AEROBIC AND ANAEROBIC BIOTRANSFORMATIONS AND TREATMENT OF CHLORINATEDPULP BLEACH WASTE CONSTITUENTS

Biotransformations and treatment of several chlorinated, hydroxylated and methoxylated monoaromatic compounds were studied in batch bottle b ioassays and continuous-flow fluidized-bed reactors. With the aerobic enrichment, polychlorinated phenols were biodegraded with simultaneous release of inorganic chloride in amounts equal to mineralization stoi chiometries. Aerobic removal of 4,5-dichlorocatechol and 4,5-dichlorov anillin were associated with the release of inorganic chlorine. The ae robic enrichment showed no activity against mono- or di-O-methylated p henols. With the anaerobic enrichment, reductive transformations of th ese compounds were observed. These transformations included reductive dechlorinations, de-O-methylations and dehydroxylations. High-rate ope ration of an aerobic fluidized-bed reactor resulted in over 99.7% biod egradation of polychlorophenols. In the anaerobic fluidized-bed reacto r, over 95% removal of chlorophenols with no apparent accumulation of lower chlorinated phenols indicated complete dechlorination.