Episode 02 - Micropollutants and Learning from Sewers on Society

This is the the 2nd episode of the Flush to Data podcast. We discuss micro-pollutants, wastewater sampling methods, sewer epidemiology.

Hosts: Jörg Rieckermann and Kris Villez
Guest: Christoph Ort

Links:
- Christoph Ort: https://www.eawag.ch/en/aboutus/portrait/organisation/staff/profile/christoph-ort/show/
- MS2Field: https://www.eawag.ch/ms2field/

Episode guide:
[0:00:00] Intro
[0:01:27] Selecting a PhD topic
[0:05:48] Monitoring micro-pollutant concentrations
[0:10:05] Model to describe micro-pollutant concentrations
[0:12:05] From dish-washer tracer experiment to system model
[0:17:25] Are stochastic process models describing anomalies?
[0:25:55] Tracking micro-pollutants in sewers
[0:38:02] Intermezzo
[0:40:38] Sewer epidemiology today
[0:45:15] Sewer epidemiology in 10 years
[0:51:30] Sewer epidemiology for the Covid-19 case
[1:00:20] Thank you and goodbye!

Bonus material
[1:01:24] A researcher's condition, maximizing the value of coincidences in research
[1:05:52] Self-discipline and saying no
[1:08:46] The sewer ball
[1:13:42] Thank you and goodbye!

Transcript

spk_0:   0:05
Hello, everybody. This is the flush to date. A podcast. My name is your very common. That's my co host, Chris. Hi. On our guest today is Dr Christopher Court from Airlock in. Didn't off high Christoph

spk_2:   0:20
are your kind, Chris. Hello.

spk_0:   0:24
Um, Christoph and we know each other quite well. Christophe has studied, um, cultural engineering or cool tour engineer raisin. A teach age Derek. Then we did. Oh, PhD's together. Another leader of illegal area. I'm Christopher was investigating sewers. Micropal Luton's maybe even stochastic processes in engineering sense. Onda had a lot of luck with dishwashers, but we'll come to that later. And then he moved to Australia for a post, doc. Um, still continuing toe work with Michael Pollutants. Andi. Now he's back in Switzerland since a couple of years on dumb, famous for his work on pesticides, like inventing new machines which can even float autonomously through the sewers. Andi has been, um, thinking about working with viruses, but, um, before we touched on these topics Christoph, can you briefly explain our listeners why you're working with wastewater?

spk_2:   1:38
To be honest, I think this was, ah, cool crowd of people who did Ah ph ds with a really cool here. And, um I just came back from Canada and ah u s a from a longer trip. And I visited Mark Norman one off our PhD fellows colleagues Ah, tanker barrack. Miss Vidic were Who is in this? Who was an assistant with medical here and then, um really, basically offered me a job and I said, Oh, yes, but I have 20 immediately said No, not yes, but you have to say yes and that said yes and I will sleep over it one day to study her to think about it and well the other day. Then I, uh, agreed to accept the job and it was in the area off from Web based learning in the urban drainage area because there was no rial course on it. And we try to make a Web based course right back in 2000 to even a bit before, and it was I I always want to be part of the PhD crowd because they had this school Wednesday seminar the doctor around in seminar. But you could only be part of it when you were a PhD student and had no clue what the PhD student does have no clothes. Academic careers are just did this two years, 2000 until 2002 for this wet based course. And then one thing gave the order and I ended up doing a PhD besides the organ and many others in sewers.

spk_0:   3:25
Yes, but like the first, the first months or for years, I remember that we were starting the over group, discussing how we could, like, deal with uncertainty or even bring uncertainty in the in the equation. So it took some time until you got your your ph D. Topic government. Remember correctly, right?

spk_2:   3:46
Yes. And I think this was together. Is Smarck on Hell Gay? And I really struggled. I think the other today enjoy it. Their freedom to dive into topics, to see on the horizon or behind the horizon, what could be there? And I think, really going. He just said, Make sure that will be three topics. You can distinguish who does which part it's not. You do this together. It's everyone does it individually, but you can benefit from each other. But you really have to find your own thing. And I think, Ah, I thought about this coincidences I started, I had an idea and I started and I think I did not really develop so well. But then wanting came into the play and this was analysis off micro pollutants. So one off the analytical chemists at that time, while together I think he even as directed Vedic were Look, we can now analyze dispenser trying. So would this be something for you? And then he told me. And then I started thinking and I found this a good idea.

spk_0:   4:50
Did you know about a giggle before?

spk_2:   4:52
No, I didn't.

spk_0:   4:53
So, like the big Professor just comes to the PhD student and sits down, And then you develop the idea, to be

spk_2:   5:01
honest, that try toe, disseminate my ideas to predict pollutant loads too many at a log. I think I was quite brave in knocking on everyone's door. And I'm really not sure whether I spoke to Walter Kiki before or not. But I think he contacted video and then he said we could do something together and I started building a model and life free. You told me you cannot predict turned to try so a community state when they failed to predict ammonia loads in 24 hour composite samples. But I didn't. I was a bit ahead of my time. But 56 years later, you would be knew why it is useful.

spk_0:   5:44
Yes, So that's Ah, I would, I would say, Let's label the first block the first fame, the monitoring micro pollutants, right? Like I remember that like this, Bentsur tries old studies that was grab sampling all over the place, right?

spk_2:   6:00
While we did grab, sending in a very special fashion, I did. My first sampling campaign was for 20 minutes every 30 seconds. There was a relatively short time friend, but it was highest temporal resolution because I believed in it. Then we actually really self fluctuations at this time scale, which is quite the big success. And the next time I knew, I can also do just every two minutes. We'll still see it so I could expand to one hour, which is still a very short time

spk_0:   6:27
for yes, and still requires a lot off fitness right into the sewer, out of the sewer, into the sewer,

spk_2:   6:36
headed to help me. At that time he was on the in the sewer, high distilled samples up. He grabbed the samples, actually, really teamwork.

spk_0:   6:46
But before we go into the details like the pencil tries old stuff, Can you Can you explain a bit what that is?

