Coupling of (methane + air)-membrane biofilms and air-membrane biofilms: Treatment of p-nitroaniline wastewater

Abstract

Membrane biofilm (MBf) technology is a promising biological water treatment process that combines membrane aeration with biofilms. To expand its application in the treatment of toxic organic wastewater, methane/air gas mixture-MBfs ((CH4 + Air)-MBfs) and air-MBfs were coupled to enhance the treatment of p-nitroaniline (PNA) wastewater. Based on exploration of the membrane permeability of methane and oxygen, a hybrid MBf reactor was constructed, and the degradation characteristics of PNA and the coupling effects of (CH4 + Air)-MBfs and air-MBfs were studied. The permeation flux of methane was found to be 1.114 g/(m2 d) when using a methane/air gas mixture at an aeration pressure of 10 kPa, and this result was better than that when methane was used as the aeration gas alone. Aeration with a methane/air gas mixture provided conditions for realizing aerobic methane oxidation; the aerobic methane oxidation that occurred in the (CH4 + Air)-MBfs promoted the reduction of PNA, and the intermediates of PNA degradation were further degraded by the air-MBfs. At an influent PNA membrane area load of 1.67 g/(m2 d), the PNA removal load reached 187.30 g/(m3 d). The coupling of MBfs took advantage of different matrix-based MBfs and promoted the degradation of PNA by utilizing the synergistic effects of various functional microorganisms.