ARTICLE

Refreshing, Recycling and Reusing Water: Q&A with Dr. Peter Scales, University of Melbourne

Introduction

As our water supplies come under increasing pressure, it is essential that we examine our water management practices and explore ways to optimize our efficient use of this resource. Many of our current practices were put into place over a century ago and are no longer able to meet the challenges of modern society. This interview with Dr. Peter Scales explores water usage, the current challenges and discusses potential solutions for overcoming the global water shortage.

John Martin, PerkinElmer:  Water connects every aspect of life on Earth, we drink it, it is essential to grow the food that we eat, industrial processes rely on it--without water, neither we nor the world around us could survive. But worldwide, the amount of water that is used for human activities is now greater than the amount that we have available.

The United Nations has estimated that more than 780 million people, one in 10 of the world's population, do not have access to safe drinking water. Nearly one million people die each year from water sanitation and hygiene related diseases, which could be reduced with access to safe water or sanitation. The race is on for clean, safe water supplies, and it's becoming more intense. Cities and farms are draining underground aquifers, rivers, lakes and other bodies of water, which in the past may have served as sources of drinking water or for irrigation, now often contain pollutants.

How have we gotten ourselves into a situation where we need more water than we have? What actions can we take to solve the current global water crisis and what can we do to ensure that we have access to the water that we need in the future?

Joining us today is Dr. Peter Scales of the University of Melbourne. Professor Scales, work includes a focus on addressing the issue of water shortages, including how we can potentially reuse and recycle water to be more efficient in its use. Welcome Dr. Scales, we're excited to have you with us today.

Peter Scales, University of Melbourne: Thank you, John.

John Martin:  Before we get into the specifics of water reuse and management, I'm curious to know how you became interested in water recycling. Was there a specific incident or event in your life that prompted you to say: This is the issue for me, this is really something I want to I want to solve?

Peter Scales: I don't think there was a specific incident, John, but I've been working in this area for about 20 years. And I think it started with working in Asia, and in particular in India and China and looking at the mega cities of India and China asking ourselves: Are the systems that we've got in place for supplying water and sanitation actually going to serve us good into the future? And you look at those systems and you think well, they're actually based upon what I call the John Snow concept, which is that John Snow worked out at the Broad Street [water] tap in London in 1854 [and he thought] that pathogens cause disease and death.

Therefore, they said, if you can protect the water supply so that you don't get pathogens in and take the wastewater as far away from the city as possible and dump it, then you'll actually improve the health of cities. And that served us very, very well probably for about 150 years. But I think in the last 40 years, it's failing quite miserably. And I think there are two reasons. One is that the level of urbanization in the world has gone up enormously, the population has gone up enormously. And the ability to protect our supplies when we've got cities of 20 and 30 million people is extremely low. That ability now is really quite poor. And the assumption that you can assimilate all the wastewater from a very, very large city by dumping it in the ocean or something like that, is also failing miserably. And so, all of that coming together said, basically, we need a new system, we need to do this a different way. And we need to rethink the philosophy that's served us very, very well.

And it's no longer just pathogens that we have to worry about. It's chemicals in our water supply. And whereas very simple systems can quite often get rid of pathogens, things like chlorination, and very simple process systems to supply safe water, [but] with chemicals that's not possible. With persistent organic pollutants and things like that, we have to actually use multiple treatment systems. And so all of this has come together as I think a bit of a perfect storm in the last 40 years where the modern water systems haven't actually kept up with population growth, increases in chemicals, increases in urbanization, and our inability to both protect our water supply and to protect the environment. And our efficiencies in this area are really low. We only use about 20% of the water that comes into the cities.

So, all of those things together sort of come to this realization that this is an area that both from an engineering, from a chemistry point of view, there's a lot of work to be done. And that's why I got into this space.

John Martin:  Now, we hear a lot in the news about droughts and water shortages. But a lot of the stories we hear are regionally based or country based, can you provide us with a higher level of global perspective on this water crisis?

Peter Scales: Yeah, the United Nations basically says that we need around about 1000 meters cubed per person per year of water to live well, and if I look at how much water I use in my house, it's nowhere near 1000 meters cubed per year. So that 1000 meters cubed is made up of: 70% of it is the water we use to irrigate our crops and the food we eat, and the other 30% is for use in our house and all the goods and services in our cities. So, it's about 70:30, 70%, for agriculture, and about 30% for our cities. There are now quite a large number of places in the world, not necessarily countries, because averages don't really work here very well, where we have no way near 1000 meters cubed per person.

So, if I just took the United States, for instance, there's places in the United States that have 3000 meters cubed per person, but other areas at different times of the year, or in desert areas, where it might only be 300 meters cubed per person. And if I look across the world, I see the North China plain, I see India, very, very large groups of people who don't have that quotient of water. And the good thing about that, there's not many good things about that, but the good thing about that is that 1000 meters cubed is based upon a very poor efficiency of use, it assumes that in our cities, we just take the water, we use it and we throw it away.

In actual fact, if we improved our agricultural efficiency, and we improved our efficiency in our cities dramatically, by recycling, we can actually potentially get it down to 400 meters cubed per person, and at that point in actual fact, there's not many people in the world who have a water crisis anymore.

