Application of construction waste residue-based compositing fillers in bioretention facility: Intensified nitrogen removal and mitigated by-product effects.

Bioretention facilities (BRF) are widely utilized in sponge cities for stormwater management, but they face challenges in effectively controlling nitrogen due to the instability of traditional fillers. Pyrite has been extensively employed as an electron donor to enhance nitrogen removal; however, it generates by-products such as H, SO, and Fe/Fe that can pose environmental issues. Construction waste residues (CWR), consisting of waste brick and concrete, have been explored as alternative fillers, but they suffer from alkaline leaching problems.