OXIC FLUIDIZED-BED TREATMENT OF DICHLOROPHENOLS

Dichlorophenol (DCP) degradation was studied under oxic conditions using celite carrier material for immobilization of microorganisms in fluidized-bed reactors. Stoichiometric release of chloride and total organic carbon removal from 2,4-DCP and 2,6-DCP (20 mg/l as TOC) indicated complete mineralization at hydraulic retention times of 1 and 3 hours, respectively. GC/MS analyses showed no DCPs or intermediary metabolites in the effluents. No 3,5-DCP degradation could be observed in the fluidized-bed reactor. Microorganisms were isolated from the reactor and their ability to degrade 2,4-DCP was evaluated in bioassays. 2,4-DCP degradation was slow by CPO III (gram-variable rod) and by CPO IV (gram-positive micrococcus) whereas the mixture of these isolates readily degraded 2,4-DCP.