By Eva Jiménez, PWW Honduras Intern
Last July, when a research team from Water for ME, the University of Maine, and students from Bangor High School and Bowdoin College were in Trojes, a filter performance study was conducted in rural schools (see related blogs). During this study, the team tested 14 water storage containers in 12 schools. They noticed a consistent issue. Of the 14 storage containers, only five were not experiencing issues with re-contamination.
Do not get me wrong. The filters themselves were working very well, with an average of 93% reduction of E. coli levels (fecal contamination indicator). What this meant is that the water in the storage container (what they are actually drinking) was not as clean as the water they were receiving into the container directly from the filter.
How can this be? Recontamination is a common issue everywhere. Some reasons for this can be attributed to not properly cleaning the storage container, not using clean water and tools in the container, and not using safe handling procedures.
PWW pays a great deal of attention to these issues, conducting extensive trainings about how to safely manage the water after filtration and how to employ safe hygiene techniques. These foundational lessons are included with every project, with required participation by all families and schools who benefit from the PWW programs.
The issue of recontamination of the storage water is particularly problematic in schools, where children are most often responsible for taking care of the water and there are so many people using the safe water container. Also, the rural Trojes schools don’t usually have glass windows, just a metallic net covering, so it can be difficult to control dust and particles.
The usual recommendation to avoid recontamination is to use chlorination after water filtration. However, the barriers found for creating this habit among the families and schools are many, including:
- Dislike of the taste;
- Cost associated with the bleach is prohibitive;
- Chlorine is simply not available;
- Not always easy to know how much to pour/use due to varying concentrations of commercial bleach;
- A general mistrust of the chlorine product itself (the bottle says it is toxic to drink).
The research team came to Trojes with an alternative technique that has the potential to help us overcome all of these barriers.
The MadiDrop is a micro porous, water permeable ceramic tablet infused with microscopic silver clusters, which slowly releases silver while in contact with water. These silver ions inhibit microbial pathogens by breaking down their nutrient and oxygen absorption and altering their replication system.
“Silver ions disinfect many different pathogenic waterborne bacteria, including Escherichia coli, Vibrio cholera, Salmonella, and Shigella. Additionally, viruses such as poliovirus and norovirus, as well as the protozoa Cryptosporidium parvum and Giardia lamblia, are susceptible to inactivation by silver.” (https://www.madidrop.com/how-it-works/)
MadiDrop does not add any taste or smell to the water; it is tested to last for a minimum of six months (with a longer-lasting version coming soon) during which it can provide up to 2,000 liters of safe water; and its use is as simple as can be. Simply place the ceramic tile in the drinking water container and leave it there!
When the team began talking with me about the MadiDrop product during our dinner conversation, we were all delighted because, although is not a very well-known technology yet, I had actually already been working with it in Zambia (where I was located before coming here). “What are the chances?!”
I had been involved with an experiment in Zambia in which we tested the MadiDrop performance under laboratory conditions (with source and filtered water) and at households (on filtered water only) and I have to say that the results were impressive.
So, the team wanted to donate some tablets to PWW and perform an experiment with rural schools to see if it can be used as an efficient sterilization method with safe storage containers in this environment.
We wanted to begin right away (this was July of last year), but the schools were closing for holidays a couple of months later. So, we left it for February when they would be opening again.
We started the project on the third week of February, installing 14 tablets in storage containers in 11 schools. We tested the storage water just before the installation and two days after. Initial results, again, were very impressive.
The World Health Organization (WHO) classifies drinking water in four categories (see table below) according to E. coli concentration (indicator used for fecal contamination). And, we also tested for total coliforms (a more general indicator of water contamination).
On the day of the first testing, every storage container showed microbiological activity (total coliforms), with only three of them showing no indication of bacteria related to fecal contamination (E. coli).
On the second day of testing, after the water had been in contact with the MadiDrop tablet for 24 hours, one container showed only one total coliform CFU / 100 mL and NONE of the containers presented any E. coli.
In the table, the WHO’s drinking water classification, according to E. coli concentration, is shown in the first two columns. The number of storage containers corresponding to each category of the classification during the first day of testing (before MadiDrop) is shown in the third column. The number of safe storage containers for each category on the second testing day (after adding the MadiDrop) is shown in the fourth column.
When interviewed, teachers reported no change in taste or smell from the MadiDrop, and they all said it was very easy to use.
We are excited about the results of this initial testing, demonstrating not only great water quality, but also a high level of acceptance. In my opinion, this can be a very effective solution for recontamination problems.
This July we will, once again, enjoy another visit from the Water for ME/University of Maine team. During this visit, we will be covering many topics, including conducting additional testing with the MadiDrop performance to better understand the length of effectiveness in the rural school setting.
Over the past several months, the organization that produces the MadiDrop has been going through some exciting changes, and they are looking to launch a newer, longer lasting version of the product very soon.
We are very excited and optimistic about the potential this product has for WASH programs in Honduras, Haiti and beyond. As we continue to conduct more laboratory and field testing, we will keep you posted!
Learn more about the additional research that PWW teams are conducting with the MadiDrop product here:
The Extended Laboratory Use of Ceramic Water Filters with Antimicrobial Silver Ion Technology
PWW Haiti Researches Disinfection Option: MadiDrop