| Summary: | 碩士 === 國立成功大學 === 環境工程學系 === 84 === Two-step Biofilm Kinetics and Characteristics of Conventional
and Tapered Anaerobic Fluidized-Bed BioreactorsGraduate Student:
Jii-Liaq Yan Advisor: Ju-Sheng HuangABSTRACT In order to
compare the differences of the characteristics and performance
of conventional and tapered fluidized-bed bioreactors, the two-
step biokinetic models including biofilm model and reactor model
(of CSTR) were derived for the simulation purpose. Thereafter,
the experimental results obtained were used to verify the
proposed models. One set of the conventional fluidized-bed
bioreactor and three sets of tapered fluidized-bed bioreactors
with taper angles of 2.5o, 5o and 10o were used to treat the
sucrose-containing synthetic wastewater. The substrate
concentrations of bulk solution at various cross-section of
bioreactor, the biofilm thickness, and the specific biomass in
the lower-, central- and upper-part of bioreactor were measured
once the bioreactor reached steady state. Meanwhile, the
weight-loss of activated carbon from biorea If the geometric
shape of conventinal bioreactor (i.e. identical cross-sectional
area) is modified to the tapered one (i.e. narrower at the lower
part and wider at the upper part), the wash-out of bioparticles
from the bioreactor can be remarkably mitigated. Excepting the
taper angle of 10o, the arithmetic mean of biofilm thickness of
the later is thicker than the former (86.6 mm), especially for
the taper angle of 5o (103.9 mm). The biomass concentration
significantly increases with the increasing tape Moreover, the
flow regime of conventional and tapered bioreacotrs determined
by tracer study are close to CSTR, and the axial mixing of the
later is more violent than the former. In addition, by using
the suspended-growth batch reactor, the Monod type biokinetic
constants of k1, Ks1, k2, Ks2 found are 28.5 mg-Sucrose/mg-
VSS-day, 145mg-Sucrose/l, 3.28 mg-CH3COOH/mg-VSS-day, and 484
mg-CH3COOH/l, respectively. The distributed fractions of
acidogenic bacteria and aceticlastic methanogens in the biofilm
aKey words: anaerobic fluidized-bed bioreactor, taper angle,
two-step biokinetic model, flow regime, substrate sucrose,
biofilm characteristics, distributed fraction of acidogenic
bacteria and aceticlastic methanogens, model verification.
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