Pipe Dreams

Roman Mars:
This is 99% Invisible. I’m Roman Mars.

Roman Mars:
Every time you go to the bathroom, you should thank Alexander Cumming. We actually featured a whole story about him because Alexander Cumming was the first person to patent a flushable toilet. He didn’t invent the flush toilet, but he did connect it to an S-shaped pipe, which uses water to stop sewer gas from coming up and stinking up your home. And before Alexander Cumming, that used to happen A LOT.

Chelsea Wald:
Whatever was underneath the toilet could come back up and people didn’t like bad smells, but they also thought that bad smells carried disease. That’s how the flush came about.

Roman Mars:
That’s Chelsea Wald.

Chelsea Wald:
I’m the author of “Pipe Dreams: The Urgent Global Quest to Transform the Toilet.”

Roman Mars:
The flush toilet took a while to catch on, but once it did it became part of a system we still use today, which Chelsea calls the gold standard. Here’s how it works.

Chelsea Wald:
Your poop, once deposited into the toilet and you flush it down, goes into a sewer system that runs under the city. And there it combines with water and with everyone else’s poop and anything anyone puts into their sinks and their toilets and their showers and their washing machines and their dishwashers… flows through to a treatment plant. And in the treatment plant, bacteria help to clean up the sewage.

Roman Mars:
The treatment plant produces cleaned-up wastewater, which is usually returned to our water supply and it filters out all the solids. The flush toilet, the sewer system, and the treatment plant make up the gold standard. In a lot of ways, it’s a really good system.

Chelsea Wald:
Toilet technology, the toilet systems that people developed in the 19th and early 20th century that we still use today fundamentally work very well at keeping our cities clean and keeping us healthy.

Roman Mars:
But look, Chelsea Wald didn’t write a whole book about how toilets are great. The gold standard has some big limitations.

Chelsea Wald:
I like to think of it as a paradox. I am very happy for the toilet that I have and that I’ve been able to use my whole life. But the paradox is that the systems are wasteful and they are not suited to the challenges of the 21st century.

Roman Mars:
Today, the problem with toilets, with Chelsea Wald.

[MUSIC]

Roman Mars:
So the flush toilet is pretty effective, but what are the problems with it?

Chelsea Wald:
I think everybody would know by now that toilets wastewater. They use fresh drinkable water most of the time to flush our poop, which just seems silly. The reason that they do this, it uses water for two purposes. One is to wash out the bowl and carry away the poop. And then the other reason is to seal the toilet to prevent sewer gasses from coming back up. Old toilets use something from 3.5 to seven gallons to flush. So it’s like a waterfall of water, of fresh water, used to flush down pee, which is crazy because that’s just liquid or your poop. And some households, that can be a quarter of their household water consumption is just toilet flushing.New innovations in recent decades have brought that down. The current federal standard is 1.6 gallons and low flow toilets are lower than that. But one thing that people might not think about is that more and more people are getting toilets every year as they hook up to piped water. And it’s not just in the US, less than the US, but around the world. This is a growing issue. Worldwide, one estimate is that people use 40 billion gallons of fresh water to flush toilets, which is six times the daily water consumption of Africa. That’s one portion of the worldwide wastewater usage, which is 100 trillion gallons of wastewater, which is a number that’s only going up. That number might increase by 50% by 2050.

Chelsea Wald:
We don’t have that water to spare. So by that time, half the world’s population is going to be living in water-stressed regions, which means that at least part of the year they won’t have enough water. People want to hook up to flush toilets that use water. They are a symbol of economic development. They’re a symbol of progress and success. And because we don’t have an alternative really that also represents that to people, they’re going to continue to hook up to flush toilets when they can.

Roman Mars:
In the book, you point out some new kinds of toilets that reduce our water usage. Can you tell me about those?

