Experimental Investigation Regarding Bioremediation Of Petroleum Polluted Soil In The Loess Area

The exploitation and utilization of petroleum in northwest loess area has a long history of more than 90 years.Due to large aera of oil field and numerous oil wells,there are large quantity astepetroleum hydrocarbon in the process of petroleum production,storage,transportation,refinement,processing and use. All of this can create oil pollution in large area,which causes the frail natural environment to be originally wicked.Because this kind of diesel oil has relatively high biological toxity and the residue is relatively permanent,people show more and more attention on how to remediate the polluted environment.Bioremediation of pesticides-contaminated environment,which exploits the ability of organisms to degrade and/or detoxify organic contamination, has been established as an efficient,economic,versatile,and environmentally sound treatment.Decontamination of polluted sites in our country with bioremediation has received increasing interest recently.This paper the Oil as a typical pollutants,From Large-degrading bacteria which have been isolated from Oil-contaminated soil,screening,isolated 4 efficient degradation of the advantages of bacterias,By Random mixing and optimizing them,Get a group of good mixed group of bacteria with the greatest increase in the level of degradation system in the activity and degradation of competency-based,That is internal research——How to maximize to strengthen the capacity their own of group of bacteria;And study the impact of mixed groups of bacteria degradation of the nutritional conditions and environmental factors pilot,Then to choose the more important of the four conditions orthogonal test to determine Mixed group of bacteria's the best growth conditions and the best nutritional conditions,Finally,under degradation of the best under the conditions,Optimal group of degrading bacteria carried out Kinetic experiments.From external factors to consider——How to make pollutants conditions and environmental conditions more suitable for bacterial degradation,In-depth,systematic study the impact of the microbial degradation of the impact of factors,environmental conditions and enhanced technology. In this study,pollution conditions of simulated test method which lasted 180 d,made 226 sets of data,the analysis of access to the following conclusions:1.Identify performance degradation of individual bacteria:Screening of oil degrading bacteria efficiently A,B,C and D,during 3d time,to reduce oil pollution in the soil 1/5 around,that is,degradation rates were 24% 19.81%,22.55% and 26.43%,the effect is more satisfactory.In contrast the test results of the removal of the oil pollution between the addition of degradation of the best advantage of bacteria D and not addition advantage bacterial degradation of indigenous microorganisms, Throughout the 40 d monitoring tests the results of removal of pollutants like oil for the addition of degradation of the best advantage of bacteria D than not addition advantage bacterial degradation of indigenous microorganisms increased by 25 percent,That specify there is obvious effects of the advantage of degrading bacteria degraded oil pollutants.2. The strengthening of bacteria: Bacteria of combinative test, access to better the efficiency of the degradation of mixed bacteriaACD-3,at 3 d time,Degradation of the oil in soil was 2/5,that is,the degradation rate reached 39.67 percent,than rate of the single-Degradation Increases by 15 percent,through Three factors four levels of Orthogonal text,we get mix of bacteria's the best ratio of inoculation is A:C:D=1:4:13. the strengthening of conditions:the study results of different concentration of crude oil,different Surfactant and different additive concentration , different temperature,PH value, ventilation volume, inoculum concentration, additive H2O2, additive nutrients and so on impact the mixed bacterial degradation rate show that:Under the same time conditions (processing time for 7 d), Optimum conditions for the mixed bacterial to degrade the crude oil from Yan'an refinery are:the best conditions of mixed bacterial system to degrade crude oil are inoculum concentration for 5 ml, pH is from 6.05 to 7.62,crude oil concentration of 3 percent,the temperature around 36℃,nutrients C:N:P for 75/8.0/3,surfactant used SDBS Tianjialiangwei and surfactant concentration of 0.5 percent, H2O2 concentration of 1.5%. conditions of aeration for the six-storey,7 d time in the soil of crude oil in addition to nearly half that rate of degradation of 47 percent or more.During 7d time the rate of degraded crud oil in the soil increase to half, namely thatmore than 47%.4. Dynamic experiment: a mixed strain in the best conditions,120 d of time, the degradation of crude oil reached 80.2 percent, even if the oil pollution in the soil decreased by 4/5,the effect of significantly through the mixture of ACD-3 degradation of crude oil during the dynamic.