day in in particular neighbourhoods of the city. So, you store water when it's available, sometimes on the roof, sometimes in the bathtub. And you use that water during the period where there is no water pressure to supply water to houses. So, I think in Australia, it's important to understand how fortunate we are to have plentiful supplies of water in most cases, and for that water to be very high quality and clean and safe for drinking. Because what we take for granted is a long way off what billions of people around the world are living with.

Mark Scott  07:41

An important practical solution is recycling water for drinking. You've done research and been involved in that what piqued your interest in that solution.

Stuart Khan 07:52

I grew up in Coffs Harbour. And in the 1980s there was a very broad discussion going on, very public discussion around proposals for sewering the northern suburbs of Coffs Harbour and part of those proposals was that there would be an ocean outfall that would be built on a beautiful, pristine headland at Emerald Beach, the headland’s called Look At Me Now Headland. I was actually born right on that headland. I spent the first six or seven years of my life pretty much on that headland. And this proposal came along that was going to discharge sewage into the Pacific Ocean off the Look At Me Now Headland. It was a pretty standard thing for a local government to be looking at, at the time. But there was a burgeoning environmental movement in Coffs Harbour at that time, particularly surfers that were very concerned about how this might lead to ocean pollution in a beautiful marine environment. People started pushing back against it. There was one particular counsellor in Coffs Harbour, he was a school teacher at the local high school, who started saying that we should not build an ocean outfall on this head land and instead, we should be recycling the water. That's the latest technology and that's where the engineering is going and you can recycle that water and use it for irrigation. Coffs Harbour obviously has lots of agriculture that people were pointing to bananas at the time was the main crop. And I actually found myself pretty excited by that campaign. And at one point there were bulldozers out on Look At Me Now Headland threatening to start preparing some of the site works for the ocean outfall. And I was out there with a group of friends. Nobody there, nobody got hurt. There was nobody in the bulldozers there actually just chained up behind some fences, who are throwing dirt clogs that these bulldozers that was our protest against it. Of course, I had no idea, I didn't know about water engineering. I didn't know whether the things that I was saying, parroting what this local councillor was saying, were accurate and useful contributions to debate or not. Now I know that they are, and I do have an understanding that what was being proposed was a realistic opportunity. And in fact, now, the wastewater from that region does support a very important blueberry industry in the north of Coffs Harbour. So, there is the opportunity to start changing the way that we think about waste and waste disposal and thinking more about a circular economy and how we might reuse the water that we're currently discharging.

Mark Scott  10:20

You know, if you go into a supermarket now, there'll be rows and rows of purified water. I mean, we talk about, you know, the purity of water, it's a luxury good in many ways. When you tell someone that the water in their glass is purified recycled water, and it suddenly would appear to be much less appealing. How do we overcome the yuck factor, that is central to the recycled water debate?

Stuart Khan 10:47

That's a very important question, because it is that yuck factor that has been holding back a lot of the progress on producing recycled water and therefore producing a more sustainable drinking water supply for many of our cities. I've come to understand that the yuck factor is actually a perfectly normal response for people to have. And it probably has a very good evolutionary basis that you know, you go back 100s and 1000s of years and those who got too close to human excrement didn't survive and those who had an instinct to avoid it and found it distasteful or yucky. Probably had an advantage by doing so. So, I think it's a very deeply ingrained response to the idea of something that might be contaminated by human faecal material.

Mark Scott  11:33

So, how can we solve that? Well, we hit the phones and grabbed leading Australian advertising executive Dee Madigan. Now, you know her from the hit TV show Gruen. How would Dee sell the idea of recycled water to the Australian public?

