Study On The Biodegradation Of Refinery Wastewater In Three-phase Fluidized Bed By Microorganism UBD

The increasing demand of freshwater aggravates the contradiction between the expansion of petrochemical industry and the shortage of water resources, which creates a valuable chance to develop wastewater disposal technology. Petrochemical wastewater was continuously biodegradaded through the intergration of the microbial embedding technique and airlift inner-loop three-phase inner fluidized bed reactor by microorganism UBD.Firstly, UBD batch treatment and adsorptive process were studied to find a better petrochemical wastewater treatment. At the optimal biodegradation conditions that were 500μL/L(V/V) concentration of UBD, continuous aeration, after 48h biodegradation, the chemical oxygen demand (COD) was decreased from 1321mg/L to 539mg/L, with the removal of 59.2%. At the same time total petroleum hydrocarbons (TPH) were reduced from 65.6mg/L to 5.0mg/L, with the removal of 92.3%. The removal of MTBE and the mixing waster of MTBE and DME were up to 90%.Secondly, the biodegradation of oily wastewater was studied under continous disposal. The optimized formulation was:PVA 4%, SA 1.5%, C1.5% and SiO2 1%(wt%); the optimized operation condition was:HTR 15h, gas velocity 180L/h, solid holdup 3% and the particle diameter 3mm. The removal of MTBE wastewater and mixing wastewater of DME and MTBE were up to 88.5% and 87.9% respectively. The wastewater from Sinopec Shanghai Gaoqiao Petrochemical Corporation was biodegraded by microorganism UBD under optimized conditions. The COD and TPH removal were 85% and 92.3% respectively. The quality index of the wastewater after treatment conformed to the first-class standard of National Discharge Standards. Hydrodynamics characteristics were also studied in this paper. The optimized condition was:gas holdup 8.13%, liquid cycle time 9s, liquid uniform mixing time 36s and oxygen transfer coefficient 20.5 min-1.Finally, the culture medium for UBD was selected and the optimized formula was: peptone, yeast and NaCl were 18 g/L,5 g/L and 10g/L respectively. The study used the medium achieve the expansion of the bacteria UBD, as to provide the following experiments with the bacteria.