 Good afternoon audience from Europe and Africa. Good night Asia and Oceania. Good morning, America. I'm Chaocheng from Tsinghua University, Beijing, China. The chairman of Disinfection Specialist Group of IWA. Welcome to join the IWA webinar entitled The Future of Disinfection in Drinking Water and Waste Water. First of all, on behalf of the IWA Disinfection SG, I would like to thank all the speakers and audience for joining this webinar. I'm told there are over 800 audience online. It is really a fantastic number. Second, I want to thank my colleges, Isabella Espinola and Regina Sacre from IWA Headquarter, Andrea Turula, Chaim Chikura from the IWA Disinfection SG. Before the start of presentations, I would like to read some announcement from the IWA Headquarter. First, this webinar will be recorded and made available on demand on the IWA website. Second, the speakers are responsible for securing copyright permission for any work that they will print it. And the third, the opinions, processes, conclusions or medications contained in the presentations and other materials are so responsibility for the speakers and do not necessarily reflect IWA opinion. Next slide. During the presentation, you can use the toolbar of Zoom for interaction. Please use the chat box for general request and for interactive activities. Please use the Q&A box to send questions to the panelists. We will answer these questions during the discussions. Please note, attendees' microphones are muted. We cannot respond to this hand. Today, we invite three well-known speakers, Mr. Gary Hunter, Mr. Patrick Smith and Ms. Maria Josefery to give the poll. Their presentation will cover three main topics of disaffection field, including the disaffection technology, the risk assessment and the disaffection byproducts. I believe all these presentations are very attractive. My colleagues, Mr. Chaim Chikura, will moderate the Q&A discussion and another poll after the presentations. There will be a poll for the audience. Isabella, please show the poll to the audience. Thank you. Okay, let's move to the introduction of Disaffection Specialist Group. Disaffection SG aims to create, exchange and transfer the knowledge and experience of disaffection-related issues in water, wastewater, flood and excreta. You can find more information from our homepage on IWA Connect. Our SG is one of the largest SG in IWA, which have 1,845 members from about 140 countries or regions. However, we still need to encourage more female members and young water professionals to join us. The gender equality and the recruitment of young blood are always our goals. Now the management committee of our SG have nine members, four came from East Asia, three from Europe, one from the United States and one from the Middle East. We will renew the management community next year. We welcome the new blood, especially the female and the young water professionals to apply. The Disaffection SG have organized three successful conferences on disinfection and disinfection byproducts in Mexico City, in Beijing and in Milan. Although the pandemic brings that compact to our event in Milan, we are happy to make it open in time and it is really very successful. I hope you will be interested in the next one, the fourth IWA Disaffection byproducts conference will be held in Elmeria, Spain in 2024. It is a very beautiful coastal city with blue sea, Asian castle and friendly people. Let's move back to science and technology. The COVID-19 pandemic has impacted the world greatly, bringing huge members of infection and deaths. Our SG will try our best to address the disaffection demand to fight against the pandemic. WHO issued a living guideline for interaction, for infection prevention and control in the context of COVID-19. In this document, the public health and the social measures include five parts. Disaffection is a key measure among them. So what are the comprehensive demand on disaffection during the COVID-19 pandemic? In my opinion, we have to achieve three goals. First, to inactivate the pathogen on each meteor as much as possible. Second, to ensure the safety of water, waste water, air, solid waste and the living conditions. And the third, to avoid the unrecoverable impact to ecology and a personal health by disinfectant. Next please. To address the disaffection demand now and in the future, our SG has prepared a chapter on disaffection in the IW report. Global trend and the challenges in water science, research and management. We invited seven management committee members by scanning, we invited seven management committee members and three researchers to prepare the disaffection chapter. The recent progress and the future perspective in this area can be found in this report. It is free to download the report from the IW website or just by scanning this QR code. I believe you can find some useful information from the report. Our SG are organizing three surreal webinars. Please pay attention to the IWA website for more details. Okay, so the introduction of our SG is up. So let's move to the first presentation, Mr. Gary Hunter from Black and Witches Water Technology Group. Here we will give a talk entitled the UVC LED, The Wave of the Future. Maybe I can introduce a little bit about Mr. Hunter. Mr. Hunter is responsible for assisting utilities in deployment of UV technology in both conventional and reuse applications. Okay, please join me to welcome Mr. Hunter to give a talk. Gary, now the stage is yours. Can you hear me now? Yes, yes, very clear. Okay, one moment. So what I want to do is talk a little bit about UV and the progress of UV within the United States and then the title is sort of looking at recent progress in UVC LED disinfection, or is that the wave of the future? If we just back up for a minute and look at UV disinfection, UV allows us to inactivate the organism we're targeting, whether that's in providing a DNA damage. So we essentially look at the dimers within the DNA code to essentially allow that to particularly happen. As we apply more and more dose to the UV system that gives us inactivation, we don't really remove the bacteria, but we essentially, we inactivate it so it won't really replicate itself. And this is a photochemical process with pretty much immediate effect. So Isabella, do I have control? Next slide, okay. So there are a lot of recent disinfection issues that we're kind of looking at, and especially within the United States for what I call basic level disinfection, that's achieving a 30 day geometric mean of 106 E coli per 100 ML. And a lot of the push with the Environmental Protection Agency within the U.S. is to move towards virus as an indicator organism. So that is causing a lot of people, a lot of utilities within the U.S. to reflect on what disinfection technology they would prefer to have. We also see a lot of the impacts of older technologies and technologies then that are being discontinued and having to replace those technologies with newer technology. And a lot of impact with especially in the western part of the U.S. on reuse, whether that be irrigation, whether that be indirect portable reuse or direct portable reuse, and how that might impact the deployment of UV in those particular communities. There are other issues as well in terms of looking at usable life capacity, trying to get more capacity out of existing systems, how to improve the control of the system through online instrumentation, as well as other emerging contaminants like PFAS, NDMA and PCB. So that leads us to looking at newer technologies like UVCLD or tubular technology. And this presentation will highlight the progress of UVCLD and how it's moving forward within the market in the United States. So why would somebody want to look at a UVCLD? Well, if we look at our current UV technologies, there are a number of issues associated with them. Some of that relates to, if we have to take