Evaluating Layered Sand-Charcoal Filters for Decentralized Rainwater Harvesting Systems

Abstract

This project compares four layered filter column designs for rainwater harvested from school rooftops. Student researchers measured turbidity, conductivity, and flow rate across 40 test runs using locally available materials. A mixed-media column with gravel, fine sand, and activated charcoal achieved the best balance between clarity improvement and sustainable flow, reducing turbidity by 71% while maintaining practical throughput. The study offers a replicable protocol for classroom-level water treatment investigations.