Abstract: With p-chloroaniline(PCA) as a selected substrate, the mixed microorganisms assimilating it as the sole source of carbon and nitrogen were obtained by acclimation technique from the enriched cultural products of degraded p dichlorobenzen(p-DCB). The mixed microorganisms immobilized in a packed-bed reactor were used to degrade PCA. In the packed-bed bioreactor, the biodegradation of PCAfollowed the Logistic equation, q = q_max /(1+e^α-βU_v ). The major kinetic parameters, K_s (half velocity constant) and q_max (maximum specific substrate degradation rate), were calculated. PCA was found to be degraded with a concomitant release of chloride ions into the substrate. Under the conditions of residence time of 3 hours and inlet stream at PCAconcentration of 360mg·L^-1, the volumetric degradation rate of the substrate was 125mg·L^-1·h^-1, with removal efficiency of 91%.

Key words: Packed-bed bioreactor, P-chloroaniline, Microbial degradation