John Martin:  You mentioned some different countries, there's some of some countries that do share rivers or water sources. Can you foresee a global effort or a global initiative to try and address this issue to try to manage water resources more wisely? Are there particular parts of the world that that do this better than others?

Peter Scales: This is one of the great problems of the world, I think. It is that trans-boundary water is usually very, very poorly used. One of the really big issues is that if we look at the use of water, and we say, who should get access to the water? The number one thing that comes back is well, farmers are first, and cities are second. In actual fact, the environment, which is probably the most important user of the water, and we don't think of the environment as a user of water really gets considered.

So, when I put a dam into a river, and I say, well, now I've got enough for all the farmers in the city. In actual fact, it's the environment that gets the rotten end of the stick, so to speak. And in actual fact, countries that have started to really address this problem basically have used the concept that the environment is an equal player at the table, there is no hierarchy of use that farmers are more important than cities than the environment. That if you say there is no hierarchy, and everyone should get a reasonable share, and if the environment was sitting at the table, what would they say about this?

If the environment was a person that was sitting around the table, would they say well, thanks very much, you've done a really good job for me? And in that concept, countries that have started to use that philosophy are starting to do better, but there's only a few of them. And guess what, we've got a long, long, long way to go.

John Martin:  Looking around us, there's a lot of water. We can see that the Earth's surface is covered approximately 70% with water, but only about two and a half percent of that is freshwater. Now, you'd mentioned efficiency earlier, is it just a matter of using that two and a half percent more wisely? Does that get us out of this crisis?

Peter Scales: It doesn't completely get us out. But it actually would go a very long way to getting us out of it. We currently use about four times more water than what we've got, temporarily at least anyway. And our efficiencies are typically around about 20%. If we could improve our efficiencies to 70% or 80%, we would almost get there. It is a bit of a vicious cycle, especially in our cities. We pollute our rivers, and we then say that water is no longer easy to treat, therefore, it's not water we can use for the city. We'll then go and pump an aquifer, the aquifer gets polluted, and we start to have a vicious cycle.

And in actual fact, in some of our cities, we have an abundance of water. And yet, we don't have safe water. And if you went to the water utilities, they'd say we've got a water crisis. And I think a lot of the water crisis is that we've polluted a lot of our surface waters of the world to the point where we have to use more complex treatments to clean them up. And there's this John Snow philosophy still running in the world that says: If I've got a protected supply, I don't have to treat it, I can just send it out to the people. And we have to move on from that.

We have to actually accept that we do have put a lot of pollution in the world, everyone lives downstream, and we're going to have to start to use especially our surface water resources for urbanized areas a lot better than what we do now. And that means cleaning them up, reusing them, accepting that they're polluted, accepting that they've got a lot of pathogens and a lot of chemicals in there and that we're going to clean them up and reuse.

John Martin:  Now this issue of pollution, chemicals that are in our water supply, surface waters, ground waters, the technology exists to detect things that are in that water, am I correct in that? And how does that technology work into this whole process of reusing and recycling? Is it as simple as doing more testing?

Peter Scales: It's really a good question, John, that's multi-level I would argue. A couple of points here. We've had the technology for probably 40 years to put together a set of barriers that can treat highly contaminated water with a whole range of chemicals, and actually produce very pure and very safe water. So, at one level, one could argue it's not a technology issue at all. However, there is a concept that water is cheap to treat. And therefore, if we put multiple barriers in, it'll be more expensive, and people won't be able to afford that. In actual fact, the cost of the infrastructure and the cost of the treatment systems in wastewater add up to a lot more than any of that. That's number one. Number two is that people still have an immense fear of what we would call the chemicals in the unknown side of water recycle.

And so, there's a social side to this that's just as important as the technical side. So, there is a technical, economic side, but there's also a social side that's very important. And the world is basically shown that if you actually go through the process of actually doing demonstrations and you demonstrate to people what is possible, then over a generation, people get to actually understand that in actual fact, this water is safe, it is good to drink, it is good to use.

There is a piece that says, well, we don't want to send all of this water back to potable standard or into the potable supply. However, there's a mass balance problem in an engineering sense, and it's a very simple one, and that is that about 60% of the water in our urbanized supply needs to be a potable standard. And if we've only got one supply line, so to speak, into every house, then we can't have a recycle system that goes past about 40% if we don't put it back into the potable supply.

So if we truly want to get to a high efficiency, we do have to say recycle the potable, we do have to understand what the chemicals are in the system, we do have to understand what the toxicity of those systems are, we have to have measures of analytics and toxicity in those water supplies that both meet regulatory requirements, but also satisfy the people that the water is safe and clean. And they might be two different things.

What we have to say to the regulator in terms of which chemicals we've taken out specifically, versus what we would say to the community about what the safety of this water is, may require different measures, or different ways of reporting, etc. And all of that together says that it is a technical problem, but not in the treatment sense. It's a technical problem in how we analyze for all of these things, how we report them, and how we bring the community along with the concept that we have to be a lot more efficient with water.