them out of service in terms of way, that might be operation in terms of time that we have to look at them in terms of warm-up and power, reliability. We have porcelains relative to durability, and a lot of these have relatively large footprint. So if we start looking at that, is there something better? Is there another technology that potentially could be used to allow us to achieve much more effective disinfection? And that's where UVCLD comes into play. It's mercury-free, it allows us an instant operation that we can do a very durable design in terms of footprint and look at compact size, very lightweight. And then probably the bigger key with UVCLD is matching the wavelength to the organism that we're targeting. So essentially the UVCLD could be manufactured to essentially achieve whatever the inactivation dose is required, the intensity is required. So there are a fair amount of advantages to moving to UVCLD over the existing UV mercury-lamp technology that we have on the market today. And you can see a lifetime up to 20,000 hours in terms of use on a UVCLD unit. That can be extended actually through good operations and good cooling. So you might even get closer to 40,000 hours. Whereas on the mercury-vapor lamp we have today that might go up to 15,000 hours. So it's still a lot working on what that actual lifetime as a detector. But one of the things that we're looking at very carefully and you can see that the ONF cycles with the mercury-vapor lamp in terms of guaranteed force per day but unlimited on the UVCLD. You can see the temperature and the mercury content which is a very big thing in terms of being able to get the mercury out of the lamp technology and use something that does not have mercury in it. But that allows us to do a lot of things like mentioning like dynamic switching of the LEDs, being able to turn down a lot and switching. So the UVCLD offers us a lot of flexibility in terms of deployment of the technology into the market. Now, UVD traditionally I will say has been used and very well I'll say within the UVCLD market. And I can show there's a number of pictures here over to the right where they've been actually deployed in drinking fountains. And if you think about that in terms of being able to provide disinfection and being able to achieve a very high level of public health in terms of removal of bacterial contamination that just essentially allows you to deploy that the technology very well. You can see that they're very lightweight point of use. You can see one of them is being used in disinfection of water and sailboats. So a lot of different progression of the smaller UVCLD units. And you can see now there are over 200,000 of these systems in use ranging from a wide variety of technologies and things probably where we wouldn't normally think that we would see disinfection allows us with the compactness of the technology to be able to deploy them in a lot of different areas. But if we're looking at it and we're looking at trying to move it into the future point of use is a very large market, but then we need to be looking at the municipal sector, both the municipal water and wastewater side of the equation. And we've been involved with a number of testing organisms testing regimes, which I'm showing here in the pictures to the right. Five different UVCLD tests, four different configurations looking at BenchVille comparable results to traditional UV. And I'll talk a little bit about the largest system that's operational now in the UK on UVVCLD, but achieve very high level disinfectant quality and removal of the organisms that we're targeting. So the first study I just wanna hit was a project that the US EPA sponsored and their laboratory in Cincinnati, Ohio. And they had a number of partners including Washington University, Every Electric Power Research Institute, AquaSense and Black and Beats. We were all able to do, but because we were at the US EPA test facility in the test a wide variety of waters including water, traditional secondary treated effluent. We looked at wet weather in terms of CSO and we did look at reuse relative to filtration. That particular study, interestingly enough was actually funded by within the United States Homeland Security and they were targeting organism called the Solis-Galabi which is a surrogate for anthrax. But in addition to that, we looked at E. Coli, MS2 and pterococcus in total coliform. So we can't cover everything but I just wanted to highlight some of the work that we were doing in the Solis-Galabi. The previous work that had been done with the Solis-Galabi really struggled in terms of being able to achieve disinfection and high log removals. And so we were actually able to get upwards of at 40. Milligial dose were up in the six log, five to six log removal, which is extremely excellent compared to the literature that had previously been shown. And that's the 40 to 60 dose are the region in which drinking water systems are designed and deployed both on the water and wastewater system in the U.S. So we can get very high protection of this particular organism with the systems that are in place today. But all of this being done with UVC LED units, this kind of gives us part of that work also looked at the ability to have both bench scale as well as flow through units. And we can see we got two different units that we tested on up to 22.7 liters per minute, one at 15.4 liters per minute and then adjusted the power. You can see we were up in terms of 80 watts per log removal. So still needing a little bit more tuning on the UV system but showing that we can effectively deploy the unit. And this was all done on wastewater at the Milk Creek facility. A second study we were working with MetaWater at the Research Laboratory sponsored by Aqua Robics in Rockford, Illinois. This essentially was the unit that MetaWater had developed using UVC LED and tested on drinking water. You can see somewhere between 200 and 1135 liters per minute on the drinking water. We were more interested in deploying it on the wastewater side and looking at the results. So we looked at both effluent, secondary treated effluent as well as filtered effluent in terms of reuse. In this particular case, Q beta was chosen as the circuit. And then on the wastewater side, we tried to test from about seven and a half to 208 liters per minute. So a lot of different tests on that particular unit trying to determine what the capacity of the unit would be on the wastewater side. This shows the kind of the moving of the columnated beam so the columnated systems manufactured by AquaSense are able to be deployed quite rapidly. And you can see the small unit on the left that allows you to move it quite rapidly from site to site in the olden days. And then adjust for any issues that might occur on site versus collecting a sampling and having to ship it somewhere. So we can take the unit, do the testing on site and then eventually have the bacteria analyzed locally without having to have to do a lot of shipping of systems. So very easy to be able to collect columnated beam data to essentially address wastewater issues now. So the results coming out of this were quite interesting actually, because we used Q beta. Q beta is a little bit more difficult to essentially use within a challenge organism. And so what we ended up having to do is work with the laboratory comparative studies between beta and MS2 to look at what that might look like if we convert it to the MS2. And you can see at a dose of 40, we were getting three to four log removal of MS2, which would match up relatively well to what one would see on secondary treated effluent in the United States, which is a really good removal efficiency. So again, real positive things in terms of being able to accomplish disinfection with UVC LED. On the building on that study, US EPA conducted another study, Dr. Helen Busey of their staff conducted