Screening High Effective Oil Degradation Strain And Its Bioaugmentation Of Oil Wastewater Treatment

Oil wastewater is one of the most widespread environmental pollution in the world. How to eliminate the contamination economically, rapidly and reasonably, has received much public attention and thus become a major social problem in the past several years. Current physical and chemical technologies such as flotation and sedimentation are often insufficient and easy to cause secondary pollution. Biological technology is the most effective, safe and reasonable method for oil pollutions treatment. Bio-fluidized bed is a high effective biological treatment technique and suitable for high concentration organic wastewater treatment. Bioaugmentation, which use selected microbes to degrade organic compounds, can combine with different treating systems to remove some objective pollutant.This study aims at the pollutants that contain high concentration of oil and applies bio-fluidized bed to treat oil wastewater by bioaugmentation with screened strains that can degrade oil effectively. With olive oil as the sole carbon source, one hundred and six strains were isolated from different oil contaminated wastewater, soil and sludge by enrichment and acclimation. And six of them with higher capability of oil degradation were identified. The strains X4 and J2 were identified as Burkholderia cepacia and Candida steatolytica respectively.Optimal conditions for oil degradation were studied. For strain X4: the optimum temperature is 30℃ and the optimum pH is 7.0. For strain J2: the optimum temperature and the optimum pH is 25℃ and 5.0 individually. Detailed studies have been carried out on the characteristics of the strain X4 and J2 in oil degradation and the results as follows: Ammonia sulfate is the suitable nitrogen source for oil degradation. To promote oil degradation and the growth, the optimum C/N is 4:1 for X4 and 5:1 for J2 individually. Surfactants can promote oil degradation at low concentration, for X4 and J2, the proper concentration of Tween-80 is 600mg/L and 900mg/L individually. Olive oil co-substrate biodegradation with 200mg/L glucose can increase oil degradation rate by 8%~10%. When the concentration of oil is below 2500mg/L, oil biodegradation by X4 follows Monod kinetics model.The un-acclimated active sludge degraded oil very slowly and 9% of oil was degraded in 24h. But the acclimated active sludge could degrade 78% of oil in 24h. The capability of treating oil wastewater was enhanced greatly by bioaugmentation in active sludge system.The studies on the hydrodynamics of the bio-fluidized bed show that it has...