Maifanite-amended Pyrite Biofilter for Efficient Autotrophic Denitrification of Low-C/n Mariculture Tailwater: Mechanistic Insights into Microbial Nitrogen–sulfur–iron Coupling

Mariculture tailwater, characterized by high nitrate (NO3−-N) and a low carbon to nitrogen (C/N) ratio, presents a significant challenge for coastal environment protection. To address this, we developed a hybrid carrier biofilter combining pyrite and maifanite (PM) to enhance nitrogen removal performance. The PM biofilter achieved 88.98