Mining and using underground resources demand high water usage, producing significant waste with environmental risks. Methods like electrokinetics prove effective in accelerating dewatering and stabilizing structures. This research provides the results of experimental investigation on dewatering silty tailings obtained from Sungun Tailings Dam (East Azerbaijan, Iran) using the electrokinetic water recovery method. Previous studies primarily examined the electrokinetic process in steady-state flow and saturated soil, with limited exploration of unsaturated soil parameters. In this research, the electrokinetic process in steady-state flow was initially investigated, and the saturated electro-osmotic permeability was determined. Subsequently, experiments were conducted in non-steady-state flow and unsaturated conditions, measuring the influential parameters with soil moisture sensors and tensiometers. Results show that decreasing sample moisture through electro-osmotic flow increases negative pore water pressure. Tailings' electrical conductivity is more influenced by moisture content, with a steeper reduction slope concerning volumetric moisture reduction over time. pH assessments show soil acidity on the anode side and alkalinity on the cathode side. Higher applied voltage gradients result in increased maximum power consumption. Importantly, the results caution against assuming that higher applied voltage improves the electro-osmotic process, as it may lead to issues such as deep sample cracking, void space creation, interrupted electrical flow, and energy loss.

The coastline of the Dardanos, a district of & Ccedil;anakkale, T & uuml;rkiye, suffers from saltwater intrusion due to excessive extraction of groundwater for domestic usage and also agricultural activities. Thus, the salinity level increased, and much of the land became unusable. The electrokinetic remediation method was employed to reduce the salinity level in the soil samples in laboratory conditions. The sample used in remediation is silty agricultural soil, with pH value and electrical conductivity (EC) of which are 8.33 and 1282 mu S/cm respectively. In the lab-scale experiments, three different types of electrodes, aluminum, copper, and galvanized steel, were used in the tests. For each type of metal, electrode pairs were placed in the soil that was filled in a plastic container. Current variation was monitored while 1 VDC/cm was applied to electrodes. Average electrical conductivity reduces to 13.5%. As a side effect, all electrodes suffered from heavy corrosion which may be prevented by using anti-corrosion additives to reduce damage for future applications.

This study investigates the influence of four soil improvement methods-microbially induced carbonate precipitation (MICP), electrokinetics (EK), chemical additives, and a combination of EK and chemical additives-on the dispersivity, mechanical properties, and microstructure of dispersive soil. A series of tests was designed to evaluate the effectiveness of these methods on dispersive soil. Both the original and treated soil samples were tested to assess changes in soil properties, including dispersivity, plasticity, pH, unconfined compressive strength (UCS), shear strength, and microstructure. Dispersivity was assessed using pinhole tests, crumb tests, double hydrometer tests, and exchangeable sodium percentage tests. The experimental results indicate that the combined EK and chemical additives method significantly reduces the dispersivity and plasticity of the dispersive soil compared with the other methods, leading to improved UCS. The EK and chemical additive methods individually demonstrate effective modification under a voltage of 48V and an additive content of 4%, respectively, enhancing the shear strength of the dispersive soil. MICP does not significantly improve the dispersivity of dispersive soil, but it does enhance the shear strength of the treated soil, with a particularly notable increase in the internal friction angle. Overall, the combined method shows more remarkable improvements in the dispersive soil than any single method. In summary, the combination of EK and chemical additives has significant potential for improving the dispersivity and mechanical properties of dispersive soil.

Sand aging, defined by time-dependent increases in stiffness and strength over periods ranging from days to months, poses significant challenges in geotechnical engineering and soil science. Despite its relevant implications, the mechanisms driving sand aging remain understood. This review systematically examines sand aging, emphasizing the classification of chemical and mechanical processes involved. Key advancements in chemical aging understanding, particularly the influence of surface chemistry and electrokinetic forces, are discussed. Additionally, the review underscores the critical role of micromechanical modeling, especially discrete element methods, in elucidating particle interactions and aging phenomena. The review also identifies essential directions for future research, notably incorporating particle shape and surface texture into aging models. Hence, this comprehensive resource aims to enhance the understanding of sand aging.

