The HOCs removal yield was assessed on the basis of random soil sampling
(10 samples each) carried out before starting and at the end of the flushing test. The
treatment used LB surfactant solutions at 2% in tap water. Gas effluents were treated
by granular activated carbon. The liquid effluents were treated by UF using eight
100 kDa cutoff polyethersulfone tubular membranes (KOCH membrane, total area:
1.6 m
2 ) after coarse filtration at 200 μm. Ultrafiltration was performed at 0.25 MPa
and the cross-flow velocity was 3 m s
À1 . Mass balances on surfactant, TPH, and
water were performed through the twice-a-day sampling of the soil leachates in the
storage tank and of the solutions at the different stage of the UF treatment all along
the flushing experiments.
The soil treatment was performed as follows: 3 days using air injection for usual
venting to remove volatile compounds, then LB foam injection (0.47 PV of LB
solution) for 7 days, then flushing with the surfactant solution for 6 days (1.6 PV)
and finally, rinsing the soil with water (0.83 PV) for 3 days. The upper cover was
removed before leaching with the surfactant solution to enable for SF from the top
soil as well. Surfactant and TPH concentrations in the recovered leachates all along
the treatment are shown in Fig. 1.16.
Using solutions instead of foams raised the injection rate by a threefold factor
because of higher injection capacity. We observed a small dip of the soil’s hydraulic
conductivity which is attributed to some surfactant adsorption in pores. Mass
Table 1.3 Measured characteristics of the contaminated soil calculated as the 95% confidence
level of three analyses
Soil
PAH (mg kg
À1
)
BTEX (μg kg
À1
)
Conductivity (mS cm
À1
)
0.45
Naphtalene
896 Æ 36
Benzene
<1
Particle size distribution
Acenaphthylene
19.9 Æ 10.0 Toluene
<1
<0.063 mm 0.54 Æ 0.17
Acenaphtene
648 Æ 30
Ethylbenzene 20 Æ 8
0.100 mm
1.17 Æ 0.31
Fluorene
571 Æ 19
Styrene
52 Æ 18
0.250 mm
37.09 Æ 5.71 Phenanthrene
1430 Æ 45
m-, p-xylene 101 Æ 21
0.500 mm
48.74 Æ 4.71 Anthracene
299 Æ 22
o-xylene
86 Æ 12
1.000 mm
10.74 Æ 2.32 Fluorantene
781 Æ 24
Sum of
BTEX
259 Æ 78
2 mm
1.18 Æ 0.46
Pyrene
531 Æ 18
TPH (mg kg
À1
)
Benzo(a)anthracene
167 Æ 31
C10–40
8340
Chrysene
107 Æ 33
Benzo(b)fluoranthene 19.1 Æ 16.5
Benzo(k)fluoranthene 69.9 Æ 6.7
Benzo(a)pyrene
52.6 Æ 4.5
Dibenzo(a,h)
anthracene
<5
Benzo(g,h,i)perylene 9.8 Æ 1.2
Indeno(1,2,3-c,d)
pyrene
14.4 Æ 6.7
Sum of PAH
5616 Æ 202
1 Contaminant Mobilization from Polluted Soils: Behavior and Reuse of Leaching. . .
45
(10 samples each) carried out before starting and at the end of the flushing test. The
treatment used LB surfactant solutions at 2% in tap water. Gas effluents were treated
by granular activated carbon. The liquid effluents were treated by UF using eight
100 kDa cutoff polyethersulfone tubular membranes (KOCH membrane, total area:
1.6 m
2 ) after coarse filtration at 200 μm. Ultrafiltration was performed at 0.25 MPa
and the cross-flow velocity was 3 m s
À1 . Mass balances on surfactant, TPH, and
water were performed through the twice-a-day sampling of the soil leachates in the
storage tank and of the solutions at the different stage of the UF treatment all along
the flushing experiments.
The soil treatment was performed as follows: 3 days using air injection for usual
venting to remove volatile compounds, then LB foam injection (0.47 PV of LB
solution) for 7 days, then flushing with the surfactant solution for 6 days (1.6 PV)
and finally, rinsing the soil with water (0.83 PV) for 3 days. The upper cover was
removed before leaching with the surfactant solution to enable for SF from the top
soil as well. Surfactant and TPH concentrations in the recovered leachates all along
the treatment are shown in Fig. 1.16.
Using solutions instead of foams raised the injection rate by a threefold factor
because of higher injection capacity. We observed a small dip of the soil’s hydraulic
conductivity which is attributed to some surfactant adsorption in pores. Mass
Table 1.3 Measured characteristics of the contaminated soil calculated as the 95% confidence
level of three analyses
Soil
PAH (mg kg
À1
)
BTEX (μg kg
À1
)
Conductivity (mS cm
À1
)
0.45
Naphtalene
896 Æ 36
Benzene
<1
Particle size distribution
Acenaphthylene
19.9 Æ 10.0 Toluene
<1
<0.063 mm 0.54 Æ 0.17
Acenaphtene
648 Æ 30
Ethylbenzene 20 Æ 8
0.100 mm
1.17 Æ 0.31
Fluorene
571 Æ 19
Styrene
52 Æ 18
0.250 mm
37.09 Æ 5.71 Phenanthrene
1430 Æ 45
m-, p-xylene 101 Æ 21
0.500 mm
48.74 Æ 4.71 Anthracene
299 Æ 22
o-xylene
86 Æ 12
1.000 mm
10.74 Æ 2.32 Fluorantene
781 Æ 24
Sum of
BTEX
259 Æ 78
2 mm
1.18 Æ 0.46
Pyrene
531 Æ 18
TPH (mg kg
À1
)
Benzo(a)anthracene
167 Æ 31
C10–40
8340
Chrysene
107 Æ 33
Benzo(b)fluoranthene 19.1 Æ 16.5
Benzo(k)fluoranthene 69.9 Æ 6.7
Benzo(a)pyrene
52.6 Æ 4.5
Dibenzo(a,h)
anthracene
<5
Benzo(g,h,i)perylene 9.8 Æ 1.2
Indeno(1,2,3-c,d)
pyrene
14.4 Æ 6.7
Sum of PAH
5616 Æ 202
1 Contaminant Mobilization from Polluted Soils: Behavior and Reuse of Leaching. . .
45