The Phenol Removal By Rhodococcus Rubbers Immobilized On Coral Sand

Phenolic wastewater is a sort of industrial wastewater. It is not only has serious effects on the environment, but also will bring great harm to the people health. In the present study, the Rhodococcus rubers was immobilized into the coral sand with porous structure, and the composite Rhodococcus rubers-coral sand were used for the phenol wastewater treatment.The orthogonal experiment results suggest that the concentration of bacteria had the greatest influence on the degradation of phenol, followed by p H and temperature, then the salinity and phenol concentration. The optimal temperature, p H, salinity, concentration of bacteria and phenol concentration for the degradation of phenol by free cells were 7.0,30℃,15g/L, OD600=1.1, 50mg/L, respectively.The simulated wastewater with low phosphorus and normal phosphorus content were treated by the Rhodococcus rubbers, and the removal rate of phenol were 29.2% and45.7% respectively, which indicated that phosphorus has played an important role as the limiting factor during the phenol degradation process. It happens that the results of experiments show that the coral sand can accumulate phosphorus from wastewater.The adsorption capacity of the coral sand for phosphorus is 0.0184mg/g. Further more, the removal rate for phenol from low phosphorus wastewater by free and immobilized cells were 56.1% and 21.4% respectively. It’s obviously the removal rate of immobilized group are more better than the free group.In the single factors experiment, experiment was performed at various temperature(20~45o C), p H(6~12), salinity(0~35g/L). The results show that the immobilized cells could protect the bacteria against the changes of external environmental condition.Reusability results revealed that the immobilized cells could be reused in ten consecutive degradation experiments and maintained a high removal rate. The removal rate of phenol was decreased obviously while the velum aged and felled off.