Rio Favela Transforms Waste Cooking Oil Into Soap and Hope

In Rio de Janeiro’s sprawling Rocinha favela—home to over 72,000 residents—a chance discovery at a local sports complex has sparked an innovative environmental solution that’s transforming both the community and its waterways.

The breakthrough came in 2020 when community leader Marcelo Santos and biology teacher Márcio Aroeira noticed a thick, oily film contaminating water reservoirs near the neighborhood gym. Upon investigation, they realized the pollution came from improperly disposed cooking oil from thousands of local households—a common problem in dense urban communities where waste management systems are often inadequate.

Rather than simply lamenting the environmental damage, Santos saw an opportunity. After months of research and collaboration with chemistry professionals, he developed a program to collect used cooking oil from Rocinha residents and transform it into soap through a simple chemical process. This grassroots initiative tackles multiple challenges simultaneously: reducing water pollution, creating useful household products, and providing economic opportunities for community members.

The project exemplifies how environmental solutions can emerge from unexpected places. What began as concern over polluted water has evolved into a model for community-driven sustainability that other favelas could potentially replicate. Santos’ work demonstrates that some of the most effective environmental innovations don’t come from corporate boardrooms or government offices, but from residents who witness environmental problems firsthand and possess both the motivation and local knowledge to address them creatively.