4.5.4 Long-Term Predictions
Due to time constraints and the slow removal of contaminants in some techniques, it
was not possible to reach a complete depletion of mass or flux. In order to extrapolate
the present results, two approaches can be considered depending on the remedial
objective: removing the maximum of mass, or eliminating most of the flux. For the
mass removal, thermal treatment is obviously the best technique. For the flux
approach, a target decrease of 99% of the flux could be considered as a satisfying
remediation goal. To extrapolate the flux for persulfate and surfactant treatments, an
empirical method using an analytical equation of the concentration–mass curves was
chosen (see Atteia et al. (2017) for more details).
The prediction concerned the number of pore volumes necessary to reach a given
mass removal. For persulfate, the calculated pore volumes include the addition of a
water washing period.
It can be seen in Fig. 4.11 that curves for both treatments give very similar pore
volumes for a given mass removed. In contrast to persulfate, surfactant data show a
clear linear trend in Fig. 4.11. The prediction consists in extrapolating the curve
fitted to the points (shown as a black straight line). Table 4.5 shows the pore volumes
required for a treatment leading to a 99% flux reduction. The surfactant treatment
requires five times more PV compared to persulfate. The mass of surfactant required
remains much smaller than the persulfate one. However, it must be outlined that in
10
100
1000
0%
20%
40%
60%
80%
100%
Cumulated pore volumes
Mass removed
PV persulfate
PV surfactant
predict
Model washing
Fig. 4.11 Evolution of the cumulated pore volumes (PV) of added treatment or simply water
(model) for persulfate and surfactant treatments as a function of the mass removed in the tanks. The
“predict” line is an exponential trend fitted on the PV surfactant curve. Vertical lines show the mass
removal required to reach 99% flux removal for the two different techniques
230
F. Jousse et al.
Due to time constraints and the slow removal of contaminants in some techniques, it
was not possible to reach a complete depletion of mass or flux. In order to extrapolate
the present results, two approaches can be considered depending on the remedial
objective: removing the maximum of mass, or eliminating most of the flux. For the
mass removal, thermal treatment is obviously the best technique. For the flux
approach, a target decrease of 99% of the flux could be considered as a satisfying
remediation goal. To extrapolate the flux for persulfate and surfactant treatments, an
empirical method using an analytical equation of the concentration–mass curves was
chosen (see Atteia et al. (2017) for more details).
The prediction concerned the number of pore volumes necessary to reach a given
mass removal. For persulfate, the calculated pore volumes include the addition of a
water washing period.
It can be seen in Fig. 4.11 that curves for both treatments give very similar pore
volumes for a given mass removed. In contrast to persulfate, surfactant data show a
clear linear trend in Fig. 4.11. The prediction consists in extrapolating the curve
fitted to the points (shown as a black straight line). Table 4.5 shows the pore volumes
required for a treatment leading to a 99% flux reduction. The surfactant treatment
requires five times more PV compared to persulfate. The mass of surfactant required
remains much smaller than the persulfate one. However, it must be outlined that in
10
100
1000
0%
20%
40%
60%
80%
100%
Cumulated pore volumes
Mass removed
PV persulfate
PV surfactant
predict
Model washing
Fig. 4.11 Evolution of the cumulated pore volumes (PV) of added treatment or simply water
(model) for persulfate and surfactant treatments as a function of the mass removed in the tanks. The
“predict” line is an exponential trend fitted on the PV surfactant curve. Vertical lines show the mass
removal required to reach 99% flux removal for the two different techniques
230
F. Jousse et al.