Clean up of heavy hydrocarbons contaminated groundwater by oil belt skimmer technology

The oil belt skimmer consists of a continuously moving belt that runs on a pulley system driven by an electric motor. Typically, belt skimmers remove very little water with the contaminant. Taking into account this consideration, the objective of our work was to verify the applicability of oil belt skimmer technology for the remediation of a groundwater polluted by heavy hydrocarbons. For this purpose, two fields of study were addressed: (i) hydrodynamic study of supernatant layer and (ii) study of the oil belt skimmer plant. The obtained results showed the feasibility of the oil belt skimmer technology in recovering oil from groundwater with a recovery efficiency of 98%. Furthermore, results showed how the recovery of oil depends primarily on the amount of emulsion (water + oil) existing initially. Considering full-scale experimentations, they showed that, after 1 year of trial, the recovery percentage were 75%, 84% and 87% for the skimmers installed in correspondence of carwash, fuel tank and repair shop (pollutions sources), respectively. Moreover, the recovery capacity of the skimmer depends on the rainfall pattern and the max recovery capacities have always occurred after intense and short rain. Still, the recovery capacity depends also on the fluctuation of groundwater in turn influenced by the sea. Although the percentage of recovery of the pump and treat was greater than in the case of the oil belt skimmer, the investigated technology allow to reduce the amount of waste to be disposed respect to the pump and treat technology. Therefore, the oil belt skimmer represents an excellent alternative for the remediation of contaminated groundwater.