This study proposes a closed-form solution for axisymmetric electro-osmotic consolidation of unsaturated soil under semi-permeable boundary conditions. The governing equations are formulated to allow for vertical and radial flows of liquid and air phases. The techniques of eigenfunction expansion and Laplace transformation are employed to develop the exact solution for excess pore-air (EPAP) and pore-water pressures (EPWP). The proposed solution is first validated by comparing it to an existing solution, followed by verification through finite element simulations. Both methods of validation confirm the accuracy of the analytical solution. Then, based on the obtained solution, the effects of vertical flow, semi-permeable boundary conditions, electrical voltage, electro-osmosis conductivity and spacing ratio re/rw on the consolidation profile have been further investigated. Parametric studies show that the EPWP at the steady state depends on the electro-osmosis conductivity and applied electricity gradient. In addition, the dissipation rates of EPWP and EPAP in the axisymmetric electro-osmotic consolidation would be underestimated if the vertical flows are neglected. The semi-permeable boundary conditions have great influences on the dissipation rate and the steady-state solution. The proposed solution could serve as a theoretical basis for axisymmetric electro-osmotic consolidation of unsaturated soil.

In this study, the sustainability of the electrokinetic remediation soil flushing (EKSFs) process integrated without and with adsorption barriers (EKABs) have been evaluated for the treatment of four soils contaminated with Atrazine, Oxyfluorfen, Chlorosulfuron and 2,4-D. To this purpose, the environmental effects of both procedures (EKSFs and EKABs) have been determined through a life cycle assessment (LCA). SimaPro 9.3.0.3 was used as software tool and Ecoinvent 3.3 as data base to carry out the inventory of the equipment of each remediation setup based on experimental measurements. The environmental burden was quantified using the AWARE, USEtox, IPPC, and ReCiPe methods into 3 Endpoint impact categories (and damage to human health, ecosystem and resources) and 7 Midpoints impact categories (water footprint, global warming potential, ozone depletion, human toxicity (cancer and human non-cancer), freshwater ecotoxicity and terrestrial ecotoxicity). In general terms, the energy applied to treatment (using the Spanish energy mix) was the parameter with the greatest influence on the carbon footprint, ozone layer depletion and water footprint accounting for around 70 % of the overall impact contribution. On the other hand, from the point of view of human toxicity and freshwater ecotoxicity of soil treatments with 32 mg kg(-1) of the different pesticides, the EKSF treatment is recommended for soils with Chlorosulfuron. In this case, the carbon footprint and water footprint reached values around 0.36 kg of CO2 and 114 L of water per kg of dry soil, respectively. Finally, a sensitivity analysis was performed assuming different scenarios.

Soil electrokinetic (SEK) is a remarkable technology that has applications in a variety of fields, such as polluted soil remediation, soil restoration, geophysics, dewatering, seed germination, pollution prevention, sedimentation, and consolidation. The current review is a continuation of our recently published series on process design modifications and material additives. There are three reviews have been recently published. The 1st and 2nd reviews were focused on SEK classification according to electrode position/types of contaminants movement (horizontal, vertical, and mixed horizontal and vertical) during (1993-2020) [1] and (2021-2022) [2], respectively. The 3rd review summarized the materials additives for enhancing the SEK intensification process during 2017-2020 [3]. Modifications were made to the shape of the electrodes to make research and operation more convenient and efficient. Based on exhaustive searches in six scientific search engines, we focused on the various roles of utilizing the perforated electrodes, pipes (a tubular section, or hollow cylinder, made of hard plastic), and nozzles (a tubular section, or hollow cylinder, made of flexible plastic) (PEPN) during SEK. The PEPN could perform SEK properly, remove nitrate, collect drainage water, reduce pH advection, enhance materials injection, distribute water throughout treated soil, incorporate a vacuum system, and monitor wells. Although the perforated electrodes may be considered an economic advantage due to the reduction of electrode surface area and, consequently, total costs, no comparative studies have been conducted to determine the effects of different electrode surface areas on the SEK efficiency, operation time, and energy consumption, which should be considered in future research.