Chelsea Wald:
If we don’t want to use water in our toilets or we want to use much less water in our toilet, we have dry toilets. Those are toilets that don’t use any water and you might use a cover material over it. And you can kind of think like an outhouse can be a dry toilet or a bucket in some cases. People have adopted those. They’re not terribly popular. They’re associated more with a hippie lifestyle or a survivalist lifestyle perhaps. There are pressure toilets also, these suck or force the waste out of the bowl. And I think that these are growing in popularity. They’re starting to be installed more and more places.

There are new coatings for toilets under development that kind of let the poop slide out of them more so that you don’t need as much water to scour the toilet and get all the poop out of it. They’re kind of more self-cleaning. There’s also a toilet under development that uses like a spatula to scoop around the toilet bowl, and then it doesn’t require water, as well. So there’s a lot of creative ideas under development.

All of these ideas. I mean, they seem futuristic, but on the other hand, there’s something so logical about them. It’s almost as if you just took the time to think about it, you might think it up yourself. How are you going to get this poop out of the bowl? Okay, I’ll get a spatula. So I think there’s a lot of clever engineering in it, but there’s also just a question of thinking outside the toilet bowl or thinking outside the box with respect to how to deal with this problem.

Roman Mars:
The flush toilet is not the most efficient way to deal with our waste, but you could replace it with another kind of toilet, but then there’s the sewer system. Most cities built their sewer infrastructure a long time ago before they had a big increase in population. And it’s a much bigger problem to deal with in the toilet because the sewer system is too expensive to replace. Can you talk about why our sewers are getting overwhelmed?

Chelsea Wald:
When you add rainwater in there, the sewers have to handle just like a much bigger flow of water and that can overwhelm the sewers. And it can also overwhelm the treatment plants at the end of the sewers. And that’s why a lot of these systems are designed to release raw sewage into waterways during these events. And because of climate change, these events are becoming more and more frequent and bigger. And so cities are dealing with more and more of these wet weather events where they are unfortunately releasing raw sewage into their local waters. It’s not something they want to do, but it’s how the systems are designed and fixing that is really expensive.

Roman Mars:
You wrote about South Bend, Indiana, where they were having overflows a lot pretty much every time there was like a 10th of an inch of rain. And this is where I was really surprised when Pete Buttigieg showed up in your book.

Chelsea Wald:
Yeah, I was writing that section when he was running for president. And the whole time I was thinking –gosh, when this book comes out, I have no idea what this section is going to mean to people — and here he is now the secretary of transportation. So I guess it worked out okay.

Roman Mars:
So one of the problems that Pete Buttigieg was trying to solve was the idea of like stormwater overwhelming the sewage system flowing out into the St. Joseph River. So what was the solution there?

Chelsea Wald:
So they have been at the forefront of developing smart sewers, so putting sensors in sewers. The sewers are definitely an old tech, but they aren’t very hard to put sensors in. So as everything in cities has gotten kind of wired up, sewers have been a little bit slower because it’s a very corrosive environment in there, but scientists at Notre Dame and some other universities worked out how to put sensors into the sewers there and get a better handle on what was happening in the sewers that they had. And what it turned out was that there was extra capacity in the sewers that they didn’t know about and they weren’t really using during these events. And they were able to put devices in that would then better use that capacity automatically during these wet weather events.

And just in that way, by better using the sewers that they had, reducing the number of overflows. It’s not a perfect solution because they still do have overflows, but it just used the capacity of the sewers a lot better. And this kind of sewer sensor technology is now really growing. I mean, there’s a lot of cities interested in it and installing it to eliminate these sewer overflows. So South Bend shows us how we can take better advantage of the sewer infrastructure that we have in place in our cities. It’s not just a question of better using the capacity of those sewers or investing in them in a way that makes them work better in the way that they’re intended, but we can also use them in new ways.

Roman Mars:
One issue is overflows and the other problems with sewers are “fatbergs.” I mean, these get covered a lot in the news, but could you describe a fatberg for people who don’t know about them?

