Ethene removal from a synthetic waste gas using a dry biobed

Abstract

A packed granular activated carbon (GAC) biobed, inoculated with the ethane‐degrading strain Mycobacterium E3, was used to study ethene removal from a synthetic waste gas. Ethene, for which the dimensionless partition coefficient for an air‐water system at 20°C is about 7.6, was used as a model compound for poorly water soluble gaseous pollutants. In a first mode or operation, the GAC biobed was sprinkled intermittently and the waste gas influent was continuously pre‐humidified, establishing relatively moist conditions (water content >40% to 45%). A volumetric ethene removal rate of 0.382 kg COD · m⁻³ · d⁻¹ (0.112 kg ethene · m⁻³ · d⁻¹) was obtained for an influent concentration of 125 ppm, a superficial waste gas velocity of 3.6E−3 m · s⁻¹ and a pseudo residence time of 45 s. However, in the second mode of operation, omitting the pre‐humidification of the waste gas influent and establishing a “dry” biobed (water content −1, pseudo waste gas residence time 43 s), the ethene removal was not limited by mass transfer of ethene through the water layer covering the biofilm. © 1994 John Wiley & Sons, Inc.