spk_2:   6:54
Well, I tried to figure out what the different sources are and I received. Ah, what would we call this? Ah, a book, not a booklet released off, uh, products that contain these compounds. But most of them were not thought to end up in sewers. So the only one that actually really campaign spent to try so that ends up in sewers. Is the dishwasher detergent, or at least this best special type off thes thes taps. Not the liquor runs, but the taps. They contain teas. So I also shopped around and tried to figure out what the content of this is because this was not available from companies because you seem to be a secret or if they didn't have to label it because it's ready. Low fraction.

spk_0:   7:41
So is the thing which protects, protects civil, Right.

spk_2:   7:45
Yeah, Well, that's that's what it actually stands. But ah, on the on the packaging. But I think it was it. It protects the dishwasher itself. And even for non metals it just gets a better a result off dishwashing. They told me Yes, I was also in contact with some off the companies that produce it, and they said it's actually not so cheap to add it. So that's why they would be happy to find another one. But they didn't succeed in finding anything that protects dishwashers. Plus makes a better result in dishwashing. That's right. Still in there.

spk_0:   8:24
And then you you ran around and collected a lot of samples. And did you do the analysis in the lab yourself with the L C M SMS?

spk_2:   8:32
No. Are just I helped preparing the samples, the solid phase extraction. At that time that was not online. It was not direct injection, large volume, direction, direction. But I helped extracting the samples and started face extraction. And, um, yeah, I mean, I saw how they did the analysis, but I did not evaluate the samples myself. Not like my PhD students. They did it Reese illicit drugs and with pesticides and other stuff that they did this analysis themselves. And I think it's really useful to know the tools that finally produced your numbers. Yeah, I did it in close collaboration with, Well, to keep his technician.

spk_0:   9:15
Yes, and I think this is, like one good thing that ever great like you don't have to ask many people because, like, it's clear that everybody benefits from such a trans disciplinary collaboration

spk_2:   9:29
or at least interdisciplinary at that time, Yes.

spk_0:   9:32
Oh, yeah. I always mix up the definitions. Multi. Trans. Yes. No, I think what I remember is like how you were struggling with these 20 minutes and the hours, right? Like you have a small snapshot off like a quite complex process. And as life said, you know, like forget it, you will never be able to predict

spk_2:   9:57
yes, and still cannot predict sperm. We at least know that it flocked waiter image ranging flocked rates or can flock. It was a real eye opener.

spk_0:   10:06
Can you can you may be briefly describe the model which you used to compare, like whether what you measured actually makes sense.

spk_2:   10:15
Well, that was merely, ah, ritual comparison because, uh, my third paper was rejected. It was reviewed by a world thrown own statistician. I remember even our directors. He had a look at the paper and she couldn't tell me, But I found that really great that she looks at the PhD students paper who she doesn't know, and I submitted it. And in the end it was retracted and this reviewer one off the reviewers. I can't remember how many reviewers there were. He said he's never seen something like this before. This is probably it will be going to three published, but I couldn't convince him. And I never published this until we did This ABC paper together is called Santa. Yes, but that somehow but still not in the way I wanted to do it. But it was a least conceptually and methodologically much more sophisticated as what I tried at that time.

spk_0:   11:19
Yes, yes, but I think, like, how does the model look like, you know, like because it's not arma model or like what? What was this disc Sarma or like?

spk_2:   11:31
Well, no, that's try, Try and we try to use thes models toe characterize the time serious but to generated time series, it was just a caution process. Richest generated pulses and I added them up. And underlying this, I had ah measured diurnal variation that I took to our composite samples and then I knew roughly how many policies that are in the two hours, and I generated t's, um, individual policies that make up this total load. And you remember when the two of US river in run off our support stuff apartment when we did a trace experiment? Yes, by seeing how long was exactly in Oregon when we try to figure out how long Ah, I m thing off the destruction lasts. Put the fluorescent dye in the dishwasher and hold and let the dishwasher run. And then we saw how long it takes until it's empty.

spk_0:   12:33
Yes, but this study we couldn't have done with grab sampling. Probably right?

spk_2:   12:38
No, we've done this reason online probe to measure the fluorescent time. Yes, in line directly. Yes,

spk_0:   12:44
yes. And I was also surprised how long it took until what would dispersion in a sense, is created in the house connection. Yep. That's like, uh, yes was It's not a plug flow, which which, which comes out there.

spk_2:   12:58
But I know. Yes, it looked rather like I looked normal distribution, but

spk_0:   13:03
yes, there's no I think what I wanted to like Hidden Dad was like that. If you make a model which relates dishwashers to something which you measure in wastewater, right? It's it's maybe it's quite strong assumption of you specify the timing off the dishwasher, right? Everybody turns on the dishwasher at six eso. ItT's rather natural to make this like stochastic one senses

spk_2:   13:34
to source the timing. It's rather stochastic,

spk_0:   13:37
yes, but in one sense, like we engineers, like with the rainfall models and the annuity, you know, and we know that not every rainfall event is alike. We are used to deal with stock plasticity, but with this class of models where you have maybe sarcastically varying parameters were very good toe simulate more than to do inference with it is quiet. I I know that it like your hair was like, quite gray. And after after you were working in that time, you know, like and maybe you can tell the listeners a bit like the transition. You know what you tried and what didn't work. We talked to the statisticians that didn't have a good solution, you know, and then going to the ABC thing. Why this might be recommendable for this type of models.

spk_2:   14:27
Well, there is probably still some systematic part the systematic diurnal variations I mean, we also see it now when we can measure this stuff online, we maybe get back to these three standards to feel later. You don't have to do the grab sampling anymore. Um, humans are just routine animals, and probably it's the same mistakes. Washers. You just don't know which one is wrong, Ben. So it's a soon as you have certain catchment. It's probably not this important anymore to have the stochastic variation, because it will tend to the systematic diurnal variation. It's more if you have rare sources around number off events like drug users or industries. We're really the timing by really than the temporal resolution. It's necessary to know whether or not or how you have to sample together representative sample. Yes, I think at the end of the day, all the stochastic part is only relevant for short term spills or for knowing how you have to send together representative sample. Not that actually there short term variation is per se so crucial or interesting because after a primary clarify ire, much of thesis level about attenuated at least,

spk_0:   15:52
so you mean like for wastewater treatment plan processes like for the removal of micro pollutants, for example, I would

spk_2:   16:01
think that this place ah, subordinate role stochastic processes and the peaks in the sewers. It's more whether or not you have a high peak of something and you have her combined sewer overflow yet might coincidence or not, coincide or not, that's probably more important than after attenuation in a primary Clary fire. Yes, so you realize I deviated from your original question

spk_0:   16:32
way. Haven't talked about the inference a lot

spk_2:   16:37
because I still think it's probably not as important or I still struggle. And there is all the low hanging fruit that we can tackle that are more important.

