A specific pilot-scale membrane hybrid treatment system for municipal wastewater treatment

• A hybrid treatment system with new configuration was designed for better efficiency.
• High removal efficiency of pollutants was achieved in all run-modes.
• Internal recycling ratio significantly effects on the efficiency of T-N removal.
• A new hybrid treatment system was successful in reducing membrane fouling.
• The energy consumption for the completion of treatment was reasonably low.

A specifically designed pilot-scale hybrid wastewater treatment system integrating an innovative equalizing reactor (EQ), rotating hanging media bioreactor (RHMBR) and submerged flat sheet membrane bioreactor (SMBR) was evaluated for its effectiveness in practical, long-term, real-world applications. The pilot system was operated at a constant flux, but with different internal recycle flow rates (Q) over a long-term operating of 475 days. At 4Q internal recycle flow rate, BOD5, CODCr, NH4+-N, T-N, T-P and TSS was highly removed with efficiencies up to 99.88 ± 0.05%, 95.01 ± 1.62%, 100%, 90.42 ± 2.43%, 73.44 ± 6.03%, and 99.93 ± 0.28%, respectively. Furthermore, the effluent quality was also superior in terms of turbidity (<1 NTU), color (<15 TCU) and taste (inoffensive). The results indicated that with providing only chemically cleaned-in-place (CIP) during the entire period of operation, the membrane could continuously maintain a constant permeate flux of 22.77 ± 2.19 L/m2 h. In addition, the power consumption was also found to be reasonably low (0.92–1.62 kWh/m3).