Study On Microbe And Heavy Metal Cu Transportation In Vadose Zone

Heavy metal pollution is the hot topic in water and soil pollution renovation.Vadose zone is not only an important medium of heavy metal pollution of the environment behavior,also is a natural barrier to protect groundwater polluted.Existing vadose zone of heavy metal pollution control methods because of all sorts of problems that limited application.Microorganisms in recent years,with its good physical and chemical properties and excellent surface properties has been used in the field of pollution control and repair,but its environmental security,biological availability and behaviors in the vadose zone rules is still unknown.Microorganisms and the transition and transform mechanism of heavy metal copper in vadose zone;To quantitatively evaluate the behavior rule in vadose zone.Establish evaluation of microorganisms on the soil heavy metal pollution repair behavior theory and method of heavy metal pollution in vadose zone and aquifer of microbial technology,environmental safety transformation provided the scientific and engineering bacteria?Based on the screening of resistance of copper microbial batch adsorption experiments,the static test,the test medium choose low reactivity of quartz sand,simulate common pore medium in the vadose zone,by isothermal batch adsorption test,discriminant adsorption type;Adsorption kinetics experiment,obtain mass transfer kinetic parameters and the distribution coefficient;Adsorption thermodynamic test,know the extent of the adsorption process and driving force.On the basis of static test,the one-dimensional soil column is used for saturated copper resistant bacteria in the quartz sand with Cu²⁺ migration test,and build mathematical model of migration the following main conclusions:1.In soil as a source of strain,isolated by gradient pressure type domestication method of copper resistance strain,after through 16 srdna sequences determine the type of copper resistant bacteria species identification of Klebsiella oxytoca;On screening of strain of the exterior form by using the scanning electron microscope?SEM?observation and measurement of cell size,see the bacteria for round rod bacteria,size?1.83???0.3?×?0.86???0.1?um,shape coefficient is 0.47?2.Growth cycle of measurement,learned from 20 ? growth curve,in 10 20 h,Klebsiella oxytoca LY into the plateau,propagation speed and decay rate unchanged,form the balance.And under the condition of 4 ?,Klebsiella oxytoca LY growth curve is very smooth.So adsorption experiments of this paper to select in late logarithmic e.coli were studied,inoculation time determined for 10 to 15 h,and in the whole experiment process,environment temperature of 4 ?,to ignore the bacteria to breed and death for experiment.3.For microbes and quartz sand,copper,and quartz sand,copper,and microbial batch static adsorption experiment.Microbes in the soil suction can use linear equation to describe the equilibrium adsorption balance process,so you can get balance of microorganisms in quartz sand adsorption coefficient of 4.457 mL/g,for microorganisms,soil except for liquid microbial adsorption filter there is stranded for;Copper in quartz sand with Langmuir equation fitting results are good,distribution coefficient K is 0.092 mg/L can be used to evaluate the size of the quartz sand to Cu adsorption affinity.In the process of dynamic response,holding the amount did not reach the maximum,and holding the effect is not stable,indicating that the effect of soil alone to control copper has great difficulty;Bacteria liquid on the adsorption of copper with Temkin equation distribution coefficient K is 19612 mg/L,in the dynamic experiment fitting coefficient of copper in the microbial adsorption kamc = 1.67,analytic coefficient Kdmc = 1.07.4.Of tracer ion,microorganism,copper ions,migration and the mixture of both the soil column experiment to obtain breakthrough curve and Cl^-BTCs show good symmetry and no obvious "tail" phenomenon,bacteria liquid penetration time earlier than tracer Cl^-,and the peak is far lower than the peak value of the tracer.BTCs heavy metals are present a different degree of asymmetry,the shape of BTCs also occurred by under low flow velocity distribution width to the change of the narrow under high velocity distribution,adsorption phase?left?and all curve becomes steeper and desorption?right side?becomes relatively flat and has a long tail.In microbiology and copper under the condition of total migration,Cu²⁺ growth through time,and the concentration of Cu²⁺ peak flow liquid in low,shows the existence of microorganisms to Cu²⁺ had an adverse effect during the migration of quartz sand,reduce microbial adsorption quantity of effluent concentration increased.5.Combining migration penetration curve characteristics and its adsorption properties of distribution coefficient,applied to describe the mathematical model of solute transport on migration of curve fitting effect is good,can the risk assessment of heavy metal pollution in vadose zone and provide basis for prevention.