Dee Madigan  11:48

With something like this I think he goes straight to the barriers people have, and think well, “Sow can I get over those?” Because you know, in this case, they're going to be, they're going to be fairly big barriers. If you Google ‘faecal matter’, right, and ‘faecal matter transplants’, think “What are the benefits of poo?” And you look at all the research being done: it's treating inflammatory bowel disease, irritable bowel syndrome, obesity (big one!), liver disease, diabetes, food allergies, autism, anxiety, depression, multiple sclerosis. And then I think the two that you really want to focus on, which is: ageing, it can supposedly reverse the effects of ageing on the digestive system, and the brain and the vision; and also can increase endurance, exercise performance. So, you could tell people that we should be doing this because it's good for the environment. And some people are gonna go “Yep” anyway. But most people are gonna go “Uh-huh, uh-huh, uh-huh, yeah. No, I'm not drinking poo water.” So, you actually have to put your carrot in there as well, and what's in it for them. And, and we know the anti-ageing market is huge. And people will take anything. Like they eat their own placenta. They eat bird poo, you can buy it on Amazon. So, that, I feel like that's where I would start, on blokes for exercise, and women, particularly for anti-ageing. And I would even start selling it before you make it available to the general public. Actually get people to pay for poo water, bizarrely, will help in the long run as well. But you probably do want to change the name. So, just like we stick, like we stick botulism in our faces, literal botulism, but we don't call it that we call it Botox. So, maybe what, you know, you're only as young as you faecal.

Voiceover 1  13:44

Want to defy gravity and head off those nasty wrinkles?

Voiceover 2 13:47

Need to boost your stamina, strength and endurance?

Voiceover 1  13:53

Why not try recycled water? It's chock full of benefits so that you can poo your way to a younger you. 

Voiceover 2 14:00

Recycled water.

Voiceover 1  14:03

You're only as young as you faecal.

Stuart Khan 14:08

All water is recycled. The water that we're drinking now has quite likely been drunk by dinosaurs in the past. And we're drinking cups of purified dinosaur pee right now. I think also by an understanding of the technology and I think growing, the appreciation of the role of science and technology in society has an impact because part of the barrier I think, is not being able to get past the idea that technology can actually solve this and then we can very competently and very confidently produce water that is very safe to drink and we have a very good understanding of what's in that water.

James Harrington 14:47

Yeah, everything in this room has been designed so it's safe to touch. So, each one of these units, apart from valves, we encourage people to touch and feel. For us seeing is believing. Touch, feel, it's all part of that. Hard to see at times but you can actually see the water flowing through those end pipes. Because it is so clear, and it's running continuously, you almost can't see it, because the water that we produce here is such incredibly high quality.

Mark Scott  15:18

So, what are the drawbacks of the technology? And what do we need to overcome to be able to scale this as a proposition?

Stuart Khan 15:24

The key drawbacks: energy, the amount of energy that's required to purify water, and the cost that's associated with that amount of energy. So, water is actually a very cheap commodity. If you look at it from a household perspective, we pay $2 or $3 per 1000 litres of water at the household level. So, if you want to invest more than $1 or $2 in producing and cleaning and supplying and pumping that water to households, then there's going to be a significant increase in the household cost. And that obviously has political ramifications as well. So, trying to implement solutions that really are low-cost solutions is very important because high-cost solutions are not going to fly unless you have a very serious problem in terms of being able to supply water.

Mark Scott  16:15

Of course, the water we're trying to recycle isn't just human waste. There are a lot of other chemicals in the light that go into wastewater. Some decades ago, there were news stories about fish being feminised by all the hormones that are now evident in the water. How do those kinds of issues impact the recycling complexity?

Stuart Khan 16:33

It's something that people became aware of in the late 1990s. In particular, there were fishermen in the UK that were catching fish in rivers, where they pull the fish out - I can't tell the sex of a fish, I don't know if you can but some fishermen can and certainly biologists can. So, what they were finding is that normally you would expect to catch a fish, look the fish, and find that the fish either has male characteristics or female characteristics and what they were finding more and more that they will fish that they were referring to as being hermaphrodite fish that had both male and female characteristics. The scientific community started to ask what was going on, what was causing that and it was eventually identified that there's actually quite a broad range of chemicals that can induce a hormonal response in fish to effectively induce female, mostly, estrogenic type hormonal responses. And an important source of some of those chemicals was the wastewater treatment plants that were discharging into the waterways in in England. So, the contraceptive pill is a chemical that we see that is not well removed through conventional sewage treatment processes, and therefore ends up in waterways and has observable impacts. Obviously, that's alarming. That's alarming from an ecological perspective, what happens to a community of fish or other aquatic organisms if you disrupt the ratio between the sexes. But it's also alarming if you start to extrapolate that some of these same chemicals might have similar or related impacts to humans. And we do know that humans and other mammals are susceptible to some of these types of impacts from some chemicals, so it's a perfectly valid thing to be concerned about. The good news is that the advanced water treatment processes that were used for purified recycled water are the most effective processes for removing these types of contaminants. And we know very confidently that we can produce water that the concentrations of these chemicals are well below anything that can be measured.

