ORIN sought to compare the effectiveness of sodium permanganate and sodium persulfate treatment chemistries on TCE and PCE contaminated soil.
Total oxidant demand testing for both persulfate and permanganate were performed with site soils. Oxidant consumption was measured over a period of 96 hours to quantify oxidant consumption over the reaction period. Persulfate and permanganate demand was calculated at 5.84 g/kg and 5.30 g/kg respectively. Based on this information, oxidant loading rates for bench scale treatability testing were set at 6.0, and 5.5 g/kg for sodium persulfate and permanganate.
Bench scale treatability testing attempts to replicate the conditions of a field scale chemical application in a lab scale microcosm. Treatment chemistries are applied to site soils, allowed to react and then sent to a commercial analytical laboratory for analysis. For this study, ORIN wanted to not only test the most effective treatment chemistry, but also to assess the effectiveness of various oxidant loading rates to arrive at the most cost effective treatment plan. As such, a high and low dose of each treatment chemistry was applied.
Soil Analytical Results
The high loading rate of sodium permanganate outperformed sodium persulfate. Interestingly, the low loading rate of sodium permanganate also outperformed the high and low rates of sodium persulfate. After discussing the results with the client ORIN prepared a cost estimate for the site. Sodium persulfate was ultimately chosen as the recommendation for this site due to the presence of petroleum hydrocarbons and some chlorinated ethanes present at the site.