Magnetite-coated granular activated carbon in electrochemical anaerobic fluidized bed membrane bioreactor to improve methane production and fouling control

초록

Enhancing both methane production and antifouling efficiency remain critical challenges for anaerobic membrane bioreactor (AnMBR) technology in wastewater treatment. Here, experimental results are presented to investigate the effect of magnetite-coated granular activated carbon (MGAC) as conductive biocarrier on methane production and fouling mitigations in electrochemical anaerobic fluidized bed membrane bioreactor (EAFMBR). The MGAC particles were prepared via co-precipitation method, resulting in a specific surface area about 15 % higher than that of pristine GAC ones without compromising mechanical stability during operational periods. Membrane fouling was reduced synergistically by fluidizing the MGAC particles together with external voltage into EAFMBR. Constant supply of external voltage (1 V) into a microbial bulk suspension of MGACEAFMBR system enhanced soluble chemical oxygen demand (SCOD) removal efficiency by 97.5 %, yielding 0.255 L CH4 g- 1 SCODremoved and this value was 34.4 % higher than the methane yield obtained by the GACEAFMBR operated at the same hydraulic retention time (12 h). Over 93 d operation, transmembrane pressure (TMP) was maintained below -0.1 bar without accelerating fouling rate. Microbial community analysis revealed the enrichment of Methanothrix and Geobacteraceae on MGAC particles, thus enhancing syntrophic interactions and direct interspecies electron transfer which can lead to superior methane production. Comparative operation of EAFMBR systems suggest that the use of MGAC particles is very effective biocarrier to enhance both methane production and antifouling control synergistically under electric fields, highlighting its potential applications for energy-efficient wastewater treatment.

키워드