Treatment of mixtures of toluene and n-propanol vapours in a compost–woodchip-based biofilter

Abstract

The present work describes the biofiltration of mixture of n-propanol (as a model hydrophilic volatile organic compound (VOC)) and toluene (as a model hydrophobic VOC) in a biofilter packed with a compost–woodchip mixture. Initially, the biofilter was fed with toluene vapours at loadings up to 175 g m−3 h−1 and removal efficiencies of 70%–99% were observed. The biofilter performance when removing mixtures of toluene and n-propanol reached elimination capacities of up to 67 gtoluene m−3 h−1 and 85 g n− propanol m−3 h−1 with removal efficiencies of 70%–100% for toluene and essentially 100% for n-propanol. The presence of high n-propanol loading negatively affected the toluene removal; however, n-propanol removal was not affected by the presence of toluene and was effectively removed in the biofilter despite high toluene loadings. A model for toluene and n-propanol biofiltration could predict the cross-inhibition effect of n-propanol on toluene removal.