Environmental Electrokinetics for a sustainable subsurface

Abstract

Soil and groundwater are key components in the sustainable management of the subsurface environment. Source contamination is one of its main threats and is commonly addressed using established remediation techniques such as in-situ chemical oxidation (ISCO), in-situ chemical reduction (ISCR; most notably using zero-valent iron [ZVI]), enhanced in-situ bioremediation (EISB), phytoremediation, soil-washing, pump-and-treat, soil vapour extraction (SVE), thermal treatment, and excavation and disposal. Decades of field applications have shown that these techniques can successfully treat or control contaminants in higher permeability subsurface materials such as sands, but achieve only limited success at sites where low permeability soils, such as silts and clays, prevail. Electrokinetics (EK), a soil remediation technique mostly recognized in in-situ treatment of low permeability soils, has, for the last decade, been combined with more conventional techniques and can significantly enhance the performance of several of these remediation technologies, including ISCO, ISCR, EISB and phytoremediation. Herein, we discuss the use of emerging EK techniques in tandem with conventional remediation techniques, to achieve improved remediation performance. Furthermore, we highlight new EK applications that may come to play a role in the sustainable treatment of the contaminated subsurface.

Remediation of Copper Contaminated Soils Using Water Containing Hydrogen Nanobubbles

“…Offsite processing, the ex situ method of restoration, is more effective and faster, but it is also more expensive. By contrast, onsite processing, the in situ method, has a lower cost and uses technologies pertinent to the characteristics of the site [2]. While some in situ remediation methods employ ecofriendly enhancers, chemical solvents are also employed, due to the inherent difficulty in desorbing heavy metals from fine-grained soil.…”

Transformation of tetrachloroethylene in a flow-through electrochemical reactor

“…Chlorinated ethenes have been unintentionally introduced to the environment causing extensive and harmful contamination of the subsurface, potentially impacting the groundwater and indoor air quality [1,2]. Effort has been put into remediation of low-permeable zones, where use of electrokinetics has shown to overcome some of the challenges faced [3][4][5][6][7]. However, the dense chlorinated ethenes slowly leak into aquifers, causing an increase in detection above regulatory maximum contaminant levels [8].…”

Modeling electrokinetic transport and biogeochemical reactions in porous media: A multidimensional Nernst–Planck–Poisson approach with PHREEQC coupling

“…Electrokinetic techniques are used in different fields of science and engineering (Lima et al, 2017;Ribeiro et al, 2016). Focusing on environmental subsurface applications, electrokinetic remediation (EKR) is a technology that uses a low-intensity electric field produced by electrodes placed in the ground to mobilize and remove contaminants and/or to enhance the delivery of amendments (Reddy and Cameselle, 2009).…”