The experimental site is an active fuel station located in the Provincia of Grosseto. The first subsurface consists of alluvial deposits with a predominance of sands, affected by the presence of a phreatic aquifer with an average thickness of 5.5 m and depth to water for 1.5 m. Groundwater contain hydrocarbons, methyl-t-butyl-ether, Benzene, Toluene, Ethylbenzene and Xylenes. The total hydrocarbons initial concentrations were in the order of 2,000 µg/l, the MTBE initial concentrations were 6,000 µg/l, the total aromatic hydrocarbons initial concentrations were in the order of 100 µg/l.
In this site a SmartStripping® remediation system replaced a previously realized Pump&Stop for which has not been granted permission to the discharge of treated water. SmartStripping® was realized with two injection/extraction wells fed by a system of air circulation: injection and aspiration.
Groundwater was monitored by the clients through a net of about ten monitoring piezometers installed in the intervention area also with the aim of ensuring the control of the water quality coming out of the site perimeter. The interstitial gases were monitored through specific gas monitoring probes.
Remediation targets have been achieved after about 20 months of activity during which SmartStripping® has removed a total of about 240 kg of hydrocarbons from underground, reducing the concentrations of MTBE, total hydrocarbons and BTEX to 6 µg/l, 16 µg/l and <0.23 µg/l respectively. The solution SmartStripping® is economically more advantageous and more effective in the removal of contaminants from groundwater compared to the Pump & Stop system previously realized.
The remediation system led to a significant reduction in the volatile pollutants concentrations and their extraction from underground. In 20 months of activity, we measured the following environmental benefits: the purification and preservation of approximately30.000 mcof groundwater, not extracted from the ground and not discharged into surface water or sewer, the missed emission in atmosphere of 1.000.000mcof air purified in the closed air-cycle of SmartStripping®, the production of zero kgof waste, since all the waste of the system, including activated carbons, have been regenerated and reused.