Chelsea Wald:
Oh yeah. So fatbergs is the other problem of mixing everything into the sewer. By now, I hope you’ve heard that flushing wet wipes is bad. A lot of people haven’t heard that yet, but there’s these growing trend toward having these adult wet wipes, adult version of baby wipes I guess, instead of toilet paper and people are flushing them like toilet paper. Those go down into the system, along with any trash in there and they mix with the grease that people, restaurants as well pour into the sewers.

And this does some crazy chemistry down there and forms, accretes into a horrible blob and it can get really hard like a rock even or it can take all kinds of different forms and textures and it just grows and grows, diapers in there and needles and everything until it can clog a sewer. And that’s what has been called a fatberg.

NEWS REPORT
[HUNDREDS CLOG UP LONDON’S 150-YEAR-OLD SEWER NETWORK, NONE BIGGER THAN THE WHITE CHAPEL FATBERG IN EAST LONDON, A 130 TON MONSTER. CREWS WORKED FOR NINE WEEKS ABOVE GROUND AND DOWN BELOW BREAKING IT UP, THEN SUCKING IT UP AND TRUCKING IT AWAY.]

Chelsea Wald:
It’s really– it’s just costing cities huge amounts of money with this problem. And it’s also a really horrible thing for sewer workers to have to go down and clean up. And I think people don’t think about that part of it, that someone actually has to go down and clean up your mess, go into the sewer gasses, you use a pickax at times, a pressure hose and then get those things out of there. So that’s why cities are sort of desperately telling residents to stop flushing the wet wipes and to stop pouring grease down their sinks. I don’t know how far the message is getting because they say it’s gotten quite bad during the pandemic, especially.

Roman Mars:
Yeah. So the last part of the process is the treatment plant. What are the limitations of our water treatment process?

Chelsea Wald:
The whole water discharges basically go into the sewers. I mean, there’s some regulation on industry about what can go in there, but pretty much anything can make its way into the sewers and flow to the wastewater treatment plant. That makes it very difficult, but the basic technology that’s used to treat the sewage, which was designed more than 100 years ago, just isn’t designed to eliminate a lot of these different kinds of pollution, toxic chemicals, and plastic pollution in the sewage that had been developed in the last 100 years.

And so wastewater treatment plants have the choice of adding on more and more treatment steps to filter out and eliminate these pollutants, which can be very expensive. And a lot of municipalities can’t afford it or they end up discharging it into waterways. It is monitored by the EPA in the US, but not for all of these substances, just for a limited number of heavy metals and other substances. So that creates a problem.

Roman Mars:
The central tension of all this is like we have a toilet that mercifully removes us from our waste problem in our house and connects to a sewer and removes it so efficiently. We think it just goes away, like it just dissolves or disappears completely. It’s still there, it’s just is collecting as a fatberg or is being released into a river or something to that effect.

Chelsea Wald:
I also just thought that it all just went away. I did imagine that– I mean, to the extent that I thought about it, which I’m sure I wasn’t really thinking, but I thought, “Poop is biodegradable. It just, yeah, disappears.”

Roman Mars:
In the book, you talk about the problems with our conventional toilet system and you also visit some places trying different approaches. Like this one you described is a subdivision experiment in Sneek, which is a city in the Netherlands. They have this new toilet technology that’s kind of mind-blowing. How does that system work and could you describe it for us?

Chelsea Wald:
I live in the Netherlands so it wasn’t a far trip for me, but it was a few hours north. It’s in a housing complex of 200 units. And each of these units has a vacuum toilet. So you might know vacuum toilets from airplanes or maybe boats, and you would not want one of those in your home. They’re horrible and they’re loud, but actually people have developed really nice, easy-to-use vacuum toilets. So I used one in the headquarters of the company that has developed this project alongside a university and funding partner. Those toilets, they look mostly like a toilet. They have these kind of glowing blue buttons and you press them and a little… There’s a tiny bit of water in there, which I don’t even think the water has to be in there. It’s described as a kind of security blanket. It just makes people feel comfortable. And, you know, it’s closed, it opens and it just goes ‘whoosh.’ And whatever you’ve put in there, comes out the bottom and it’s very concentrated.

