Removal of oxyfluorfen from spiked soils using electrokinetic soil flushing with the surrounding arrangements of electrodes

Abstract

This work reports the results of a study in which the remediation of soil that undergoes an accidental discharge of oxyfluorfen is carried out by using electrokinetic soil flushing (EKSF). Two different electrode configurations were tested, consisting of several electrodes surrounding an electrode of different polarity (so-called 1A6C, one anode surrounded by six cathodes, and 1C6A, one cathode surrounded by six cathodes). A pilot plant scale was used (with a soil volume of 175dm(3)) to perform the studies. During the tests, different parameters were measured daily (flowrates, pH, electrical conductivity and herbicide concentration in different sampling positions). Furthermore, at the end of the test, a complete post-mortem analysis was carried out to obtain a 3-D map of the pollution, pH and electrical conductivity in the soil. The results demonstrate that electrode arrangement is a key factor for effective pollutant removal. In fact, the 1A6C configuration improves the removal rate by 41.3% versus the 27.0% obtained by the 1C6A configuration after a period of 35days. Finally, a bench mark comparison of this study of soil remediation polluted with 2,4-D allows for significant conclusions about the scale-up and full-scale application of this technology.

Scale-up of the electrokinetic fence technology for the removal of pesticides. Part I: Some notes about the transport of inorganic species

“…The soil used in this work is provided from a region of Castilla la Mancha (Spain), with important agrarian activities. This soil has been used in others works carried out to our research group (Risco et al, 2015(Risco et al, , 2016a(Risco et al, , 2016b(Risco et al, , 2016d. It is classified as low plasticity soil, according with ASTM D2487 (International, 2006) and ASTM D4318 (International, 2010a) and as silty loam within the textural classification of USDA (Staff, 1993) (clay=4.9%, silt=68.2% and sand=26.9%).…”

“…This work reports important information about the scale-up of electrokinetic fence (EKF) technology for the remediation of soil polluted with herbicides, by comparing results obtained in a prototype of 32 m 3 with those obtained in a mockup of 175 L. These lower-scale results were obtained in different works previously published in the literature (Risco et al, 2015, within a wider-scope research program in which different electrodes placement were compared for the efficient removal of pesticides from soil (Risco et al, 2016a(Risco et al, , 2016b(Risco et al, , 2016c(Risco et al, , 2016d. At this point, a preliminary work about scaleup informs about the many inputs that should be accounted for proper scale-up study (López-Vizcaíno et al, 2016).…”

Techno-economic analysis of the scale-up process of electrochemically-assisted soil remediation

“…These technologies are based on the application of an electric potential gradient (V/m) that produces a low electric current (A) between electrodes especially positioned in the soil, being the placement selected very important to get highly-efficient processes (Risco et al, 2016c;Risco et al, 2016e;Risco et al, 2016f). The electric field favours the movement of fluids, ions and charged particles by different transport phenomena, namely electroosmosis, electromigration and electrophoresis, respectively (Acar, 1993;Acar et al, 1995;Alshawabkeh et al, 1999;Reddy and Cameselle, 2009;Virkutyte et al, 2002).…”

“…The work presented in this manuscript aims to reduce this limitation, by discussing the technical aspects and the economic requirements of the scaleup of EASR, based on the experience acquired by the authors in the recent years, with the application of these technologies in different studies aimed to evaluate the remediation of soils polluted with PAH and pesticides. In those studies experimental setups of different scales that include lab, bench (Mena et al, 2016a;Mena et al, 2016b;Ramírez et al, 2015), pilot (Risco et al, 2016a;Risco et al, 2016b;Risco et al, 2015;Risco et al, 2016d;Risco et al, 2016e;Risco et al, 2016f) and prototype (López-Vizcaíno et al, 2016;López-Vizcaíno et al, 2017a, b) scales were used. This work presents not only an economic investment estimation of the assets but also an evaluation of the cost associated to all stages involved in start-up, operation and dismantling of EASR processes, giving also valuable information about the knowledge that can be obtained in each of them.…”

Comparison of Electrokinetic Remediation on Lead‐Contaminated Kaolinite and Natural Soils

“…Furthermore, manipulation of the systematic design and operation strategies, including alternating electrode polarization, using ion exchange membrane, or approaching anode technique were also adopted to promote the desorption, dissolution and migration of potentially toxic metal(s)/element(s). The EKR process was also combined with other technologies to promote the migration of potentially toxic metal(s)/element(s) and improve the remediation efficiency, including EK‐flushing, EK‐permeable reactive barriers, electro‐Fenton, and EK‐phytoremediation …”