John Martin:  Now, water is obviously used for a great many things besides just human consumption. There's agriculture, there's manufacturing, and so on. Now, how are these water shortages affecting those industries? Are they taking any steps to reduce their consumption and to be more efficient? And how do they fit into this whole puzzle?

Peter Scales: I think there's probably about a third of all our water used in cities, on average, is used by industry, sometimes around 40%. And it's rare that they actually need potable water for the industrial processes. And if I look around the world at where recycle is really starting to become embedded, it is peri-urban agriculture, and it is industry that has taken up the mantle, one would argue, in the reuse area.

My issue with that is not that they're not doing a great job, they are, and it is an important first step in the recycle process to have customers, but ultimately the customer has to be mum and dad, and you and I in our houses wherever we live. And in industry, they've taken up the mantle, and they're actually paying quite a high price for their recycled water. And in actual fact, we're probably paying it because the utilities often supply that at a low cost, even though it's been treated with many, many barriers. And the reason is, the treatment of water, the cost doesn’t scale linearly, it actually goes down enormously as we go up in volume. So, in actual fact, everyone says: Well, these costs are too high on things like recycled water to treat them to a very high level. Well, the answer is, it is if we do it in small volume.

But once we get to very large volumes, those costs will be not a lot different, in actual fact than the cost we have in treatment now. And all of a sudden, it becomes a very viable option. So, we need industry to help us to get over this step. And in actual fact, I believe they're doing a really good job because they're paying what we would call above the odds because the treatment systems are small at this stage. And there's a lot of philosophical arguments about which way you go there, but ultimately customers are important in starting the process.

John Martin:  The problem, to me, as we're thinking about it here, is that we're talking about different countries, industry, homeowners, governments, and the problem seems big, seems daunting. Do you really think that this is something that we can solve? What is the ultimate solution here?

Peter Scales: I'd like to think we can solve it--I suppose some of the hardest problems to solve in the world are not the technical ones. The ones that involve bringing technology and the community and industry and the social side of problems together are always--and politics--are always the toughest ones to solve. I would argue we have to solve it though.

Currently, our environment cannot actually cope with the level of waste that's being put into it. I always say that if one thinks about the solid waste we produce that we put into landfill, the gaseous waste, like CO2 that we put out into the atmosphere, and the wastewater that we put out into our rivers and oceans, every single one of those is in an unsustainable situation. We're seeing that through climate change with CO2. We don't see it as much in our oceans and everything, even though people who are in the oceans would say, it's all around us. And if you're in very populated areas of Asia, you see it as breakdown in fishery stocks, and a whole range of really poor outcomes.

So, I would say that--like CO2 into the atmosphere and like trying to get around solid waste into landfill, etc.--this is an imperative of urbanized society. We've moved from 27% to 50% urbanization in the world in the last 40 years, as we move to 70% urbanization, in the next 30 years, if we don't solve this problem, we're quite unsustainable, and not just in CO2 and in solid waste. So, this, to me, is one of the big issues of urbanization and modernization in the world. We say we've modernized, but in actual fact, we haven't solved the waste problem.

And until we take the waste out of water, and we make it into a one water piece, the environment suffers, people get unsafe water, and the health system suffers, everyone suffers. And so, I see this as part of the triumvirate of solid waste, gaseous waste and water waste, and the biggest single waste we produce in the city every day is wastewater.

John Martin:  Now, one last question for you, Dr. Scales. Before we let you go, what can we, as individuals, do to try to solve this problem?

Peter Scales: Once again, I think that's a really tough question. Because everyone says: Well, what do I do in my house or something like that?

I think the single biggest thing that we see when we start to look at recycle of water is, moving people from accepting or not accepting that they would say drink wastewater again to drinking it, requires the community to get together and say: We want water resilience, we want to have a safe environment, and to work with things like the water utilities and produce answers. The water utilities technically can produce that answer. A lot of people say there's a political thing where they say, Oh, the politicians need to do something. I don't know of a politician in the world who says I'm going to do something when only 40% of the people believe in it. Politics doesn't work like that.

Therefore, to me, this is not a political issue. It is a community issue. And it's the community working with the water suppliers in the world to say we want a different system. So, the individual, to me, working with the water utilities, as communities, and community groups, and community peoples, will change this problem. Politicians won't change the problem. Politicians, if the community says we want it, and the utility says we can deliver it, the politicians will tic the box. And that's one of the big dilemmas of the world, people saying I want the politicians to do something. No, the individual has to say: No, us as a community need to live in a safer environment. We need safer water; we need more resilient supply. We need a better environment around us because we've got good resilient water supply. How do we achieve that?

As individuals, we get together with others and we talk to our utilities and we work with them around that problem. And that's what I say the role of the individual is. In a funny way, not to be individual. It's to actually work in the community.

John Martin

Great, well, thank you so much, Professor Scales for joining us today. I really enjoyed talking to you. Thanks for taking time out of your busy schedule.

Peter Scales:

Thanks guys.

John Martin

And to learn more about Professor Scales and his work, you can visit the University of Melbourne website at: www.unimelb.edu.au. And thank you for joining us as well. We look forward to seeing you again on the next edition of EnviroChat.