And from there, it flows to a treatment facility that’s on the premises of this housing development. It’s a little house just in the center. You would not know what it was. You would think it was like the headquarters of this housing development or a rec center or something. And in there is an anaerobic digester in which microbes turn this toilet waste into biogas for the housing complex, so they use it to heat the housing complex. So it’s just like your poop is powering your home or heating your home. And they also add to that food from their sink. So they have food grinders in their sinks and they send that in there too, and that can be digested as well by the microbes. Conventional wastewater treatment plants use aerobic digestion and aerobic bacteria require a lot of oxygen. And so that requires a lot of energy to pump the oxygen through the sewage, but an anaerobic digester does not require an oxygen pump. And so it uses much less energy in addition to creating energy.

Roman Mars:
Yeah. I mean, it’s really remarkable and when you hear about it, you think, “Ooh, this is the greatest thing in the world. Why doesn’t everybody do this?” And people from all over the world tour this facility and with the mindset that maybe they’ll change their sewage and toilet systems, and then what happens?

Chelsea Wald:
I asked that question. People I was talking to who worked on this system just told me in a very disappointed way like — It’s been very difficult, everyone just goes home, and we think what they do is they install conventional infrastructure. They just don’t really trust that the system is going to work. They don’t want to take the risk to find out if people will like the vacuum toilets, if the plumbers will be able to fix them, if they can get all the regulatory stuff in line. There’s just a lot of barriers when you have a system that’s so widespread and so standard as the conventional system to adopting something so novel.

Roman Mars:
I mean, it’s disappointing that people don’t want to try a better toilet system, but also using poop for energy sounds really radical and maybe gross to a lot of people. Do you think that our own taboos and discomfort with our excreta makes it so that design innovation is more different?

Chelsea Wald:
It’s funny because after spending years working on this topic and writing a book, it’s a little hard for me to connect to my own sense of disgust around the topic. So it takes talking to other people for me to recall what it feels like to be uncomfortable about talking about poop and I’m spreading it on my garden or whatever. Of course, I think poop smells bad, but I don’t have that same kind of disgust around it. But yes, I mean, research shows that disgust is a very strong emotion. It is a problem that, as I was doing this research, came up again and again — could people overcome the yuck factor and could the yuck factor rear its head at a very inconvenient time? So say you’re halfway through a project or you have a fertilizer project going, and you’ve invested all of this time and effort into it. And then suddenly the public gets a hold of it and they’re disgusted and you get shut down. Something like that could happen. So there’s a real fear of that. I think it’s changing as people start to care more and more about the problems that innovators are trying to solve. I think that can counterbalance the disgust, but the disgust is a real factor.

[MUSIC]

Roman Mars:
The gold standard toilet system isn’t perfect, but there are still hundreds of millions of people who don’t even have that. What is it like in areas of the world without a modern flush toilet system?

Chelsea Wald:
There’s usually something there, but it’s informal or it’s not organized. So you might have pit latrines. And the problem is that when those pit latrines fill up, people have to call somebody to empty them. There’s often not a professional service or the professional service that does exist is too expensive. And so they call an informal worker, someone who’s highly stigmatized who comes in and digs it out and then leaves the contents from the pit latrine somewhere other than a treatment plant, for sure. Maybe even just digging a hole next to the house and putting it there or dumping them in a waterway. So you have a really disorganized system.

