The Selection And Effectiveness Studies To Uranium Of Native Microbial Consortium

The treatment of uranium containing wastewater are classified into physical,chemical and biological methods,physical and chemical methods are high cost,easy to produce secondary pollution.However,microbial treatment has the advantages of low cost,economic and environmental protection.The authors selected and cultured uranium-tolerant indigenous microbial flora from the uranium tailings pond and explored the removal effect and mechanism of U(VI)by microbial flora.To investigate the effects of temperature,p H,initial uranium(VI)concentration,and bacterial dosing amount on the adsorption of uranium(VI)by microbial flora.Under the optimal conditions,the effect of uranium(VI)removal by the dead and living microbial floras and tolerance of uranium(VI)by microbial flora were investigated.The community characteristics of microbial consortium were analyzed by high-throughput sequencing technique,and the SEM-EDS,FTIR and XRD were used to investigate the removal mechanism.The results showed that the microbial consortium consisted of Citrobater?Acinetobacter ? Chryseobacterium ? Enterobacter,which are accounted for51.58%,25.49%,12.82% and 8.5% respectively.Studies have shown that the microbial consortium have the property of resistance characteristics of uranium and other heavy metals.Therefore,the microbial flora as a whole has a certain significance.Through the single-factor test,the removal rate of uranium(VI)can reach96% when the p H is 7.0,the temperature is 30?,and the initial concentration of U(VI)is 9.6 mg/L.The removal rates of live and dead microbial flora atreaction time t=0.5h were 86.5% and 77.8% respectively,and the final removal rates were 96.87% and 85% respectively.These results show that the microbial consortium is not only based on adsorption but also reduction?It was observed that the growth status of microbiome in uranium(VI)concentration was 0,5,10,30,50,80,100,120mg/L.It was found that when the concentration of uranium(VI)is 80mg/L,the microbial flora grows well.When the concentration of uranium(VI)exceeds 100mg/L,the growth of microbial flora is inhibited.Microbial consortium has better uranium resistance than individual microorganisms.When micro-organisms were repeatedly treated with low-concentration uranium-containing wastewater under their own nutrient-rich conditions,it was found that the microbial flora still has a certain degree of removal of uranium(VI).By SEM-EDS analysis,cell surface appears particulate matter,there were large amount of microbial consortium and closely packed after the microbial consortium contracting with U(?).The occurrence of uranium peak accounted for 28.10% of the cell weight ratio.It shows that microbial consortium has a good removal effect on uranium(VI).The FTIR showed that the amino,hydroxyl,carboxyl,amide and phosphate groups play a major role in the process of uranium(VI)removal in microbial consortium cells.XRD showed that the microbial consortium has certain mineralization on uranium(VI).In summary,the microbial consortium has a better removal effect on uranium(VI)and certain resistance to uranium.It is mainly for adsorption and reduction,supplemented by mineralization.