LAUSR

In this work, an electrochemically assisted vertical flow constructed wetland (E-VFCW) achieved efficient PO43--P (92.9-96.6%), NO3--N (50.8-91.8%) and TN (38.8-73.1%) removal from synthetic sewage effluent within 1-12 h at 12 °C. Abiotic reduction, Fe(II)-, S- and H2-dependent denitrification, as well as coupling of fermentation, acetogenesis and heterotrophic denitrification might facilitate NO3--N removal in the E-VFCW. Particularly, electron resupply for NO3--N reduction by the in-situ deposited FeS, FeS2 and S0 in the E-VFCW would occur during electron supply-demand disequilibrium situations (e.g., lower HRT or temperature). Stoichiometric results suggested that 21.7-278.7 mmol e- d-1 from the in-situ deposited S contributed to NO3--N reduction under HRT of 1-6 h at 12 °C, which improved the resilience capabilities of the E-VFCW to temperature and nitrogen loads fluctuations. Overall, this work provides new insights into the modes of S cycle mediating NO3--N conversions in the E-VFCW under low temperature.