Multiphase Bioreactor Design

parameters by fitting the model to experimental data on substrate consumption rates in
laboratory or larger scale reactors. Most of the time, the external mass transfer resistances
were not taken into account, and only the apparent kinetic constants were estimated.
Since it is considered that in wastewater treatment processes using biofilms the apparent
kinetic order is in most cases 1/2 (Harremöes, 1978), Table 10.2 indicates typical values
of the apparent half order constant (k1/2ap), which, from Equation (27), is:

(^) (43)
Although the data in Table 10.2 display some scattering, the order of magnitude of the
k1/2ap values is the same and there are no large inconsistencies in aerobic heterotrophic
and autotrophic systems. This is somehow remarkable in view of the considerable
differences between the cases studied (different reactors, different substrates, etc.), often
without a real accurate control of the measured variables. Anyhow, design

Table 10.2 Apparent half order kinetic constants in

wastewater treatment (k1/2ap.)

Biological process and
Limiting metabolic factor

Reactor type K1/2ap·10^5

(kg1/2.m−1/2.s−^1 )

Reference

Aerobic, heterotrophic biomass
Oxygen

Fixed bed 0.12 Grasmick et al.

(1982)

Aerobic, heterotrophic biomass
Oxygen

Rotating drum 0.12–0.15 Harremöes et al.

(1980)

Aerobic, heterotrophic biomass
Glucose

Rotating drum 0.12 Harremöes (1978)

Harremöes et al.

(1980)

Aerobic, heterotrophic biomass
Toluene

Waste gas

trickling filter

0.07–0.11 Pederson and Arvin

(1996)

Nitrification, autotrophic biomass
Oxygen

Rotating disk 0.075–0.14 Gönenç and

Harremöes (1985)

Nitrification, autotrophic biomass
Oxygen

Submerged filter 0.05–0.10 Çeçen and Gönenç

(1994)

Nitrification, autotrophic biomass
Oxygen

Circulating bed

reactor

0.15 Nogueira et al.

(1998)

Nitrification, autotrophic biomass
Ammonium

Rotating disk 0.06 Gönenç and

Harremöes (1985)

Anaerobic, methanogenic
biomass Acetate

Downflow filter 0.12 Hamoda and

Kennedy (1987)

Anaerobic, methanogenic
biomass Acetate

UASB 0.05 Brito and Melo

(1997)

Anaerobic, methanogenic
biomass Molasses

Upflow filter 0.04–0.48 Gönenç et al. (1991)

Biofilm reactors 313