Title: | Biofilm structure and mass transfer in a gas phase trickle-bed biofilter |
Author(s): | Zhu X; Suidan MT; Alonso C; Yu T; Kim BJ; Kim BR; |
Address: | "Department of Civil and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221, USA" |
ISSN/ISBN: | 0273-1223 (Print) 0273-1223 (Linking) |
Abstract: | "Mass transport phenomena occurring in the biofilms of gas phase trickle-bed biofilters are investigated in this study. The effect of biofilm structure on mass transfer mechanisms is examined using experimental observation from the operating of biofilters, microelectrode techniques and microscopic examination. Since the biofilms of biofilters used for waste gas treatment are not completely saturated with water, there is not a distinguishable liquid layer outside the biofilm. Results suggest that due to this characteristic, gas phase substrates (such as oxygen or volatile organic compounds) may not be limited by the aqueous phase because transport of the compound into the biofilm can occur directly through non-wetted areas. On the other hand, for substrates that are present only in the liquid phase, such as nitrate, the mass transfer limitation is more serious because of the limited liquid supply. Microscopic observations show that a layered structure with void spaces exists within the biofilm. Oxygen concentration distributions along the depth of the biofilms are examined using an oxygen microelectrode. Results indicate that there are some high dissolved oxygen zones inside the biofilm, which suggests the existence of passages for oxygen transfer into the deeper sections of the biofilm in a gas phase trickle-bed biofilter. Both the low gas-liquid mass transfer resistance and the resulting internal structure contribute to the high oxygen penetration within the biofilms in gas phase trickle-bed biofilters" |
Keywords: | "*Biofilms Chemical Phenomena Chemistry, Physical Equipment Design Gases Microelectrodes Nitrates/metabolism Oxygen/*metabolism Volatilization Waste Disposal, Fluid/*methods;" |
Notes: | "MedlineZhu, X Suidan, M T Alonso, C Yu, T Kim, B J Kim, B R eng England 2001/05/31 Water Sci Technol. 2001; 43(1):285-93" |