a study looking at Legionella as a follow-up to the study of the first study that was done. Dr. Busey looked at four different Syria groups and three different UVC LED wavelengths, 255, 265 and T80, but looking at more of a point of entry point of use and essentially looking at 280 nanometers wavelength. So a lot of work in this kind of explains looking at a couple of different of the Syria groups and recognizing that the Syria groups, while we see tailing similar to what we had to do on the wastewater side as the organisms come up, we also see that we can't organize the Syria group and the Syria group items are very different. This was not expected as we move forward. So a lot of work being done, now trying to deploy UVC LED in a lot of different applications and another major health issue associated with Legionella. So this kind of looks at some of the movement. So taking a lot of that work and look at UVC LED, the benefits, we kind of highlighted relative to mercury field, mercury free and the selectable wavelengths, but the picture on the upper right side is a facility that actually is deployed in Las Vegas, Nevada with a capacity over 2 million gallons a day with that particular unit. So now you're able to get much higher flow rates out of these systems than what we expected and been looking at. So we moved from the point of use market into the actual deployment of small scale communities up to 2MGD and this shows the other deployment of the UV technology sensors. So now we have sensors that actually can measure the UVC LED coming out. So a lot of growth, not only within the technology, but also within the sensor technology to match up with the technology that we're working with. So this is the world's first and largest UVC LED system. And it's located in the United Utilities in the UK, 28 MLD. So relatively big, this was really good in terms of being able to, because of the compactness of UVC LED, they were able to install this particular system within the piping gallery of the UV system which allowed for a deployment within the system not having to build additional buildings. And they actually have had it validated. And so they met four log tryptosporidium at a dose of 22 mL per centimeter squared. So you can see we have the ability now the systems are getting much bigger. They're being able to be deployed within the drinking water much more successfully than in years past. So maybe just some final thoughts as we kind of wrap this up. Thank you, Gary, for all the wonderful work. All right, my phone's out here. I got a couple of extra slides. So UVC LED can be deployed relative to AOP as well. And so as we move into reuse and advanced contaminant, these particular systems on small scale can essentially be used to oxidize emerging contaminants. And so that's a lot of work being done in that particular area. And then just essentially, if it goes to the last slide here before I hit something. Anyway, right here, final thoughts. UVC LED deployment is growing fast. It's based on what they call high law which looks at both deployment of the UV, LEC wafers as well as time. And it's moving quite rapidly. I think over the next seven, the 10 years, the output of the systems will match within what we're deploying on the mercury vapor. In some cases, it's already there in terms of some of the technologies we're looking at. So UVC is growing faster. As you can see, it's growing larger. We're able to essentially deploy it on drinking water systems to meet a large number of microbiological removal. So that allows us to provide these sort of systems across the world relatively easily and simply allow for much more deployment and protecting public health. And as we looked into the future, the crystal ball tells us that there's a great future for UVC LED as we move into the future. So with that, I will turn it back to Chao. Thank you, Gary. Thank you very much for your wonderful presentation. I believe there will be more and more application for UV LED. I noticed there are some questions and comments from the audience. So we will reply them together in the Q&A session. So due to the time limit, let's move to the second presentation from Mr. Patrick Smith. Yeah. Okay. Mr. Patrick Smith from QWR Water Research Institute, Netherlands, have you given a talk entitled risk-based water quality management to reduce the disinfection and the DBPs in Netherlands? Patrick Smith is an expert in microbiology, water quality and health with over 20 years of experience in safe water supply. So WSP and QMRA of drinking water are his main activities in the Netherlands and abroad. So please join me to welcome Patrick to give the talk. Patrick, now the stage is yours. Okay, thank you Chao. I hope you can hear me. Yes, very clear. Okay, and see me. So thank you first of all for inviting me to join this conference and give a presentation. Now, I know the slides are a bit slow, so I hope it's moving. So I want to talk about how in the Netherlands we try to control disinfection byproducts actually by using as little disinfection as possible and maybe a short history of using disinfection and chlorine in the Netherlands because traditionally we have used it in the 1930s to disinfect surface water with brave point chlorination. But around 1970, Dr. Rook found out that trihalomethane are formed with this chlorine and that that would have a negative health impact. And therefore we started reducing first of all chlorine use in the treatment of drinking water. And from the 1980s onwards, we also abandoned chlorine residual as a preventive measure in the distribution systems. Now in the groundwater systems, we never used chlorine, but also for the surface water systems, we've now actually abandoned chlorine residual as a whole and we've reduced the use of chlorine or other chemical disinfectants in the treatment system. So I want to briefly explain how we do that and why. Actually at the moment there's only as an end disinfection only chlorine dioxide is used at a few systems where we're still looking for alternatives. I did push the button for the next slide. So why do we do implement chlorine-free systems? Well, we think that if you manage your drinking water systems well, chlorine can actually be an unnecessary measure. So, and in general as a concept, we don't like to add anything to the drinking water which is not necessary. Also, you find out that chlorine, if the water is chlorinated, it might actually give you a false perception of safety meaning that people will implement less safe behavior and be less careful when handling drinking water. Well, of course, a main reason has been that the byproducts may cause adverse health effects. And also the taste of odor is negatively affected by chlorine. I remember living in Delft where one part of the city was provided by water with chlorine and the other one without. And people would always go to the other side of the city to get their drinking water for drinking simply because of the taste and odor. Nowadays, you can drink chlorine-free water everywhere. And a final problem is that chlorine can also mask any contamination by inactivating E. coli. We're using E. coli to monitor if anything is, if there's a breach in your system. And if you have chlorine that E. coli might well be inactivated, whereas other pathogens are not. So the basic approach to water safety is saying, well, know what the threats may be and monitor for the right quality in your source water. Then, of course, you have to target your treatment to take care of those contaminants and produce safe water. And during distribution, you just have to protect it very well to prevent recontamination. And in our case, we don't add chlorine to mask or protect for any contamination that may happen, basically because we want to prevent that contamination from happening in the first place. And if we do that, then we should be able to provide