spk_0:   16:45
Yes, but But, like you think it's like not so important for for science. Well, for our podcast now, probably both because I was also using stochastic models at some point, I couldn't, like, use like similarity tests. You know, it's it's all wow. And then, Peter, I should showed me this approximate Beijing computation, which is still approximate. So it's not like a super good solution that a toll east you have ah, like a solid inference process. I would say

spk_2:   17:25
that he posed this question toe crease. How do you deal with this with the anomaly detection. I mean, is it in a normally, when it's a random process, or is it just bearing to a degree you cannot predict? But it's still in certain bounds that is considered normal. It's still not, but it's not as predictable us if you're deterministic process, because in the end, even the dishwasher is a deterministic process. If we knew where it's flushed which type Tad was used, we will know when what pulse comes.

spk_1:   17:59
I think the dishwashing is is so it's a deterministic. Um, it boils down to how where you put assistant boundaries. If you put if you put the brain of the human deciding to start dishwasher inside their system, then there's arguments to be made that this person has no free will. And this this would be a physics based argument and therefore X deterministic toe football for ah, realistic simulation. Um, but in reality, we don't know the state off that brain. So because there are is hidden variables that we cannot measure directly, it becomes unknown. Variable your stand. To this day, we can only really attack or handle through a stochastic process way. Assume that there is a random process happening in this brain. And this was This is done dealt with by placing the system boundary slightly inward so that the human brain is outside of the system and generates some sort off trigger on disturbance starting the dishwasher. And from there on, you could consider that the minister system. So then, at that point, it becomes a mixed system on stochastic inputs on deterministic processes. Um, coming back to the anomaly point. That's an interesting question, because generally and anomaly is something unpredictable, something strange. And that puts things of better conundrum because now your definition of anomaly, the bends or whether you have a model that can predict it, so you're you're running into circles if you don't have a model to predictive than any special event is normally. But as soon as you have a better model that predicts rain or predicts when people will switch on their, their dishwasher disappears from the definition of an anomaly.

spk_0:   20:12
Maybe you have to like, get our listeners into the boat because we all know what what we're talking about in terms of anomalies and the other send project. But maybe tae say 23 sentences about the background

spk_1:   20:27
so that yes. So the reason this comes up in conversation here is So I was managing a project on I'm still managing, predict a certain degree on anomaly detection, and then the Post took working with me, we had, uh, not fierce but intense discretion on whether sensor drift was under normally. And in my mind, I had ah, considered our normal ease and faults sense of faults, anomalies kind of in the same. Been in this year's thing. But she said, No, no, we're not looking at sensitive in this project because sensor drift happens all the time. And since it's happens all the time, it's not. Normally, it's another rare event, just fundamental to the definition of a normally, that it's a so rare that an event so rare and frequency that you you don't you can't possibly collect enough data to predict the future anomaly. Or what are the next or the nature of the next anomaly? Yeah,

spk_0:   21:37
but isn't your thing like it's what easy toe change the definition? No, I think it's like fall detection must be than a harder problem than anomaly detection.

spk_1:   21:48
No, I think fault detection is easier because you have repeated patterns. It was not necessarily rare. Um, example. The metaphor that I've come up with is a normally, if not necessarily a degraded performance, right. It's just a rare event. Work to play the lottery and win on a normally Onda bank would look at my bank statements and maybe help. This is strange. Doesn't untraditional $1,000,000,000 coming to account with nowhere? That just knocks. Definitely anomaly. I wouldn't consider it a fault because having a $1,000,000 maybe nothing. Bad thing. Um, and on the other hand, you have faults unfaltering not necessarily rare, particularly in waste of the sector. Certain sensors are faulty more yes, for the majority of the time, compared to depending on what kind of a good to see you want. But I think we would find people saying that the majority of the time senses a faulty You could argue that it's just the case. Therefore, ah, 40 sensors is not an anomaly. It's it's happening all the time. So I think that's the background of this anomaly versus fault discussion on Di Dio. Ultimately, I have to agree. What this post Arquit Stefania that that she was right. We could not deal with sense of drift in the same way as any other sort of fault, which is more anomalous, meaning rare and and frequency and short in duration. So so So, yeah, But with the anomaly coming back to the model park, by definition, a normally make being rare unpredictable means that you don't have a model to predict it, so but it's funny. As your models evolve, you may be able to predict things previously considered anomalies and therefore the more life

spk_2:   24:06
we'll even probably depends on your level of knowledge about the season because, but it's an anomaly to someone else. Maybe just a fault or much more frequent events to others because they know the system much better,

spk_1:   24:20
miss. So we could tie it to the ongoing Corona virus crisis. Certain epidemiologist certainly predicted something like this to happen. They are not so surprised by this, uh, the whole world was not prepared for it. So so the models off the medium ologists might be more refined. But just the models that we applying our daily life as we go about our business are not the same models, of course. So so for us. It's an anomaly it may be for in the radiologist. That's quite quite a normal thing to consider and to think about

spk_2:   25:02
it. And if you have seen the curves, how they develop without any measures, it's It's amazing how how predictable it wants. Then,

spk_1:   25:12
yeah, again, I think this gun we can bring it back to the human brain with the dishwasher, the onset, the exact time off this fire stands for from one animal to human. That's probably very hard to predict once it enters one human. I could imagine some video muller medium elliptical models could could do quite a good job. I'm at least predicting a range of scenarios.

spk_0:   25:41
Yes, there was a breath was really surprising, although the data they had in the beginning Now they're like testing like quite widely. So the date and they had in the beginning were heavily biased. And that's that also fits our topic. But I will. I would still like to come back, um, to the micro pollutants in the sewers, because time is ticking. And I think we've talked about dishwashers quite a lot. Maybe Christophe, you could say what the difference is in the work you did with your PhD student Laina Matzner, on the past decides where, like grab sampling, especially in many catchments, was simply not an option.