James Harrington 18:31

When we talk about the filtration steps, people really think about their high school chemistry or high school science where they did experiments where they would put water through a flat piece of paper, and that's a filter. Ours look a bit different. They're a big fibreglass tube, almost a metre long, which inside it has a very tightly wound spiral membrane. So, there is hundreds of layers as we've wrapped it round and round and round. And this membrane is so, the pores are so small that he can remove some of the smallest particles down to salts. When you think of salt water, how much salt can be dissolved in water, this membrane has the capability to remove it. We use 42 of these in this plant, we do three sets of them. So, we go from one end to another in our big barrel, so that we can progressively concentrate those salts and impurities that we don't want to move along, and then extract that clean water and move that along.

Mark Scott  19:33

One of the, I think, interesting questions about big civil engineering projects is the level of support they have and the amount of ambition they demand. When the Opera House recently turned 50 there was a lot of debate, ‘Could Sydney build an opera house now or would the opposition be too loud? Would we ever be able to get the ambition together to build the Snowy Hydro again?’ When you think of opposition that will probably always be out there to recycled water, how do we help politicians work their way through noise and opposition to reach policy solutions that might be effective and long term?

Stuart Khan 20:12

In some ways, I think many politicians in Australia actually overestimate the obstacles. I might be naive in saying that, but I look at it fairly closely, and I've looked at the studies that we've seen around public perception, I look at the community engagement that the different water utilities around the country have done as they've been planning future water supplies, I actually see quite a high level of acceptance for purified recycled water. I see more and more people understanding the case for purified recycled water. I see more and more people understanding that it's the reality that there are actually cities around the world that have been doing it successfully for a long period of time. We're still a little bit scarred from a bad experience in Toowoomba, in 2006, where there was a purified recycled water scheme proposed that ended up being politically controversial, and ultimately didn't go ahead because it didn't have the community support.

Archival Media Clip 21:10

The Darling Downs, west of Brisbane, is suffering its worst drought on record. And as water supplies slow to a trickle, Toowoomba authorities are taking drastic measures. But some well-known residents don't want to be pioneers.

We had the image of a garden city here with carnival flowers and a lot of things being put in to build that image. Now you go around Australia right now and we’re known as ‘Poo-woomba’ or other dirty names, sort of thing. So that’s no good for our image.

Stuart Khan 21:37

That's a case study that many of our decision makers have observed, and then have not wanted to repeat. And in fact, it's become an international case study, literally, in textbooks around the world on how not to do community engagement.

Mark Scott  21:49

What not to do.

Stuart Khan 21:51

Right. So, many politicians are nervous that you can't build enough community support. And I think there's a question around how much community support do you actually need to go ahead with something that's as fundamental and important as water supply. And I look at fluoridation, about 20% of the population say that they're opposed to adding fluoride to our drinking water for the purposes of oral health. And there are all sorts of conspiracy theories around fluoridation, all sorts of concerns around the public health implications, most of which, or all of which, are exaggerated. Yet, we add fluoride to drinking water, we see this as something that has a net benefit. And those benefits outweigh the low level of dissatisfaction and unhappiness with the fact that there is fluoride in our drinking water. And I think that we should probably be taking a similar approach to purified recycled water. We invest the energy in communicating and enabling people to understand why it's an important thing to be doing. We build support as much as we can. But we accept that there will always be a small proportion of people who will never think that that's a great idea. And we'll never be completely happy about it.

James Harrington 23:03

We are seeing some positive sentiment, we're seeing people far more in support, once they understand what are the checks and balances, what does the treatment do. And they're coming out with an understanding that we can treat any water to any standard. It just takes extra steps. And that's what we're doing here. We're accelerating a natural cycle, which has always been going around. We’ve always recycled water. So, really purified recycled water is just a little bit faster and a little bit more controlled.

Mark Scott  23:33

Think several decades ahead, cast right forward to the end of the century. If we get this right, what does our world look like? What do our cities look like in an environment where we've embraced this technology?

