The Simulation And Evaluation Of Plant-microbial Remediation Of Petroleum Hydrocarbons Contaminated Soil

The infiltration and migration of petroleum hydrocarbons(PHs)pollutants in the soil unsaturated zone is a complicated process.The study of its migration mechanism and the recognition of the fate of PHs pollutants in soil can provide guidance for the control of soil pollution.This article established theoretical model of pollutants transformation and migration under the remediation system.The safety and technical economy comprehensive evaluation efficiency of the plant-microbial combined remediation was conducted.The results are of great significance for remediation of PHs contaminated soil.Based on the mathematical equation of the organic solute migration and the plant-microbial remediation process,the Hydrus-1D model was used to simulate the diffusion,adsorption or desorption,microbial degradation,and plant adsorption of PHs in the soil-water system.After verifying the model reliability,the behavior change of PHs in soil with time and depth was studied,and the fate of PHs in soil under different remediation conditions was compared.The PHs remediation efficiency under different conditions was evaluated.The effect of potential limiting factors(PHs pollutant concentration,soil moisture content and depth of PHs pollution,etc.)on the degradation of PHs and the migration process in saline alkali soil was researched,and it was revealed that the space-time change of PHs pollutants in soil is related to environmental constraints.The PHs concentration and pollution depth can significantly affect the combined remediation efficiency.The suitable soil moisture is of vital importance to remediation.The pollution index method was used to do the safety evaluation according to the simulation.After the plant-microbial remediation,the PHs pollution index of soil is significantly lowered.The soil depth with the highest pollution concentration is light polluted.The 15 cm topsoil can basically achieve slightly polluted-no pollution levels.The soil fertility level increases by one level,which is the general fertility level.The potential ecological risk of soil environment is of low degree after remediation.The quantification and comparison of economic costs of different remediation methods were done by survey analysis.Results show that the remediation cost is low.The MCA method was used for the comprehensive analysis of safety and technical economic effect.It is concluded that the plant-microbial remediation have the double benefits in safety and technical and economic aspects.