The kinetic parameters for combined carbon/nitrogen removal in a four-
stage aerated submerged fixed-film (ASFF) bio-reactor of 50 l volume w
ere evaluated using a synthetic wastewater at 20 degrees C. Influent C
OD concentrations were in the range of 0.057-1.8 g COD l(-1), and infl
uent NH3-N concentrations were in the range of 0.0152-0.48 g NH3-N l(-
1) with hydraulic loaning ranging from 0.028 to 0.112 m(3) m(-2) day(-
1) coed nitrification was achieved even when high mass loadings were a
pplied. The substrate (GOD or ammonia) removal in the reactor was desc
ribed by a substrate-limiting phenomenon (reaction or mass transport).
Substrate-removal rate followed Monod kinetics in the first stage of
the reactor but was better described by first-order kinetics in the se
cond to the fourth stages as the substrate concentration became much l
ower: The order of the reaction was apparently a function of the hydra
ulic lending, indicating the influence of mass transfer on the 'appare
nt' order of the reaction. Copyright (C) 1996 Published by Elsevier Sc
ience Ltd.