Behavior of LNAPL transport using multi-layer observation V sand experiments

Experiments were conducted to investigate the behavior of LNAPL under constant water table condition. The ground water flow field was established first, and then a solute transport model incorporating a volume-fixed dissolution term was used to describe the dissolution and transport of toluene from the entrapped nonaqueous phase mixture. Two LNAPL (C7H8) concentrations of 100 ppm and 400 ppm were released from a small source zone on bottom of the flow cell into a saturated, homogenously packed sand column. Four layers of observation (i.e. 20 cm B40 cm B60 cm and 80 cm) were carried out to monitor mass transfer of different advection length in homogeneous porous media. Results showed that the breakthrough curves at different layers were distinct. The peak of concentration decayed with advection length, and the skewness of breakthrough curves were larger as well.