Sediment-based biochar endows pervious concrete with enhanced electron transfer capacity and strengthened biological...

Riparian restoration facilitated by biochar-based pervious concrete is an engineering-feasible method to maintain the stability of riparian zones and control the excessive accumulation of nitrate in rivers. The concrete with sediment-based biochar (C-SB) treated at pyrolysis temperature of 500-900 °C (C-SB500 - C-SB900) demonstrated excellent engineering performance compared to C-control (concrete without biochar), with an f_i value of 0.86, while C-SB300 performed worse than C-control. A maximum total nitrogen (TN) removal rate of 0.89 ± 0.040 g N m^-3 d^-1 with a nitrate nitrogen (NO₃^--N) removal rate of 0.97 ± 0.011 g N m^-3 d^-1 was achieved when C-SB700 was added. The denitrifying enzyme activity, such as NAR, was significantly correlated with electron-accepting capacity (EAC, r = 0.976, P < 0.01) and electron-donating capacity (EDC, r = 0.898, P < 0.05) of C-SB, thereby improved denitrifying species abundance via obtaining strong correlation with NO₃^--N removal (r = 0.934, P < 0.05). To sum up, this work offers a cost-efficient way to promote restoration of the riparian environment and facilitate nitrogen removal from fluvial systems using novel pervious concrete.