Formatted Title
Enhanced Dynamic Skimming: A New and Highly Effective Approach to LNAPL Recovery
Background/Objectives
The recovery of light non-aqueous phase liquids (LNAPL) poses significant challenges in environmental remediation. These challenges include issues related to high viscosity, susceptibility to clogging in extraction systems, substantial energy consumption, fluctuations in groundwater levels, effluent generation, and the complexities of handling thin contaminant layers. Traditional methods often struggle to effectively address these multifaceted challenges.
Certain skimming solutions have been developed to address these limitations. These solutions involve dynamic vacuum suction of hydrocarbon-free phases at various depths, creating an imbalance between the free phase level within a well and the surrounding soil. This imbalance facilitates well recharge and immediate pollutant extraction. The frequency of pumping depends on factors such as the time required to recharge the well with the pollutant and the duration of suction per well, which is correlated with the quantity of free phase present. These solutions utilize proprietary floats connected to pumping units via flexible hoses, with pumped mixtures automatically transferred to settling tanks for storage and subsequent removal by specialized companies. Minor quantities of effluent are treated in coalescence separators.
However, the effectiveness of this technology is contingent upon soil permeability and LNAPL viscosity, with pumping times influenced by well recharge dynamics. In response, our approach seeks to enhance LNAPL recovery efficiency by harnessing the inverse relationship between temperature and viscosity.
Approach/Activities
Advanced dynamic skimming enhancement: Our innovative approach seamlessly integrates into a comprehensive remediation strategy for contaminated sites, complementing techniques such as soil excavation, thermal desorption, bioremediation, and chemical oxidation. Our method leverages the temperature-viscosity relationship by increasing temperature through in situ thermal desorption, thereby reducing product viscosity. This expedited well filling process enables faster dynamic skimming.
Our approach ensures the complete removal of even the thinnest free phase layers and viscous layers when combined with heating, surpassing the performance of traditional methods. Observations from multiple in situ thermal desorption sites, where LNAPL pumping was conducted alongside soil heating, have demonstrated substantial improvements in product recovery. The combination of in situ thermal desorption and dynamic skimming significantly reduces project timelines.
Results/Lessons Learned
This abstract highlights technological advancements and the potential for enhancing the efficiency of LNAPL recovery through the application of heat. The presentation will include results comparing the amount of product recovered with and without aquifer heating, offering valuable insights into the effectiveness of this innovative approach.