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Abstract
Biofiltration degradation kinetics of an aldehyde mixture containing hexanal, 2-methylbutanal, and 3-methylbutanal was investigated using a bench-scale, synthetic medium based biofilter. The adsorption capacity of the synthetic medium for 3-methylbutanal was 10 times that of compost. Higher moisture content leads to higher removal efficiency. RTD analysis showed no compaction or channeling. Kinetic analysis suggested an overall first order model was more appropriate. In the range of 20-50 ppmv inlet each, hexanal had a significantly higher reaction rate compared to the branched aldehydes. SEM analysis of the medium samples showed microbial growth suggesting removal of the aldehydes could be attributed to biodegradation. Methanethiol was added into the system 15 months later. Low removal of methanethiol was observed, yet the reaction rates of the aldehydes increased. DMDS was formed along the reactor. An external mass transfer model was fit to the data suggesting the overall reaction was limited by mass transfer.