Study on Biodegradation of 4-chlorophenol by Immobilized Microorganism in Aerobic Biological Fluidized Bed

In this paper, biodegradation of chlorophenols which is harmful to environment was studied. The experiment was divided into 5 facets. At the beginning, the factors influencing the biodegradation of 4-CP, such as different growing condition, nutrition condition and mixed culture was discussed. The results showed that the input of Fe~2+ and Fe3+ could improve the degradation of 4-CP;the input of carbon sources , such as glucose and peptone with the optimum dose had, could also increase degradation rate.The second is to compare the removal efficiency of 4-cp by two addition methods and two kind of reactors. As the result, removal efficiency was low using 4-CP as sole carbon source;the loading capacity of SABR was higher SBR, and the removal efficiency using SABR was better than SBR.In the third, two kinds of startup methods with ceramic as the carrier was compared. The results showed that the quantity of suspended microorganisms was more than the quantity of biofilms in the fluidized bed by the two methods. The main reason is the Reynolds number is over high and the collision of carriers is violent.The fourth is that activated microorganisms balls were immobilized in the PVA-boric acid with embedding. The removal of 4-CP with immobilized microorganisms and free microorganisms was compared at different condition of temperature, pH and the quantity of microorganism. The results showed that the degradation efficiency of immobilized microorganisms was apparently superior to that of free a microorganisms, the optimal condition of degrading 4-CP was temperature 25℃~35℃, and pH 6-8.At last, the degradation of 4-chlorophenol by immobilized microorganisms in the aerobic fluidized beds was studied. The operating parameters of concentration of influent, HRT and air flux were discussed. The results showed that the average velocity of 4-CP degradation in aerobic fluidized beds was better than suspended microorganisms;the removal efficiency of the 4-CP was improved with decreasing HRT, but too long HRT made the growth of suspended microorganisms so fast that the operation of fluidized beds was inhibited;the air flux had an optimal range, because the air with high flux made the immobilized microorganism break up.