David Sedlak is a professor in the school of Civil and Environmental Engineering at UC Berkeley. He is also the Deputy Director of the NSF Engineering Center named Renuwit, which stands for Reinventing the nation's urban water infrastructure, and a member of the Berkeley Water Center. http://www.ce.berkeley.edu/~sedlak/ http://urbanwatererc.org/
Transcript
Speaker 1: Spectrum's next [inaudible]. Welcome to spectrum the science and technology show on k a l x Berkeley, a biweekly [00:00:30] 30 minute program bringing you interviews featuring bay area scientists and technologists as well as a calendar of local events and news.
Speaker 2: Good afternoon. My name is Brad swift and I'm the host of today's show. Our interview is with UC Berkeley Civil and environmental engineering professor David Sedlak. He is the deputy director of a new NSF engineering center named renew it, which stands for re-inventing the nation's urban water infrastructure. The center partner [00:01:00] institutions are Stanford, the Colorado School of Mines, New Mexico State University and UC Berkeley. Professor said Lac is a member of the Berkeley Water Center and has been teaching at Berkeley for 17 years. This interview is prerecorded and edited. Professor Sedlak, thanks very much for coming to spectrum and talking with us. Oh, you're welcome. I'm really happy to be here. I wanted to start by laying a foundation a little bit for people who may not be familiar with the [00:01:30] kinds of work that you're doing and the issues related to water that you deal with.
Speaker 3: I think my main area of interest is really the way in which we manage water in cities. So that includes everything from the drinking water supply, the waste that we generate, the storm runoff that comes through the streets and the entire urban water cycle.
Speaker 2: Can you describe the water cycle in a city?
Speaker 3: Sure it is. Yeah. There's no one urban water cycle [00:02:00] in the city. The water cycle that we all learn in junior high school is that the water evaporates from the ocean. It falls in the mountains, the mountain runoff create the streams, the streams throat floated the ocean and then there's a city on the stream. The city picks up water from the river, it goes through a water treatment plant. People use it in their houses, it goes down the drain, it goes to a sewage treatment plant. It goes back in the river and it goes to the ocean. And that might've been the situation 70 or 80 [00:02:30] years ago, but now our cities are much more crowded and the situation's much more diverse. So, for example, many cities that river where they collect their drinking water from is downstream of another city. So the water in that river is already been in and out of the previous city. And so the water supply consists of river water mixed with sewage effluent.
Speaker 2: And do you think it's helpful to assess water [00:03:00] globally to give a context in the sense of how much fresh water is there, how much wastewater is there?
Speaker 3: There's been a lot of good work done on water, especially at the national or regional level. And one of the things that people often miss is that water in cities is quite different from water at a national scale. So for example, at a national scale, cities only use about 20% of the water. The other 80% goes to agriculture and power plant cooling. But [00:03:30] if you're a city and you run out of water, there's not much solace in the fact that there's a farm hundreds of miles away that has water, or there's a power plant in another state that has that water. So water is a local issue. And cities are places where there's a very large demand for water in a very small space and that stresses their ability to deliver water and leads to water shortages. So you can have a situation where you have a country or a state which has [00:04:00] plenty of water, but you have a city that's running out of water and doesn't have a good option for providing more.
Speaker 3: Just to give you an example of a city that almost ran out of water a few years ago, so many of us have seen the photos and news stories about Brisbane, Australia last year when they had tremendous flooding that almost washed away the city will about four or five years ago, that same city almost ran out of water. So Brisbane is a city of around a million people along the gold coast [00:04:30] of Australia. It's Australia is equivalent of Florida that it's a place that developed mainly during the 70s up until the present and they don't have an imported water supply from a long distance. And so they were beholden mainly to one main reservoir. And when Australia went into a drought about 10 years ago, the level of water in that reservoir kept sinking and sinking and sinking. And about four years ago they had about 15% [00:05:00] capacity in the reservoir and they were using about one or 2% a month. And so if the rain didn't return, they were going to actually run out of water and there wasn't going to be any water for the city. So they'd already done the water conservation, they'd already stopped all the wasteful uses of water and they were reaching a point where they would have to shut down the city or take emergency measures to bring water in at very high prices.
Speaker 2: Cities [00:05:30] really can't know that this is going to befall them, but they all need to take a much more active role in figuring out what the wiggle room is and their water supply.
