| Organic pollution is one of the main problems of groundwater.At present,the green way of remediation and removal of groundwater organic pollutants is biodegradation.However,the occurrence of biodegradation will inevitably disturb the original biogeochemical process of the aquifer,and the disturbance effect of the degradation process on the chemical environmental factors of groundwater is worth exploring.Firstly,this paper combines the theory of organic matter degradation with the theory of hydrogeochemistry,theoretically deduces the biochemical response model of groundwater chemical composition to typical organic pollution,and reveals the influence mechanism of organic matter degradation on groundwater chemical factors.Secondly,through indoor experiments to simulate the change rule of typical pollutant degradation on groundwater environmental factors,the experimental data were fitted with the model.Finally,combined with the data of an oil contaminated site,the amount of toluene degradation was deduced through the change of the site inorganic salt ion concentration,and the model was verified.The main conclusions are as follows:(1)A biochemical response model of groundwater chemical composition to typical organic pollution was established.Biodegradation mainly affects the changes of various substance concentrations and relevant indicators in groundwater by affecting the p H and total carbon content of the system.This paper combines the theory of mass conservation,electron conservation and carbonic acid balance to establish the response model of groundwater chemical composition to toluene nitrate biodegradation.It is found that the relationship between hydrogen ion concentration and the changes of toluene and nitrate degradation rate satisfies a quadratic equation,The concentration of each substance in the carbonic acid balance can be calculated according to the concentration of hydrogen ion.(2)The influence of organic matter degradation on the carbon dioxide carbonate system is revealed.In the process of biodegradation,the change of calcium ion concentration and hydrogen ion satisfy a quadratic equation,and the concentration of carbonate,bicarbonate and carbonic acid are all functions of hydrogen ion.(3)The influence of organic matter degradation on the chemical environmental factors of groundwater is revealed.Indicators such as acid-base property,dissolved inorganic carbon,redox potential and total dissolved solids in groundwater change with biodegradation.For most degradation reactions,Eh in the system decreases and soluble inorganic carbon increases with the decrease of organic concentration.The changes in p H,total dissolved solids,total hardness and other indicators need to be analyzed in combination with specific reactions. |
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