spk_2:   26:23
Your true I mean, we would also have been interested in the dynamics in these sources from combined sewer overflows or from store both route. Let's. But it was just not feasible. And they want to have the main focus on where actually which pollutants come from in which catchment, whether this correlates his land use for example because this Russians, we knew there everywhere in Switzerland, everyone use it. You know this occurs, but for surface runoff, Do we have flat roofs? Do we have for essays to be half agricultural activity? Do we have gardens? Whatever. That was much harder to predict, and we wanted actually to know whether we can have ah, screening or a model to predict it. And for this we needed data. And to get data from many catchments with just one PhD student, even if it's a very good and very enthusiastic PhD student seemed only possible when using passive sampling. I've never been a big fan of passive sampling, but in this context, I thought, and I still think it's a useful tool to screen and get semi quantity for quality to state, or whether or not pollutant stare or not at all. This would already be good information.

spk_0:   27:43
So a passive sampler is a small piece of plastic, like a kind of disk, right?

spk_2:   27:48
It's a disgrace. A special sort of material. Yes. Which certain chemicals Miss Affinity Toe Be a good sampler for chemicals,

spk_0:   28:01
right? Yes. And you put this into stone water and wastewater systems

spk_2:   28:07
mainly, only mixed. Ah, sewers, Right. Combined source story

spk_1:   28:15
from a jump in. If you know where to choose between active sampling and parts of sampling. With this new knowledge, what would you make the decision on? Is it depending more on the question you're trying to answer? Or more on the kind off compounds in the way so that you want to measure? How would you select between? Well, it's

spk_2:   28:40
both, but obviously I mean the passive sampler. It's only suitable for a specific range off chemicals, polar organic chemicals you wouldn't be able to sample for solids or heavy metals. He would have to use a different sort of material, a different passive sample. Obviously, you could just bring out two discs for one compound. Range to this for another compound range and another tool for another. But you would never be able tow sample for solids. This right there is also some types of bottles that sort off Phil passively that don't have to actively suck. But I've never tested these in my life.

spk_0:   29:25
Yes, but is the passive samplings that assigns tool? Or is this maybe even ready for for applied questions like the utility manager wants to see whether his river stretches really bad quality, because off whatever this seaso or like this storm water inland all this agricultural rain, maybe which might or might not like being input off pesticides if

spk_2:   29:54
I remember correctly at in you level or at the regulatory level, even in Switzerland, I think it's similar toe, uh, are USA stepped? I have to admit, I'm not up to speed exactly what the state to sister. But I remember couple years ago at least they were not considered as reliable as taking an active sample and then analyse for the specific compounds in there. Although passive samplers and bio essays for different reasons have their advantages because they they basically represent an endpoint or they don't have to rely on pumping and clocking etcetera. But there is. There is many pros and cons for the one and the other. And that is not the run. The one solution that fits all.

spk_0:   30:48
Yes, yes, that is. That is what I think.

spk_2:   30:52
But I think, Ah, an operator who wants to know whether or not some spills contain a certain pesticides. Then a passive sampler is a good thing to deploy, because if you don't find it, it's very likely it's either not there or it's under the land. Ah, environmental quality standard. We've seen that even for short events below half an hour, we can detect relevant concentrations with Mr Passive Samplers. Yes, for the street off pesticides?

spk_0:   31:30
Yes. Thanks. So life we've come to from dishwashers to pesticides. Andi, that ah, monitoring and analytical technique is quite a bottleneck in that sense, right? Maybe not so much for wastewater treatment plants where you say the primary clarify levels out concentration fluctuations, but for sewers and for stormwater systems and maybe rivers. You know, maybe you have, like, a quite large sampling bias with with current grab sampling techniques or the altar samplers, which collects weekly samples. Right. So what I would like to talk about briefly is the latest project which you've been running with the chemists where you try to measure micro pollutants every 15 minutes, which at first sight sounds like a crazy idea.

spk_2:   32:22
Yeah, we had, ah, common interest in getting a better hand. Love what the dynamics is because we've seen or they have seen, the analytical chemists have seen that even in the 3.5 day composite samples that environmental quality standards are exceeded. But you never know how much they are exceeded because it's still a 3.5. They average so on die to stated. We stay screwed for scrap sampling, but you cannot do this, but try to stay the hearing driver. You can hear what any time and you will see it dynamics. But this rainbow trinh always rain driven events. It's much more difficult to anticipate or to the logistics.

spk_0:   33:11
Yes, it could be. Wonder what's right. Just like one hour discharge from

spk_2:   33:15
it,

spk_0:   33:15
or like maybe £10 is over three

spk_2:   33:18
and a

spk_0:   33:18
half days, and now

spk_2:   33:22
and now we just basically put it simple we took one off the top notch high resolution more spectrometers in its trailer and encrypted with a pump and a lot off other equipment for safe operation and control remote control and dumped the boat from the source directly through the trailer and in the trailer every 20 minutes. Um, a sample is prepared and to measure tight. Ah, high resolution mass spectrometer

spk_0:   33:53
that sounds so easy. But like each sample means how many terabytes of data.

spk_2:   33:58
Well, I think in a day we collect something like, Ah, couple of gigabytes. So it's no okay. If I'm not mistaken, I think it's a couple of gigabyte per day. Yes, if you operate it for 23 months, it also adds up.

spk_0:   34:15
But each 20 minutes you basically get a spectrum of mass spectrum right and that can be analysed for how many substances

spk_2:   34:27
while we re spike to. Still, do the conventional target analysis respect a couple off. Dozens, I think, are something around the hundreds internal standards to for direct quantification, at least with the preliminary data evaluation, have it on the fly directly every 20 minutes in the Internet and then with regard toe, non target or suspect screening. It's much more that we don't have a pipeline yet that can do this online. This is always those protesting.

spk_0:   35:01
Wow, that sounds like science fiction. Still,

spk_2:   35:06
it still sounds like science fiction, but there's already people quite, and they can analyze Corona virus online directly. I'm not yet sure whether this is possible or not, but

spk_0:   35:23
like online, You mean like in the in the water face

spk_2:   35:26
in the world Affairs? Yes.

spk_0:   35:28
Wow. Yes, I would like to come back to the Coronas. Maybe in the at the very end to ever kind of perspective. Um, but with Mr Field, can you briefly tell us what are the lessons learned? Like in terms off substances? Maybe. Did Did you find the same pattern off dishwashing detergents as you did, like, 15 years ago?

