Experiment Study On Treatment Of Acid Mine Drainage Using Zero-valent Iron Cooperatives With Sulfate Reducing Bacteria

According to the characteristics of acid mine drainage which has lower pH,higher iron and manganese,higher sulfate content,direct emissions pollution problems and traditional neutralization precipitation method and artificial wetland law was insufficient,therefore,based on microorganism immobilization,take zero-valent iron as mainly matrix components,and organic combinationwithsulfatereducingbacteria,madeintohighlyactiveimmobilized particle,construct a Fe⁰/SRB synergistic system to repair AMD.Firstly,the proportion of the kinds of scrap iron,dosing quantity of scrap iron,particle size of scrap iron optimized by single factor experiment and response surface methology experiment.The results showed that using single factor experiment is simply studied out the optimal proportion was that the kinds of scrap iron was pig iron for steelmaking,dosing quantity of scrap iron was 0.6g,particle size of scrap iron was 200³00 mesh.Consider single factor can not be analyzed consecutive points,and has some limitations.Using response surface methology experiment,by model building and variance analysis relative coefficient.Finally,definite the kinds of scrap iron was pig iron for steelmaking,the dosing quantity of scrap iron was 0.6g,the particle size of scrap iron was 200³00 mesh,using these indexes to made into immobilized particle.In this case,its outflow pH was 7.01,the average removal rates of the TFe?Mn²⁺?SO₄^2-was 95.40%,57.82%,73.88%,the cumulative release of COD was 1457mg/L.Secondly,study the apparent traits,physical and chemical properties of immobilized particles bySEM?ScanningElectronMicroscope,SEM?,XRD?X-RayDiffraction,XRD?,expansion,stability,moisture content,mass transfer,adsorption capacity and kinetics analysis.The results showed that the immobilized particle was dark bright,internal has rich pore structure,its chemical component mainly includ C?H?O?N?Si?Fe?Al and so on.It can resistant acid solution?pH=4?,and keep a best stability in alkaline solution and salt solution.In addition,after it treatments AMD solution,moisture content increases,the particles remain intact,its adsorption capacity of Mn²⁺agree with Freundlich isotherm equation?R²=0.9865,1/n=0.4896?,its adsorption kinetics consistent with Elovich kinetic model?R²=0.9964?.Once again,undertaking different initial concentration of pH,SO₄^2-,Mn²⁺handling characteristics experiments of AMD by static beaker experiment,and analysis by SEM and XRD diffraction instrument.The results showed that,particles can resist the shocks of pH=4 AMD solution,but when pH=2,the treatment effect was worst;Particles of low concentration SO₄^2-(SO₄^2-=800mg/L)has the best treatment effect,but when SO₄^2-=2500mg/L,it can inhibit the activity of SRB;Particles have different resistance of different concentrations of Mn²⁺,when Mn²⁺=40mg/L,it can inhibit the activity of SRB,the treatment effect was worst.Finally,by building dynamic column of SRB immobized particle with zero-valent iron and without zero-valent iron,research on the process of each matrix in immobized particle,determine synergies mechanism of zero-valent iron and SRB.The results showed that zero-valent iron and SRB synergism system has a better effect on repairing AMD.The outflow pH was 8.06,the average removal rates of the TFe?Mn²⁺?SO₄^2-was 99.93%,48.38%,45.85%,the cumulative release of COD was 110.9mg/L.In a word,zero-valent iron and SRB synergism system can strengthen the process of immobilized particle treatment AMD.