Study On Transport And Diffusion Of Nitrobenzene In Groundwater Environment And Technology Of Cut-Off Wall In The Pollution Zone

The pollution of nitrobenzene which destroy water resources has become serious gradually in chemical plant in city and this problem has attracted more attention. So the pollution of nitrobenzene should be studied abroad.Nitrobenzene is a kind of virulent matter and it is one of fifty-eight preferential control virulent matter in our country. Nitrobenzene is a chemical material which applies abroad and mainly consists in industry waste water of dye, detonator and tan. The degradation of nitrobenzene is hard and it can resort in soil for long time. Then it can transfer into organism and threat the healthy of people.This paper mainly studied the law of transformation and transplantation of nitrobenzene in groundwater which based on actuality of serious pollution in certain city which need study imminently in theory and control technology. And also study the prevention and control technology of the pollution of nitrobenzene.In the paper, we should firstly understand hydrologic data in pollution area and nitrobenzene's character and hazard. Through the experiment, we study the law of transformation and transplantation of nitrobenzene in groundwater and also explore the in situ remediation technology which include the building method, technology essential and blocking effect of blocking wall in pollution area.1.In order to explore the theory of remediation of nitrobenzene pollution in groundwater, we should do the experiment including soil column experiment and seeping trough experiment. Then through these experiment, we mainly study the transport process of nitrobenezene and transport effect from diversified ions in groundwater system.Soil column experiment: Volatilization,adsorption,biological function can often affect the transport and transformation of nitrobenenze in groundwater.Through the experiment, we find adsorption is a dominant factor in the process of nitrobeneze transport. pH and content of NO₃^- affect the content of nitrobenezene.The different value of pH affect the subsisting state of compound of nitrobenzene,pH can enhance nitrobenzene's adsorption and transformation, so the correlation between pH and content of nitrobenzene is contrary correlation. NO₃^- is electorn acceptor of mricroorganism and also offer nitorgen for microorganism,so the correlation between NO₃^- and nitrobenzene is positive correlation.Intension of ion inderrectly affect nitrobenzene's adsorption through affecting the solubility of nitrobenzene and with the increase of ion intention souluble organic carbon would come out from solution.Adsorption ability of nitrobenzen would enhance with increase of ion intention.So Cl^-,Ca²⁺and Mg²⁺ would affect transport and transformation of nitorbenzene in certan degree,but the influence is very small.Seeping trough experiment:Aquifer have ability to adsorb nitrobenzene,but the ability of adsorption of soil is more strong than aquifer's. And microorganism also can adsorb nitrobenzene.Nitrobenzene can penetrate through aquifer and soil layer in 240 hours.Comparing with soil layer,ability of adsorption of aquifer is very limite and the function of microorganism is not obvious.Nitrobenzene which is heavier than water transport fast in aquifer and in the process of transporting nitrobenzene would go downwards with the direction of the water flowing which is important factor of affecting the content of nitrobenzene.In the experiment, we select three different velocity of flow which is 0.23m/d,0.39m/d,0.78m/d. In the condition of three different velocity of flow, we study the content of nitrobenzene.In the condition of 0.23m/d-0.39m/d,we find velocity of flow is main factor affecting transport of nitrobenzene and the content of nitrobenzene would increase with the increase of velocity of flow. But when velocity increase to 0.78m/d, the content of nitrobenzene would not increase and keep balance. This because of the Viscosity Characteristics of nitrobenezene and the resistance of soil interstice medium.The fast of velocity of flow would weak the function of adsorbing in soil and enhance the function of microorganism.2.Studying the composing, structure and constructing method of flocking wall through experiment: Based on the different function of iron powder, clay, calcium sulphate and zeolite, we design an experiment about component experiment to make certain the component and proportion of flocking wall. Based on the injecting manner of back-irrigation of slurry, we adopt the method of piling back-irrigation and make sure the value of pressure. In order to test the effect of flocking wall, we design an experiment to observe the content of nitrobenzene and the value of turbidity. The purpose of this paper is that reveal the form of transport, attenuation rule and influence factor of nitrobenzene.And then,find the method of prevention and control and construction of flocking wall.Selecting component of flocking wall: Component proportion of flocking wall is that water: iron powder: zeolite: calcium sulphate=1:5:0.05:0.1:0.1, in that condition we find nitrobenzene can be flocked effectively. So flocking wall is a effective method to treat high content of nitrobenzene and it is a better means combining with other methods of treating nitrobenzene. At the same time, the experiment of pressure can offer the basis of practical engineering.Seeping trough experiment of flocking wall: The purpose of this experiment is that test the effect of flocking wall. We design four well along with direction of water flow and add nitrobenzene with the flow of water, then, inject the slurry which has already been prepared, test the each index. We find flux of exiting water is decrease and the content of nitrobenzene keep stabilization after adding slurry. Concerning with above discussion, the experiment testify flocking wall a good method, especially to high content of nitrobenzene and flocking wall itself can not pollute groundwater futher.