Enhanced DCH4 recovery via wave pulse mixing coupled in-situ hydrophobic membrane in AnMBR treating municipal wastewater

Anaerobic membrane bioreactor (AnMBR) has been increasingly applied in municipal wastewater treatment to recover resources by converting organic matter into methane. However, the effluent of a conventional AnMBR usually contains supersaturated dissolved methane (DCH4), causing energy loss and the greenhouse effect. In this study, the recirculation mixing approach was replaced by a novel wave pulse mixing approach in AnMBR to achieve superior organic removal (97 ± 1 %) and mitigation of DCH4 supersaturation (34.2 ± 1.3 %). For further DCH4 recovery, a hydrophobic membrane was placed inside AnMBR. Compared to the hydrophobic membrane under semi-submerged placement, better DCH4 recovery was achieved under fully-submerged placement, in which the lowest DCH4 concentration (11.20 mg/L) was attained at 25 kPa vacuum and the purity of the collected biogas was higher. Energy analysis showed that the positive net energy could be reduced by 87 % in the novel AnMBR versus conventional AnMBR. The newly developed AnMBR in this study is promising in resource recovery and energy conservation for treating municipal wastewater. [Display omitted]