Experimental Research About Manganese Autotrophic Denitrifying Bacteria For The Removal Of Nitrate And Mn²⁺ In Groundwater

The problem of nitrate pollution in groundwater and the excessive manganese ion in the groundwater has become more and more prominent with the development of economy.Lots of research showed that the seriously overweight nitrate possible to induce high iron hemoglobin disease,Alzheimer's disease risk,multiple sclerosis,spontaneous abortion or congenital defects,and increase the risk of cancer.Excessive nitrate threatens people's health.The commonly used methods of nitrate treatment include reverse osmosis,electrodialysis and ion exchange method,but these methods are relatively high cost.The biological method has little pollution,low costs,the advantages gradually replace other ways.Due to the heterotrophic denitrification secondary pollution problems.So researchers around the world in recent years had gradually shifted to the research subject in autotrophic denitrification.The autotropHic denitrification has no need for adding additional organic carbon,researchers in hydrogen,sulfur ions,iron ions as electron donor,the nitrate gradually reduced to a great breakthrough on the methods of nitrogen removal in groundwater pollution.But the use of manganese ion as electron donor nitrate removal problem but few people research Therefore,the main content of this paper is to manganese ion as electron donor to complete the process of biological nitrogen removal The main contents of the experiments were as follows:(1)Screening of high manganese autotrophic denitrifying bacteria,and to observe the bacteria combined with electron microscopy.(2)16SrRNA sequence analysis can be concluded that the similarity of H-128 species with sp.Acinetobacter reached 69%,so it can be determined that H-128 is sp.Acinetobactes.(3)Fe²⁺,Mn²⁺,and S^2-were used to determine the nitrogen removal characteristics of H-117,A14,H-128 and WGX15.The experimental results showed that the removal rate of nitrate was the highest when Fe²⁺was used as electron donor,and the removal rate of nitrate was higher than 60%in the medium of Mn²⁺as the electron donor,and the effect of S^2-was the lowest.(4)The study of different temperature,pH,concentration of manganese ion and carbon source conditions nitrogen removal characteristics of H-117,WGX15,A14,H-128.The results showed that pH=6,at 30?,manganese ions in 100mg/L,C/N ratio of 5 when several strains of bacteria nitrogen removal effect is best.(5)The compound test confirms the optimal combination,the effect is observed,and the effect of the combination of the raw water is used to detect the effect of the compound.Using three-dimensional fluorescence fluorescence detection of raw water before and after comparison.(6)The effect of water inlet nitrate concentration,pH value,water retention time on the removal rate of nitrate in the reactor was investigated by using the method of surface design,the removal rate of nitrate was 75% when the water retention time was 12h.