Speaker 3: With wise planning. Cities can anticipate these pinch points or these crunches in their water supply, but that assumes that you have some foresight. I'll give you an example of a place that has a lot of foresight about their water supply. And that would be Singapore, where water is actually considered national security. So [00:06:00] Singapore, if you're not familiar with the geography, is surrounded by Malaysia. And when the British left and they created two countries in that region, Singapore was still receiving its water from Malaysia. So there's a foreign country that controls your water supply and the founder of Singapore, Lee Kuan, you realize that the country will be very susceptible to Malaysia holding them hostage over their water. And so they established an aggressive plan [00:06:30] to develop alternative water supplies so they can wean themselves from their imported water. And today Singapore's at a place where the imported water supplies only fraction of the total water used in the city.
Speaker 2: That kind of planning is that growing worldwide and in the United States,
Speaker 3: in the United States especially, it seems like we wait for an emergency to happen. And so when a drought happens, someone says, Gee, we [00:07:00] should be doing something about this. And so in places where droughts have occurred and people have seen the start of this progression of shortages, city managers and water utilities have taken some steps to build up the water supply and make themselves more secure. Good example of that would be orange county in southern California, Orange County which grew after the rest of the Los Angeles area has relatively junior water rights relative to the city of Los Angeles [00:07:30] and many of the other communities that get imported water. And so in order to grow they've had to keep improving their local water supply and take on some innovative programs to augment the public water supply that break them away from imported water sources.
Speaker 1: [inaudible]
Speaker 2: you are listening to spectrum on k a l x Berkeley. We are talking with Professor David [00:08:00] said lack about current and future urban water systems. Is there something that individuals can do in terms of recycling water that has an impact?
Speaker 3: The best thing people can do to improve the urban waters situation is just to use less water. So the average American uses a hundred gallons or so of water a day, 10 gallons every time we take a shower, a 40 gallons when we washed a load of clothing [00:08:30] in a few gallons. When you flush the toilet, everything else. So if you just think in terms of water use, it's possible to save a lot of water around the house and all of the water you save means that there's that much more water to go around and there's that much more water, water around for the environment. So that's the first thing everyone can do. And I think most of us are guilty in some way or another of wasting water, either leaving the water running while we brush teeth or taking super long showers or just being prolific that with, with our [00:09:00] water use.
Speaker 3: I think the other thing that many people don't realize is that there's a connection between water and energy. So there's a lot of energy use in heating water for the house. So if you look at the urban water cycle, we could probably go a long way towards running our urban water system if we didn't heat the water. After all the Romans had flowing water and they didn't have electricity. A lot of our water system functions on gravity, but the minute we start heating many gallons [00:09:30] of water in the home, we're burning a lot of electricity. The other thing that you could do with respect to water is think about runoff and what goes down down into the street. All the junk that we throw out eventually finds its way into the bay and I think most people would be hesitant to just throw a plastic bag or a bucket full of soapy water into the bay if they were standing right next to it.
Speaker 3: Well, when you pour it in the street or wash your car or throw some trash in the street, that's [00:10:00] essentially what you do in the home. Is there a way for people to reuse water? There are a lot of people who really want to make a difference with respect to their water. And there's a lot of enthusiasm in the public for something called gray water and gray water is this idea that you have all this water in your house, it's relatively clean. It's the stuff that you, you know the water that was in the sink when you washed your vegetables or it's even the water that was in your washing machine that rinse your clothes after you wash them. [00:10:30] And that we should be able to use this water somehow. And I think it's great that there's this intention to save water and to reuse water and you certainly can collect this water and put it on the plants and the garden.
Speaker 3: But it's really not a solution to our larger urban water problems. And there are a couple of reasons for that. One is to do this in an organized way, takes a collection and distribution system. So if you have water from your sink or water from your shower, then [00:11:00] you have to have a way to collect it and you have to have a way to use it and maybe you're going to use it in the garden, but there's no guarantee that that water is going to be safe and free of microbes that can make people sick and there's no guarantee that that's going to be economically attractive once you price out the cost of building all these other pieces. And so new construction, there are many ways to make a building more water efficient, [00:11:30] low flow fixtures and water conserving practices. But the way in which it seems that we're going to make the biggest difference is to think about the whole urban water system and how it can be reinvented to do things differently.