Stuart Khan 23:46

I think very importantly, we're talking about sustainability. We're talking about a circular environment. So, at the moment, we have a system if you think of Sydney's drinking water, we captured water in the in the mountains in the catchment. The water flows down through the catchment into small streams and then into the larger waterways. The Cox's River and the Wollondilly River and ultimately into Warragamba Dam. So, we capture water in big dams, we take that water, we treat to drinking water quality. We pump it to our homes and industries in Sydney and we use that water once whether it be for shower, for a bath, to flush the toilet, to brush our teeth. Whe water is used once and then it's discharged down into the sewer. And the sewer takes that water to the sewage treatment plant and sewage treatment plant to the sewage outfall and the outfall out into the Pacific Ocean. In the future, we really need to think of that linear process that one way conveyor belt being transformed into a circular system. So, a circular water supply would be to then take the water from the wastewater treatment plant, purify that water, and then deliver it back into the system at some point before people use it. And so, we will, instead of just using water once, as it becomes available to us, some of that water will be able to use 2, 3, 4 times and therefore having a significant impact on the amount of water that we need to take fresh from the environment.

Mark Scott  25:20

There's an old line in politics that you never let a good catastrophe go to waste. Do you think we need another big drought to fundamentally change the psyche around recycled water? And would you expect that politicians would move more aggressively on this technology in light of falling dam levels?

Stuart Khan 25:39

Well, we know that's the case, that when we have droughts is when we get political interest in managing sustainable water supplies. And Australians tend to have short memories. And when the drought finishes, we tend to move on to different priorities. And that's really a problem. And we also do know that the droughts have led to increased understanding, obviously, around issues of water scarcity and vulnerability to running out. The problem is that by the time you're in a serious drought, that's not the time to be building water supply infrastructure. These things take years to build and to plan properly. I really hope we don't wait for the next drought because we won't build the optimum solution if we're in the next drought.

Mark Scott  26:24

I'm Mark Scott, Vice Chancellor of the University of Sydney. Professor Stuart Karn is a leading expert on water quality and treatment. He is the Head of the University's School of Civil Engineering and is a very civil man to boot. You also heard from Dee Madigan, the Creative Director of Campaign Edge.

Dee Madigan  26:44

And you know, there's that coffee beans that people have that's actually been pooed through some animals. Like this kind of, people embrace the grossness if they think there's a benefit to them.

Mark Scott  26:57

And you got a tour of Sydney Water’s PRW Demo Plant. Thanks to Plant Manager James Harrington.

James Harrington 27:03

You probably can't get cleaner water than what you get here.

Mark Scott  27:11

Ollie Jay is one of the world's great experts in heat. He has a laboratory here at the University of Sydney that simulates heat waves. He's constantly learning about how to keep us safe on the hottest of days and in the most oppressive conditions.

Ollie Jay  27:27

The people that are dying during heat waves are doing so predominantly outside of the gaze of the public. They're dying home alone, isolated, often in circumstances that they won't be found for days and days later. So, well, I think that probably contributes to people's tendency to maybe not think that heat is as dangerous as it actually is.

Mark Scott  27:50

I had a great conversation with all Ollie Jay and you can listen to that on The Solutionists wherever you get your podcasts. The Solutionists is a podcast from the University of Sydney produced by Deadset Studios. This episode was recorded at the Faculty of Arts and Social Sciences media room and our thanks to the technical staff here.

The Solutionists is podcast from the University of Sydney, produced by Deadset Studios. Keep up to date with The Solutionists by following @sydney_uni on Twitter, Facebook, and Instagram.

Sourcing/credit: Archival media clip from ABC News.

This episode was produced by Monique Ross, with field recordings by Harry Hughes. Sound design by Jeremy Wilmot. Executive editors are Kellie Riordan, Jen Peterson-Ward, and Mark Scott. Thanks to the technical staff at the at the Faculty of Arts and Social Sciences Media Room.

This podcast was recorded on the land of the Gadigal people of the Eora nation. For thousands of years, across innumerable generations, knowledge has been taught, shared and exchanged here. We pay respect to Elders past and present and extend that respect to all Aboriginal and Torres Strait Islander people.