General Cleanup Technology

The time variability of groundwater flow conditions in conjunction with the quantification of the natural retention and decomposition processes at contaminated sites (Part 2)

The time variations in the flow conditions can significantly affect the form and length of the pollutant plume. Given reliable measuring points for all the control levels, the maximum concentration and the pollutant load are suitable for evaluating the natural attenuation processes.

Summary

The dispersion of pollutants and thus the spatial development of pollutant plumes in the groundwater is governed by various processes. The transport of pollutants in solution generally takes place by means of advection and hydrodynamic dispersion. The formation of a pollutant plume in the aquifer is, however, slowed down by natural retention and self-cleaning processes and may even come to a complete halt. Targeted utilisation of these self-cleaning processes could potentially replace the decontamination process itself at suitable sites and the only costs incurred would be those for investigative and monitoring measures.

The aim of the project was to compile an assessment basis for object-related government regulations and directives. For this purpose, data sets were collected in test fields and a concept to implement the natural attenuation or enhanced natural attenuation process was developed, taking into account time variables.

Results:

  • Reliable statements can only be based on observations made over several fluctuation periods and on measurements that provide sufficient information about the time variables in the flow conditions.
  • Dosimetric measurements are suitable for evaluating the stationarity, with time-integrated measurements over several periods being required.
  • The information quality of a control level depends on the density of the measuring points, thus the measuring point interval should be adapted to the width of the source and the heterogeneity of the aquifers. If there are reliable measuring points for all the control levels, the maximum concentration and the pollutant load are suitable for evaluating the natural attenuation processes.

More Project Informations

Project number:  0330514

Project period:  01.01.2003 - 28.02.2006

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Source: Federal Ministry of Education and Research (BMBF)