Reclamation of contaminated groundwater using cooking oils in a novel, eco-friendly and high-efficiency solvent extraction process

• A new process was developed for the removal of VOC compounds from contaminated groundwater.
• This is a two-steps process; solvent extraction followed by VOC removal from the oil by distillation.
• High-efficiency centrifugal contactors are used in the extraction using cooking oils as solvents.
• High affinity of the VOC to the oils was demonstrated, indicating efficient extraction.
• Simulations and distillation tests showed that the VOC can be efficiently recovered from the oil.

In this study, a new eco-friendly process was developed for the removal of volatile organic compounds (VOC) from contaminated groundwater. The new process included two steps. The first step is a solvent extraction process using a high-efficiency centrifugal contactor, in which the VOC's were extracted from the groundwater using cooking oils, acting as safe and environment-friendly solvents. In the second step, the VOC's were removed from the oil by a distillation process, after which the cooking oil can be recycled for another extraction. Using five cooking oils, distribution ratios showed high affinity of the VOC's to the oil phase, indicating efficient extraction. Hydraulic tests showed that corn oil performed best in terms of ease of mixing and separation from the water. A stage efficiency test showed that high stage efficiency, in excess of 90%, can be achieved in the centrifugal contactor. Finally, a distillation test, using a wiped-film distillation unit, showed that more than 95% of the VOC can be removed from the oil under mild operating conditions. Based on these results, a proof-of-concept for the new technology was achieved.