These are places where it’s not easy to imagine building the kinds of source systems that we see in American cities. Nor as I’ve described, I mean, our sewer systems necessarily – big sewer systems – aren’t necessarily the best option. People are working now as a kind of an incremental improvement on making these pit latrines into a more organized system. So creating services that can safely empty them and then take them to treatment plants. That’s a step that would go really far in the right direction. And it requires a little bit of innovation, but really a lot of organization and political will mainly to serve these informal areas that have very little infrastructure. But another piece where people don’t have sewers currently, there’s a lot of opportunity there to do something new in places that have not yet been able to afford these kinds of comprehensive sewer systems.

Roman Mars:
It is interesting that it’s like a transport problem. It’s just like we have one transport system, which is a great deal of water moving things through a system, or you have people taking buckets of things out and moving them to other places, essentially. It really is like a systems and transport issue when you get down to it, right?

Chelsea Wald:
Yeah, I guess so. Yeah, yeah. How can you get this stuff someplace safe? There is the idea of these hyper-local decentralized systems where everything could be kind of treated on the spot. The Gates Foundation had the “Reinvent the Toilet Challenge,” which encouraged research teams to come up with ideas for these kinds of toilets that could neutralize the waste and create resources on the spot in places where there is no infrastructure.

I mean, so far those are still in development, let’s say. It’s a big dream. It’s a big dream, but a worthy one and I think that the idea that the Gates Foundation had – Bill Gates had – that people could kind of leapfrog the conventional system and get to something better — don’t go down that path, find a new one, make a new one. I think that communities need to decide for themselves how they want to organize their own waste and in part, they need to be consulted in that as well. But it is a problem that’s still unsolved. I mean, obviously if it were solved, we wouldn’t be talking about it. But I think we’re seeing increasing attention to it and a lot of different kinds of solutions appearing enough that there’s reason to be hopeful.

[MUSIC]

Roman Mars:
I want to talk about another equity issue around toilets, which is access to public toilets. The number of public toilets around the world has gone way down, especially in the United States. Why is that?

Chelsea Wald:
So public toilets are a big cost to a city. My understanding is there used to be quite a lot of public toilets in the US, but they were paid toilets. Problem was the women paid, but the men didn’t have to. And so in the 1970s, people started pointing that out as being sexist, which it was, and demanded free toilets for everybody, which they got except for the fact that that meant that cities didn’t really want to keep up those free toilets. Yeah, they just turned into big burdens for cities and cities started taking them out. And the public toilets that did exist were kind of gross and nobody wanted to really use them.

Chelsea Wald:
As a result, our cities are really depleted of public toilets and it’s a really big problem really for everybody who wants to go out into public life. The privilege of doing so can often walk into a cafe and use it, but there really are a lot of people who don’t have that privilege, who won’t be invited into a cafe and allowed to use the toilet there.

Roman Mars:
Yeah. And we’re relying on a private system. Public toilets are basically in private cafes, in Starbucks, in hotel lobbies and things like that. I’ve found when I travel, I often wear a suit when I travel — and one of the things that a suit affords you is you can walk into any place and use the bathroom if you’re wearing a suit.

Chelsea Wald:
Yeah, I believe that. You’ve noticed that.

Roman Mars:
Yeah, I have. I was sort of like as I was reading this part, I was imagining the Shangri-La in which, like good public toilets that are well-maintained are just part of the city infrastructure and maybe coupled with public transit or something to that effect. It just seems like that would make the world just a tremendously better place like every city a better place.

Chelsea Wald:
City planners have forgotten that people have basic bodily functions, even when they’re outside. I don’t know. You can’t always run home and some people don’t have homes. One option is to actually pay private establishments to open their toilets up to the public. That has worked in some places, although with the pandemic with all these establishments closed, you can see the limitations of that. What happens after hours? There’s also the possibility of combining toilets, as you said, maybe with public transit, but maybe with a private business, but that the toilet leads.

