Transport and Reaction of Aromatics, O sub(2) and CO sub(2) Within a Membrane Bound Biofilm in Competition with Suspended Biomass

• Published in: Water science and technology 1995-01, Vol.31 (1), p.129-141
• Main Author: Debus, Oliver
• Format: Article
• Language: English
• Subjects: Benzene; Biomass; Bioreactors; Carbon dioxide; Freshwater; Mathematical models; Membranes; Oxygen; Q1; Volatile organic compounds; Xylene
• ISSN: 0273-1223

Volatile organic pollutants were degraded in a biofilm bound to a membrane, through which oxygen was supplied to investigate the effect of time on the transport and reaction processes. A technical mixture of o-, m-, and p-xylene and ethylbenzene was used. The experimental data were interpreted using a mathematical model that examined aerobic xylene degradation, biofilm growth, transport processes in the gas, biofilm, liquid boundary layer, and bulk fluid compartments, and spatial profiles of pH in the biofilm. The biofilm thickness grew from a starting value of 4.5 mu m up to 2000 mu m within 39 d. The high xylene conversion plateau of over 90% was due to the spatial transport processes of O sub(2) and xylene in the biofilm. The first sub-maxima of the conversion by suspended biomass was determined by a maximum O sub(2) flux through the membrane-bound biofilm into the bulk. Oxygen became limited in the bulk later, and less xylene was degraded by suspended biofilm, which led to a maximum transport of xylene into the biofilm and subsequent maximum conversion of xylene. The transfer of carbon dioxide from the biofilm into the gas phase was up to six times higher than the transfer of CO sub(2) from the biofilm into the bulk.