| Summary: | 碩士 === 國立中山大學 === 環境工程研究所 === 90 === This research was to evaluate the treatment efficiency of a chlorinated hydrocarbons contaminated site by combined technologies of electrokinetic processing-Fenton process-catalytic iron wall.The L9 orthogonal arrays were utilized to investigate the effects of four experimental factors (i.e., H2O2 concentration, size fraction of iron particles, mass of iron particles and elapsed time) on the treatment efficiency.The experimental results were further subjected to the analysis of variance (ANOVA) and regular analysis.According to the ANOVA of results of nine experiments conducted under an electric gradient of 1 V/cm, the H2O2 concentration, mass of iron particles and elapsed time were determined to be very significant parameters for the destruction and removal efficiency (DRE) of 1,1,2,2-tetrachloroethane (TeCA) . In this system, the optimal conditions with respect to the DRE of TeCA would be 2﹪H2O2, 50-100 mesh iron, 0.2 wt% iron and 20-day treatment time.Under this optimal conditions, it was able to obtain a DRE of 69.56% and the corresponding operating cost would be 672.9 NT$/m3.
Aside from the constant voltage operation, the constant current operation also was employed in this study. The latter was found to be superior to the former in terms of electroosmotic flow quantity and DRE.
Experimental results of soil column tests showed that TeCA was transformed to trichloroethylene (TCE).TCE could be regarded as a daughter product of TeCA degradation.Results of Tests 17 and 18 showed that destruction dominated the DRE of TeCA, whereas removal played a much more important role in the DRE of Test 19.Regarding the treatment efficiency of a 9-day pilot test using the same combined treatment technologies, it was found to be very satisfactory. DREs of vinyl chloride, dichloroethane, and TCE were found to be >96%, >96%, and >94%, respectively in the anode and cathode wells. The concentrations of TCE in both anode and cathode wells were found to be lower than the regulatory threshold (i.e., 2μg/L) and the operating cost was determined to be about NT$57.5/m3.
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