Temperature effects of trickle-bed biofilter for treating BTEX vapors

Abstract

Effects of temperature change in the range of 15-50 degrees C on the performance of a trickle-bed biofilter for treating benzene, toluene, ethylbenzene and o-xylene (BTEX) vapors in air streams were investigated. In the steady-state condition, the BTEX removal efficiency increased as the operating temperature increased in the range of 15-30 degrees C. However, an opposite trend was observed between 30 and 50 degrees C. The trickle-bed biofilter appears to be an effective treatment process in the temperature range of 25-35 degrees C. The microscopic observations showed that the morphologies of the leading microorganisms within the first-stage biofilm were rod-shaped bacteria in association with filaments, bacilli, and cocci at 15, 30, and 50 degrees C, respectively. A theoretical evaluation on the temperature coefficient (theta) indicated that the temperature effects on the performance of a trickle-bed biofilter are more significant under lower BTEX loading rates. Furthermore, the mean theta value for a trickle-bed biofilter was equal to 1.021, which is in the typical range of some commonly used aerobic processes (1.0-1.10).