REUSE OF BIOLOGICALLY REGENERATED ACTIVATED CARBON FOR PHENOL REMOVAL

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 Science Ltd. All rights reserved.