Performance of a styrene‐degrading biofilter containing the yeast Exophiala jeanselmei

Abstract

A general mathematical model developed for a description of pollutant degradation in a biofilm was used to evaluate the performance of a biofilter for the purification of styrene-containing gas. The biofilter contained perlite as an inert support on which a biofilm was present composed of a mixed microbial population containing the fungus Exophiala jeanselmei as a major styrene-degrading microorganism. Although styrene is a moderately hydrophobic compound, the biofilter was reaction limited at a styrene gas phase concentration of 0.1-2.4 g/m 3 . Limitation of biofilter performance by the mass transfer of styrene was only observed at styrene concentrations lower than 0.06 g/m 3 . A maximal styrene degradation rate of 62 g/(m 3 ⅐ h) was maintaind for over 1 year. At a high styrene concentration, the maximal styrene degradation rate could be increased to 91 g/(m 3 ⅐ h) by increasing the oxygen concentration in the gas from 20 to 40%. After 300 days of operation, the dry-weight biomass concentration of the filter bed was 41% (w/w), and an average biofilm thickness of 240-280 µm, but maximal up to 600 µm, was observed. Experimental results and model calculations indicated an effective biofilm thickness of about 80 µm. It is postulated that the thickness of the effective biofilm is determined by the oxygen availability in the biofilm.

Biofilter Treatment of Volatile Organic Compound Emissions from Reformulated Paint: Complex Mixtures, Intermittent Operation, and Startup

“…The fact that many fungal species are able to degrade the VOCs present in the waste gas stream, however, raises the distinct possibility that they contributed to VOC removal. 21,[25][26][27][28][29][30] No attempt was made to enumerate microbial populations in Biofilter 2, so a direct comparison between the two systems is not possible. As described in the following section, however, differences in the quantity of biomass between the two systems were readily apparent from microscopy analysis.…”

Construction and Economics of a Pilot/Full-Scale Biological Trickling Filter Reactor for the Removal of Volatile Organic Compounds from Polluted Air

“…Lower pollutant removal performance was expected since styrene is known to be much more difficult to biodegrade than CH 2 Cl 2 is. 18,21 On average, styrene inlet concentrations ranged from 0.5 to 1 g/m 3 . At the startup, the reactor was inoculated with activated sludge, and early performance monitoring of the reactor showed that styrene elimination capacity was 15 g/m 3 /hr with 70% removal efficiency ( Figure 4).…”

Isolation and characterisation of fungi growing on volatile aromatic hydrocarbons as their sole carbon and energy source

“…Interestingly, Hartmans, van der Werf & de Bont (1990) isolated two fungi able to grow on styrene as a sole carbon and energy source. One of those strains, the yeast-like fungus Exophiala jeanselmei, was used successfully for treating of styrene-polluted air in a biofilter , Cox et al 1997. More recently, the deuteromycete Cladosporium sphaerospermum was isolated from a biofilter that had been used to remove toluene from contaminated air.…”