PB2
The 'Kuil van Keet' Natural Attenuation Project
Based on earlier findings (1996) a study was undertaken to quantify the amount of
natural attenuation in the saturated zone and unsaturated zone with special
interest the capillary fringe including the smear zone.
For this underground laboratory was installed in a 1.2 m (4 ft.) diameter
steel tube reaching 6 m. (24 ft.) Below
the surface.
3 floors were constructed from which measurements could be made with sensors
through holes in the tube wall. The sensors were connected to analytical
instruments (GC-TCD, UV-Vis) and data processing and logging instruments in the
container seen in the background. This way continuous recording was possible of:
Air movements (3D) in the unsaturated zone (down to 1 mm/hr); concentration of
gasses (O2, CO2, N2O, CH4, H2S
and HC vapors); in the data processing unit these two were combined as flux of
the individual gasses; The system
records also the groundwater flow direction (2D) using the G&H groundwater
vector-sensor and variations in depth, NO3 concentration in capillary fringe to
measure diffusive movement, meteorological conditions: wind speed and direction,
sunshine intensity, air temperature and humidity, rainfall and
evapotranspiration.
Most data were recorded every 15 minutes for a 6-month period.
For results ask for full report (e-mail) or see under
articles / publications at poster presented at Battelle's first contaminated
sediments conference held in Venice Italy 10-2001.
