Electrokinetic Treatment Research Articles

Electrokinetic Treatment of Polluted Soil with Petroleum Coupled to an Advanced Oxidation Process for Remediation of Its Effluent

Electrokinetic Treatment of Polluted Soil with Petroleum Coupled to an Advanced Oxidation Process for Remediation of Its Effluent

Secondary consolidation of a consolidated kaolin slurry during electrokinetic treatment

The increment of secondary deformations due to electrokinetic treatment (EKT) was studied considering that these deformations are associated to the mobilization of the water adsorbed by the clay minerals. This water is at the level of microstructure, and therefore volume changes occur while water is flowing from the micro to the macropores. Water transference can be explained based on the unbalance of the chemical potentials of microwater (at the surface of the clay minerals) and bulk water. Electrical potential increases this transfer of water, increasing the rate of secondary consolidation and therefore increasing the deformations. The comparison of secondary consolidation coefficients measured in consolidated kaolin slurry samples with and without electrical potential applied only during secondary consolidation made possible to understand that the flow due to electrical gradients appeared to be independent from the vertical stresses applied, unlike the flow due to hydraulic gradients. Under the same stresses, however, the application of electric current increases the amount of creep. Considering the total duration of each loading step, the electrical potential increased the elastic compressibility index defined at the level of the microstructure, but almost had no effect on global compressibility. This increment in the compressibility was explained by the mobilization of adsorbed water reducing repulsive forces between the clay minerals. A deeper knowledge of the electro-hydro-mechanical behaviour of clays will be useful for optimizing in-situ application of EKT in terms of its duration and consequences.

Removal of mercury from marine sediments by the combined application of a biodegradable non-ionic surfactant and complexing agent in enhanced-electrokinetic treatment

In this work, the Hg removal potentiality of an electrokinetic (EK) decontamination treatment enhanced by a biodegradable complexing agent (MGDA) also in combination with a biodegradable surfactant (Tween® 80) was investigated to decontaminate heavily contaminated marine sediments. The main results revealed that the nature of sediments and their interactions with different enhancing agents significantly influenced the remediation processes. A general increase of pH values along the sediment specimen was observed due to the strong buffering capacity of the carbonates, which are the main constituent minerals. This, in combination with the high organic matter and sulphide sediment content, resulted in very poor contaminant mobilization without any appropriate conditioning agents. The use of EDTA as a processing fluid resulted in a modest increase in Hg removal of ∼15%, whereas a further improvement in the Hg removal rate (∼39%) was achieved by replacing EDTA with MGDA as the anodic solution in response to its ability to form stable negative complexes with mercury, which can be moved towards the anode. A significantly higher Hg-removal of ∼71% was obtained by the simultaneous use of MGDA and Tween® 80 due to their synergic action in remedial processes and, especially, due to the improved selective action of the non-ionic surfactant adopted in favour of organo-Hg-complex removal. Compared with other Hg-removal technologies, the investigated enhanced-EK treatment allows the achievement of remediation targets, which can hardly met by one-stage processes. The data can be useful for predicting the remediation activity responses, as well as for guiding the design and scaling-up of EK treatment of Hg-contaminated sediments. In addition, the knowledge of the investigated Hg-removal mechanism can provide basic information, which is helpful for improving the development of further novel enhanced-EK technologies.

Surfactant and MGDA enhanced – Electrokinetic treatment for the simultaneous removal of mercury and PAHs from marine sediments

Abstract Mercury (Hg) and Hg-PAH removal effectiveness of several electrokinetic (EK) decontamination treatments, including the combined use of eco-friendly enhancing agents, was investigated in this work as a potential remedial treatment of heavily contaminated marine sediments. After a 400-h EK treatment, main results revealed a very poor Hg mobilization without the use of an appropriate conditioning agent, mainly due to the strong Hg-bounds with carbonates, organic matter and sulphides, which were present at high concentrations. The use of EDTA as processing fluid resulted in a slight improvement of Hg removal (∼15%). A further increase in Hg removal rate of ∼39% can be achieved with methylglycinediacetic acid (MGDA) as anodic solution. The best Hg-removal of ∼71% was obtained by means of the simultaneous use of MGDA and Tween® 80 due to their synergistic action in remedial processes. The same type of treatment led to a slightly lower total Hg-removal of ∼67% when a shorter time of 240 h was considered. In the case Hg and PAHs as sediment co-contaminants, results revealed a total PAH-removal of 59.45%. The co-presence of PAHs significantly affected the electric current circulating in the system and the electrosmotic values, leading to a reduction of about 5% in Hg removal respect to the case where PAHs were not present in the sediments. Nevertheless, the combined application of Tween® 80 and MGDA in enhanced-EK treatment allows the possibility to successfully remove both highly persistent Hg and PAHs from marine sediments with high removal percentages. Obtained data can be useful for further enhanced EK treatments of sediments contaminated with Hg and PAHs, as well as providing basic information for future cost analysis.

