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As UNESCO marks 50 years of its Intergovernmental Hydrological Programme (IHP) in 2025—a milestone in global water research and innovation—Anna Luísa Beserra Santos’s invention stands as a powerful example of grassroots, science-driven solutions.

Through our UNESCO Green Citizens initiative, we are spotlighting changemakers like her, whose ingenuity and commitment are shaping a more sustainable future.

Today, still live without access to safely managed drinking water. Confronted with this reality, Anna Luísa set out to find a solution—and at just 15 years old, she created Aqualuz, an affordable, solar-powered device that purifies rainwater without chemicals or complex filters.

Now, her invention is improving access to clean drinking water in rural Brazil, with ambitions to expand across Latin America, Africa, and Asia. But scaling an innovation is no easy task. In this interview, Anna Luísa shares her journey, the lessons she wishes she had known at the start, and why she believes solar purification could play a critical role in the future of water security.

(This interview has been edited for clarity and length.)

In 2013, I had this realization that changed everything—I saw that the solution could be incredibly simple. Even as a kid, I could understand how this technology worked, and that meant anyone could too. I knew then that if I could create something easy to use and replicate, communities could take control of their own water purification. That moment made me think, ‘I have to make this happen’. 

Aqualuz is a rainwater treatment system using sun radiation to kill microorganisms. 

One of the biggest misconceptions in water filtration projects is assuming that every filter has a lasting impact. Many solutions are designed as quick fixes, working for just a year or so, but they don’t provide real, long-term support for communities. We focus on durability. The Aqualuz system lasts 20 years because true impact comes from sustainable solutions, not short-term interventions. We also ensure that we only implement projects where there is a real need, so our work creates meaningful, lasting change. 

If I could go back, I would have gone to the field from day one. In the beginning, I was still in a purely scientific mindset—everything I knew about the problem came from research papers and technical studies. It wasn’t until much later, when I actually met the families facing water scarcity, that I truly understood the challenges they face every day. I remember meeting a mother of five whose child was sick due to unsafe water. She had to buy expensive bottled water, which she could barely afford, and she couldn’t work because she had to take care of her children. That moment changed how I approach solutions and work with communities. Research is important, but nothing replaces learning directly from the people you’re trying to help.  

The most important thing is making the community part of the solution. That’s why we hire local technicians—they train with us, go to the field, and take the lead in monitoring the technology’s impact, including waterborne disease reduction. When the people using the solution are also the ones helping implement and improve it, it becomes more than just a project—it becomes theirs. It’s not outsiders coming in to teach; it’s a shared effort where their insights and feedback shape how the technology evolves. 

Aqualuz was just the beginning. Since developing it in 2013, I’ve created additional technologies to address different water challenges. Aquasalina uses sunlight to desalinate water, Aquafilter provides three-step filtration for communities of up to 100 people, and Aquatorre adapts that system for schools and areas without water infrastructure.

So far, over 10,000 people actively use these solutions, and in 2024 alone, we reached 40,000 people. Seeing these technologies make a real difference in daily lives is what drives me to keep innovating. 

One of the biggest myths about social entrepreneurship is that it’s the same as running an NGO. While both aim to create positive change, social enterprises operate as businesses—they pay taxes, generate revenue, and don’t have the same benefits or funding opportunities as NGOs. This means they have to balance impact with financial sustainability, proving that purpose-driven businesses can be both socially and economically viable. 

My vision is for Aqualuz to be widely implemented across Latin America, Africa and other regions facing water scarcity, ensuring that more rural and vulnerable communities have sustainable access to safe drinking water. I also hope that, alongside Aqualuz, we can expand our portfolio of accessible water solutions, empowering local communities through education and technology.