Biofiltration of hydrophobic vocs with filamentous fungi: modeling and experimentation

Biofiltration is nowadays one of the leading Air Pollution Control (APC) techniques for low VOCs concentrations. In these systems, the VOCs are oxidized by immobilized microorganisms in a solid support and CO2 and water are the main end- products. Biofiltration has important advantages such as low power requirements, it does not use dangerous substances nor uses extreme conditions for its operation and the polluting agent is destroyed and not only transferred to another phase. On the other hand, these systems have shown to be less efficient to treat hydrophobic compounds which are sparsely soluble in the biofilms, which usually contain high water content to allow metabolic activities. Furthermore, the flat bacterial biofilms offer low surface for the transfer of these contaminants to the biologically active phase. One alternative to improve these limitations is the use of filamentous fungi as the biological agents in biofiltration. These organisms are more resistant to acid and low- humidity conditions and the transfer of the hydrophobic pollutant has been shown to be improved by the increased transfer surface, due to the formation of the aerial mycelium, and the more favorable phase equilibrium with the hydrophobic nature of the fungi.