Abstract

In this study, a two-step method was applied to build and start up a fungal–bacterial biofilter. The reactor was built by controlling pH and adding an antibiotic based on a conventional biofilter. A low pH (5.9) and the addition of chloramphenicol were favorable for the construction of the fungal–bacterial biofilter. The results illustrated that it took only 15?days to complete the start-up of the fungal–bacterial biofilter. The removal efficiency (RE) and the mineralization rate (MR) were 93.0% and 77.6%, respectively, at a toluene concentration of 1,000?±?112?mg?m^?3 and an empty bed residence time (EBRT) of 45?s. The new method effectively overcomes the unstable performance and nonuniversality of such a reactor, which was constructed by inoculating a pure fungal culture into a bacterial biofilter. Removal performance comparison and PICRUSt analysis showed that the higher the relative abundance of benzoate degradation-related genes in activated sludge is, the more suitable the sludge is for inoculation. The increase in toluene MR and the apparent morphology and scanning electron microscopy (SEM) results of biofilms in the top layer of the fungal–bacterial biofilter suggest that the biofilter performance enhancement can be attributed to the ability of fungi to distribute toluene-degrading bacteria.