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 30–45°C 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 40°C 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 30°C to 45°C. 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.

KEYWORDS:

• Biofilter
• n-butanol
• temperature
• transient-state
• intermittent loading

Acknowledgements

The authors would like to gratefully thank Ms Shiva Abdolrahimi for some editing and Mr Mehdi Eshraghi for his help in adsorption experiments.

Disclosure statement

No potential conflict of interest was reported by the author.