Sometimes, the simplest scientific solutions have the biggest impact. Using empty plastic bottles and sunlight, Professor Kevin McGuigan’s research is certainly proof that a little bit of science can go a long way.
This is a key message from this year’s Science Week, which celebrates its 30th birthday in 2025. Co-ordinated by Research Ireland, they want to share how science and research have shaped and improved the lives we live today, with even the simplest of solutions, while exploring tomorrow’s questions and challenges.
McGuigan is director of the RCSI Solar Disinfection Research Group, which has developed hugely effective solar-based technologies for water treatment. A physicist - and former chair of the Institute of Physics - he has found himself working on a number of groundbreaking projects supporting access to clean water in low income countries over the past three decades.
“Back in the 1990s, when I started at the RCSI, a very nice retired tropical medicine professor approached me because he’d had the idea that perhaps we could use solar energy to disinfect water, to kill whatever pathogens or bacteria are in the water that cause waterborne disease,” McGuigan explains. “He had the idea, but he didn’t have the technical know-how, so he asked me if I’d help him set up the experiments.”
RM Block
McGuigan got to work, preparing empty plastic bottles - “essentially empty two litre Coca Cola bottles” - by lacing them with high populations of the faecal bacteria E.coli. “We effectively inoculated them, and stuck them out on some windowsills at the front of the college, not really expecting to see much of an effect,” he recalls. “But we found that, even if you were starting with a million E.coli per milliliter, within two hours, they were all gone. So it was very effective at inactivating the bacteria.”
Proof of principle achieved, McGuigan and his team set out to see if their approach would have the same effect on other diseases. “Think of any kind of waterborne disease, such as cholera, dysentery, polio, we looked at all of the microbes that caused those diseases and we satisfied ourselves that it worked. In our laboratory environment, we’re able to kill those very easily.”
The next step was to bring their technique into the real world. A health impact assessment was carried out in the Maasai community in southern Kenya, and similar assessments followed in Zimbabwe, Cambodia and South Africa.
“Each time we find it’s extremely effective at reducing diarrhoeal illness in children under the age of five, and we get reductions somewhere between 24 per cent up to maybe 78 per cent of the incidence of diarrhoea and dysentery,” McGuigan notes.
And the impact goes far beyond the immediate health benefits. He recalls one of their studies, carried out during a prolonged drought in Kenya. “When the drought was finished, there was an outbreak of cholera. We saw that the children who were using solar disinfection, they were seven times less likely to get cholera,” he recalls. “So we have seen they have better child development - they’re not getting diarrhoea as frequently, so they can absorb the nutrients from their food. They tend to have higher median heights, and we see fewer school absences.” In addition, parents aren’t losing income generating opportunities because they’re looking after a sick child nor are they spending money on medication or transport to health centres. “So from a very simple technology, it has a huge impact not only on health, but on their development, their education, and the family finances.”
The beauty of the technique lies in its simplicity but, crucially, it’s also cheap. “Those communities that are most at risk, they’re the ones that can’t really afford any fancy technology, and it doesn’t get any simpler than a transparent plastic bottle, to be honest,” McGuigan says.
Yet, the solution is so simple, the communities that McGuigan operates in do not necessarily believe in its effectiveness. “We always have to partner with organisations that have already established a good trust relationship with the communities, such as a charity or university. The simplicity of the solar disinfection, you stick the water in the bottle, you put the bottle out in the sun for six hours. And then after that it’s safe to drink. But some people just don’t believe that and so our local partners help us to convince the local community that they can trust it.”
One of McGuigan’s current projects, SURG-Water, is seeking to combat the impact of the escalating climate crisis on clean water supplies. As part of this project, which is funded by Research Ireland, in partnership with Irish Aid, under the SDG Challenge Programme, his team worked with a number of local partners in Malawi to develop a UV-based water treatment technology solution for rural maternal health facilities.
“What we’re doing in Malawi is different because now we’ve moved away from the households and we’re providing treated, harvested rainwater into rural health clinics,” McGuigan says. “We are now using solar disinfection to assist with infection control, producing clean water for hygiene purposes.”
A step up from the two-litre Coca Cola bottles, this project involves 200-litre reactors, filled with rainwater collected from the roof of these facilities. “It’s treated and then it’s piped directly into the delivery room of the maternity wards in these rural health centres.”
And again, the potential impact is far-reaching, in what is one of the poorest countries in the world. “The next part of that project is we want to redesign the reactor so that we can make it with local materials and local work power, the local workforce in Malawi,” McGuigan explains. “If we can do that, and if we can manufacture them and they work effectively, what we are providing is a new source of income, a new industry, a new skill set, and they can be used not only in the health centres, but they could be used in schools or any large-scale community setting.”
The project is a true multidisciplinary effort, and McGuigan is keen to impress that the science is just one small part of it. “Often, the most important members of the team, they might not be the scientists, they might actually be the sociologists or the anthropologists who are presenting the project in a way that conforms with the belief systems of the local community,” he notes. “The science for this, some of this, it’s really simple, it’s basic microbiology, it’s basic physics and a little bit of chemistry. The most challenging part is convincing the community that they have a problem.
“So someone may not have an interest in science, but it’s very easy to get involved in science projects because we need people with linguistic skills who are going to do the translations for us, we need people who have the art and design skills to present the information in a way that the communities are going to accept it, and of course we need the physicists, we need the chemists. It’s a truly inclusive atmosphere when you’re involved in these kinds of large scale, multidisciplinary projects.”
Science Week, which is coordinated by Research Ireland, runs from 9th – 16th November, with 14 festivals and hundreds of events taking place nationwide. The theme for this year is ‘Then. Today. Tomorrow’.