spk_2:   35:53
Well, I mean, you know, Ben to try. So is one off the compound he will find in the highest concentrations, I think also in the river off Rhine. We've actually measured in the effluent off the primary clarify where this short term fluctuations are already attenuated to some degree. So I couldn't directly compare them. Um, but we've also seen other compounds were surprised how regular the patterns are. For example, the condoms are tone of the vaulter turned the blood pressuring, lowering agents. They reach highest levels in the influence with regard to concentrations. Each morning at between six and eight, you have to steep increase and you have probably a factor off more than 10. If I remember correct between the night, many moment, the morning peak, that was astonishing to see. And then you have other compounds like I would have. I have to admit, I would not have been able to draw any off the compounds in the correct at

spk_0:   37:03
You mean the polluter

spk_2:   37:04
graph? Yeah, photographs at the 20 minute resolution in the effort off the primary clarified. Because some are extremely regular, extremely systematic, and some are so random or stochastic, you don't know why and how and if what process leads to it.

spk_0:   37:24
Fascinating. Is this like can can How can our our listeners, like, learn more about this? Is this published?

spk_2:   37:32
Now we're testing the course of finalizing I actually received today. I think the latest version off the manuscript well, or at least off the I don't know how many pages off supporting information we have to document everything. I think it exceeded 40 pages just for the supporting information.

spk_0:   37:52
So the best the best shot is to go at the home page and look for new.

spk_2:   37:56
Yes. Just go to air work dot c h slash M s to field.

spk_0:   38:01
Good. Right. So that's a lot to talk about. Like the super ball, maybe like even more about the pesticides and prediction model. But of course, many people know you for the work on the sewer. Pittman, your epidemiology, which I would like to come back to, but before I would like to make a small breakout session. And we did this last time with our guest. Where we asked him when you call this Chris like a It's a choice question, right? Yeah. So, like, 10 maybe 12 things. And you have to say which one you prefer. Okay, on. Um shall we should reiterate this, Chris,

spk_1:   38:46
Let's Ultimate. Yeah,

spk_0:   38:48
OK, then I would start. Sorry. Um, which What do you prefer? Beer or caipirinha?

spk_2:   39:00
Nowadays? It's to be year. I have to explain.

spk_0:   39:08
Just laugh away.

spk_2:   39:12
Evolve or messiness? We're CDs.

spk_0:   39:16
Micro pollutants are suspended solids,

spk_2:   39:20
Micro pollutants or raccoons are Beavers, Beaver's,

spk_0:   39:26
um, tent or five star hotel

spk_1:   39:30
Trent. Bands are three years old or diclofenac.

spk_2:   39:38
I have to pick one, right? Yes, The D Cliff in Iraq.

spk_0:   39:45
Olympic champion or science? Paper?

spk_2:   39:49
Science Paper.

spk_1:   39:52
Oh, mountain biking Are touring skis.

spk_2:   39:58
Ah, because it's just to finish off the ski touring season

spk_0:   40:03
to know. Now we come to Ah, music. So it's It's Michael Jackson on Nina,

spk_2:   40:16
you know?

spk_1:   40:18
So how much or biohazard biohazard

spk_0:   40:26
on the last one? Maybe stones or beetles? Stones. Good. It is Break good. Okay, take a take a big breath. Everybody also heartlessness. Um, yes. I don't even know where to start the sewer epidemiology thing. Um, historically, you went to Australia to, like, further investigate micro pollutants. And then somehow the the special substances came in the way. Maybe I leave this. I leave this to you, right? Like, can you tell our re our not readers or listeners briefly what the idea behind it is And like maybe what your contribution is.

spk_2:   41:17
Well, it 2001. There was the first mention off the possibility of using sewage to learn about behavior off hidden consumption off specific substances that is explicitly illicit drugs. I think there was one or two early papers. 2000 moment in 2005 or six. Andi researchers Satti addressed World Management Center were contacted by public health experts off School of Public Health off epidemiologists. Whether this could be something, whether this is something that would have a future and I was there and I said, Well, we can look at it from a perspective for further the sampling is suitable or what we would expect that we have reliable represented the samples and then I didn't really follow it up by did at that time hospital race, water, which was also challenging to sample. And then it was smaller or less only when I returned back to airlock when you brought me to one off these meetings at the M C d D, where some off the people gathered some analytical chemists and toxicologists, epidemiologists gathered at M C d d a. For a sort of a kickoff. How, how and what one should do to establish or to learn more, whether we can use this as a tool. This is how I got into this.

spk_0:   42:52
Yes, and the big concern was data quality, right? because some people just took a grab sample somewhere, right? Like the I remember this video with some guys from Germany were doing representative sampling in the in flow for wastewater treatment plant with a scoop. Yes, exactly.

spk_2:   43:11
We're currently taking a representative grab sample. What was in Flint off the treatment plan?

spk_0:   43:16
That was the quote of that video. Yes.

spk_2:   43:18
And that exactly? Yes, I think that was also the best part of my PhD defense.

spk_0:   43:26
So? So when you came with this to the chemists or like epidemiologists, they I didn't really know what you're talking about or

spk_2:   43:35
no, not really. But it also proved long, long, Ah, time. Later it it proved that most off the large treatment plans that use some good sampling techniques or, ah, representative sampling scheme that this is suitable. It's more for the small treatment plant or for the runs just using a the free consider for an hour where it seemed to be a problem.

spk_0:   44:04
Yes. So at the moment, it is somewhat established that every year there is a community off wastewater treatment plants who collects samples in a synchronized fashion. And then these are analysed for specific substances.

spk_2:   44:21
Yes, is that correct? Er's Yes, it used to be now the 10th year, but the tense years now. Ah, somewhat interrupted by Corona. But it will be interesting no matter whether we can. Some countries can stick to this in vestige da normal week in spring, although it's not gonna be normal and some others will just have to delay sampling. But it will be interesting anyway to see.

spk_0:   44:51
So this is like established method if you if, if you want to say so in a sense,

spk_2:   44:58
you are. The interpretation with regard to absolute numbers is still challenging, I think, for various reasons. But I think the relative differences both in space and time that's quite reliable.

spk_0:   45:15
Okay, so if you if you could make a prediction in 10 years, where will this? Where will this be?

