FACTORS ENHANCING THE BIOREMEDIATION OF A POLYCHLOROBIPHENYL-CONTAMINATED SOIL IN SLURRY-PHASE AND FIXED-PHASE BATCH BIOREACTORS

The influence of the availability of nutrients as well as exogenous sp ecialised bacteria on the bioremediation of a polychlorobiphenyl (PCB) -contaminated soil originating from a dump site was studied in this wo rk by using both slurry-and fixed-phase batch bioreactors. Significant disappearances of the soil PCBs were generally attained in the presen ce of biphenyl and O-2. These nutrients were found to enhance the surv ival of indigenous PCB-and chlorobenzoic acid-degrading bacteria and t his, in turn, probably determined a more rapid and complete PCB deplet ions. The soil inoculation with a PCB-degrading bacterial culture or a co-culture of two chlorobenzoic acid-mineralising bacteria in the pre sence of biphenyl and O-2 was found to favour the depletion rates and yields of some soil PCBs. This result can be considered the direct con sequence of the higher availability of specialised bacteria observed i n the inoculated bioreactors.