safe drinking water. Actually, there's two main frameworks that provide water safety at different levels. For making safe drinking water, there's a legislative requirement in the Netherlands to do a quantitative microbial risk assessment, or QMRA, which I will explain in a minute. And for protecting your water during distribution, the hygiene codes that we use provide a basis or a framework that allows us to do that. So I'll go into more detail for both of them. So the first challenge is to produce safe drinking water. Now in the Netherlands, as I said, there's a legislative requirement to do quantitative microbial risk assessment, certainty for surface water systems. Through that QMRA, you have to demonstrate that your risk of infection is less than one infection per 10,000 persons per year. Now, if you do the calculation, you might find out that corresponds to about one pathogen in a million liters of water, which also immediately gives the impression that it's impossible to monitor for these pathogens in water. So the image below shows you a general approach to QMRA, but I'll explain that also in a minute. Now, why do we want to do this QMRA instead of just monitoring for E. coli? Well, as most of you know, we are using E. coli as a indicator organism because it's present in high levels in wastewater or in deeply contaminated water and then the human gut, and also in animal gut. So if you find E. coli, you're actually quite certain that there's feces in your water and therefore there might also be pathogens. Now, one issue with these indicator organisms is that they have very specific characteristics which determines their survival in the environment, their survival through water treatment. For example, the viruses are very small, are able to get through finer filters, they're more persistent in chlorine. Protozoa are especially very persistent in chlorine as we noticed through several outbreaks where protozoan cryptosporidium or Giardia caused big outbreaks despite the fact that there was chlorine in the water. So rather than just looking for E. coli in the drinking water, we want to really target our treatment systems for these various pathogens that all have their own challenges. So in general, we do this for what we call index pathogens which are the most persistent or the most challenging pathogens that we know, at least for the drinking water situation in the Netherlands which would be enterovirus, compiler bactocryptosporidium and Giardia, although at the moment we're also keeping an eye on other possible emerging pathogens such as adenovirus especially because adenovirus is quite persistent against UV disinfection. So how do we perform then this legal QMRA? Well, first of all, we have to know how many pathogens there are in our source waters for. So to do that, we monitor pathogens in source water once every three or four years to estimate how efficient treatment is. We monitor indicator organisms before and after the treatment steps which will work during the first steps of your treatment and then translate that to the log reduction of pathogens that you can, that have similar behavior. So, and we just talk about log reductions because we know that we need a lot of reduction of pathogens, thank you Isabella. So two log reduction means 99% removal. So a four log removal means 99.99% removal. So that is why we prefer to talk in log units. Now, if we don't have indicators anymore in our treatment system, we need to use process models or pilots or other ways to then finally calculate the number of pathogens that we have in drinking water. And when we know how much water is being drunk by people, we also know how many people may ingest a pathogen and using those response we can also find out what chances of them getting an infection. And that has to be less than 10,000. So next slide please. So how do we use this? I mean, what has been the impact of this, this cumulative was implemented legally in 2002. Practically, we really started using it in 2005 and by now we've had a few cycles. Well, this graph shows you for an example system where the red bars indicate the log removal required to meet 10 to the minus four infection targets. And the colored bars show you the log removal that is being achieved by different treatment steps. And you can see how the different pathogens actually respond differently to different treatment steps. And now also the challenges for different pathogens are different. In this example, the system would be non-compliant. And with the knowledge you have, you can then see which process you would need to add to actually meet the targets. You can go to the next slide, please. So in this case, if we would add UV disinfection it would add enough disinfection of all the other pathogens of all these pathogens to meet the targets for all of them. Similarly, you can see that different systems in the Netherlands also apply different approaches to achieve this log reduction. Again, this graph shows you in red bars the required log reduction, but in this case they are all for cryptosporidium but it shows you 10 different systems. So you can see that some systems have dirtier waters than others requiring somewhere between four and almost seven log reduction of cryptosporidium. And you can also see how the different systems all apply different treatment steps to actually achieve this log reduction. And you can see some larger bars which would be mainly through soil passage where with our infiltration systems in the dunes you can get a lot of log removal. But you can also see that there's other combinations where this is achieved. Now a very nice example of how you can use cumulative target your decisions or your treatment system or to support decisions is what's with the Amsterdam waterworks where in theory the ozoneation that they are using to break down organics would also inactivate B. coli up to eight or 10 logs in theory because that's the relationship that you get from lab experiments. Now we know that in reality mixing et cetera is less ideal. So we use a continuously stirred tank reactor model to estimate or to model the log removal of organisms. But when we did extensive monitoring we actually saw that these could still sometimes find a coli after ozoneation and that the expected log removal was not achieved at all. So next slide. Through modeling and further investigations we saw that the whole water mixing that we assumed would take place was not taking place in the ozone contactors and there were also small leakages et cetera. And we also found that there's very little efficient mixing with ozone. So by implementing quite basic and but very efficient improvements both the mixing through a static mixer of ozone and water was improved but also the flow through time through the contactors was much improved which led to a lot more disinfection than initially with at the same dose and therefore also at the same disinfection byproduct production from ozone. And because the QMRAE showed that then they were actually overshooting the required log reduction the Amsterdam Water Works decided to reduce the ozone dose still keep enough disinfection but also reduce any overall disinfection byproduct production even though initially it was already under the standard you know a lower level is always better and also more efficient. So I think that's always a very good example of how you can balance the two objectives of disinfection against low disinfection byproducts. This is a slide that demonstrates how the different institutes in the Netherlands work together through this QMRAE cycle. So on the one hand there's the drinking water industry with the utilities themselves their water laboratories and KWR where I work which is the research institute for the drinking water companies. On one hand and on the other hand there's the government with the inspectorate and the RVM who is the national