Intrinsic and stimulated in situ biodegradation applied in in-situ treatment zones at sites contaminated with hexachlorocyclohexane (HCH)
TNO Milieu, Energie en Procesinnovatie
Harder, W. (editor)
Arendt, F. (editor)
The pollution of soil and groundwater with hexachlorocyclohexane (HCH) has caused serious environmental problems. Mineralisation of some HCH isomers can be expected under aerobic conditions whereas all isomers are known to be bioconverted to intermediate products under anaerobic conditions. Hence, redox conditions can be expected to have strong impact on the intrinsic degradation behaviour of HCH's is soil and groundwater. This was investigated at two HCH polluted sites in the Netherlands. A field characterisation at the two polluted sites showed anaerobic conditions and a significant intrinsic biodegradation of HCH. Three breakdown products (monochlorobenzene, benzene and chlorophenol) were found in the core of the HCH-plume at one site, whereas the concentration of HCH seemed to decrease with time. The second site, an industrial site, showed high concentrations of HCH, and relatively low levels of intermediate products, indicating intrinsic biodegradation as insufficiently protective, and the need for a stimulation of the biodegradation processes. To proof the feasibility of our bioremediation concept, the research will focus on two processes: I) fully activated anaerobic biodegradation and II) partial intrinsic anaerobic biodegradation followed by stimulated aerobic biodegradation. Both processes depend on the capacity of endogenous microorganisms, which will be tested in laboratory batch experiments with subsurface materials from the sites.
To reference this document use:
Thomas Telford, London
Consoil 2000 : 7th international FZK/TNO conference on contaminated soil, organized by Research Centre Karlsruhe (KZK, D), TNO, in cooperation with UFZ Leipzig, 18-22 Sept 2000. Vol. 2, 960-967