Modification of properties of reinforced concrete through nanoalumina electrokinetic treatment

An attempt was made to drift nanoalumina particles into concrete pores through electrokinetic treatment. An external electric current (current density=3A/m2) was applied for 3and15daysinreinforced concrete blocks toward steel reinforcement and microstructural characterizations (i.e. morphology observation and porosity analysis) were performed on concrete fragments of different depth from exposure surface. The morphology observation evidenced transport of nanoalumina from the exposure surface even reaching the rebar-concrete interface (up to 25–30mm, in 15daystreatment). The porosity analysis of treated samples revealed that reduction of porosity of rebar interface was more pronounced as compared to the exposure surface and the treatment for 15dayswas more beneficial for porosity refinement than treatment for 3days. Effects of the electrokinetic NA treatment on strength of rebar-concrete interface were evaluated through pull-out test. The results showed that by increasing current density, bond strength of rebar-concrete interface increased.

Enhanced electromigration and electro-osmosis for the remediation of an agricultural soil contaminated with multiple heavy metals

The remediation of agricultural soil contaminated with Cd, Co, Cr, Cu, Pb, and Zn was carried out by enhanced electrokinetic remediation using sulfuric acid or organic acids (EDTA, Citric acid and Acetic acid) as the processing fluid. The unenhanced electrokinetic treatment with DI water in the anolyte and catholyte resulted in some mobilization of the heavy metals, but only minor removal was observed. The use of EDTA and acetic acid in the catholyte favored the mobilization of the metals and the formation of chelates and complex ions. Citric acid was very effective in the solubilization and removal of heavy metals because of: (a) the acidification of the soil specimen and subsequent mobilization of metals, and (b) the enhanced electro-osmotic flow that favored the transportation of mobilized cations towards the cathode. The removal of Cd, Co, Cu and Zn was over 70%, whereas Cr and Pb showed very limited removal (below 12%) because of their strong immobilization in the soil.

Performance of electroremediation in real contaminated sediments using a big cell, periodic voltage and innovative surfactants

The present work focused on evaluating the electrokinetic (EK) treatment of real contaminated sediments with toxic metals and polycyclic aromatic hydrocarbons (PAHs), using a big laboratory EK cell, periodic voltage and recently tested non-ionic surfactants. The results indicated that the “day on-night off” application mode of voltage, in conjunction with the selected solubilising agents, favoured the overall EK process. Arsenic, nickel and chromium exhibited the highest removal percentages, obtaining 83%, 67% and 63%, respectively, while zinc and lead attained 54% and 41% at the maximum. Furthermore, in the experiments where the non-ionic surfactants were introduced in the electrolyte chambers, there was a major uniformly removal of PAHs from the entire sediment across the EK cell, indicating the high solubilisation capacity of the enhancing agents. Essentially, transport and in some cases removal of PAHs (particularly from sections adjacent to the electrolyte compartments) also occurred in the unenhanced EK run, mainly due their negative charge, their potential weak bonds to the soil matrix and to the periodic application of voltage. Maximum removal was obtained by the use of Nonidet P40 where app. 1/3 (ca. 6498μg out of 20145μg) of the total initial amount of PAHs were removed from the cell.

Enhanced Electrokinetic Remediation of Pyrene-Contaminated Soil Through pH Control and Rhamnolipid Addition

Abstract Electrokinetic (EK) remediation is considered an effective technology for removal of persistent, toxic, and hydrophobic polycyclic aromatic hydrocarbons, such as pyrene, from soils. We propose a method involving use of pH control and rhamnolipid addition for enhancing pyrene removal efficiency of EK remediation. Pyrene removal efficiency was successfully improved by cycling the electrolyte, exchanging electrodes, and implementing an electrolyte pH of 7, with high values of 12.12%, 10.48%, and 14.00% being achieved, respectively, compared to the 0.35% achieved with traditional EK treatment. Effect of rhamnolipid addition on the EK removal of pyrene was also investigated. When rhamnolipid was added to the electrolyte, solubility of pyrene increased, thus resulting in improved removal efficiency. With an increase in rhamnolipid concentration from 0.5 to 2 g/L, pyrene removal efficiency increased from 14.74% to 24.81%, reaching 93.60% in the section closest to the anode. These results indicate that u...

