In Situ Chemical Oxidation (ISCO) entails the introduction of chemical oxidant into the subsurface for the oxidation and treatment of organic constituents of concern (COCs). This paper presents a case study that involved bench-scale testing and field demonstration of ISCO via Mechanical Auger Mixing (MAM) that resulted in over 95% removal of chlorinated and non-chlorinated chemicals identified as recalcitrant. Also presented are ISCO’s effects on dissolved oxygen levels in the underlying aquifer. Mechanical mixing of soils with an oxidant solution is an improved remedial strategy that facilitates more effective mixing of reagants with affected soils and hence in more effective treatment than from injection of oxidant. Based on the apparent effectiveness of persulfate in bench-scale tests, ISCO utilizing persulfate and a source of alkalinity was then applied to the demonstration site. The site is a 1970s era waste disposal area where a multitude of different types of wastes were disposed. Six chemical constituents comprised the most abundant COCs at the subject site. These compounds are: 1,1-dichloroethane, vinyl chloride, acetone, 1,2-dichloroethane, benzene, and tertiary butyl alcohol. Solutions of 20% sodium persulfate and 2% of different alkaline sources were found to be most effective in bench scale tests. After the successful field demonstration, it was noted that dissolved oxygen levels increased in the underlying aquifer within about one month and persisted for about nine months. Ground water data as well as field test and bench-scale test data are presented in the paper.
Bost, Richard C. and Perry, Robert G.
"Evaluation Of In Situ Chemical Oxidation Of Soils At A Mixed Waste Site And Assessment Of Effects On Ground Water Quality.,"
Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy: Vol. 13
, Article 11.
Available at: http://scholarworks.umass.edu/soilsproceedings/vol13/iss1/11