| The effect of a combined chemical (ozone) and biological (mixed microbial population) process, for the treatment of 50mg/L aqueous-PCB suspensions, was studied. The oxidative pretreatment was influenced by the PCB mixture being treated (Aroclors 1242, 1248, 1254 and 1260), the applied ozone dosage, as well as the temperature and pH of the aqueous system. An aqueous ozone concentration of 35mg/L, applied for one hour, had the greatest destructive capability and subsequently, was used to pretreat PCBs in combined treatment experiments. Using these ozonization conditions, 1242 underwent 44.6% destruction (c.f. 23.8% at high temperature and 14.4% in basic pH); 1248 was reduced by 15.9% (c.f. 14.1% at high temperature and 1.4% in basic pH); and 1254 and 1260 were unreactive under all experimental conditions.;The potential of ozone to enhance PCB biodegradability was examined by comparing the degradability of preoxidized and untreated aqueous suspensions, of 1242 and 1248, using batch cultures of activated sludge and a mixed microbial population from past PCB-contaminated soil. (Abstract shortened by UMI.). |