Variation in properties of the sediment following electrokinetic treatments

ABSTRACT Many studies have reported variation in properties of the sediment within electrokinetic treatments (EKTs). However, we aim to reveal the variation in properties of the sediment following EKTs through laboratory experiments. We collected sewage-derived sediment from a littoral region, and passed it through a 2-mm sieve. We used a potentiostat to cause electrical current in EKT. We measured the sediment properties such as pH, redox potential (ORP), and hydrogen sulphide (H2S) concentration at the end of EKT and at 30 days following EKT. Results showed decreases in pH, increases in ORP, and decreases in H2S concentration at the end of EKT. Compared with the sediment without EKT, the decrease in ORP for the sediment within EKT was higher at 30 days following EKT. These suggest that anaerobic digestion of organic compounds occurs in the sediment following EKT, of which the oxidants produced by EKT serve as electron acceptors and organic compounds serve as electron donors. Furthermore, we found that EKT can remove H2S from the sediment and reduce H2S production in the sediment within EKT when compared to the case without EKT. These ensure that EKT can be used to remove H2S and control H2S production in the sediment.

Electrokinetic removal of radionuclides contained in scintillation liquids absorbed in soil type Phaeozem

Control samples of scintillation liquids – Phaeozem soil mixtures were prepared with different scintillation liquids as the support electrolyte, Install Gel® XF, (Ultima Gold AB™ and Ultima Gold XR™), to construct the polarization curves, and to select the cell potential with the highest mass transfer to remove 24Na (15 h) and 99mTc (6 h) as radiotracers from polluted Phaeozem soil. During the electrokinetic treatment (EKT), the removal of radionuclides contained in scintillation liquids absorbed in Phaeozem soil, liquid phase was characterized by Gas Chromatography coupled with a Flame Ionization Detector (GC-FID) and Fourier Transform Infrared Spectrometry (FTIR), solids by FTIR, before and after the application of cell potential. In this sense, the support electrolyte was selected based on the highest current generated (1 mA), as in the case of scintillation liquid 50% Ultima Gold XR™ + 50% Water (1:1), which was used for 6 h in the presence of a mesh and a titanium rod, as anode and cathode, respectively. Finally, the removal percentage accumulated in the liquid phase after the EKT of Phaeozem soil polluted by 99mTc was 61% close to the anode after 4 h. It was also 61% for 24Na close to cathode after 2 h, and after 4 h it was 71.8%.

Assessment of IrO2-Ta2O5|Ti electrodes for the electrokinetic treatment of hydrocarbon-contaminated soil using different electrode arrays

In recent years, physicochemical processes such as electrokinetic treatment (EKT) have gained acceptance as suitable alternatives to restore hydrocarbon (HC)-contaminated sites. EKT entails relatively short times and high removal efficiencies, usually being applied in heterogeneous soils with low permeability. In this work, 1D (one-dimensional) and 2D (two-dimensional) configurations have been tested employing Ti cathodes and anodes, as well as purpose-made IrO2-Ta2O5|Ti as dimensionally-stable anodes (DSA®). After EKT and from GC-MS analysis of fat and oil content, it has been found that the radial 2D array with one central Ti cathode and six IrO2-Ta2O5|Ti anodes performed the best removal efficiency of hydrocarbons. The removal efficiencies of using modified electrodes with a configuration of circular 2D electrodes had double the removal efficiency (58%) over the use of a configuration of face-to- face 1D array (21%) with the IrO2-Ta2O5|Ti anode and Ti cathode. Finally, the superficial morphology of IrO2-Ta2O5|Ti anode and Ti cathode were not affected by EKT, which was demonstrated with the same appearance before and after EKT in the micrographs obtained by SEM.

ApplicationsofElectro-kinetic Principles for Enhancing Durability of Concrete

Electro-kinetic treatment has been recognized as a promising technology for different purposes in both civil and environmental engineering. The main focus of this study is to improve the durability of cement concrete by application of electro-kinetic method.This method can be used mainly in pre-cast, pre-stressed and reinforced concrete members like railway sleepers, girders and other precast and prefabricated structural elements. Durability of structures is of global concern, many engineers and researchers are working to enhance durability of concrete elements.The durability of concrete can be improved by pore filling effect by ionic migration by adopting electro-kinetic concepts.