Speaker 3: For example, there may be a future when toilets and washing machines don't use water anymore. I have a friend who works for the EPA and he has a vacuum toilet in his house that functions just like [00:12:00] those vacuum toilets on airplanes. So there's nothing that says that 50 years from now we're going to be washing our waists down the toilet with water where there are companies that had been exploring washing machines that use very small quantities of water. So many people were already switched from top loading washing machines to front loading, washing machines that use a fraction of the water. There may be a future where we even cut that two to a fraction once again. So I'm much more confident that technological [00:12:30] innovations will lead the way as opposed to these small scale piece by piece solutions that people feel good about because they're taking an active role but ultimately either turn out to be more expensive than the system we have or have their own sets of limitations.
Speaker 3: What sort of advances have there been in sewage treatment over your time of interest? Sure, so sewage treatment plants were [00:13:00] originally designed to to protect surface waters. So really the main reason people built sewage treatment plants was there was too much gunk going into rivers and the fish were dying from lack of oxygen. When you talk about building a sewage treatment plant because you want to recycle the water, perhaps even to put it in the potable water supply, it's a whole different level of technology. So over the last 20 years, technologies have been developed to purify water to a point that you can [00:13:30] have sewage coming in one end of a treatment plant and the water that comes out looks like bottled water coming out of the the store. And there's a whole host of different technologies that are getting less and less expensive every year and are making it more attractive to build these kinds of advanced sewage treatment plants.
Speaker 3: Is there a lot of construction of sewage stream and plastic gotta be very expensive? I would imagine that. So the place where you see construction of sewage treatment plants [00:14:00] is in the cities where there's a need to recycle water or to reclaim this sewage as part of the water supply. So, for example, um, Orange County, which I talked about earlier in southern California, built an advanced treatment plant because they wanted to take their sewage and instead of putting it out in the ocean like they used to, they wanted to put it back into the drinking water supply. So they built a very large advanced sewage treatment plant that takes the water and puts it through reverse osmosis membranes. [00:14:30] Those are the same kinds of membranes that are used to desalinate seawater and then subjected to ultraviolet radiation to kill the pathogens along with hydrogen peroxide to break down the chemicals and then putting it into the drinking water supply.
Speaker 3: So it's not your grandparents sewage treatment plan. It's really something that's a lot more advanced. And how is that being accepted by the the users? There's a mixed record of public acceptance of advanced sewage treatment [00:15:00] plants for augmenting the water supply. So in Orange County they've had pretty good public acceptance, but they also had a very long program of public education about their water situation. In other places. I'm in San Diego as an example or in Brisbane, Australia. These advanced treatment plants came at the public out of the blue and they really weren't aware that there was a problem and they weren't aware that there were technologies that [00:15:30] had been used as solutions in other places, so when the public heard that there was sewage water going into the water supply, they couldn't accept it and the projects died. A quick death in public hearings.
Speaker 4: [inaudible] you are listening to spectrum on k a l x Berkeley. We're talking with Professor David Sedlak about [00:16:00] current and future urban water systems.
Speaker 3: I was wondering if you want to talk about, sure. The kinds of research, my own research mainly focuses on chemicals and water and I'm very interested in the chemicals mainly that are present in sewage that might find their way back into the environment because our treatment plants aren't perfect. I first got into this topic about 15 years ago when I saw a talk from a scientist [00:16:30] from Britain who had found that fish living near sewage treatment plants were feminized. That is they would go out and collect fish below the sewage treatment plant and they couldn't find any male fish. They all were female. And this phenomena of feminisation was really fascinating to me because I thought to myself, well, if this is happening to the fish when they're at the sewage treatment plant, it's quite possible that there's some chemical in there that's responsible. And so that got me very intrigued by [00:17:00] saying, well, I don't really know of any very potent biologically active chemicals that might be able to pass through a sewage treatment plant.
Speaker 3: And that started a, a line of inquiry that has stayed with me to this day. The substance that you're talking about, pharmaceuticals, metals, things like that, are there other things that are in the water that you're looking at? Well, so in the case of the feminized fish, it turned out it was steroid hormones. So it was residual amounts [00:17:30] of estrogens, some of them from birth control pills, some that are just produced within the body and they were president minute quantities, part per trillion levels. And that was enough to feminize the fish. But since then we've expanded and looked at a whole range of different chemicals. And what is very interesting about it to is that these are not the kinds of chemicals that people had been looking for before. So up until interest turn to sewage, affluent people were interested in [00:18:00] chemicals that might come from a factory or an industrial process.
