Effects of filling methods on the degradation of ethyl acetate and the microbial community in biofilters

Abstract

Two biofilters (BFs) for treating ethyl acetate (EA) were constructed with magnetite, activated carbon, perlite and gravel added via layered filling (BF1) or mixed filling (BF2). This study demonstrated the effect of filling method on the degradation of EA and the microbial community in the BFs. The results indicated that the EA removal efficiency (RE) of BF1 and BF2 reached 86.3 ± 3.0 % and 88.9 ± 2.1 %, respectively, under low inlet load (L-IL; (224 g/(m3·h)). Meanwhile, BF2 exhibited stabler RE than BF1 at high IL. BF1 achieved the highest REs of total phosphorus (TP), total nitrogen (TN) and ammonia nitrogen (NH4+-N) under moderate inlet load (M-IL; 336 g/(m3·h)), with average values of 95.8 ± 3.5 %, 83.4 ± 0.4 %, and 85.7 ± 0.3 %, respectively. The removal of TP, TN and NH4+-N in BF2 was superior than BF1 at L-IL and M-IL condition. Moreover, the genera Burkholderia, Acinetobacter, unclassified_Rhizobiales and unclassified_Burkholderiales were the dominant EA-degrading bacteria in BF1, while the EA-degrading bacteria in BF2 were dominated by unclassified_Chloroflexi, unclassified_Bacteroidetes and unclassified_Anaerolineaceae. Furthermore, the mechanism investigation of the mechanism revealed that the types of filling method affect EA degradation by shifting the abundance and diversity of key microorganisms in biodegradation. This study provides an effective strategy for improving the biodegradation efficiency of volatile organic compounds VOCs.