Electrokinetic treatment of an agricultural soil contaminated with heavy metals

ABSTRACTThe high organic matter content in agricultural soils tends to complex and retain contaminants such as heavy metals. Electrokinetic remediation was tested in an agricultural soil contaminated with Co+2, Zn+2, Cd+2, Cu+2, Cr(VI), Pb+2 and Hg+2. The unenhanced electrokinetic treatment was not able to remove heavy metals from the soil due to the formation of precipitates in the alkaline environment in the soil section close to the cathode. Moreover, the interaction between metals and organic matter probably limited metal transportation under the effect of the electric field. Citric acid and ethylenediaminetetraacetic acid (EDTA) were used in the catholyte as complexing agents in order to enhance the extractability and removal of heavy metals from soil. These complexing agents formed negatively charged complexes that migrated towards the anode. The acid front electrogenerated at the anode favored the dissolution of heavy metals that were transported towards the cathode. The combined effect of the soil pH and the complexing agents resulted in the accumulation of heavy metals in the center of the soil specimen.

Electrokinetic Treatment of Mercury - Polluted Soil Facilitated By Ethylenediaminetetraacetic Acid Coupled with a Reactor with a Permeable Reactive Barrier of Carbon to Recover Mercury (II) from Water

Electroremediation or electrokinetic treatment (EKT) has been successfully applied in a variety of polluted soils; this technology refers to the application of an electric field or direct current through a pair of electrodes (anode and cathode). These electrodes are inserted in the soil, where an electrolyte improves the conductive properties of the electric field [1-2]. Enhancing solutions can be added to the soil to improve the efficacy of the treatments [3-4]. The most common enhancing solutions are ethylenediaminetetraacetic acid (EDTA) [5-6], which is a compound with four carboxylic and two associated amino groups, which can act as electron pair donors or Lewis bases. EDTA, in an aqueous solution, forms an octahedral complex with mostly divalent metal cations (M2+). A very strong mercury-EDTA ([Hg-EDTA]2-) complex is formed, with a log b of 21.8 [7]. Considering the negative charge of this complex, most mercury moves towards the anode side, where it can be recovered. In this study, a soil sample polluted with mercury was treated with electrokinetic treatment (EKT). Seventy-two h was necessary to remove most of the mercury present in soil from the cathode to the anode with a removal percentage of 76.30%. During this period, we measured the interfacial potential and current. We analyzed the physicochemical properties before and after EKT where physical properties such as color, soil particle, real density, porosity and fraction of organic matter did not change; chemical properties such as pH and electric conductivity changed due to the electric field applied to the soil and the addition of EDTA as a facilitating agent. Finally, the remaining solution obtained from the EKT was treated in a reactor with a permeable reactive barrier (PRB) of carbon, where close to 99 % of Hg2+ was recovered from water after 2h (Figure 1), which is a good alternative than PRB of iron, where 84.47% of the Hg2+ was recovered from water. References. [1] R. Stegmann, G. Brunner, W. Calmano, G. Matz, Treatment of Contaminated Soil: Fundamentals Analysis Applications, Springer, Germany, 2001. [9] I. Robles, T. Serrano, J.J. Pérez, G. Hernández, S. Solis, R. García, T. Pi, E. Bustos, Influence of EDTA on the electrochemical removal of mercury (II) in soil from San Joaquén, Queretaro, Mexico, J. Mex. Chem. Soc. 58 (2014) 333. [3] J. Virkutytea, M. Sillanpää, P. Latostenmaa, Electrokinetic soil remediationcritical overview, Sci. Total Environ. 289 (2002) 97. [4] H. Niroumand, R. Nazir, K.A. Kassim, The performance of electrochemical remediation technologies in soil mechanics, Int. J. Electrochem. Sci. 7 (2012) 5708. [5] H.E. Allen, P.H. Chen, Remediation of metal contaminated soil by EDTA incorporating electrochemical recovery of metal and EDTA, Environ. Prog. 12 (1993) 284. [6] D. Lestan, C.X. Luo Li, The use of chelating agents in the remediation of metalcontaminated soils: A review, Environ. Pollut. 153 (2008) 3. [7] M. Haitzer, G.R. Aiken, J.N. Ryan, Binding of mercury (II) to dissolved organic matter: the role of the mercury-to-DOM concentration ratio, Environ. Sci. Technol. 36 (2002) 3564. Figure 1

