| Summary: | 碩士 === 國立宜蘭大學 === 環境工程學系碩士班 === 99 === Acid washing has been a common restoration practice for cleaning up the heavy metals from contaminated soil. However, such method usually result in serious fertility degradation. Cropland contamination with heavy metal is not only acquired the environmental concern but also caused the anxiety about food safety in Taiwan. Arbitrary discharge of plating wastewaters has caused many canals serious pollution with heavy metals, but dumping the water in such canals for irrigation leads to many cropland contaminated by copper. An innovative method for recovering the heavy metal-contaminated soil was proposed and performed. The object of this study was to restore a serious Cu-contaminated soil and reserve its fertility by treating with EDTA, citric acid, and dissolved organic carbon (DOC) solution. DOC solutions were extracted from the waste sludge that was obtained from a local whisky distillery. The parameters affecting the removal of Cu were the pH, organic carbon concentration, extraction solid to liquid ratio (S/L), extracting time, and reaction temperature. It is economic and effective to wash the soil 60 min using pH 8.5 and 1,500 mg/L of DOC solution with S/L ration of 1:30 at ambient temperature. Most of fertility indexes were improved significantly after the DOC treatment. Soil organic content was increased from 15 to 28 %; N-NH3 content was increased from 7 to 17 %; available phosphate and potassium were increased approximately 30 and 400 %, respectively. Carboxyl was the major functional group in DOC molecule to extract the Cu.
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