institute for public health and the environment that advise the inspectorate. And through all phases of this cycle different entities work together to make this this risk estimate and get a continuous improvement cycle going. Now that we've produced safe water we also have to protect it during distribution. So there's of course a couple of basic rules. Physical integrity of your distribution system is important. You have to constantly pressurize it so any leakage will go out. Also prevent negative transients when you need sealed distribution reservoirs the distribution reservoirs especially are very sensitive because they are not pressurized. And at the connexious connections or industrial connections you really have to take care of backflow and cross-connecting prevention. And when you work on the system you have to have very safe operations and maintenance. That is to prevent any recontamination. The second challenge is to prevent growth by having bio stable water in your system but also not adding any growth promoting materials in your system. And we are able to do it this way because we can keep the temperature so far under 25 degrees. How do we achieve this physical integrity of the network? First of all we have a very good maintenance program keeping the leakage rate or non-revenue water really below five and a half percent. By implementing water hammer vessels we also prevented the occurrence of negative pressure trensions keeping enough backer power for the systems to prevent these trensions. And there's some pressure monitoring going on in the network and of course we're lucky that we are in a very fat country so we don't have a lot of issues with very high or low pressures. Backflow prevention is really implemented in our legal requirements obviously for industry but even at the household level all water meters are provided with a backflow prevention and even appliances that are connected to the drinking water system have to have backflow prevention. Also by having regulations at various levels of building regulations we can implement this. Next slide please. Then safe operations and maintenance. As I said we have very strict hygiene codes for when you work in the distribution system because not only the part where you're working where the leak is or the repair is vulnerable but also other areas where the pressure is taken up. So there's very strict measurements on that and because we don't use chlorination we basically flush the systems and then check whether they're clean. We also do not mask any contamination by killing off E. coli and keeping the pathogens in. Then the bio stability of course is a big challenge and because we see risks of optimistic pathogens like Legionella might grow in there we also get odor and taste complaints or color complaints. So we pay a lot of attention by producing biostable water with a low assimilable organic carbon content. We keep the temperature there's a requirement to keep it below 25 degrees and there's still maybe some challenges with other interests in the underground but we can keep it going. And yeah as I said we use biostable materials and try to keep our networks clean by also just introducing very little solids into it. So I think this I get to my resume now on the next slide. Yeah, so we use cube or A basically to balance disinfection against the BBB production. So saying that safe water is when it's safe when it's safe enough. And when we have a way we try to use other treatment processes that do not produce disinfection by products but the ones that do actually mostly have other goals also by breaking down micro organics or reducing AOC. Yeah, we optimize then the non-chemical treatments for lock reduction. And we try to keep all risks in place from source to tap through design, through operation, through procedures through monitoring it's a big package that has to be in place to keep it safe. So even though we don't officially use water safety planning we do cover all those steps which has been demonstrated in our work that we did with our RVM by a health on the bear. And yeah, because we have a good biological stability we can also, that's one requirement why we can have chlorine free distribution. So thank you all, I think you can go to the last slide which means, yeah thank you for all your attention and I wish the next speaker good luck. Thank you Patrick for your very excellent and informative presentation. I believe the approach in the Netherlands is very inspiring for us although it's a quite a different approach. So due to the time limit let's move to the next presentation given by Ms. Maria Houssé-Fauré from the Catalan Institute for Water Research in Spain. Her topic is the Disinfection by Products in the contact of global change. Maria has been working on Disinfection by Products since 2008. She is the coordinator of the new Horizon Europroject into DPP in noted tours to control organic matter and the DPPs in drinking water. Please join me to welcome Maria to give the talk. Maria? Hello, yes. The studio is yours. Can you hear me well? Sure. I think I may have the same problems with passing the slides as Patrick had, so I'm not sure if it's not enough. Maybe it's a bit like I help you. So if you can control. Yeah. So first of all, I would like to thank you and the organizers for having invited me for this seminar. So I'm going to talk about Disinfection by Products and to start, I will give some very basic. So we know most of us, we are very familiar with this topic, but for the newcomer, so Disinfection by Products are side effects or half of those compounds that can be formed when disinfecting the water, mostly with chemical agents. And these are the table I show the ones that are included in the European Drinking Violence, trihalomethane, halocetic acids, and bromate chloride and chloride. And this is just the very tip of the iceberg because organic matter reacts with disinfectants to form many of them. More than 700 have been described, but there's still many more. So next slide please. So these DVPs are important also because they are present at the microgram level concentration, so that's different from the most of the contaminants we have in water, which are the nanograms per liter level. And as I said, more than 50% of this halogenated content, so this total organic halogen is still unknown. So we know very well that the toxicity increases as per the iodinated Disinfection by Products are the most toxic one, followed by the brominated and the chlorinated, and in general the nitrogen containing DVPs are more toxic than the carbon-based DVPs. And the most toxic DVPs that have been discovered so far they are not still regulated, such as NBMA, Dibromocetonitrile, Iodosethic acid. So here are the typical fuels of showing the toxicity, produced mostly by the laboratory of Dr. Pleva, where the difference in the toxicity that I just mentioned is shown, but also in the right-hand side, you can see a typical concentration of DVPs in water on the top, and how it translates on the toxicity. So for example, in orange are the halonitrile that correspond to a 10% in concentration, but if you have a look to the toxicity, that's pretty much 50%. So how are we exposed to DVPs? So although the drinking water directive, the states that all members should take the measures necessary to ensure that DVPs are kept as low as possible without compromising this infection, and some of them are regulated as I just mentioned, we are exposed through ingestion, inhalation of derma absorption if the water is disinfected when using it or when drinking it. So minimizing the formation of DVPs is an overall public strategy, mostly because these have been shown that these DVPs are genotoxical cancerogenic. And we have to balance these risks of acute, due to the microbial risk with the chronic risk of DVP presence. So the formation of DVPs depends on, mostly on the