CHEMICAL ENGINEERING TRANSACTIONS VOL. 40, 2014 A publication of The Italian Association of Chemical Engineering www.aidic.it/cet Guest Editor: Renato Del Rosso Copyright © 2014, AIDIC Servizi S.r.l., ISBN 978-88-95608-31-0; ISSN 2283-9216 Dependence of Sulphurous Odorants Reduction on Loading Rates in Inoculated Biofilter Columns Dezhao Liu* a , Lise B. Guldberg b , Anders Feilberg a a Department of Engineering, Aarhus University, Hangøvej 2, 8200 Aarhus N, Denmark b SKOV A/S, Department of Research and Development, Hedelund 4, DK-7870 Glyngøre, Denmark *deli@eng.au.dk Odour emission from intensive pig production is a major source of local nuisance and sulphur-containing odorants (e.g. hydrogen sulphide and methanethiol) have been recognized as key odorants. Biological air filter has emerged as a cost-effective technique to remove odorants from ventilation air. However, low removal efficiencies for sulphurous odorants have been observed when a large volume of air has been applied with low concentrations. Recent kinetic studies on full scale biological air filters indicate that the removal of odorants is related both to mass load and air load of odorants but the dependence of sulphurous odorants on loading rates are not clear due to the very low and highly varying removal efficiencies. In the present study, two inoculated biofilter columns were applied to test the dependence of sulphurous odorants (hydrogen sulphide, methanethiol and dimethylsulfide) removal on air loading rate, mass loading rate or concentration. Specially designed commercially available ceramic saddles and cellulose pads were selected as biofilter media for the experimental tests. Whereas the air loading rate varied from around 10 to 1300 m 3 m -3 h -1 , the mass loading rate varied from approximately 10 to 500 mg m -3 h -1 for hydrogen sulphide. Concentration levels varied from around 10 to 3000 ppbv for hydrogen sulphide, covering the typical concentration range of H 2 S emitted from pig facilities. The results indicated that the removal of hydrogen sulphide and methanethiol was closely dependent on air loading rate for both biofilter columns. Whereas the removal of hydrogen sulphide was observed to be also dependent on mass loading rate and concentration for the ceramic saddles packed biofilter column, the removal efficiency of H 2 S was independent on mass loading rate or concentration for cellulose packed biofilter column. Further, significant competition between methanethiol and hydrogen sulphide was observed for the ceramic packed biofilter column, when the mass load of hydrogen sulphide was increased. On the other hand, no such competition was observed for the cellulose packed column. Kinetics analysis indicated that both Grau second-order kinetics and Stover-Kincannon model can generally be applied to describe the degradation of both hydrogen sulphide and methanethiol in biofilters, except a small deviation observed for methanethiol, when applied to Stover-Kincannon model. 1. Introduction Recently global pig production increased rapidly with a 50% increase over the previous 15 years (Best, 2010). Odour emission from the intensive pig production is a major source of local nuisance (Nimmermark, 2004). Thus it is vital to develop efficient odour reduction techniques ensuring low emissions of odorants to the surroundings. Sulphur-containing odorants (e.g., H 2 S and methanethiol) have been recognized as key odorants (Feilberg et al., 2010b; Hansen et al., 2012). Biofiltration has emerged as a cost-effective way to remove odorants from ventilation air (Nicolai and Janni, 2001; Melse and Ogink, 2005; Chen and Hoff, 2009). However, generally low removal efficiencies (RE) for sulphurous odorants (with low concentrations) have been observed when a large volume of air has been applied with low empty bed residence time (EBRT < 10 s) (Feilberg et al., 2010a; Hansen et al., 2012). A recent kinetic study on a full-scale biotrickling filter (packed with structured cellulose pads) indicated that the removal of odorants are both related to mass load and air load of odorants but the dependence of sulphurous odorants on loading rates are not clear due to the very low removal efficiencies and large variations of RE except for H 2 S (Liu et al., DOI: 10.3303/CET1440034 Please cite this article as: Liu D., Guldberg L.B., Feilberg A., 2014, Dependence of sulphurous odorants reduction on loading rates in inoculated biofilter columns, Chemical Engineering Transactions, 40, 199-204 DOI: 10.3303/CET1440034 199