Biological Removal of Hydrophobic Solvent Vapors from Airstreams

Abstract

R~moval of benzene and to~uene vapors from airstreams was studied in packed-bed biological reactors known as blOfilters. The reactors, pleXlglass columns 10 cm in diameter and 75 cm in height, were packed with a mixture of peat and I?erlite f~rticles (volume ratio 2:3). A microbial consortium capable of completely mineralizing benzene and toluene was Immobilized on the sUrface of the porous packing material, andformed a biolayer. Prehumidified air carrying either benzene or toluen~ was passed through the reactor. The solvent vapors and oxygen were transported to the biolayer where the ~ontammants underwent biodegradation. The eXp'erimentally observed maximum removal rates were 4.5 g(m-3-packmgj-l h-lfor .benzene, and 24.8 g(m-3-packingj-l h-1 for toluene. Under all operating conditions tried, toluene vapor was removed easier than benzene. Steady-state data are accurately predicted with a detailed mathematical model which a~~ounts for possi~le limi~ation of the process by oxygen. However, calculations show that, when compared to hydrophiliC compounds, blOfiltratlOn of hydrophobic substances is not much affected by oxygen.