Evaluation and Comparison of the Electric Field in the Physicochemical Properties of a Vertisol Type Soil and Sodium Bentonite

Soil electro-remediation is a technique that allows the removal of organic and inorganic compounds [1-4]. Changes in the soil matrix during application of the electric field affects desorption and/or absorption, and even the mobilization process of pollutants [5]. Changes caused by the potential gradient in a model soil (sodium bentonite) and the results of pH and contaminant transport of a model designed in Visual Basic were compared to evaluate the process of electro-migration which was simulated through the transport number. When we compared the behavior of the model soil with a Vertisol soil, the parameters evaluated throughout the cell were: pH, electrical conductivity and z potential. The behavior between the model soil and the Versitol type soil pH is similar in the area near the anode where there is a decrease in pH attributed to the generation of H+ and the cathode pH was slightly increased by the presence of –OH (Figure 1). However, the behaviors of the electrical conductivity and z potential are not similar due to the presence of organic matter, microorganisms and the diversity of ions contained in the Versitol type soil. The observed changes in these parameters promote the removal of pollutants. In the case of Vertisol type soil the observed changes in the soil matrix are minimal, which is an advantage of electro-remediation in comparison of another treatments of soil, as biological and chemical procedures. References. [1] K. R. Reddy, Technical challenges to in-situ remediation of polluted sites. Geotech. Geol. Eng., 28(3), 211-221 (2010). [2] M. Pérez-Corona, A. Corona, E. D. Beltrán, J. Cárdenas and E. Bustos, Evaluation of IrO2 – Ta2O5|Ti electrodes during the electroremediation of hydrocarbon – contaminated soil. Sustain. Environ. Res., 23 (4), 279 – 284 (2013). [3] A. Medel, D. Patiño, E. Méndez, Y. Meas, L. Godínez, J. Manríquez, F. Rodríguez, A. Rodríguez and E. Bustos, Novel electrokinetic remediation system – boron doped diamond (EKR-BDD) process for the destruction of polyaromatic hydrocarbons (PAHs) in liquid phase. Environ. Engin. Manag. J., 14 (4) 879 – 886 (2015). [4] I. Robles, M. J. Lozano, S. Solís, G. Hernández, M. V. Paz, M. G. Olvera and E. Bustos, Electrokinetic treatment of mercury – polluted soil facilitated by ethylenediaminetetraacetic acid coupled with a reactor with a permeable reactive barrier of iron to recover mercury (II) from wáter. Electrochimica Acta 181, 68 – 72 (2015). [5] I. Robles, E. Bustos and J. Lakatos, Comparison of the sorption behavior of mercury (II) on inorganic, organic and biomass substrates in the presence of different counter-ions. Sustain. Environ. Res., 25 (5), 255- 260 (2015). Figure 1

Optical fiber detector for monitoring volatile hydrocarbons during electrokinetic treatment of polluted soil

Optical fiber detector for monitoring volatile hydrocarbons during electrokinetic treatment of polluted soil

Humic substances-enhanced electroremediation of heavy metals contaminated soil

The effects of catholyte conditioning and the use of humic acids (HAs) and fulvic acids (FAs) as chelating agents to improve electrokinetic (EK) remediation efficiency were investigated using a real and highly contaminated soil. By applying a constant voltage (2.0V/cm) to the soil, pH and current changes and heavy metals (HMs) concentration were investigated through a range of durations and positions. The observations demonstrated that both catholyte conditioning with 0.1N HNO3 and using humic substances (HSs) enhance remediation efficiency. After 20 days of EK treatment, the removal efficiency of HMs in HS-enhanced EK remediation was about 2.0–3.0 times greater than when unenhanced. The quantity of HMs moving toward the cathode exceeded the anode, from which it could be reasonably inferred that most negatively charged HM-HS complexes were moved by electroosmotic forces. Further, free HM cations and positively charged complexed HMs migrated to the catholyte compartment by electromigration. The results obtained in this study, demonstrate the suitability of HS-enhanced EK remediation in HMs contaminated soil.

