Simultaneous carbon, nitrogen and phosphorus removal in sequencing batch membrane aerated biofilm reactor with biofilm thickness control via air scouring aided by computational fluid dynamics.

[Display omitted] • Membrane aerated biofilm has optimal thickness for simultaneous C, N, P removal. • Air scouring aided by CFD was used to detach outer biofilm for thickness control. • Biofilm yield stress was matched with air scouring induced shear stress on biofilm. • Periodic air scouring enhanced nitrogen removal and reduced biofilm thickness. • Intermittent aeration and air scouring in one cycle simultaneously removed C, N, P. Membrane aerated biofilm reactor (MABR) is challenged by biofilm thickness control and phosphorus removal. Air scouring aided by computational fluid dynamics (CFD) was employed to detach outer biofilm in sequencing batch MABR treating low C/N wastewater. Biofilm with 177–285 µm thickness in cycle 5–15 achieved over 85 % chemical oxygen demand (COD) and total inorganic nitrogen (TIN) removals at loading rate of 13.2 gCOD/m2/d and 2.64 gNH 4 +-N/m2/d. Biofilm rheology measurements in cycle 10–25 showed yield stress against detachment of 2.8–7.4 Pa, which were equal to CFD calculated shear stresses under air scouring flowrate of 3–9 L/min. Air scouring reduced effluent NH 4 +-N by 10 % and biofilm thickness by 78 µm. Intermittent aeration (4h off, 19.5h on) and air scouring (3 L/min, 30 s before settling) in one cycle achieved COD removal over 90 %, TIN and PO 4 3−-P removals over 80 %, showing great potential for simultaneous carbon, nitrogen and phosphorus removals. [ABSTRACT FROM AUTHOR]