Multiphysics Implementation of Electrokinetic Remediation Models for Natural Soils and Porewaters

Abstract

Models of electrokinetic soil remediation systems have been developed significantly in recent decades. A wide range of physicochemical phenomena occurs in this type of process, which makes it difficult to capture all of the system's complexity in a model. Therefore, existing models do not attempt to simulate the behaviour of the entire geochemical system of natural soils and their porewaters but rather focus on the pollutant compounds of interest. This paper proposes a conceptual and numerical model that includes geochemical speciation other than the phenomena that have been described by other authors. In addition, a comparative modelling exercise is performed with a composition of natural porewater and a simplified equivalent composition. The results show that the buffering system of carbonates affects the temporal evolution and spatial distribution of the pH. Because the pH controls many of the phenomena that occur during this type of remediation, simulations using realistic geochemical systems are critical.

Calcite buffer effects in electrokinetic remediation of clopyralid-polluted soils

“…4) in previous experimental work [55]. to cathode [26]. However, if we compare the spatial distributions at the same observation times, we can see how there are notable differences between the two tests analysed.…”

“…Its adaptability and capacity for gradual implementation of improvements are easy by the fact that the base module has been programmed in a multiphysical environment. [26].…”

“…The level of electrolyte in compartments is constant during the tests by adding anolyte through gravity and extracting the catholyte by overflow of the CC. This modelled experimental setup has been outlined in detail in preceding studies [26,36,37]. Fig.…”

“…The numerical tool used was the M4EKR module, Multiphysics for EKR [26]. M4EKR is a numerical model developed by the authors as a result of the knowledge gained over the last years in the treatment of contaminated soils using electrokinetic techniques [27][28][29][30][31][32][33][34][35].…”

Electro-kinetic remediation processes-a brief overview and selected applications

“…The pH is a crucial factor that controls various phenomena that occur during the electro-kinetic remediation. 5 Therefore, the pH should be carefully monitored during the entire remediation process. After the electro-kinetic remediation process, the positively charged species may be deposited at the anode or may remain in the electrolyte solution and they can be removed by ion exchange columns and chemical precipitation as needed.…”