Enhancing performance evaluation and microbial community analysis of the biofilter for toluene removal by adding polyethylene glycol-600 into the nutrient solution.

Polyethylene glycol-600 (PEG-600), as a carrier for slow release of organic substances, can improve the biocompatibility of packing fillers and the construction of biofilms. The gradient experiments were established to evaluate the feasibility of adding different content of PEG-600 to the biofilter for enhancing toluene removal. In particular, the evolution trend of microbial community embedded in packing fillers was measured by 16S rRNA-based gene sequencing. Results showed that the toluene removal efficiency of biofilter with 7.5% adding content of the PEG-600 was greatly improved, and the maximum elimination capacity of 152 g/(m3·h) was obtained. The introduction of PEG-600 enhanced the tolerance ability to withstand the transient impact loading and intensified the production of extracellular polymeric substances and bonding strength of biofilms. It should be noted that the abundance of Pseudomonas and Steroidobacter at genus level increased significantly. The microbial community evolved into a co-degradation system of toluene and PEG-600.