Pump-and-treat remediation of a partially satured sand: centrifuge and numerical prediction

 

Centrifuge and finite elements were chosen as modelling techniques to study effectiveness of the extraction through recovery wells of LNAPL from the unsaturated zone ofcontaminated site. The contaminated scenario consisted of a deposit of sand 3.6 mdeep resting on an impervious boundary. A static water table was present 1.35 mbelow the ground surface.

 

Centrifuge and finite elements were chosen as modelling techniques to study effectiveness of the extraction through recovery wells of LNAPL from the unsaturated zone ofcontaminated site. The contaminated scenario consisted of a deposit of sand 3.6 mdeep resting on an impervious boundary. A static water table was present 1.35 mbelow the ground surface.

LNAPL was discharged into the sand from a tank placed on the soil surface. The cleanup of the subsurface was carried out by removing the free LNAPL floating on the water table by means of a pumping system, which run for 2 months. The centrifuge test was continuously monitored by a camera which enable digital processing of the recorded images. Due to the use of image processing technique, the variation of the LNAPL saturation in the contaminated volume of the soil, the drawdown generated by the extraction well, and the volume of LNAPL recovered with time were measured throughout the progress of the test. Numerical modelling was executed by using a commercial finite element code. The results of the numerical modelling were compared to those derived from the centrifuge modelling. The polluted volumes of subsurface were very similar, while the recovered amount of LNAPL modelled in the centrifuge was larger than that calculated with the numerical model. Both modelling confirmed that LNAPL trapped in the vadose zone was not recovered by simple pumping.


  Centrifu …


AUTORI: Esposito G.
RIG ANNO:1999 NUMERO:2
Numero di pagine: 5


Allegato: https://associazionegeotecnica.it/wp-content/uploads/2010/03/RIG_2000_2_5.pdf
Allegato:
Articolo completo: https://associazionegeotecnica.it/wp-content/uploads/2010/03/RIG_2000_2_5.pdf