Speaker 3: But when we look inside of our homes and when we look inside of our commercial activities inside of our kitchens, we see that there are all of these things that are in sewage that we either wouldn't want to put into a river or we wouldn't want to put back into the water supply. So a lot of this then comes down to educating the population so that they stop putting these things in the water. If only it were that easy. You know, many of these chemicals [00:18:30] that we've been studying are not the result of someone doing something wrong. So you know that the interests that people have had in pharmaceuticals over the past 10 years, pharmaceuticals that show up in water, people say, well, we just have to start pouring our pills down the drain when we're done with them. Well guess what? The pills getting poured down the drain is a very minor fraction of the whole.
Speaker 3: The majority of the pharmaceuticals that end up in the sewage come from normal use because those drugs go [00:19:00] inside of our body. They do the great things that we've come to rely on and then they come back out and the molecule hasn't been changed at all. So in many cases, if a pharmaceutical is used correctly, it's final repository is the sewage treatment plant. And I don't know of too many people who are willing to give up their aspirin or their heart medication or whatever it is because they want to protect a fish or a downstream drinking water user. [00:19:30] Technology has evolved to the point where these elements can be removed from the water. As a matter of course, we can remove anything we want from water. It's just a question of cost. And I think that that always, that's always the rub in this whole situation.
Speaker 3: So if we wanted to, we could take the nastiest water in the world and make it into water that's so clean, we could use it for semiconductor manufacturing. And that's a lot cleaner than drinking water has to be. The problem is that people have come [00:20:00] to expect their water and their wastewater treatment bills to be low. And so if you want to remove these things, it's going to cost money and oftentimes it's going to cost more money than people are willing to pay. You've done a certain amount of work with wetlands and what's your experience with trying to recreate wetlands? So we talked a little bit already about how the systems for removing contaminants from water have to be inexpensive. [00:20:30] And so starting about 25 years ago, people started to toy around with the idea that you could build wetlands and have the wetlands removed some of these residual pollutants for you.
Speaker 3: The idea is you have a sewage treatment plant and instead of that water directly into the river, you put it into an area that has wetland plants in it, cat tails, bull rush, the usual kinds of plants, and in that system the pollutants will disappear because [00:21:00] the plants and the bacteria that break down the decaying plants will also degrade the pollutants. And that certainly works quite well for one of the main pollutants in wastewater, which is nitrate. So nitrate, which is a water pollutant, and it's also a nutrient that causes algae to bloom in rivers. Nitrate can be removed quite well in treatment wetlands. What we've been doing for the past few years has been experimenting with wetlands that [00:21:30] are optimized to remove things like pharmaceuticals and personal care products and the chemicals that we find in wastewater. And one of the ways in which we do that is by exploiting sunlight.
Speaker 3: Many of these chemicals are unstable in the presence of sunlight. And so if we can build a wetland where we have lots of sunlight penetration, we can actually take advantage of this natural process. And the good news is that it's pretty much free. You're just relying upon [00:22:00] the gravity to flow the water through the wetland system and the sunlight and the bacteria and the plants to break down the pollutants for you. Now there is another aspect of the work we've been doing with wetlands that I think is also important and that is the idea that we can build wetlands within our cities to help treat the storm water runoff and the polluted water that flows through the cities and improve the habitats that way while providing some aesthetic benefit. So perhaps in the [00:22:30] future or urban creeks instead of being concrete channels to quickly move water out, we're even underground drainage pipes might actually have an element of a natural treatment system built into them.
Speaker 3: The new center that you've just become part of here at cal, do you want to describe what that is? You know, over the past decade or so in my research, I've been looking at different pieces of this water puzzle. But I recognized a few years ago along with several of my colleagues [00:23:00] that this is too big a problem to solve with individual technologies. It really takes a holistic look at the entire urban water cycle to solve the problem. And so an opportunity came a couple of years ago to apply for an NSF engineering research center. And, and in this case we decided to go after this question of urban water systems and how they're gonna make the transition from their current state, which is a reliance on imported water consumption of energy [00:23:30] pollution to a future state in which they're more self sufficient and immune from droughts. They use less water and they leave the environment in better condition than what they found in.
Speaker 3: We put in a, and we were successful, the center launched at the beginning of August. So the acronym is renew it, reinventing the nations, urban water infrastructure. And that's really what we're all about. We would like to see a system that developed during the 19th [00:24:00] century and the 20th century evolve into something that's going to be suitable for the 21st century and you're going to be involved in project work and field work. I think the thing that's the big challenge with our center is to take the technologies that we develop in the laboratory and study at our test sites and actually get them into the urban water system, but really the success of this project is measured by whether [00:24:30] we have a reinvented urban water system in 10 or 20 years. Professor said, luck. Thank you very much for coming on spectrum. Thanks very much for having me.
