Kinetics of dechlorination by Dehalococcoides mccartyi using different carbon sources

Stimulated anaerobic dechlorination is generally considered a valuable step for the remediation of aquifers polluted with chlorinated ethenes (CEs). Correct simulation and prediction of this process in situ, however, require good knowledge of the associated biological reactions. The aim of this study was to evaluate the dechlorination reaction in an aquifer contaminated with trichloroethene (TCE) and its daughter products, discharging into the Zenne River. Different carbon sources were used in batch cultures and these were related to the dechlorination reaction, together with the monitored biomarkers. Appropriate kinetic formulations were assessed. Reductive dechlorination of TCE took place only when external carbon sources were added to microcosms, and occurred concomitant with a pronounced increase in the Dehalococcoides mccartyi cell count as determined by 16S rRNA gene-targeted qPCR. This indicates that native dechlorinating bacteria are present in the aquifer of the Zenne site and that the oligotrophic nature of the aquifer prevents a complete degradation to ethene. The type of carbon source, the cell number of D. mccartyi or the reductive dehalogenase genes, however, did not unequivocally explain the observed differences in degradation rates or the extent of dechlorination. Neither first-order, Michaelis–Menten nor Monod kinetics could perfectly simulate the dechlorination reactions in TCE spiked microcosms. A sensitivity analysis indicated that the inclusion of donor limitation would not significantly enhance the simulations without a clear process understanding. Results point to the role of the supporting microbial community but it remains to be verified how the complexity of the microbial (inter)actions should be represented in a model framewor

Extrapolation and transference of Remediation Technologies and generic approaches to new selected test locations - AQUAREHAB WP8

The last year of the AQUAREHAB project was foreseen to evaluate and test the generic character of some finding from the first three project years. More specifically, the aim was to apply generic rehabilitation guidelines, approaches and tools to other river basins/sites with other pollutant conditions and climates. With this goal in mind, four case studies have been selected and started focussing on: (1) The capacity of wetlands and soils indenitrification and elimination of pesticide; (2) Estimation of the long term performance of Zero Valent Iron (ZVI) Permeable Reactive Barriers to eliminate Chlorinated Aliphatic Hydrocarbons (CAHs) via a combination of improved lab scale tests and model tools; (3) The feasibility of micro scale ZVI injection into the subsurface to eliminate CAHs contaminants; and (4) The development of REACHER-local, a prototype management tool for groundwater management at a regional scal

Extrapolation and transference of Remediation Technologies and generic approaches to new selected test locations - AQUAREHAB WP8

The last year of the AQUAREHAB project was foreseen to evaluate and test the generic character of some finding from the first three project years. More specifically, the aim was to apply generic rehabilitation guidelines, approaches and tools to other river basins/sites with other pollutant conditions and climates. With this goal in mind, four case studies have been selected and started focussing on: (1) The capacity of wetlands and soils indenitrification and elimination of pesticide; (2) Estimation of the long term performance of Zero Valent Iron (ZVI) Permeable Reactive Barriers to eliminate Chlorinated Aliphatic Hydrocarbons (CAHs) via a combination of improved lab scale tests and model tools; (3) The feasibility of micro scale ZVI injection into the subsurface to eliminate CAHs contaminants; and (4) The development of REACHER-local, a prototype management tool for groundwater management at a regional scale