So you have the public toilet, but it’s also a cafe or like a stand for coffee or something like that. They sell things alongside of it and that helps fund the toilets. People want to bring back– some people want to bring back pay toilets. I think that people would be willing to pay a little bit for a toilet and I think with apps that that’s easier. You don’t have to carry around a quarter. You don’t have exact change or something for the toilet, but you can just tap your phone and use the toilet. And then you could provide something like toilet stamps for people who couldn’t afford it. That sounds promising to me

Roman Mars:
In the book, you lay out an idealized vision for toilets and you call it “Loo-topia,” which is pretty good. What does Loo-topia look like?

Chelsea Wald:
Yeah. So I came up for the book with the concept of Loo-topia, which is the place where our toilets allow us to live in more harmony with each other and with nature. And one of the points that’s really important to me in this book is that there is no one type of toilet in Loo-topia, but it’s in fact a kaleidoscope of toilets. So we have this notion that has come down to us from the past of what the toilet or what the ideal toilet system is, which is what we’ve been talking about, the flush toilet connected to the sewer system, connected to the centralized treatment plant.

But what we really need for the future is a range of different kinds of toilet systems that are appropriate for different places, with different resources, with different needs. And that is really I think how we’re going to get to something like Loo-topia, where toilets are healthier, more sustainable and more equitable.

Roman Mars:
You may not realize it, but there’s a good chance that you’ve been drinking recycled wastewater and it’s been totally fine. More with Chelsea Wald after the break.

[BREAK]

Roman Mars:
So we just published a book last year called “The 99% Invisible City.” And the first chapter of the book is about utility markings and how underground utilities are color-coded like the color orange is used to indicate communications infrastructure, and red is for electrical. And you write about lavender. There are lavender utility markings and also lavender pipes. What are those for?

Chelsea Wald:
The purple is for non-potable water. It’s possible to take the water that comes out of a wastewater treatment plant and clean it up to a level where it can be reused very often. It is very clean. It’s possibly even cleaner than the water body that it gets discharged into at times. More and more we’re going to see water scarcity in our cities. And so utilities are reusing this water in some way and non-potable means you don’t drink it, but it’s still very useful for things like irrigation, industrial uses, even flushing toilets.

This color purple, it’s sort of a really nice lavender color. It’s the color that a rose is the best color in Irvine, California. I think a manager at the wastewater treatment plant who was colorblind found that it stood out and really the reason you want to have different color pipes is because you don’t want a plumber to accidentally plumb the non-potable water into a drinking fountain, say. So that’s why you color-code it.

Roman Mars:
People have a hard time with the idea of drinking recycled water. Lots of people would probably feel uncomfortable drinking a glass of water if they were told that it used to be wastewater from someone’s toilet. But you write in the book, we’re indirectly drinking recycled water all the time. How does that work?

Chelsea Wald:
So what has been done to now is often instead of feeding it directly into the drinking water system, they will use the water to, say, recharge groundwater. And then it gets pulled back up into the drinking water system. And so it sort of goes through this intermediary step, which is sort of unnecessary, but useful for sort of cleansing the mind at least. Other people are thinking about sort of clever ways of bringing this concept to people’s attention like using this water to make beer. So beer uses a lot of water. It’s not water-efficient. And so utilities have been working with these brewers to deliver them this very clean water, actually, in some cases it’s sort of like very tasteless water because they’ve cleaned it so much of minerals and stuff. They have this sort of clean palette on which to make this beer.

I don’t know if this is apocryphal or not, but I mean I’ve heard many times that, for example, the medieval period, people drank beer instead of water because it was safer. So maybe there’s also a kind of long history of thinking that the brewing process is a kind of cleansing process for liquid. And also when you drink beer, you pee more. So it’s sort of got a circular logic to it as well.

Roman Mars:
Because we’ve lived in a period of time of abundance, I think, and that might be shifting, do you think it’s possible to change our thinking about this stuff globally considering climate change? And are you hopeful?