disinfectant that is used, that in other parameters too. And here in the table are the most typical disinfectants and the related to DVPs. And chlorination is the most common disinfectant used in Europe subsequently. And trihalomethines are the ones that are regulated and were regulated in the previous European directive. So there is a lot of data on trihalomethines across Europe. And that has allowed the epidemiologists to study the relations between trihalomethines and cancer. And they have the health report that the core levels are related to a significant burden of blood cancer. DVP exposure has been also associated to the reproductive and the pregnancy outcomes, although this evidence is less conclusive. Next slide please. So this is just to show that the results from the right to water initiative. So this was a public consultancy on the trust in tap water. So it was shown in Europe that only 50% of the people that answered these questions were drinking water directly from the tap. And when they were asked which were the parameters that were not considered and that would be important, DVPs were not there even though that were listed but they are not in the main one. So they would be in this order 20%. But what we believe is that the improvements in operational monitoring and human optimization to achieve the quality goals related to microbial protection and DVP reduction will maximize public health protection for the full range of water quality conditions. So if trust in tap water increases, there will be a reduction of water water expected which is very environmental hazard. Next one. So now this was a little bit of the introduction but the main topic of the presentation was why DVPs will become even more relevant in the near future and what are the main research challenges and opportunities involved due to the global change mostly. So in the figure on the bottom, I will be showing that through the presentation that basically it gives the different aspects of DVP research. And the first one is effect of global change that includes water scarcity, increasing temperatures, increasing water demand, water table depression and so on. So we go to the next one. So water scarcity, we don't know we are in a scenario where the results show here in the, in the slides on the left-hand side is the current situation which means it's shown that 22% of the European territory is in a warning condition right now and 27 in another condition. And in the right-hand side, we see the projected change in annual and summer precipitation from 2021 to 200. So that as you can see, this is going to be very extreme and the decrease in this rainfall will, or the water scarcity will decrease the ability of surface water bodies to absorb the impact of wastewater emissions. But on the other hand, there will be also an increase for water reclamation. So all these means that there will be a new pool of DVP propulsors that are different to the traditional drinking water DVP. As an example for the regulations. So in this table, I'm comparing the European directive with the US EPA and the values from the World Health Organization and a RISACO water that's from Australia. But what I want to show is that the values when we talk about RISACO water normally are more stringent and also new species appear like NDMA. So and I'm going to talk a little bit about NDMA because this is a DVP that it's relevant at very low concentrations in the nanogram liter level and also is important when there is wastewater. So for NDMA to reform, there are specific conditions. So there has to be chloramine or ozone occurring in the presence of ammonia that if there is wastewater, it's a precursor that will be there that having said so global change will mean that there will be because what I said in the previous slide that there will be high concentration of NDMA propulsors in drinking water sources and that needs to be assessed. So in the next slide, I'm showing the results of a study if you can change to the next year of a study with it in Barcelona that's the Yobrega River is one of the main catchments used to produce drinking water in the city of Barcelona. So we work with the Catalan Agency of Water to investigate where there were many parameters investigated in a water reuse scenario. But what I'm going to show now it's only the results of NDMA. So basically there was this trial that was conducted during seven weeks where wastewater was treated in a tertiary treatment and there was disinfected with chlorine or not disinfected. So the four first weeks where the water the tertiary treated water was emitted to the river and then this river 8.5 kilometers downstream was used to produce drinking water. This was done without chlorine during four weeks and then three weeks was done with addition of chlorine because there was ammonia in this tertiary treated effluent there was chlorine information. So if we go to the next slide we can see how the NDMA and how the NDMA precursors where being how the concentration was changing during the trials on the left hand side we can see the concentration of NDMA. And we observe that the river before discharge of the tertiary treated effluent contain very low concentration of NDMA even though this river is already compromised with a lot of industry and wastewater discharge around it but it increased the NDMA formation as soon as the chloramine was forming the effluent when chlorine was added in the presence of ammonia. Nevertheless, NDMA was removed in the river during this 8.5 kilometers mostly due to phytolysis and dilution. And we observe in the drinking water produced to Barcelona a maximum value of 7.39 grams liter. Regarding to the precursors as the concentration of the NDMA precursors was already quite high in the river that was because of the fact of reuse that it's happening already in that river per se. But once we the tertiary treated was put into the river the concentration of precursors increased up to 700 nanograms liter. There was also a natural attenuation of these precursors and the maximum concentration was around 12.5 nanograms liter in the drinking water. Another apart from water scarcity the other factor that is going to affect the DVP formation is the increased temperatures and especially the modification. So in this increase in temperatures is going to modify the hydrology of catchments and the biochemistry of soils and it will increase the trends of this over organic matter concentration in run-offs. It will also change the thermostructure mixing of regimes in lakes and it will increase the magnitude of frequency of extreme events. So this means that we need to be ready and to adapt source protection strategy and adapt treatment technology to overcome these new challenges that they are already here. Another thing is that there is a seawater intrusion also and this what will happen is that the concentration of bromide and iodide in drinking water source will increase. So therefore we need to develop also treatment strategies to increase the removal of iodide and bromide in water. You remember at the beginning I mentioned that brominated and iodinated are more toxic than the chlorinated analogs and that's mostly because of what I'm explaining here. I don't want to go too much into detail but basically bromine reacts faster than chlorine to form brominated BBPs which are more toxic and bromate which is toxic is the formation of bromate is undecided. This happens with ozone for example. But iodine for example will form iodinated BBPs which are the most toxic ones if not oxidized to your date because your date is not toxic. So in the presence of chloramines for example because they are not powerful enough to oxidize iodine to iodate they will be forming iodic BBPs. And for example in this graph where I showed the toxicity effect of this iodocetic acid which is the most genotoxic BBP identified to date. So here I think