spk_2:   45:25
It depends on whether we get more clinical data on excretion rates. I think this is one off the biggest efficiencies at the moment because we don't know which absolute number is excreted. It varies depending on administration around depending on level off. Use it to Tetra. But I think if we again use this phenomenon off, a large population tends to demean. We wouldn't need that money subjects, I would say to get better information on excretion rates.

spk_0:   46:02
So So there we end up with the dishwasher again, where basically our models can predict minute data, but we can't observe them. But if you would observe like a really high spike in your in your time Siri's than you could in, like, infer that this would be like a heavy user,

spk_2:   46:24
you're all Maybe it really depends also on the physical properties off the drainage system, whether there s something or not. I mean, if you have only rare number off users and you have no pumps and you would just have toilet flushes, then you would probably see if you just have one. We've done that wants this cattle inhuman Australia to see one patient in 100,000 people. And it's just bean like the only one that was treated that day. Wow. Um, then you see it exactly. But if you have ah, Siri's off overlaying policies or if you have pump stations very could have an accumulation of toilet flushes, it's going up. It's probably not gonna be so simple.

spk_0:   47:10
So the farm akel, what is it pharmacology or kinetics kinetics. They're still challenge, like from wastewater systems or wastewater signs. What's what is our bittle? Biggest bottleneck?

spk_2:   47:26
So I did not understand your question now,

spk_0:   47:28
like what is from engineering or waste waters perspective? What is the biggest bottleneck in that thing is that now the temperature in the sewer evolves or like the Redox potential, Or I don't know, the biomass we have, or even how much sewage we lose on the way to the westward freedom plant.

spk_2:   47:51
Well, it's probably just serious that you mentioned and I understand what you meant. Yes, yeah, it's it's transformation studies. And if you know what on the rich conditions, how this spatial distribution off these conditions is in the sewer system, that's probably the biggest challenges. And how much so it's really lose.

spk_0:   48:14
And how how is the next generation of scientists going to tackle this?

spk_2:   48:21
Probably rece. More sophisticated sensors that can map a spatial temporal Odenton generate spatial temporal maps off all this with regard to ex filtration, your mortar expert and I am well, Mr Guard, too.

spk_0:   48:42
I was once really stores are still leaking, I suppose. Yeah, yes, but like the societal implications like I found it Quite interesting. Like how much attention this topic gets, right? Like sewers, Waste water. Yeah, it's not so sexy. It stinks. But like once you talk about drugs, you know, then the judges calling you

spk_2:   49:14
Yes, that's correct. I don't know. This is probably because it's ah, it's a hidden to hidden process or something you cannot. You don't have same state that you have only indirect information. And all of a sudden we have direct information that seems even to the ones who are who are, um, not concerned to our ah, skeptical about the use of sticks. I mean, they see Okay, it's basically what what goes in must come out at some point. And no matter whether you know the absolute numbers correctly, if you see the the explainable or the anticipate, the difference is that you can anticipate and when you can normalize it. This, for example, smoking. But you know, we're more or less how much smoking, what the prevalence is and you see or the sewage data is not lying, or it's actually fitting toe what we expect for the one phenomena on, we can now measure ALS and other phenomena where we have no quantity state. I think that's what makes it so interesting.

spk_0:   50:33
Do you think this could also be its like, Ah, a Trojan horse? In a sense, to communicate the importance off wastewater to society, Think of wastewater treatment in general.

spk_2:   50:47
Your fear. What, By using this?

spk_0:   50:50
No, it's like people don't think about the wastewater system. You know, you flush the toilet and then disappears Our sense, yes, and nobody cares. Like that's not much innovation in the field, in a sense, you know, if you compare it to telecommunications, for example. But could this be a vehicle to put the topic on people's agenda?

spk_2:   51:12
Maybe that it gets attention. It's probably similar toe. I mean, micro biologists and chemists states this waste will the based epidemiology for different purposes. But they just didn't name it this way. Yes. I mean, you told me a couple of years back, while the true value would be if we could use it for the force. Arthur Mares. And now here we are. And now everyone jumps on it.

spk_0:   51:39
Yes, everyone. Well, everyone jumps on it for me. It sounds like still like science fiction, like you're talking about measuring Corona viruses in toilets.

spk_2:   51:50
Yeah, well, the people thought that when we publish this that this is possible. It's Ah, 1st April like what you call this hoax hoax. Exactly that they thought it. It's not a coincidence that this was published on this state. So it's it's still if you read the comments online and some feedback off my colleagues, they didn't believe it.

spk_0:   52:18
Yes, so like the information when we were exploring this a couple off years ago, that was, lad. It's seeing the DNA or the pattern of a virus in, like such, Ah, when you say, like a hodgepodge like off wastewater, Because there's everything from bird poop to human excretion to maybe animal manure things, you know. So like, um, tell our listeners a little bit about the general idea and then maybe what you are doing in this field and like, um, what you think What's the What's the perspective?

spk_2:   53:00
Well, currently, we collected a lot of samples. I think we probably really get ah from the first stage and the first people Where are the first cave was Case was reported in Switzerland. Behalf samples every with the expectant toe, Maybe not measure much, but hopefully we would see that we can be one or two weeks ahead off clinical reporting when people with symptoms present at hospitals. But we first have to get our methods Stone, which we do in collaboration with CPFL. Um and then see what the data looks like. We have no clue what it will look like. We have our ideal case. We say it's gonna look like more or less the qualitatively similar. The curve would develop USAA clinical cases, but just want to two weeks before because the viruses are set in feces of infected people. We don't know the dynamics yet. We don't know the amounts yet, but the knowledge would be that we will see it in switch.

spk_0:   54:14
So, like you are talking about like, um, idea toe collect wastewater and then not back calculate the number off infected people must find them or, like, have a detect non detect signal.

spk_2:   54:29
Well, well, the the minimum hope would be 10 40 tax non detect and say what the detect means It's 100 people or it's one person in 100,000 or 10,000. Um, ideally, at some point, we probably could also estimate with some conservative uncertainty estimates Ah, number off infected people I think we want probably get there at some point. But this will still require a lot off. Very total and careful both analytical work. Also considerations with regard to sampling, we have no clue how much is in the solid or in the liquid face. How much we can extract how much I always stare re presented this sample. I've done some working in the liquid face and on temporal variability, but I have no clue yet on viruses in ah, um, routine sample off a wastewater treatment plant.

