Granular biologically activated carbon (GBAC) is in principle suited f
or removal of phenolic substrate from wastewater. In this study a wast
ewater model was used and special attention was paid to the operation
of separate aerobic bioregeneration of carbon and reuse of bioregenera
ted carbon in a new stage of the experiment. In order to assess the ef
fectiveness of bioregeneration, the efficiency of the biosorption syst
em both before and after its bioregeneration was monitored at the subs
trate concentrations ranging from 1.9 to 1053 mg l(-1). All kinetic pa
rameters for the biosorption system were determined for both fresh and
already used GBAC. A 92-100% efficiency of phenol removal was achieve
d irrespective of whether the fresh or bioregenerated GBAC was used. T
he process of bioregeneration for the once-used GBAC was faster than f
or the one that was used several times. It was also faster when phenol
alone was used as substrate than in the case of a phenol mixture. Res
pirometric measurements indicated that a mixture of substituted phenol
s showed inhibition effects on microorganisms. Calculations based on t
hese measurements, as well as the findings of GC/MS analysis. indicate
d that deterioration of the adsorbent quality was taking place continu
ously. It was concluded that bioregeneration, carried out as a separat
e operation, could not be recommended for practice. (C) 1998 Elsevier
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