Improving Water Quality by Combined Sedimentation and Slow Sand Filtration: A Case Study in a Maasai Community, Tanzania

Some Maasai communities in northern Tanzania face severe water quality and scarcity issues, significantly impacting the health and living conditions of the local population. To address the water quality challenges faced by one of the Maasai communities, where thousands of residents consume water with high turbidity and contaminants, a team of volunteers, primarily engineering students from Ben-Gurion University of the Negev, conducted a project in 2023. This project aimed to improve water quality through the implementation of combined sedimentation and biofilm-based slow sand filtration systems. These systems utilized mechanical filtration via sand bed percolation and biological filtration through biofilm formation, which effectively reduced turbidity and removed contaminants. The biofilm maturation significantly enhanced filtration efficiency, achieving turbidity reduction from levels exceeding 10,000 to below 5 NTU, meeting WHO standards. Comprehensive water quality assessments revealed contamination in the water sources, with elevated levels of lead (up to 11 mg/L), which pose health risks. In addition, we evaluated locally accessible materials such as chalk and limestone for coagulation and precipitation, enhancing water clarity and removing contaminants. Despite constraints that shortened the mission duration, the results provide a solid foundation for future efforts to improve water quality in the region. This study highlights the potential of low-tech biofilm-based filtration systems for sustainable water purification in resource-limited environments. It demonstrates the effectiveness of small-scale household systems and presents a development protocol optimized for local materials and water contamination characteristics.