Effect of sludge pH and treatment time on the electrokinetic removal of aluminum from water potabilization treatment sludge

Algerian's municipal sewage treatment plants generate around 10 6 m 3 of sewage sludge annually. Recently, rapid expansion of wastewater treatment plants without equal attention to the treatment of the produced sludge has generated increasing concerns. While the sludge is usually incinerated or used as an agricultural fertilizer and may contain numerous nutrients, there may also be harmful substances that complicate sludge management. Hence the removal of pollutants from the sludge is necessary before further usage. This paper discusses the characteristics of potable water treatment sludge containing a high aluminum content. Furthermore, an electrokinetic treatment is proposed to remove aluminum from this sludge by varying the type of solution contained in the cathode compartment and modifying the treatment time to optimize the efficiency of the process. Successful results were achieved where 60% of aluminum was collected on the cathode side with a consumed energy around of 1000–2000 kWh kg −1 of sludge weight. Les stations de traitement d'eaux résiduaires en Algérie génèrent annuellement environ 10 6 m 3 de boues d'épuration. Récemment, on a pu observer une préoccupation croissante quant à la gestion de ces boues d'épuration, en raison des risques pour l'environnement qui ont résulté de l'expansion rapide des stations de traitement des eaux résiduaires, sans qu'on ait apporté une attention égale au traitement des boues produites, qui sont habituellement incinérées ou utilisées comme fertilisants en agriculture. Les boues peuvent contenir un certain nombre de nutriments, mais aussi une infinité de substances nocives qui compliquent la tâche au niveau de la gestion des boues. C'est pourquoi l'élimination de polluants des boues est nécessaire préalablement à leur utilisation. Ce travail expose la caractérisation d'une boue de traitement d'eau potable contenant une grande quantité d'aluminium. En outre, un traitement électrocinétique permettant d'éliminer l'aluminium de cette boue en faisant varier le type de la solution qui conditionne la cathode ainsi que le temps de traitement a été également discuté afin d'optimiser le processus électrocinétique. Des résultats encourageants sont obtenus quant à l'utilisation de cette technique ; jusqu'à 60% de l'aluminium présent initialement dans la boue a été recueilli dans la cathode, pour une énergie consommée d'environ 1000 à 2000 kWh kg −1 de boue sèche.

Restoration of saline greenhouse soil and its effect on crop’s growth through in situ field-scale electrokinetic technology

ABSTRACTAn in situ electrokinetic (EK) system was designed and applied to highly saline greenhouse soil with a view to investigating the effects of the EK process on growing crops. In situ EK tests in field scale were conducted on the salt accumulated lands in the greenhouse where cabbages and lettuces were being cultivated. A voltage gradient of 0.25–0.6 V cm−1 was applied for 50 days in the cultivated lands. The changes in the process, viz. current, voltage, and soil temperatures, were monitored. After the EK process, the initial electrical conductivity (EC, 6.0 dS m−1) of the soil was reduced to about 1.7 dS m−1 homogeneously below the recommended value (2.5 dS m−1). The growth rate of cabbages and lettuces under EK treatment was about twice higher than those in the untreated area. The present study revealed that the EK process encourages the growth of the crops considerably and also removes the salts in the soil efficiently during the growth of the crops.

Influence of Electric Field Operation Modes on Nickel Migration during Electrokinetic Treatment

ABSTRACTNickel-contaminated sediment can be remediated by electrokinetic techniques. In practical application, nickel may migrate into deep layers and potentially pollute unpolluted layers. In this study, the influence of different types of electric field operation modes on nickel migration in sediment layers was studied. The following experiments were conducted: without current application (NC), with horizontal electric field (HEF), with vertical electric field (VEF), and 2D electric field (horizontal and vertical). The following Ni overall removal efficacies were achieved: 48.9, 49.4, 55.7, and 58.1 after VEF, NC, 2D, and HEF, respectively. Using a vertical electric field in 2D and VEF resulted in less Ni found in the vertical sediment bed (25% and 60%, respectively). The available Ni content in a contaminated sediment bed decreased significantly after using the electrokinetic treatments: 46%, 62%, and 79% after HEF, VEF, and 2D, respectively. Vertical electric field is the most efficient for Ni removal in terms of the amount of Ni that migrated into deeper layers of sediment bed and its amount in mobile form. Thus, the vertical electric field is a promising and practical method for the remediation of nickel-contaminated sediments. Risk analysis indicated the efficiency of EK treatment as available Ni content was reduced after the applied treatments to a degree that poses no risk for the environment.