Speaker 1: Oh,
Speaker 5: well
Speaker 1: the [inaudible] center website is urban water, e r c.org a regular feature of spectrum is to mention a few of the science and technology events happening locally [00:25:00] over the next few weeks. We can cargo ski joins me for the calendar
Speaker 5: in our last episode, Kashara Hari, you mentioned that the bay area science festival is having a pub crawl tonight from six to nine 30 with various venues in San Francisco's mission district participating. This will be a very busy night with lots of places you can stop. Some highlights include nerd night speed dating at the makeout room, which will include lightning talks on dating and romance, a guided tour of natural oddities. I Paxton Gate, a physics circus at Atlas Cafe and a talk [00:25:30] at black and blue tattoo who's hosting Carl Zimmer's presentation on science theme. Tattoos. For more information on these and other activities tonight, visit www.bayareascience.org on Monday, November 7th from seven to 9:00 PM the Berkeley Rep theater at two zero one five Addison is hosting the Berkeley labs science at the theater this month. UC Berkeley's College of natural resources. Professor John Hart will moderate a panel on the secrets of soil. Panelists will discuss how soil microbes change with climate, [00:26:00] how these microbes can lead to better biofuels and how they adapt to extreme environments and mission is free.
Speaker 5: Visit www.lbl.gov for more info. MIT President, Dr Susan Hockfield is speaking at the Silicon Valley Bank. Three zero zero five Tasmin drive in Santa Clara on Wednesday, November 9th she'll talk about investing in innovation and scientific research to retain the economic power of the United States. The program starts at 7:00 PM with a check in at six 30 [00:26:30] the event is $7 for students, $12 for Commonwealth club members and $20 for standard admission. Visit www.commonwealthclub.org for more info now several stories. Science insider reports that Lawrence Livermore national laboratory has chosen, noted physicist and National Security Policy Expert Penrose Parnia Albright as their new director. Albright is the 11th director of the lab since it was established in 1952 you places [00:27:00] George Miller who is stepping down after six years. Albright previously served as assistant secretary of the Department of Homeland Security and we'll assume directorship in December, www.llnl.gov has more information. Science news reports at the Advisory Committee on immunization practice announced the recommendation that the vaccine against the human papilloma virus or HPV be used for boys starting at age 11 or 12 HPV can cause genital warts and is the [00:27:30] most common cause of cervical cancer.
Speaker 5: So the vaccine is already recommended for girls. While the disease is rarely symptomatic, it is the most commonly sexually transmitted infection in the United States. More than 6 million new infections each year. The vaccine doesn't seem to work against HPV that has already infected an individual, but it is preventative for the uninfected prompting for its early use in both boys and girls. The castle solar car team competed in the world solar challenge in Australia during [00:28:00] October and finished 20th out of 37 teams. The Red Berry commonly called Miracle Fruit has spawned flavor tripping parties as it makes sour foods such as around lemons or bitter foods such as beer, taste sweet like lemonade or ice cream without adding any sugar. While it has been known for more than 40 years that the protein miraculous is the active ingredient in the miracle fruit. It hasn't been clear to how that protein works.
Speaker 5: In a paper published in the September 26 edition of the proceedings of the National Academy of Sciences, [00:28:30] University of Tokyo, biochemists, Keiko Ayub and her team state that the miraculous is interaction with the tongue sensors depends on acidity. The team used molecular modeling and experiments where they used human kidney cells, engineered to produce sweet receptor proteins with fluorescent markers and miraculous and substances with different Ph levels. They found that miraculous had no effect ph 6.7 or higher but had an effect that increased as the Ph decreased from 6.5 to 4.8 they suggest that miraculous [00:29:00] binds to sweet receptors at neutral ph and then functionally changes in acidic environments. Studying miraculous may eventually lead to better ways of sweetening foods without increasing caloric content.
Speaker 1: [inaudible] music card during the show is from a less Donna David album titled Folk and Acoustic [inaudible]. Thank you for listening to spectrum. You're happy to hear from listeners. If you have [00:29:30] comments about the show, please send them to us. Our email address is full spectrum dot kalx@yahoo.com join us into [inaudible] time. [inaudible].
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