that how we are working we work with another catchment not the Yobregat river that I mentioned earlier but this is the third river and the system of three reservoirs that are connected in line and provide also water to Barcelona to the other side of Barcelona let's say another cities. But basically what we investigated here in a context of European project was the concentration of precursors of the system how was changing during the seasons and also in the spatial so depending on the situation of the catchment and also in the depth depending on what was the water being withdrawn. And what we're doing right now also in the context of another project one APN is trying to model and to predict these changes in the catchment to be able on one hand to predict the precursor's concentration at the entrance of the drinking water treatment plant and later on and in collaboration with our friends from Lekia, UDG we are using their models that they already built to be able to predict the BBP formation at the plant. So what are the BBP precursors and we can mostly mention the first three so these organic matter not organic matter so the conventional source of BBPs then bromide and iodide will change the speciation of the disinfection by products and now effluent organic matter which means that will generate hallucinated transformation products. Cristina Postigon susan who has already published a few years ago this review where they were showing how the pharmaceuticals were good precursors for many BBPs and in fact, we've been working also in NICRA trying to identify which are the main fractions related or how trying to identify the precursors which were the transformation products mostly formed during chlorination and that were responsible of the higher toxicity we've been doing that with effect direct analysis and that's a very, very hard work and time-consuming that we try but in the next slide I would like to show how is our approach so what we want to work or how we want to work is not trying to target the specific contaminants but just to do a holistic characterization of the organic matter and we try to do that with orbitrap mass spectrometry so in the past the characterization of the self-organic matter was hard mostly because of low resolution instrumentation but right now this field is developing very fast and in that field which is very nice in my opinion you can see how the methods for the characterization of the self-organic matter are related depending on the complexity for implementation with the specificity of the analysis so there are three different main types of analysis so isotopic, optical and molecular and here we're working with the lower range of the molecular ones which is this orbitrap so with these tools with MS high resolution mass spectrometry what we obtain is this kind of signal that's a van Krevelen diagram where we plot all the signals that are coming from the orbitrap in a diagram showing the oxygen to carbon ratio to hydrogen to carbon ratio and this was initially used for characterization of petrol and fuels and later on for the trying to understand the origin of the natural organic matter and more recently has been used to investigate the treatment and the source of contamination so basically what we are using is this region so you can divide the diagrams in different regions and there are different ways of analyzing them but we're using the one that is in the right hand side in this immunology and oceanography methods and if you go to the next slide the regions that we are using are the ones selected here in blue and this is an example of how we visualize the results so this is the same study I was talking before about the Jovrega river and that's comparing each of these boxes corresponds to one sample before and after the treatment so in blue you can see what is in red and in yellow what is depleted in the treatment so the first column corresponds to the samples that were during the trial when the treated water was not disinfected with chlorine and on the second one during the weeks that the treated water was disinfected with chlorine and we can see changes such as in green this reaction of chlorine that you can see the loss of this signature and also in red when we were comparing the P3 so the inlet of the drinking water treatment plant to the drinking water itself so we could see the removal of aliphatic and aromatic compounds but also the production of more oxidized molecules due to the ozoneation that this plant uses so what about this infection strategy? So I already showed the conventional treatments for chlorine, chloramine, ozone, chlorine dioxide and UV disinfection but there are many more and that's a very big field so UV chlorine based systems other advanced oxidation processes organic acids mostly for wastewater electrochemical systems and so on and also novel engineering solutions so how to mix the reagents for example and I believe that there will be a seminar in the next series of this one that will focus on these disinfection strategies. The other interesting part and I'm about to finish so it's how we monitor and yet these DVPs are monitored at the drinking water and also at the distribution but it's important to obtain real time source to supply information so that we can know if there are problems and be able to react on time so there are different sensors these ones are the optical sensors with UV or fluorescence chemical sensors already using many, many utilities biosensors or bioreporters that would give us an indication of the toxicity and also portable spectrometric sensors so I believe that we will need a combination of some of those and it's important to understand how many where to place them and what are the prediction capabilities I didn't want to forget that so non-target screening is a field of having a major influence in characterization of contaminants in water and for DVPs it can be also used but this is the typical sequence of how confident are we with identification of a non-target compound and basically the problem with DVPs is that there are no standards or it's very difficult to find the standards for DVPs so reaching the level one it's very hard although there have been already published in this normal network a very first list of DVPs where you can do a suspect screen for those. Next one so that's basically our vision so by means of different measurements mostly we are putting a lot of effort in MS but also others like fluorescence or LCOCD and data treatment we want to predict what is happening so using the precursors we want to be able to know what will happen when different disinfectants are being in place so that the optimization can be reached before the plant is here we can do this prediction we're working on that in two different projects but we want to... so we go to the next slide we're starting this very exciting into the project in December where we are 13 partners plus two international ones and we will tackle some of these issues and we hope to have four years of very interesting research going on and with that I go to my key home messages so basically millions of people are daily exposed to DVPs for ingesting inhalation of the MS solution when drinking or using municipal water so that's a reality that the reduction of DVPs should not compromise acute microbiological risks we believe that the improvement in operational monitoring and treatment optimization to achieve water quality goals related to DVP reduction will maximize public health protection for the full range of water quality controls so we hope that there will be there should be an increased public trust in drinking water and a reduction of water consumption the global change will bring new challenges but also opportunities for DVP control so based on what I say water scarcity and increased water demand increasing temperatures see what the intrusion of extreme events