Treatment Of Oil-containing Wastewater By Biosorption And Reutilization Of Recovered Lipid

This paper focused on the phenomenon that strain Mycobacterium sp. QJ3011 adsorb lipip from the waste water and developed the craft route that constituted by four steps of wastewater madulation,cell proliferation,biosorption,filtering and recovery.In this foundation,the key step of this craft route that the forming process of cell - lipid complex had been discussed. Finally, the lipid recoveried by the above craft would be used as the carbon source in microorganism fermentative process of sufactin. Using the lipid recovered from the oil-contain waste water as the resources would be explored.Reduced content of the other bacterium by modulated of the wastewater and got the competitive advantage for strain Mycobacterium sp. QJ3011 to grow well; The range of the biological adsorption processing in oil-containing wastewater was studied,as a reasult, the lipid may be recoveried about 40%, and COD may reduce above 70% after dealed with the wastewater contained the oil of 0.1～5% by used the biosorption craft processing;The research discovered, when the chemical synthesis emulsifier content in the wastewater is higher than 0.1%, the obvious adverse effect would be caused;The effect of several process parameters:the initial concentration of bacteria,cultivation time, adsorption time on adsorb were examined. The best adsorption condition is : initial bacterium content 1.0×10⁷cfu/mL, adsorption time 18h, adsorption time 36h.Under this condition, the lipid adsoptive rate was 62.44%, COD droped 58.9% in the waste water.The balanced relation of inactivated bacteria absorb on lipid was studied, synchronously monitored the growth curve , the curve of cell-surface hydrophobicity and the curve of lipase activity during the whole biosorption process in order to gave the formation process and correlated mechanism of cell - lipid complex, the basic structure of cell - lipid complex was observed by electron microscope in order to prove the credibility of the formation of the cell-lipid complex. The research shown, there were sevel steps during the formation of the cell-lipid complex.:(1) the lipid was absorb when the bacteria transfer to the surface of oil;(2) the oil was stable after the bacteria aggregating on the surface of oil;(3) the cell-lipid complex was form after the oil that was steadied by bacteria mass together.The effect of temperature,rev, bioactive on the formation of cell-lipid complex.The result shown,the cell-lipid with more lipid will be loose because of the smaller oil by reason of higher temperature or more shear force of fluid.The cell-lipid complex would form faster for the bioactive of Mycobacterium sp. QJ3011.The lipids recovered from oil-containing wastewater by biosorption were used as carbon source for Bacillus subtilis FO211 fermentation to produce biosurfactant , while the rapeseed meal was supplied as nitrogen source. Optimization of the fermentation media for surfactin production was carried out. Single factor test and response surface methodology(RSM) were combined to explore the main factors influencing surfactin production, such as the quality ratio of recovery lipid and rapeseed meal, the concentration of Fe(â…¡)and Mn(â…¡). The results shown that the optimal conditions for the fermentation were as follows;the concentration of FeSO₄ was 2.4mg/L;and that of MnSO₄ was 0.09g/L;the recovery lipid was 0.8g/L and rapeseed meal was 1.2g/L.Finally,the biosurfactant extracted from the fermentation media was indentified as surfactin.