Effect of operating temperature on transient behaviour of a biofilter treating waste air containing n butanol vapour during intermittent loading
ABSTRACT Transient state removal of n butanol vapour was investigated in a biofilter (BF) packed with compost and lava rock at different operating temperatures in the range of 30 45degC under intermittent loading (8 h per day) Adsorption on the inactive bed and biodegradation in the microbial active bed were studied separately at an empty bed residence time (EBRT) of 1 min and inlet concentrations of 2.6 3.2 g m 3, respectively. According to the transient experiments, the highest removal efficiency (RE) around 86% was obtained at 40degC due to a high microbial activity. Comparison of CO2 production and pure adsorption of n butanol showed that adsorption was the major mechanism in the start up of BF at each operating condition; although the impact of adsorption declined as temperature increased from 30degC to 45degC. The process was reaction limited at all operating conditions. Based on the determination of stoichiometric coefficients of n butanol biodegradation, the CO2 production level was significantly lower than that of the chemical oxidation process which resulted in a decrease in environmental pollution.
Environmental technology