spk_0:   55:33
Yes. And how are the virologists overcoming? Like there? This this mixture problem, right? You're looking for the needle in the haystack. Basically,

spk_2:   55:41
where are we do fill trade alliances infiltration on then cleaning up this or in a cleaning up to minimize inhibition and then message just ah, the fragments. But this does not matter whether it's actually for inactivated already.

spk_1:   55:59
So if you want to look at it at a future case on a new virus so between let's say I don't difficult Unification of the irony pieces off a new virus on deployment off this kind of tool for a specific virus. What kind of timeline they expect in the future?

spk_2:   56:23
I have no clue. But I mean, if we do the case and if they it's the test, the clinical past is similar to what we do in the waste voter. It's using the same primers analyzing for the same fragment if this is known and if it was developed in another country before and we have no reported cases here recode star using this. But obviously, if you don't know what you look forward and you first have to sequence it.

spk_1:   56:51
Yeah, it was more ticket once. It's once it is sequenced.

spk_2:   56:54
Want city sequenced?

spk_1:   56:56
Yeah. How quickly can you move to an online measurement?

spk_2:   57:02
I have no clue that this still be feasible at some point with the online, But if it's sequence and if you have all, uh, what is needed to do the PCR, I think while you can call the treatment plant had a sample and clean the same plot concentrate and measure similares where no to a clinical sample. Uh huh. Obviously with much lower concentrations. Then in a patient, obviously,

spk_0:   57:33
yes. And the perspective is then to work on like catchments off 100,000 people. So you get good enough averages in your sample. Or is there also the possibility to use this old cotton swab method off the fifties or sixties where they were tracing back? Was it

spk_2:   57:55
confident when I e asked about this? Ah, Microbiologist told me, It's It's probably not feasible. Go for another sampling technique because we currently collect 300 milliliters and concentrate this I don't know if it's just Mystic Opens Web. It would just be too small. Volumes. Yes, we would not speak to it.

spk_0:   58:20
So a passive sampler for viruses has to be invest invented first. Yes, yes, wow, yes, that's exciting. And what's the state off the project?

spk_2:   58:34
We can now go back to our labs with the special permits, and we try toe synchronize were can get calibration curves and make sure that what both slaps measure is the same quality control. And then we can start tackling real world samples.

spk_0:   58:54
So this is when I understand it correctly. The very beginning, right? There's not even a home page. There's not much funding.

spk_2:   59:01
Notre. It's not much funding yet. We have some internal funding that kept us going or starting because it was really in a talk decision toe. When I was in skiing holidays in, the microbiologist asked me whether I still do something. I said, No, I don't do sampling, but it's a unique opportunity and be immediately organized this Swiss cantonal authorities and motivated treatment plant operated operators. Richard's reading Incredible. This surrounded provide.

spk_0:   59:30
And let me guess if I if I had called the guys or Chris had called the guys, they would not have responded so quickly.

spk_2:   59:38
I don't know. I didn't know the person, but I knew the person through some other, some some other people at airlock, and she never spoke to me before and that she didn't know who I am, and it just works. I I explained to her, and she was enthusiastic about it because she said she had already protectors here walk and it was ready, productive and interesting to collaborate. And she said that the colleague affairs will now contact the treatment plant operators for this work writes mostly

spk_0:   1:0:12
awesome. So that is like something which we are going to look back to like in a couple of years. No Andi, If I look at the time? It's like almost in our I think we have finished. Um, I would thank you. A Christoph like for taking your time. Thanks to Chris on to you, listening to this material briefly Sum it up. We've been talking about, let's say, the first fame about monitoring like a pollutants from grab sampling. Too fancy online mass spectrometers. We've been mentioning sewer epidemiology, and 11 could learn from society on society from sewers. Andi the last opens up the bright future off, like making use of wastewater analysis for new problems. Maybe even like detecting viruses which are not yet known. Onda um adding another dimension to the sanitary and health engineering. So thanks, Christoph.

spk_2:   1:1:20
You're right of outcome. Thanks. Thank

spk_0:   1:1:22
you. Goodbye, everybody and the flush to data podcast Get some extra time now with a few minutes of bonus material from Chris your and the guest. What did we miss? Was there anything we we should have talked about?

spk_2:   1:1:46
Well, it's probably bean people and relationships and coincidences and self discipline and struggling times and good times. And like thes absent downs that you see in PhD comics or in 10 year track comics or in senior scientist comics?

spk_0:   1:2:07
Yes, yes. I mean, that's true. Like it sounded like a very smooth, you know, in retrospect, on like, Oh, yeah, it's fun. And I we have this cool idea. We realize it, but yeah, it's as you say. It's like often you just have to push through, right?

spk_2:   1:2:26
They are not Remember my girlfriend. She told me she really hopes that I get out of this hole at the end off the PhD. I was obviously not enough. Unbearable.

spk_0:   1:2:37
So all PhD students who are listening to this like hanging like the future after your PhD is bright, even if it doesn't sound, see, look like this now, yes, but I think also what What came out? Maybe a little bit. Is this coincidence thing, right? Like, ah, if I look a

spk_2:   1:2:57
try, so yes, but we go on. Very stay epidemiology that to rely on expert expertise from urban drainage. Yeah.

spk_0:   1:3:09
Yes. And you also need, like so, like mentor type figures. Right?

spk_2:   1:3:16
That's true. I think I would have benefited from having official mentors I had in official mentors. I remember one or two tattoo this very experienced people, but I think I should have. In retrospect, try to get a mentor to talk more frequently or more regularly. Raise

spk_0:   1:3:39
yes, but it's also probably that times are changing right with this. Me, too. Like the power Grady in between your supervisor and the PhD students like at E th. They're talking out about PhD committees where you have more official roads of this, but I don't not know many people like you, Christophe, who can so easily speak to chemists to viral Justo many people across many disciplines. And so the you mentioned the people aspect off it. I guess that place a quite large role, right?

spk_2:   1:4:15
It's true. On the one hand, sounds like I can talk to everybody or to anyone different disciplines through. On the other hand, sometimes I think in my own home discipline, I'm not so at home because I'm afraid of an outsider.

