Construction of a sandwich-structured biofilm system and efficient removal of methyl tert-butyl ether

The extensive use of methyl tert-butyl ether (MTBE) as a gasoline additive has led to serious environmental problems because of its toxicity and recalcitrance. In this study, activated carbon (AC) and Zeolite Socony Mobil-5 (ZSM-5) molecular sieve pellets were used as carriers, and a sandwich-structured biofilm reactor (A-Z-A) was established. Bacterial aggregation and biofilm maturation were promoted due to the strong hydrophilicity of ZSM-5 and the high specific surface area of AC, which shortened the start-up time of the reactor and increased the thickness of the biofilm from 55.0 to 82.8 µm. Moreover, the A-Z-A structure improved the stability of the biofilm and optimized the structure of the microbial community, thus facilitating the removal of MTBE from water and achieving continuous and efficient operation under heavy metal co-contamination.