Chelsea Wald:
Yeah. I think I’m hopeful about it. I mean, it depends on the day how hopeful I am about the global situation that we find ourselves in, in general. It’s not such a hard topic for me to cover as an environmental journalist because plastic pollution kind of depresses me because every time I use a piece of plastic, I feel guilty and bad about it. But I don’t really have to feel bad about pooping. I mean, it’s just something every animal does. And so it’s all opportunity. There’s room for a lot of different solutions. It is a problem that we have to confront as a species.

It’s also hyper-local so it’s like the scales go from extremely local like your own private toilet and what you can do there to the global and every scale in between. I found in my reporting people at all those scales doing all the kind of work, maybe not everyone’s paying attention to that, but it is going on. And I think the more that people tie what they’re doing into larger global issues that are really concerning all of us, the more that those innovations can take hold.

Roman Mars:
Thank you so much for the book and for talking with me, Chelsea.

Chelsea Wald:
Oh, thanks so much for having me. This was really fun.

———

Roman Mars:
Chelsea Wald is the author of the book “Pipe Dreams: The Urgent Global Quest to Transform the Toilet.” Get it wherever fine books are sold.

99% Invisible was produced this week by Chris Berube.

Music by our director of sound, Sean Real. Sound mix by Andi Kristinsdottir.

Our senior producer is Delaney Hall. Kurt Kohlstedt is the digital director.

The rest of the team includes Vivian Le, Joe Rosenberg, Emmett Fitzgerald, Christopher Johnson, Lasha Madan, Katie Mingle, Sofia Klatzker and me, Roman Mars.

We are part of the Stitcher and SiriusXM podcast family, now headquartered six blocks north — in beautiful uptown Oakland, California. You can find the show and enjoy discussions about the show on Facebook. You can tweet me @romanmars and the show @99piorg. We’re on Instagram and Reddit, too. You can find other shows I love from Stitcher on our website 99pi.org, including “Freakonomics” — uncovering the hidden stories of the world through the lens of economics. Find a link to it and every past episode of 99pi at 99pi.org.

 

 

 

Credits

Production

Host Roman Mars spoke with Chelsea Wald, author of Pipe Dreams: The Urgent Global Quest to Transform the Toilet.

This episode was edited by Chris Berube.

  1. David Schwan

    Many cities in the Bay Area split their sewage system from the storm drain system, that is why you often see stenciled goes to bay on the storm drain runoff in the street.

    Fremont/Newark/Union City (Union Sanitation District) has a co-generation (power) facility at their treatment plant.

  2. Bryan Swansburg

    This podcast struck close to home.

    I built a high efficiency house 10 years ago. We used a sawdust bucket toilet during construction to avoid a chemical toilet on site. Most of the workers thought that was pretty weird; but when you gotta go…

    Then we installed a Puxin biogas digester
    http://en.puxintech.com/hbs
    which is comnected to our flush toilet and runs the main cookstove. For government approval we just sent in the forms with no extra comments and some civil servant just files it away un-noticed. Everyone who sees it says it’s a good idea. I have the forms for building them and in these 10 years of flawless operation and ‘show and tell’ only one other person (a plumber who helped install mine) has duplicated my system.
    I have seen statistics that there are 200 million of these systems; mostly in the tropics. Mine appears to be one of the coldest installations on earth up here by 54.40 at the BC-Alaska border, buried under my greenhouse.
    I truly believe toilets can help save the world, but we as a society can’t get past the yuck factor.

