Utilization of Trickling Bed Air Biofilter in the Treatment of Hydrophobic Odors

This study is the continuation of long term research in improving the degradation of hydrophobic volatile organic compounds (VOCs) using trickle-bed-air-biofilters (TBABs) in our laboratories. Many studies investigated the effect of change of the operation's parameters of the TBABs such as utilization of surfactants or changing the biomass consortium for degrading hydrophobic VOCs. The main research objective of this study is to enhance the removal of recalcitrant compounds that are not readily bio-available due to mass transfer rate limiting step between the liquid and gas phases by introducing and suspending a hydrophilic VOC. n-Hexane was used as a model compound to represent hydrophobic VOC. For this purpose, and in order to increase the bioavailability of n-hexane, a mixture of n-hexane, and methanol, a hydrophilic VOC, with the following ratios by volume: 70% methanol & 30% n-hexane, and 80% methanol & 20% n-hexane were investigated while introducing and suspending the methanol use. Four biofilters were run and fed with different nutrient pH buffers. The four TBABs achieved more than 98% methanol removal efficiency. For n-hexane, in presence of methanol, the removal efficiency fluctuated between 88% and 41.1% depending on the nutrients pH and the ratio of the mixture of methanol to n-hexane. However; when methanol has been suspended, all TBABs achieved more than 94% in n-hexane removal independently of the nutrient buffers.