Geochemical and microbiological characteristics during in situ chemical oxidation and in situ bioremediation at a diesel contaminated site.
While in situ chemical oxidation with persulfate has seen wide commercial application, investigations into the impacts on groundwater characteristics, microbial communities and soil structure are limited. To better understand the interactions of persulfate with the subsurface and to determine the compatibility with further bioremediation, a pilot scale treatment at a diesel-contaminated location was performed consisting of two persulfate injection events followed by a single nutrient amendment. Groundwater parameters measured throughout the 225 day experiment showed a significant decrease in pH and an increase in dissolved diesel and organic carbon within the treatment area. Molecular analysis of the microbial community size (16S rRNA gene) and alkane degradation capacity (alkB gene) by qPCR indicated a significant, yet temporary impact; while gene copy numbers initially decreased 1-2 orders of magnitude, they returned to baseline levels within 3 months of the first injection for both targets. Analysis of soil samples with sequential extraction showed irreversible oxidation of metal sulfides, thereby changing subsurface mineralogy and potentially mobilizing Fe, Cu, Pb, and Zn. Together, these results give insight into persulfate application in terms of risks and effective coupling with bioremediation.
Environmental Technology, Wageningen University , Bornse Weilanden 9, 6708 WG Wageningen, the Netherlands.
Nora B
NB
Sutton
Mariusz
M
Kalisz
Janusz
J
Krupanek
Jan
J
Marek
Tim
T
Grotenhuis
Hauke
H
Smidt
Jasperien
J
de Weert
Huub H M
HH
Rijnaarts
Pauline
P
van Gaans
Thomas
T
Keijzer
D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002244:Carbon / Q000032:analysis; D004553:Electric Conductivity; D004785:Environmental Pollutants / Q000032:analysis*; D004787:Environmental Pollution / Q000032:analysis*; D005742:Gasoline / Q000382:microbiology*; D060587:Groundwater / Q000382:microbiology; D006838:Hydrocarbons / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D009862:Online Systems; D016877:Oxidants / Q000737:chemistry; D010084:Oxidation-Reduction; D010865:Pilot Projects; D011044:Poland; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil / Q000737:chemistry*
D004785:Environmental Pollutants; D005742:Gasoline; D006838:Hydrocarbons; D016877:Oxidants; D012336:RNA, Ribosomal, 16S; D012987:Soil; D002244:Carbon