The International Information Center for Geotechnical Engineers

Soil Remediation Techniques: Examination of In Situ Chemical Oxidation

 

6. Disadvantages of ISCO Technique

Disadvantages of this remediation technique include the potential of oxidant delivery problems if there is subsurface heterogeneity such as with the hydraulic conductivity of an aquifer. This issue could affect the transport of the oxidant so that it is not able to reach the full volume being treated. The subsurface layers and hydraulic conductivity of each must be clearly identified. There can be a short persistence of some oxidants due to fast reaction rates in the subsurface (Derby, 2009)

Although there is generally a lower lifetime cost, fast treatment requires spending a lot of capital quickly. If a contaminant is not fully treated or reduced to a less harmful species, it can be mobilized by transport induced by the oxidation (Derby, 2009). For oxidation to occur there must be a large redox potential which generally requires special safety requirements to handle these oxidants. There are limitations for application at heavily contaminated sites and you may have less oxidant or hydraulic control relative to other remedial technologies (Derby, 2009). 

Mass transfer can be beneficial for increasing the active area of the oxidant but this can also further spread the contaminant from the area originally being remediated (Clark, 2013). Permeability could potentially be reduced as a result as well. Additional challenges to ISCO implementation include the presence of non-aqueous phase liquids or high concentrations of sorbed COCs, heterogeneous or low permeability soil, and current site conditions with sensitive utilities such as gas, steam, petroleum, communication lines, etc (Clark, 2013).

 

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