Study On Pollution-free Treatment Of Oily Sludge From Tank Bottom By Microorganisms

Oily sludge is a waste,it will become a resource and bring certain economic benefits if we can search a set of economical and practical way to deal with it.Biological treatment method for its no secondary pollution,simple operation,low cost is considered a better method of treating oily sludge currently.The recent study focused on a single strain of the oil degradation.In this thesis,oil degrading and surfactant-producing strains were isolated from oily sludge of oil-tank firstly,and via combination,the mixd culture Flo.2 was obtained, further studying the optimizational conditions of oily sludge,by shaing flask test,the biodegradation experiment of oily sludge from tank bottom was finished with mixd culture. This will be providing a technical way to control pollution caused by oil-tank sludge.Objectives:Oil degrading and surfactant-producing strains were isolated from oily sludge from oil-tank and oil-contaminantd soil firstly in order to construct a mixd culture; study on the optimizational conditions of oil degradation of mixd culture;through shaing flask test,the biodegradation experiment of oily sludge from tank bottom was finished with mixd culture.This will be laying a theoretical basis for the realization of oily sludge treatment. Methods:Through enrichment and separation,the oil degrading and surfactant-producing strains were obtained;and via combination,a mixd culture was constructed;by using morphological,physiological and biochemical methods of the various strains in the mixd culture;choice of single-factor experiment for the best oil degradation of nitrogen and phosphorus nutrients,the suitable pH value range and rotate speed;the optimal inoculation proportion of strains and the optimal conditions of oil degradation were screened by L₉(3⁴) and L₁₆(4⁵) orthogonal experiment;the biodegradation experiment of oily sludge from tank bottom was finished with mixd culture by shaing flask test.Results:two strains of oil degrading strains(numbered PB10,SY-8) and 3 strains of surfactant-producing strains (numbered SY-3,PB2,GJ4) were isolated from oil-tank sludge,the mixd culture composed of PB10,SY-8,SY-3 and PB2 was abtained via combination test,the strains SY-3,SY-8,PB2 and PB10 as Bacillus sp.,for the four strains the suitable pH value range is 5～9,the temperature range is 25℃～50℃,the range of salt concentration is 2～12 g/L,the optimal conditions:the temperature 35℃,the pH 7.5,the salt concentration 7 g/L;The optimal oil degrading ingredient of Flo.2 was:N sources and P sources were respectively NaNO₃ and K₂HPO₄,the optimal range of pH value was 7～9,rotate speed 180 r/min;the best inoculation proportion of each strain was PB2:PB10:SY-3:SY-8=5:1:5:1,the optimal conditions of oil degradation were that pH 8.0,initial oil concentration 12 g/L,NaNO₃ 4 g/L,K₂HPO₄ 3 g/L, inoculation volume7%,under the optimal conditions,the oil degradation rate reached 73.19%, the viscosity reduced 61.83%.The result of biodegradation experiment found that the oil degradation rate was increased rapidly when adding both nutrients and mixd culture Flo.2,in 16 days,it reached 71.4%.Gas chromatography detection analysis showed that Flo.2 can degraded saturated and aromatic hydrocarbon drastically,the oil and sand were separated effectively after degradation.Conclusions:This research provides some strain resource and information in solving oil field environment pollution,and also a feasible way in aspects of the biological control for future pollution caused by oil-tank sludge or other oil pollution.