So, welcome, I'm Maggie Montgomery from the World Health Organization. I'm here today to talk about the evaluation and the validation of household water treatment technologies. So, I want to thank Dr. Johnston for inviting me. And let's get started. So, there's going to be three main things I'd like to talk to you about today. The first is why is it important to assess the performance of house water treatment. And I'll talk just briefly about the fact that house water treatment, the main benefit is health. And so, it's important that we know how well house water treatment technologies remove pathogens so we have some indications of the protection of health. And second is I'll talk about the WHO global standards on the performance of house water treatment, and give a bit of background about how they were developed. And lastly, I'll talk about what WHO is doing to implement these standards. Specifically, discuss the WHO international scheme to evaluate house water treatment technologies. There's two main reasons why it's important to assess the performance of house water treatment technologies. The first is to understand if these technologies are achieving the objective of improving health, which requires first of all that they remove the pathogens that are causing the diarrheal disease in a specific population. Now, in some cases, we know specifically which pathogens are causing the disease. For example, in a cholera outbreak, it's very well known that is the bacteria vibrio cholera that is causing the diarrheal disease. But in other cases, for example, people living with HIV/AIDS who are much more susceptible to diarrheal disease, it could be a suite of pathogens that are causing this disease. And in all cases it's important that the devices that are being used with this specific populations are removing the pathogens we are most concerned about. And if we don't know exactly which pathogens those are, it is prudent to make sure that these devices remove a suite of pathogens. The second reason why assessing house water treatment performance is important is that governments, especially as well as implementors and funders, need to know that the devices that they're investing in are achieving the aims that they set out to achieve. And this requires a vigorous evaluation of house water treatment. Now, in many countries where house water treatment is most needed, i.e., where the water quality is poor and the diarrhoeal disease burden is high, governments don't have the resources nor the capacity to do such evaluations. And lastly, I just wanted to emphasize that while today's talk is going to be focused on the performance, realizing the health benefits from house water treatment also requires that users correctly and consistently use house water treatment when their water quality is compromised. So, in order to facilitate the evaluation of house to water treatment, WHO came up with global recommendations on how to asses performance. Now, these global recommendations, the goal is to protect the health of the users and also to ensure that more house water treatment products that achieve minimum performance standards are being distributed and used to those that most need safe water. Now, specifically, the recommendations, look at three main classes of pathogens, and these three classes of pathogens, I know you've already talked about with Dr. Johnston, and hopefully you understand well at this point. But these are the three main classes that cause diarrheal disease in humans, and they are viruses, bacteria and protozoa. From these three classes of pathogens, we derive targets. And what I mean by targets, we derived what are the minimum amounts of removal that need to be achieved in order to achieve a certain minimum amount of risk in a population? Now, these targets were derived based on what has already been done in the WHO guidelines for drinking water quality, and these guidelines use what is called quantitative microbial risk assessment. So, quantitative microbial risk assessment are basically models that allow us to predict what will be the health consequences in a population if they ingest a certain concentration a pathogens with a certain frequency. So, for these models, we obviously had to pick specific pathogens within each of these classes of viruses, bacteria and protozoa to come up with an estimate. Now, from that estimate, we also decided what was the minimum amount of risk we're willing to accept. And I'll talk about that in the next slide, that allowed us to then develop our removal targets. We also use a tiered approach. So, rather than setting one very high bar for house and water treatment, we recognize that even devices that maybe are not the best but do provide some protection and even limited protection, can have a very significant impact in populations where the concentrations of pathogens are very high and the diseases burden is very high. So, this tiered approach was done to acknowledge the fact that even lesser performing devices can still have an health impact. It was also created because we recognize in some situations it's just simply not economically feasible to have the very top device, and cheaper, and perhaps less protective, devices can still have an important impact. Lastly, the recommendations provide some information on the laboratory protocols, or how you would actually go about doing experiments to test the performance of these household water treatment devices. Before I present the performance standards, I want to just to briefly highlight what log-removal is and what it actually means when we're talking about concentrations of pathogens. So, let's say, for example, we start with 100 cryptosporidium before we put the water through a filter. We put the water through the filter, and after filtering we have 10 cryptosporidium. So, that means we've removed 90 cryptosporidium. Pretty simple math. We can equate that to a percentage, and we say we have 90% removal. And that is equivalent to 1-log removal. Now, let's say that with that same source water, we still have 100 cryptosporidium. But after filtering, we use a better filter, more highly performing filter. We only have one cryptosporidium remaining in the water after it's been filtered. This means we've removed 99 cryptosproidium, or achieved a 2-log removal. Assessing performance. So, based on the quantitative microbial risk models I spoke of earlier, we were able to develop specific reduction targets for each of the three classes of pathogens based on allowable risk. Now, the most stringent requirements were the category where we're allowing the least amount of risk in a population, specifically 10 to the negative 6 DALYs per person per year, is the highly protective category. Now, in this category, devices must achieve at least 4-log removal of bacteria, at least 5-log removal of viruses and at least 4-log removal of protozoa. Now, you'll notice that for the viruses, the log reduction is even greater because we know viruses are more likely to cause infection and disease with just a single virus compared to the other pathogens. Now, for the protective category, we're allowing a slightly less conservative risk in the population. It's 10 to the negative 4th DALYs. And consequently, the Log removal doesn't have to be quite as high. Two, at least 2 for bacteria, at