Sustainable porous collectors for Agricultural Runoff Treatment

Excess nutrient and pollutant loading from agricultural runoff is a key driver of water quality degradation, necessitating low-cost, in-situ treatment solutions. Filtration beds are commonly employed for this purpose, yet the traditional use of sand as the dominant filter medium is increasingly unsustainable due to resource scarcity. Crushed recycled glass is emerging as a promising alternative, though its performance characteristics and potential for surface modification remain underexplored. This study evaluates the filtration efficiency of crushed recycled glass, both unmodified and surface-modified with iron oxyhydroxides, across a range of particle sizes and heating temperatures. A 3 × 4 factorial design was used in column experiments to assess removal efficiency across multiple water quality parameters, including turbidity, total organic carbon, orthophosphates, and metals. Surface-coated media modified at 90 °C significantly outperformed the control for turbidity removal (p <0.05) for the two coarsest size fractions (1190 µm and 2000 µm). No significant differences in surface elemental composition were identified between modified media dehydrated at 90°C and 100°C. Modified media across particle size fractions and temperature treatment did not leach B or Fe > 0.1 ppm. Instead, Fe removal was of at least 76% for all tested modified media. These findings demonstrate that surface-modified recycled glass can effectively enhance contaminant removal in water treatment, while highlighting that particle size distribution and column configuration (L/D ratio) influence overall performance. The results support the potential of modified recycled glass as a practical, low-cost, and environmentally sustainable filter medium.