The ability of selected filter materials in removing nutrients, metals, and microplastics from stormwater in biofilter structures

Creative solutions to manage stormwater include ecologically based designs, such as biofilter structures. A laboratory experiment was established study the ability of biofilters remove nutrients, metals, total suspended solids (TSS), and organic C originating from roadside melted snow. Special attention paid removal P. In addition, fate microplastics (MPs) in followed. The materials selected for were (a) crushed light-expanded clay aggregates without biochar or amended with biochar, (b) Filtralite P aggregates, (c) concrete, (d) filter sand. layer support grass growth placed above these materials. Stormwater rich TSS associated which substantially retained by all biofilters. concrete had almost 100% removal, but high pH adverse effects on plants. Light-expanded lower retention P, and, when mixed (30% v/v), leaching increased N improved. None ideal treating both nutrients sand generally best. Vegetation improved infiltration. Plant roots formed preferential pathways water substances, evidenced accumulation MPs along root channels. No found discharge. Given loading contaminants snowmelt traffic areas their efficient biofiltration, results this suggest implementation management road verges.