SUITMA 2005 Cairo - Remediation process assessment for PAHs and heavy metal simultaneous removal
SUITMA 2005 Cairo
| This abstract is about one of the papers of the Consumed mining and military areas theme of the SUITMA 2005 symposium. |
| Stéphanie Ouvrard,i | Joëlle Fismes,i |
| Jean-Louis Morel.i |
- i - Laboratoire sols et environnement (LSE), ENSAIA, Université de Lorraine - INRA, Nancy, France.
The remediation of polluted sites is a challenge since it must deal with complex problems including the soil heterogeneity and the pollutant nature and concentration. The chosen remediation solution usually depends on different criteria such as the extent and the nature of the pollution, the remediation target (future land use, threshold values for residual pollution) and the amount of money that can be invested in the process. Most cleaning processes are dedicated to a class of pollutants (organics, heavy metals) and when a mixed pollution situation is encountered, containment of the polluted matrix is often the chosen solution in order to avoid the expense of two or even more cleaning processes. This work evaluates the efficiency of a cleaning process dealing simultaneously with both heavy metals and organic pollutants. We focused our study on polycyclic aromatic hydrocarbons (PAHs), which remain some of the most recalcitrant organic compounds to remove from polluted soils, and heavy metals. We selected a polluted soil from a former industrial site where both coking and metal industry had been in activity. The collected soil contained multiple pollutants among them about 1500 mg kg-1 of the 16 PAHs of the US-EPA list, 684 mg kg-1 of Pb, 2.31 mg kg-1 of Cd, 260 mg kg-1 of Ni, 2680 mg kg-1 of Zn.
Plant-assisted degradation of organic compounds was the chosen process to remove PAHs. Two options were selected to deal with metallic compounds. The first one used hyperaccumulator plants to extract heavy metals, these plants being also involved in the phytodegradation of PAHs. The second option consisted in stabilizing the heavy metals in the soil matrix using paper-sludge, which acted in some way like a liming treatment. The efficiency of these treatments was tested under controlled conditions in growth chambers. The soil and plants pollutant content was followed throughout a growth cycle and the effectiveness of each treatment was compared.
