Assessment of Chemical Oxidation for Treatment of DNAPL in Fractured Sandstone Blocks

作者：Schaefer Charles E^*; Towne Rachael M; Root Duane; McCray John E

来源：Journal of Environmental Engineering, 2012, 138(1): 1-7.

DOI：10.1061/(ASCE)EE.1943-7870.0000466

• PCE
• Bedrock
• Oxidation
• DNAPL
• Fractures
• Permanganate
• Persulfate
• Remediation

Laboratory experiments were performed in discretely-fractured sandstone blocks to evaluate the use of chemical oxidants to treat residual dense nonaqueous phase liquid (DNAPL) tetrachloroethene (PCE). Persulfate (chelated ferrous iron and alkaline activated) and permanganate oxidants were evaluated. Results showed that the maximum DNAPL mass removal rates ranged from 4,700 mg/L/day by using permanganate, to 2,600 mg/L/day by using chelated iron activated persulfate, to 480 mg/L/day by using alkaline activated persulfate. The rate of DNAPL mass removal rapidly declined over the 10 to 60 day application period, limiting DNAPL mass removal rates to only 2 to 20% of the residual DNAPL present on the fractures. The permanganate experiment was terminated after 10 days owing to plugging of the fracture. In the persulfate-treated fractures, substantial rebound in dissolved PCE concentrations were observed after persulfate addition ceased. Use of interfacial tracers in the persulfate experiments showed that the decrease in DNAPL removal accompanied a decrease in the effective DNAPL-water interfacial area, likely owing to obstruction of these interfaces resulting from oxidation by-products. Fracture aperture distribution, oxidant type, and oxidant activation all affected overall treatment effectiveness, and DNAPL dissolution mass transfer controlled the overall treatment process. DOI: 10.1061/(ASCE)EE.1943-7870.0000466.

• 出版日期2012-1