Investigation of factors on a fungal biofilter to treat waste gas with ethyl mercaptan.

The biofilter is cost-effective for the waste gases treatment. The bacterial is the main microorganism in the conventional biofilters. However, it faces some problems on the elimination of hydrophobic compounds. In order to overcome these problems, the biofilters with fungi were developed. The objective of this study is to investigate the factors affecting ethyl mercaptan (EM)-degradation using a fungal biofilter. A laboratory experiment was set up. The effects of loading rate, empty bed residence times (EBRT) and pH on EM degradation were investigated. Over 95% removals of EM could be achieved, under the condition of the influent loadings below 50 g/(m x h). Removal efficiencies improved to 98% with EM loading decreased to 45 g/(m x h). For long EBRT of 58 s corresponding to a low rate of 0.3 m3/h, the EM removal efficiencies of over 98% were observed. However, when EBRT was decreased to 14 s, the removal efficiencies fell under 80%. The pH range of 3-5 was feasible to fungi.