> The reactor used by the researchers consists of an undivided electrolysis cell in which dimethyl sulfoxide (DMSO) is used as a solvent
They remove the DDT from the soil into the solvent (itself quite unpleasant). From there, it's pretty easy to filter out the soil and clean it up. Add water and boil or freeze dry to extract it back out, preferably capturing it to be reused.
"Cleaning" soil is an interesting concept. At what point does it just become dirt? Presumably some of the nutrients will remain, but it seems like this would sterilize it.
Dirt still has use, of course, but soil is expensive to produce for a reason.
Considering the existing DDT contamination, ending up with dirt that needs to be fortified with compost is hardly the worst trade-off.
I would definitely bet against this if I could. Soil is far more potent than DDT can harm.
DDT, like organic mercury compounds, bioaccumulates up the food chain. Contaminated soil is sequestered to prevent it from contaminating insects and animals and then humans.
Hence, the trade-off: DDT in the ecosystem, or killing soil and rebuilding it with compost and time.
Rather, it is a more permanent solution compared to sequestration, where the benzene production offsets the cost.
If, as they plan, it can be done on-site, that would also eliminate transporting the soil and avoiding accidentally spreading it elsewhere, which is appealing as well.
Sanitary landfills (the sort that prevent seepage) are not exactly cheap either, and pose an ongoing risk in that the DDT is always there, waiting to get back out.