• • Achieved 91.3% tetracycline removal and 71.7% TN removal (83.3% NO3−-N) in Fe-C-Mn CW, versus 27.2% TC and 7.8% TN in gravel control, demonstrating superior simultaneous removal for secondary effluent polishing.
• • Fe(0) oxidation to Fe(II)/Fe(III) and Mn(IV) reduction to Mn(II) synergistically enhanced electron transfer, mitigating iron passivation and sustaining autotrophic denitrification and TC degradation over extended operation.
• • Selective enrichment of Trichosporon and Bacillota (TC degraders) and unclassified_f_Rhodocyclaceae (denitrifiers) despite lower overall diversity indicates a tailored microbial community driving synergistic pollutant removal.
• • TC degradation proceeds via demethylation, hydroxylation, deamination, and ring-opening, converting TC into smaller metabolites, confirming effective mineralization and reduced toxicity.