| The research target of this experiment is a lake in Daqing.It was allowed to accept pollutants in 1988,and has repeatedly accepted oily wastewater discharged by oil refineries.Because of the long-term acceptance of oily wastewater,the water quality is lower than the five types of water quality.The water body began to become eutrophication and the ecological environment was destroyed.Analyze the research object's water quality test results and environmental status survey over the years,it was found that the raw water contained a large amount of petroleum hydrocarbons.In order to restore the lake water quality,microbial in-situ remediation technology is used to remove petroleum hydrocarbon pollutants in the water.The purpose of this research is to isolate indigenous microorganisms with good petroleum hydrocarbon degradation ability from the experimental target bottom mud,and identified and analyzed;Study the degradation characteristics of the strains on petroleum hydrocarbons to determine the most suitable degradation conditions;Finally,the degradation efficiency of the strains in the treatment of pollutants in lake raw water was investigated,and the influence of environmental factors on its degradation efficiency was explored.The significance of this research is to provide excellent strains and theoretical guidance for the subsequent in-situ bioremediation technology.First,through enrichment,separation,and sequencing analysis,two high-efficiency petroleum hydrocarbon degrading bacteria were screened out from the polluted lake sludge,and they were named LYC-1 and LYC-2.Through morphological observation,physiological and biochemical tests and 16 S r DNA sequencing analysis of the two strains,it was determined that LYC-1 is Acinetobacter modestus,belonging to the Acinetobacter genus;LYC-2 is Pseudomonas aeruginosa,belonging to Pseudomonas Genus.This study investigated the degradation characteristics of the two strains and found that the strain LYC-1 has a p H of 8,a temperature of 25 ?,a dissolved oxygen of 6.5 mg/L,an inoculation ratio of 5%,a C/N of 6,and a substrate concentration of 1500 mg /L,sodium acetate is a co-metabolism substrate,and the degradation rate of petroleum hydrocarbons in 7 days is more than 70%;Strain LYC-2 has a p H of 7,a temperature of 30 ?,a dissolved oxygen of 5.0 mg/L,an inoculation ratio of 5%,a C/N of 6,a substrate concentration of 2500 mg/L,and sodium acetate as a co-metabolic substrate.The degradation rate of petroleum hydrocarbons in 7 d is over 65%.Analyzing the products before and after degradation by GC-MS technology,it was found that the content of C12-C19 linear hydrocarbons in the system was significantly reduced after degradation,and a small amount of C11-C17 branched chain hydrocarbons remained.Investigating the water quality of the polluted lake found that the raw water has a p H of 9.2 and a TOC of 74.88 mg/L.The content of phosphorus and ammonia nitrogen in the water is less;the COD is 263.5 mg/L,and the content of organic pollutants is relatively high.Subsequently,the effects of strains LYC-1 and LYC-2 on the treatment of organic pollutants in raw water were explored,and it was found that without changing environmental conditions,the degradation efficiency of LYC-1 strain in 72 hours was16.10%,and that of LYC-2 strain Is 35.12%.Explore the effects of three conditional factors of p H,C/N and co-metabolism matrix on the degradation efficiency of the two strains.Studies have found that the degradation effect of LYC-1 is 52.20% when the p H is 8,C/N is 6,and the co-metabolic substrate is sodium acetate,which is 36.10% higher than that of the blank group without changing environmental conditions;LYC-2 When the p H is 7,the C/N is 6,and the co-metabolism substrate is sodium acetate,the degradation effect is 47.96%,which is 12.84% higher than that of the blank group without changing the conditions.It shows that the two strains have good degrading ability to the organic pollutants in the raw water. |
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