  3. Craig Allan

    Chelsea Wald is probably a good journalist, and 99PI is very entertaining, but municipal engineers will be spluttering apoplectically at this podcast.
    If you had a medical series, you’d probably get a doctor to check it for accuracy, but I suspect you didn’t find an engineer to comment on this podcast before broadcast.
    To add balance, may I say:
    Yes, much of the world is water stressed, but water used to wash sewage down the pipes is not ‘lost’. All of it eventually goes back to natural water systems. All of it, every drop. Most of it ends up in a river and is used happily as intake water by the next town downstream. A few towns in dry areas, like Windhoek, operate a closed system and pump treated effluent back into to join the intake of the domestic water supply.
    South Bend, Indiana, may indeed have rainwater surcharges in their sewer systems. They probably have the cheap and nasty single trunk system that carries both storm-water and sewerage. As such, it is their decision to go with cheapness that leads to pollution; blame that. Don’t blame generic water borne sewerage. My town uses the widely adopted segregated system whereby storm-water travels in different (bigger) pipes and is discharged, untreated, into rivers and the sea.
    The Netherlands experiment with vacuum systems is charming, but very expensive, so nobody replicates it. Pipes don’t deal with vacuum very well, as they tend to collapse, so you need costly strong pipes. Vacuum is not free like gravity, so you have to run a vacuum pump all the time. Their small packaged disposal plant is far more expensive per gallon than a big central plant. Burning residual solids (sludge is the trade term) is no innovation – it has been done for decades. Sludge is a difficult fuel.
    It’s not true that sewage treatment works only use aerobic digestion. Most use both aerobic and anaerobic digestion. The anaerobic digestion produces biogas, mostly methane, which is burned on-site for process heating.
    Also, energy intensive forced aeration with beaters or air pumps is a design choice. A less energy intensive and very common process for aerobic digestion is to trickle sewerage gently over high porosity filter beds (before fancy ceramics they used pebble beds).
    Supplying non-potable water broadly is duplicating a system, and very expensive, but supplying lots of non-potable water to a few intensive users like breweries or paper works does work well. For domestic systems it is far better to use local captured rainwater (where available) for flushing and gardening.
    OK, balance is not quite restored, but these inputs will go a long way in that direction

  4. This was a great episode and I really appreciate the attention to the problem of wastewater management. I work for a Wastewater Treatment Plant and I wanted to share a couple of links that highlight efforts our city is putting forth to handle the problem of sewage overflows and the quality of water released into our river.

    CSO Tanks always help by containing combined sewer material during high flow events and releasing it slowly back into the system in a way that does not overflow the pipes that deliver the sewage as well as the treatment plant itself at the end of those pipes.
    https://spokaneriver.net/news/water-quality/city-of-spokane-final-and-largest-cso-tank-goes-on-line/

    Our new next level treatment facility is a tertiary treatment that removes much of the plastic and phosphorus material that escapes into the river in a normal wastewater treatment plant.
    https://my.spokanecity.org/projects/next-level-of-treatment-at-the-riverside-park-water-reclamation-facility/

  5. Jackie Kahle

    The show neglected to mention the millions of us who already have a self-sustaining, natural way to deal with our waste at its source – they are called individual septic systems! In rural NH, I have been in our old house for more than 35 years, using a septic system that is even older. Our modern flush toilets deliver waste to an on-site holding tank, where natural microbes process the hard waste, leaving water to drain out a pipe into a leach field, where it naturally dissipates into the ground, which further purifies it as it seeps into the aquifer. A side benefit is being extremely aware of what happens to our waste and where it goes, and understanding what we need to do to keep it healthy, like not flushing anything but waste products, and not dumpling anything down our kitchen drains but water. If we aren’t careful, we could develop our own personal “fat berg” that we would need to deal with!

  6. My first experience with split water systems was on a visit to the Marshall Islands in 2003. The placement of settled areas on narrow atolls almost entirely less than 10′ above sea level makes fresh water scarce and complicates maintenance of infrastructure water supplies. Toilets and other things not sensitive to salinity use salt water. There is a non-potable piped water system that is used for things like showering, dishes, etc. Drinking water is purchased in 5 gallon containers. The big news when I was there was that the price for one of these containers had dropped from $6 to $5.

  7. Eric

    Something within the house still has to bring the waste from the bowl to the sewer and currently that’s water. All of those toilet designs address the toilet, but not really what happens below the closet flange to move that waste out of the house.

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