spk_0:   1:4:32
You mean if it if you do, if we talk about the runoff coefficient or like

spk_2:   1:4:36
yes or surface runoff for rainfall patterns or whatever. But that's the way you cannot do everything you have to choose. Sometimes it's explicit choices. It's executive decisions, as you would say, and sometimes it's coincidence.

spk_0:   1:4:59
Yes. I still remember this situation where you were applying for a postdoc in Australia and then your girlfriend at that time. What? Yeah. Should I? How do we do this? And then she also applied with her global company. And then your proposal had not been finished like

spk_2:   1:5:19
No, I haven't submitted at that time when it was not evaluated.

spk_0:   1:5:23
Yes, but so she

spk_2:   1:5:26
told her company, Aiko, with Christoph, either reserve is out. You. Then it's imprinted was cleared. The TV will go. I will go with their respective for whether I will get funding or

spk_0:   1:5:40
not. Yes. So there thes are the situations which you just have to carry on, right? Like yes and hope for hope for the best. And you mentioned the self discipline. You mentioned the self discipline part.

spk_2:   1:5:58
Yeah, well, this is maybe more sports or more organized. Everyone has the impression I'm extremely organized. But I have I I think I'm the only one who does not have to impression that I am organized. Probably. I don't know why I make this impression. Maybe it's because I'm not doing too many things at the time because I know I could do, but it will be 100 good opportunities. Maybe I can realize or doing in a satisfactory manner for my quality. Expectations are for my involvement with people of these projects. Two or three. So why should I kill me, Miss? Five for seven projects? Because I cannot do 100. Anyway. Maybe this is small artists, and I also I'm also the person that likes to say no. I also suffer from saying no so

spk_1:   1:6:59
feeling. You say no too much. Are you having

spk_2:   1:7:03
well allow these days? Yeah, I I think I have toe say too much. No, because there's simply too many requests to collaborate, and I just simply can't do this, or I don't have a big enough group that I can I don't want to spread myself thin. Uh huh. Yes, I don't I don't want to delegate too much. I also still want to do some stuff myself. I have, ah, interesting balance off tasks, not just managing, but that's probably also luxury.

spk_0:   1:7:37
And luckily we are in the position that we have the freedom to do so right. If Chris talks about his experience from, or like some colleagues somewhere else, where they say, Oh, you're published. What? 10 papers this year or 12? Very nice. Next time. 15 please. Next year, like, come on, go. That's totally unreasonable. No

spk_2:   1:8:03
look leaving untouched on quality and not quantity. And also quality not only from output, but also from supervision. Because I can simply do better supervision if I have fewer people.

spk_0:   1:8:22
Yes, and maybe also because you're more refreshed if you're if you didn't spend the weekend in the lab. But, like, carried your mountain bike up past for three hours, you know, no chance of writing up, but like carrying up that frees your brain

spk_2:   1:8:42
through a district and helps you focus the other day.

spk_0:   1:8:47
So we did not talk about the sewer ball at all. Yeah, And the

spk_2:   1:8:52
part of my third life, the first life Waas. Ah, monitoring and sampling. Then it was wasteful, the based epidemiology. And now it's new tools.

spk_0:   1:9:03
Yeah, but for a reason, right? Like, do you want to say to lines on the sewer ball? Maybe with this open hardware perspective?

spk_2:   1:9:13
Yeah, that was ah also some luxury. Protect that. I employed a person with the background that I had no clue off electron ICS and mechatronics. And it was just basically developed a sensor that can float in a sewer to map the spatial distribution off variables that determine transformation of illicit trucks. And it turns out it's much more useful for many other things like, for example, infiltration or hear or see voter intrusion. And not for the transformation of illicit drugs. Primarily, as I initially sought

spk_0:   1:9:57
that signs, right, you started. One of you end up in another part.

spk_2:   1:10:02
Yes, they're building hard varies heart.

spk_0:   1:10:06
In which sense?

spk_2:   1:10:08
Well, because it needs to be wrote to proof it needs to be robust. ID s o many things. I mean, I still have not a clue off how to improve circuit boards, etcetera together it off interference, etcetera, and get the proper signals out.

spk_0:   1:10:26
Yes, but that's something which we're where we should never have a clue, right while

spk_2:   1:10:33
you and I not

spk_0:   1:10:34
Yes, yes, Yes, we like us engineers like wastewater engineers, right? So far, but it it doesn't,

spk_2:   1:10:43
but the combination is good. Yes, it's great that we have sensor guys who are not the friend of wastewater and that we have to free them off, employing more off sensor people rather than another natural scientists or wastewater engineer.

spk_0:   1:11:05
Yes. So you have this little ball. This the sewer quality instrumented device. The squid? Yes. Andi, where is this going now?

spk_2:   1:11:16
Well, I don't know yet,

spk_0:   1:11:21
so the project is over. The design plans are on somebody's hard disk. They're a couple of prototypes. And if

spk_2:   1:11:28
you want and we collaborate these people who use it I think that it's Ah, artery on our My former postdoc is now manufacturing some off them And you can purchase them? Yes.

spk_0:   1:11:41
Is this patented?

spk_2:   1:11:43
No. It's at the time when we had to decide about the patent, we decided to not do it because it would have been too expensive. Too much work,

spk_0:   1:11:54
right? And because we are not the ones who would like to commercialize it, right, it s in this tool had existed. You would have supported probably for a reasonable

spk_2:   1:12:06
Yes. Exactly. Yes, it's bean very, very expensive. If you would have to do this Ah, to pay, pay back the investment.

spk_1:   1:12:19
So you say you don't know where it's going, But could you highlight Where would you think it would be useful of the unifying? So who who should be interested in buying this silver ball.

spk_2:   1:12:37
I think if you want to know more about different processes or discharges in your system, but to do this more easily, we have toe. I think we would have toe equip it. Also be some underground navigation and some either much louder beacon for signal or light or whatever to recover it, because we still have to use a net to to catch it.

spk_0:   1:13:12
Yes, magnets like the superpower magnet, which pulls it out of the shit. It's

spk_1:   1:13:20
an interesting point. And the previous episode we talked about scaffolding on this was more related to self driving cars. But it's the same principle. You, your frame, the mobile device in a system. Yeah,

spk_0:   1:13:38
good, yes, very good, thanks to everybody.