Study Of The Removal Of Organic Pollutants In Groundwater By Microorganism/nano-valent Iron Technology

The hydrophilicity of dioxane is high,so it can rapid migration in the aquatic environment and it is one of the potentially hazardous organic pollutants.Because it is commonly used as a stabilizer for chlorinated solvents,so the areas where has dioxane pollution are often accompanied by contamination with organic chlorinated solvents.Therefore,dioxane pollution and its co-contamination with chlorinated organic solvents should be given high priority.In this paper,dioxane,trichloroethylene and trichloromethane are treat as target pollutants,and chose microbial remediation method and nano-iron coupling to solve the combined pollution.?1?Compared with microorganism degradation of target pollutants,the efficiency of nano-iron and microorganism in removing pollutants is improved.The Trichloroethylene and trichloromethane can be degraded within 300 hours in co-pollution system which consist dioxane and trichloroethylene or trichloromethane,and the dioxane can be degraded within 600hours in this system.?2?High-throughput sequencing technology was used to study the diversity of microorganisms.It was found that the composition of dominant bacteria in the co-pollution degradation group of dioxane and trichloroethylene or trichloromethane was similar,However,there is a large difference in the composition of the co-metabolism degradation group with dioxane and tetrahydrofuran.The Pseudonocardia bacteria can co-metabolize dioxane.Dehalococcoides bacteria can dechlorinate chlorinated hydrocarbons to ethylene in the presence of electron donors.Macellibacteroides and Geobacter bacteria are disproportionate iron-reducing bacteria that can be decomposed by oxidative degradation of dioxane under anaerobic conditions.?3?Through chemical analysis and microbiological analysis of co-contaminants,it is found that nano-iron/microbial coupling method is beneficial to the degradation of co-contaminants.In theory,nano-iron was the first to dechlorinate hydrogen to offer electron to decomposition organochlorine compound and in the meantime,Fe²⁺and Fe³⁺enrichment in the system,so the Macellibacteroides and Geobacter bacteria were begin to reduced iron oxide ions to provide energy for the decomposition of dioxane mineralization.Moreover,the process improves the activity of nano-iron,thus causing the degradation of chlorinated hydrocarbons in circulation.The degradation time of pollutants in the actual test is also much higher than that of microorganisms.