and that new tools to predict DVP formation can be useful for treatment optimization in a context of water global change so that was my last slide and I would like to thank you for your attention thank you very much Maria it was really very interesting presentations and we saw that you did a lot of work in wastewater also in drinking water and now I will go to the questions there were a lot of questions but our panelists were active they answered most of the questions and they also are still answering I will start with you Maria since you just finished with your presentation there is a question from François Bernadis he says how to measure this DOM in drinking water production directly your results are in nanograms per liter of DVPs but this must be from lab analysis can we use typical UV-254 or wider optical spectrum sensor direct inline to detect this DOM as indicators of potential DVPs in the UK there is still a lot of chlorination your answer? yeah in Spain too a lot of and it's a legal requirement to have chlorine in the drinking water so we have still a way to go until we are in the Netherlands situation but so far so we have to deal with them and this DOM so no you cannot measure them directly so you need to do an extraction eye for limitations of the time today I couldn't go into the details but you do an extraction of this organic matter and then this extraction is no well it depends obviously in drinking water you have to extract a lot of water to have a signal in the orbitrap and this is to measure the precursor so DVPs is a different extraction and a different methodology so yeah these are obviously once the water is disinfected and DVPs are extract form you extract them and you analyze them and you get in the lab the results of DVPs but what we want to look for is for the connection so by measuring the DOM are we able to predict what will be the DVPs form and yes there is a lot of work on UV-54 or SUBA mostly and the relation of those with mostly trihalomethane and yeah you can use them and it's a pack for drinking water without wastewater or without any new precursor so that can give you an idea but also the problem is that what we are trying to understand in the community is like trihalomethane and halosedicates are not our indicators but are not the responsibles for the most of the toxicity of these compounds or these family of compounds so these others that are generated at much lower concentration and that are not related to trihalomethane formation such as NDMA for example which has a total different mechanism so cannot be measured the precursors cannot be measured with these new simple measurements Thank you maybe another question from Jamping from China you mentioned removal of iodine and bromide what type of removal technologies do you refer to that can achieve effective treatment without causing iodine and bromide related to DPPs? Yeah there are different so actually in Catalonia we have in the Obregat too we have one of the major drinking water treatment plants using traversal electrodialysis so this is one but also different absorbance so yeah it's not I'm not super expert in that field but there has to be yeah we have to achieve solutions to be able to remove those One question from the same person to Patrick what is the typical retention time in the water distribution system in Netherlands was the regulated monitoring parameters and monitoring frequency for this distribution system to prevent biofine growth without having chlorine residuals in the distribution system we're not hearing you Patrick Patrick you need to now we can So typical residence times are in the range of several hours to days and some of the systems can go up to a week I think even travel times until the now the requirements for monitoring biofilm growth there are not really requirements but water utilities do monitor for biological growth through some parameters coliforms may grow so if you get that problem the name doesn't pop up in my head but there's a few of these growth organisms that we monitor but it's the drinking water utilities themselves that actually take care of that if you're talking about Legionella that's really a plumbing system issue and for that there's legislation in the Netherlands that, well not houses but common high-risk buildings like sports facilities, swimming pools, etc. they have to have a Legionella monitoring program and management program which I don't know by heart what the number of monitoring moments is Thank you Does that answer the whole question because I didn't see the question Yeah, okay, thank you and Gary, the same person also asked you something the general approval process for using UV lead in drinking water, wastewater plants are there as safe as traditional UV are there any guidance related to approval like we have UV guidance I think it's still very new but you know better That's a very interesting question I appreciate it let me see if I can answer in a couple of different ways and I can only draw on what experience I have I generally work on the wastewater side so we do have within the United States each of the different states have regulatory bodies that have requirements relative to UV at this point we would be looking that UVC on the wastewater side should be comparable to what we've been seeing with UV that's been deployed essentially at wastewater facilities over the last 30 or so years now that we can kind of stop there if we go to drinking water there are a number of regulatory bodies US EPA, the Environmental Protection Agency has requirements each state has requirements there are various different types of requirements associated with drinking water and a lot of work is going on right now to work with the regulatory agencies to determine a lot of the different issues associated with reliability and redundancy and issues associated with power outages and how those that we know about relative to traditional mercury vapor UV systems and how those are applied to UVC LED you know what our challenge right now the sum in some respects is as far as I know there are only very limited number of UVC LEDs in kind of almost a full production type applications versus point of use applications and point of use applications in the United States are all governed under NSF so there's a lot of different let's say there's a lot of different regulatory factors playing into this particular scenario so I'll just say that's an ongoing discussion that we're having with a lot of the regulatory agencies right now Yeah, I will say thank you now maybe another final question and this one is to you do you know of any UV LED used as a post treatment in seawater dissemination systems? Gary? I don't know of any I mean, I know that let's say if we're talking specifically about UVC LED I don't know of any I would have to do some research on that I would suspect on the traditional UV systems there could be ones being used on that type of application so I'd have to do a little bit more work on that particular question to give a Okay, I think as the technology will advance it will be like UV, UV AOP systems after desalination and everywhere, why not? Okay, thank you with this we terminate already the presentations and now we have also some final polling and one minute you want to put this polling Yeah, the question is very important because it's would you like to join the IWA specialist group of this infection? So you can say yes or no or would you join the next webinar which is on the 7th of December? It's on emerging disinfection technologies for water and wastewater treatment it will be very interesting more practical and also academic so you can just answer, thank you So with this we just finish our webinar and thank you very much for all panelists for your effort and also thank you very much for all the audience to be present, attendees thank you very much thank you for your contribution