Degradation Of Oil Smoke With Immobilized Mix Bacteria

Oil smoke is a kind of mixed contaminant. To decrease the deleterious contents, different strains which could degrade grease, toluene and hexanal separately were inoculated in biofilter. To select a strain which can decrease grease, a strain was screened from soil which was contaminated by oil smoke then statistical experimental design was applied to optimize the fermentation process of lipase. Firstly, three important parameters, which affected the lipase production, were screened among 11 parameters by Plackett-Burman Design. The amount of soybean power, K2HPO4 and the rotate speed of rocking bed were found to be the most important factors. Then Central Composite Design was applied to fit a response surface function. The response surface function was:y = 507.12 + 84.42x1 + 145.34x2-7.36x3 -31.33x₁² -156.43x₂² + 0.02x₃² - 16.00x1x2 + 0.08x1x3 + 0.76x2x3 Through the function we can get the optimum fermentation conditions: soybean power 1.32%, K₂HPO₄ 0.688%, rotate speed of rocking bed 120r/min. A maximum yield of enzyme was obtained.The diameter of the biofilter was 250mm and the height of the filling was 300mm. The biofilter was filled with Sperculiaceae flavonoibs wood (20mm×20mm×10mm). The performance of a pilot-scale biofilter in the treatment of oil smoke has been evaluated in this study. The operational parameters investigated were the gas-flow rate, temperature and inlet concentration. The optimal operation temperature was 30 ℃ and an adequate moisture content(60%) was found to contribute significantly in the performance of the biofilter. In this condition, when the inlet concentration was less then 380mg/m³ and the gas-flow rate was less then 0.6m³/h, the removal efficiency was more then 90%. The long-term performance of the biofilter is stable, the removal efficiency could stay at 91%.