Abstract
Degradation of tetrachloroethene (PCE) by using a two-stage anaerobic/aerobic bioreactor system was investigated. A PCE-dechlorinating anaerobic consortium was immobilized on the surface of crushed scallop shells. The maximum rate of PCE dechlorination to cis-1, 2-dichloroethene (cDCE) with an anaerobic fixed-bed upflow reactor containing the biofilm on the shell was 30μmol PCE·l-1 reactor volume·h-1. A phenol-oxidizing bacterium, capable of co-metabolic degradation of cDCE was immobilized in κ-carrageenan gel beads. Gaseous cDCE purged from effluent of the anaerobic reactor was degraded with an air-lift aerobic reactor containing the immobilized cells. To degrade PCE continuously, yeast extract was added to the anaerobic reactor feed, and phenol was added to the aerobic reactor feed. The life of the two-stage anaerobic/aerobic bioreactor had been tested for one month at a PCE supply rate of 17μmol PCE·l-1 reactor volume·h-1. The activity of the aerobic reactor decreased gradually, although the activity of the anaerobic reactor was stable during the experimental period.
