DNAPL remediation with in situ chemical oxidation using potassium permanganate: II. Increasing removal efficiency by dissolving Mn oxide precipitates

摘要: Abstract In situ chemical oxidation (ISCO) schemes using MnO 4 − have been effective in destroying chlorinated organic solvents dissolved ground water. Laboratory experiments and field pilot tests reveal that the precipitation of Mn oxide, one reaction products, causes a reduction permeability, which can lead to flow bypassing inefficiency scheme. Without solution this problem plugging, it is difficult remove DNAPL from subsurface completely. companion paper, we showed with batch oxide be rapidly certain acids. This study utilizes 2-D flow-tank examine possibility nearly complete removal by ISCO , when acids are used oxide. The were conducted small glass tank containing lenticular silica-sand medium. Blue-dyed trichloroethylene (TCE) provided residual, perched pooled DNAPL. KMnO at 200 mg/l was flushed through horizontally. Once plugging reduced permeability prevented further delivery oxidant, citric or oxalic pumped into dissolve precipitates. Organic ligands removed precipitates relatively quickly, permitted another cycle flooding. Cycles /acid flooding continued until all visible removed. monitored analysis visualization. A mass-balance calculation indicated end experiments, results show also how heterogeneity adds complexity initial redistribution DNAPL, efficiency