Transport, Fate And Remediation Of Chlorinated Solvent In Porous Media

It is significant to investigate the transport of chlorinated solvent in porous media for analysis of natural attenuation and remediation of groundwater pollution. Based on the batch test of trichloroethylene (TCE) adsorbed to fine sand and to quartz, the Linear-Langmuir-Freundlich (LLF) model, which can reveal the mechanisms of adsorption and partition, was established through fitted curves with calculated and tested values. In the sandy column experiments, Langmuir isotherm model could describe best the adsorption mechanisms of TCE. The nonlinear adsorption-advection- diffusion model, which reveals the transport mechanisms of TCE in porous media, was established based on the experiments and the inversed parameters with genetic algorithm. The competition adsorption between perchlorethylene(PCE) and TCE was studied by BP Neural Network, the multicomponent competitive adsorption-advection-diffusion model was established on the base of BP Neural Network.In many kinds of metals which was used to degrading PCE and TCE, the Zn(0) was most effective. Through the batch experiment of reductive degradation of PCE using Zn(0), the mathematical model of multi-chain and parallel reaction was established assuming each reaction fitting pseudo first order kinetic reaction. The kinetic parameters were inversed with hybrid function generic algorithm. The primary reaction pathway was PCE→TCE→t-DCE(trans-dichloroethylene)→C2H2→C2H4 and PCE→C2Cl2→t-DCE→C2H2→C2H4. At the end of tests 94.77% of PCE was degraded to C2H4, 5.23% to vinyl chloride (VC). Comparison the degradation of TCE by Zn(0), the primary pathways and reaction model were different from the degradation PCE by Zn(0), so there may be interactions among PCE, TCE and intermediates.In the reaction column, the 1-D nonlinear adsorption-advection-diffusion-reaction model of multi-component reaction solute was established. According to the experiment result, the model parameters were inversed by using generic algorithm. The different adsorption models and the spatio-temporal distribution of TCE,c-DCE and t-DCE were confirmed. At last the thickness of PRB can be designed by using the nonlinear adsorption-advection-diffusion-reaction model.