TY - ABST

T1 - Feasibility and Performance of Full-Scale In-situ Remediation of TCE by ERD in Clay Tills

A1 - Broholm,Mette Martina

A1 - Damgaard,Ida

A1 - Chambon,Julie Claire Claudia

A1 - Manoli,Gabriele

A1 - Pade,Dorte Moon

A1 - Christiansen,Camilla Maymann

A1 - Binning,Philip John

A1 - Westergaard,Claus

A1 - Tsitonaki,Aikaterini

A1 - Christophersen,Mette

A1 - Kerrn-Jespersen,Henriette

A1 - Bjerg,Poul Løgstrup

AU - Broholm,Mette Martina

AU - Damgaard,Ida

AU - Chambon,Julie Claire Claudia

AU - Manoli,Gabriele

AU - Pade,Dorte Moon

AU - Christiansen,Camilla Maymann

AU - Binning,Philip John

AU - Westergaard,Claus

AU - Tsitonaki,Aikaterini

AU - Christophersen,Mette

AU - Kerrn-Jespersen,Henriette

AU - Bjerg,Poul Løgstrup

PY - 2012

Y1 - 2012

N2 - The feasibility and performance of full-scale applications of ERD in clay tills were investigated in a research project including 2 sites in Denmark, which have been undergoing remediation since 2006. At both sites organic substrates and bioaugmentation cultures have been injected in TCE-contaminated clay till. An integrated investigative approach consisting of water and clay core sample analysis, including stable isotopes and specific degraders, as well as analysis for chlorinated solvents, degradation products, donor fermentation products and redox-sensitive parameters combined with modelling has been applied. The results showed that the chlorinated solvent TCE was converted into its daughter products (cDCE, VC and ethene) but complete conversion of contaminants to ethene (as expected) was not achieved<br/>within a timeframe of 4 years. Large variation in the effect of ERD in the clay matrix between sites, boreholes and even between cores was observed. Four years post ERD initiation, the mass removal at the 2 sites varied between &lt;5% and 50% within the treated zones. Low mass removal was associated with degradation being restricted to narrow bioactive zones (few cm) around high permeability features in some parts of the clay tills. The bioactive zones may expand in zones where both donor and chlorinated compounds are present. In some cores TCE was depleted (degraded to DCE) in zones up to 1.8 m thick – an extent which could not be explained by diffusive loss to narrow bioactive zones. Hence, biomass migration in the clay matrix appears to play an important role in terms of contaminant mass reduction.

AB - The feasibility and performance of full-scale applications of ERD in clay tills were investigated in a research project including 2 sites in Denmark, which have been undergoing remediation since 2006. At both sites organic substrates and bioaugmentation cultures have been injected in TCE-contaminated clay till. An integrated investigative approach consisting of water and clay core sample analysis, including stable isotopes and specific degraders, as well as analysis for chlorinated solvents, degradation products, donor fermentation products and redox-sensitive parameters combined with modelling has been applied. The results showed that the chlorinated solvent TCE was converted into its daughter products (cDCE, VC and ethene) but complete conversion of contaminants to ethene (as expected) was not achieved<br/>within a timeframe of 4 years. Large variation in the effect of ERD in the clay matrix between sites, boreholes and even between cores was observed. Four years post ERD initiation, the mass removal at the 2 sites varied between &lt;5% and 50% within the treated zones. Low mass removal was associated with degradation being restricted to narrow bioactive zones (few cm) around high permeability features in some parts of the clay tills. The bioactive zones may expand in zones where both donor and chlorinated compounds are present. In some cores TCE was depleted (degraded to DCE) in zones up to 1.8 m thick – an extent which could not be explained by diffusive loss to narrow bioactive zones. Hence, biomass migration in the clay matrix appears to play an important role in terms of contaminant mass reduction.

ER -