A novel fluidized bed respirometric technique for determination of in situ biofilm kinetics.
A respirometric approach has been developed to determine heterotrophic biofilm kinetics using fluidized bioparticles--particles with attached biomass. Lava rock particles of 600 microm were used as a biomass carrier medium. The modified respirometer successfully estimates in situ biofilm kinetics of the bioparticles collected from a pilot-scale liquid-solid circulating fluidized bed (LSCFB) bioreactor. The observed maximum specific growth rates (micro(max)) of 3.69 +/- 0.44 d(-1) and biomass yields (Y(H)) of 0.36 +/- 0.03 g COD/g COD in the fluidized bed respirometers were significantly different from the micro(max) of 5.57-5.72 d(-1) and Y(H) of 0.54-0.59 g COD/g COD observed in the conventional respirometric tests for bioparticles and detached biomass. The higher Monod half-saturation coefficient (K(S)) of 186-219mg COD/L observed in the fluidized bed respirometers relative to the 49-58 mg COD/L in the conventional respirometers reveals the presence of mass transfer resistance in the LSCFB despite fluidization. Significantly reduced yields in the fluidized bed respirometers and the estimated maintenance coefficient of 1.16 d(-1) for the particulate biofilm in the LSCFB clearly emphasize that a substantial amount of substrate was utilized for cell maintenance at the low food to microorganism (S/X) ratio of 0.5 g COD/g VSS.
Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, Canada N6A 5B9. nchowdh3@uwo.ca
Nabin
N
Chowdhury
George
G
Nakhla
Jesse
J
Zhu
D018407:Bacterial Physiological Phenomena; D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors / Q000382:microbiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007700:Kinetics; D010100:Oxygen / Q000032:analysis*; D010101:Oxygen Consumption / Q000502:physiology*
D010100:Oxygen