least 3 for viruses and at least 2 for protozoa. The final category, limited protection, are actually technologies that achieve at least two of the targets for the classes of pathogens in protective. Now, these may be technologies that do really well for two of the classes, but not on the third. And in populations where we are very sure of the main pathogen that's causing disease, they could be a very effective option. Now, for each of these classes of bacteria, viruses and protozoa, we had to choose one specific organism to represent the class as a whole in order to develop the models and come up with the specific log reductions. So, we chose pathogens that we know in human populations do account for a significant proportion of diarrheal disease. And bacteria, specifically, it's campylobacter, virus is rota virus and protozoa was cryptosporidium. Now, what are some examples of technologies that are already being used in the field and have been tested quite rigorously in the lab that meet these performance standards? Well, for highly protective, the number one technology, or actually it's a method, is boiling. This is by the oldest method that we have, and it's very efficacious in the removal. But the problem with boiling is recontamination, so that's an important issue to consider. Ultra filters, I know you've just learned about filtration, are also very efficacious, as well as a combination of approaches. So, you may do filtering followed by chlorination in order to achieve a higher level of protection. In the middle category, we have membrane filters as well as many flocculant disinfectants. And lastly, in the limited protection category, some examples include chlorine, which we know is very effective against bacteria, especially cholera, but fairly ineffective against protozoa, especially cryptosporidium. Ceramic filters and some biosand filters also fall into this limited protection category. Now, you may wonder why did we have three levels of performance. Well, there's two main reasons. First of all, we know in populations where there is a high burden of diarrheal disease and a high load of fecal contamination in the environment, and therefore in the drinking water, even devices that achieve the protective or limited protection level could have a significant impact on health. We also know that in many of these areas, economics and costs are huge barrier. And sometimes the highly protective devices may also be cost prohibitive. So, we don't want to prevent other, maybe lesser performing but still having some protection devices, such as protective and limited protection, from reaching those populations. Nuts and bolts of testing. So, how do we actually test these devices, and what kind of water do we use to see that we're actually achieving a certain level of performance? Well, we want to really mimic the types of waters that we find in the environments and the communities that would use these devices. So, in order to do this, we've developed two types of waters. The first is a general test water. Now, this is water that represents high quality ground water or rain water. It will have a very low turbidity so there's not a lot of particulates in the water. And a fairly, a temperature that is fairly consistent with the ambient temperature. It is the non-stress phase of testing, so it's not technology specific. We also, though, want to see how these devices will perform when we have really turbid or contaminated water, like this river you see here in Lao. Many people are still using surface water, and this challenge water is supposed to represent such surface waters like rivers or ponds, so the turbidity is very high as well as the TOC. Now, this is the stressed phase, challenge phase of testing. And depending on the different product, we may vary the conditions as different products will fail under different conditions depending whether or not it's s filter or a chemical additive or some combination of approaches. We've talked about why it's important to assess the importance of house hood treatment, and we've also talked about the global recommendations on performance of house water treatment. The third thing I want to talk about is the WHO scheme to evaluate house water treatment technologies, which is specifically how WHO and governments are working to implement these recommendations. There's two main objectives to this scheme. The first is to promote and coordinate the independent testing and evaluation of house and water treatment products based on the WHO criteria. Now, I would like to stress the word independent because often we find that laboratories, especially in particular countries, do not have the ability to provide independent and objective evaluations. The second is to support national governments in building the technical capacity of research institutions. So, improve the ability for governments to assess local products, to do complementary testing in the field of house and water treatment products, especially after they've been in use for some time. And this is all linked to WHO's greater work in water quality on applying the WHO guidelines on drinking water quality. In summary, I'd like to stress two main points. First, hopefully by now you understood that the assessment of house water treatment performance is important for protecting health. Now, I spoke only about the microbiological performance of house and water treatment. The chemical performance of house and water treatment also is important and is something that WHO recognizes needs to be addressed, but hasn't been developed yet in terms of a set of global guidelines. I also want to make sure you leave by remembering that it's equally important that these products are used correctly and consistently by the groups that are most at risk for diarrheal disease. So, young children, people with HIV/AIDS, those in emergencies or in cholera outbreaks are just a few examples. Secondly, the WHO international scheme to evaluate house and water treatment aims, first of all, to inform and to provide objective information about performance. But it also hopes to spark innovation. And already we're seeing that manufactures are trying to develop technologies that not only are highly protective, but also are low cost, easy to use and can be easily distributed in places where water quality is at its poorest. And lastly, the scheme aims to build capacity. So,some day in the future, we can work ourselves out of the job, and governments themselves can evaluate and regulate house water treatment technologies. So, we'd like to thank you for your attention. I'd like to point you to some additional resources and information. First of all, if you want to read the performance recommendations I spoke about, you can find them online at this web address. These are the recommendations. Also, if you want to learn more about the scheme, you can go to the website that presents all the information about the scheme, the related protocols, the laboratories. And lastly, if you're just interested in house and water treatment more generally, I refer you to the WHO/UNICEF International Network on Household Water Treatment and Safe Storage, which is working on a variety of issues to try to make sure household water treatment gets to where it's needed and used by those most in need. So, thank you.
