Treatment of volatile fatty acid gases with a fixed-film bioscrubber

Abstract Volatile fatty acid (VFA) gases cause malodorousness and affect both humans and the environment. The biological processes commonly treated unpleasant odors, because they were environmentally friendly processes with few negative effects on humans and high removal efficiencies. This study aimed to isolate microbial groups capable of degrading VFAs, such as acetic acid, propionic acid, and isobutyric acid, and then apply these microorganisms into a fixed-film bioscrubber system. The investigation focused on factors influencing the treatment efficiency, such as the gas flow rate (100 and 200 mL min − 1 ), empty bed retention time (EBRT) (63 and 126 s), and liquid flow rate (10 and 20 mL min − 1 ). The results showed that microorganisms cultured in selective medium containing VFAs as a carbon source were able to grow and increase in cell number. When the microorganisms were applied to a fixed-film bioscrubber for treating VFA gases with a gas flow rate of 100 mL min − 1 , an EBRT of 126 s, and a liquid flow rate of 10 mL min − 1 , removal efficiencies of 96% for acetic acid (gas elimination capacity (GEC) 1290 mg m − 3 h − 1 ), 91% for propionic acid (GEC 665 mg m − 3 h − 1 ), and 96% for isobutyric acid (GEC 1015 mg m − 3 h − 1 ) were achieved. The optimal gas loading and system operation conditions enhanced microbial degradation, which increased the number of cells growing on the packing media and suspended in the recirculation liquid.