Study On The Remediation Of Oragnic Polluted Sediment By The Technology Combined Geotextile Bags And Microorganisms And The Technology Combined Sediment Washing And Washing Solvent Oxidation

Sediment is an important medium for the storage of organic pollutants.Organophosphorus pesticides（OPS）,Polycyclic aromatic hydrocarbons（PAHs）and Organochlorine compounds（OCPs）can exist in sediment for a long time,which pose a serious threat to the ecological environment and human health.Therefore,the remediation of organic polluted sediment is imminent.In this study,the easily degradable OPs polluted sediment and the hard degradable PAHs and OCPs polluted sediment were used as the research objects,and the technology combined geotextile bags and microorganisms and the technology combined sediment washing and washing solvent oxidation were used to repair them.The relationship between the two technologies and the molecular structure parameters of pollutants was studied,and the main research conclusions are as follows:（1）The degradation rates of malathion,quetiapine,diazinon,and dimethoate were 93.17%,93.78%,60.91%,and 78.11%under the influence of aerobic bacteria respectively,while the degradation rates affected by anaerobic bacteria were 96.64%,92.13%,61.50%,and 83.34%respectively.The degradation kinetics of OPs fit well with the first-order kinetics models.Through the calculation of the quantum chemical parameters E_LUMO,E_HOMO,and E_GAP of the four OPs,the results showed that quantum chemical parameters may help to explain the degree of difficulty for microorganisms to degrade OPs in geotextile bags in terms of their molecular structure.（2）When the solid-liquid ratio of the sediment to the washing solvent is 1:10,the washing removal rate of PAHs and OCPs pollutants in the sediment is proportional to the concentration of the washing solvent and the washing time.For PAHs polluted sediment,the removal ability of the three washing solvent is Tween-80 solution>ethanol solution>hydroxypropylβ-cyclodextrin solution.In order to remove OCPs pollutants in the sediment,the oder of ability is ethanol solution>Tween-80 solution>hydroxypropylβ-cyclodextrin solution.Taking the actual situation of the project implementation into account,the optimal engineering conditions for sediment washing are determined as follows:the solid-liquid ratio of the sediment to the washing solvent is 1:10,the washing solvent is an ethanol solution of 500ml·L^-1,and the washing time is 240 min.47.88%PAHs and64.35%OCPs can be removed respectively from sediments under the condition.The Elovich equation can fit the kinetic process of washing PAHs and OCPs from the sediment by three washing solvent well.Compared with OCPs pollutants,PAHs are removed by washing solvent faster.（3）Configuring ethanol washing solvent according to the best engineering conditions of sediment washing,this study found that under mild pressure boiling oxidation conditions（temperature=373K,pressure=102.025k Pa）,the removal rates of 15 PAHs and 10 OCPs pollutants within60min reached 99.11%and 93.25%respectively,which were higher than those under the conditions of reaction pressure=101.325 k Pa and reaction temperature of 298K and 323K respectively.In addition,the removal rate of pollutants under the condition of micro pressure boiling is faster than that under the other two reaction conditions.Therefore,the best engineering method is to treat the washing solvent using 100 mmol·L^-1H₂O₂ for 60min under the condition of micro pressure boiling oxidation.（4）The model equations between reaction ln K and molecular quantitative parameters,reaction temperature and pressure of 25 organic compounds oxidized by H₂O₂ under three reaction conditions were established.The optimal QSAR model ln K=-10.925+0.0275T-6.5752f（+）_max-4.728f（-）_max+27.7295f（-）_min has been constructed.The R²,q²and Q²ext of this model are 0.762,0.617 and 0.693,which meet various inspection demands and have good stability and predictive ability.（5）It is estimated that the construction cost of the technology combined geotextile bags and microorganisms to repair the OPs polluted sediment is386,600 yuan.Based on the daily treatment of 40 m³ of OPs polluted sediment and 250 days of annual treatment,the estimated annual operating cost of the project is 878,400 yuan.It is estimated that the cost of the construction of the technology combined sediment washing and washing solvent oxidation to repair the organic polluted sediment is 560,000 yuan.Based on the daily treatment of organic polluted sediment 2m³ and the annual treatment days of 250 d,the annual operating cost of this project scheme is estimated to be 4.3 billion yuan.