Characterization and evaluation of recycled glass sand as water filtration media

Recycled glass offers a promising, cost-effective alternative to silica sand for water filtration. This study evaluated its performance in a gravity-driven flow system using three particle sizes: gravel (G), coarse sand (CS), and fine sand (FS). As expected, a tradeoff was observed between turbidity reduction and permeability. FS achieved the greatest turbidity reduction (96.6% in particulate filtration and 93.1% in environmental water filtration) and Escherichia coli log removal of 1 ± 0.2, but low permeability. Higher permeability but poor turbidity and E. coli removal was achieved using G. To balance these tradeoffs, a layered filtration system was used to improve permeability with effective turbidity reduction (96.9% in particulate filtration and 93.5% in environmental water filtration). Without coagulant treatment, the E. coli log removal was 0.27 ± 0.15; with coagulant pre-treatment, it increased to 2.5 ± 0.4 for the layered filtration system. These findings demonstrate that crushed recycled glass can be used as an effective filtration medium and the filtration system can be configured with different particle sizes and/or layers to meet application-specific requirements.