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Electrochemical remediation - Efficiency vs treatment configuration
Abstract
Conform Agenţiei Europene de Mediu, necesitatea decontaminării solurilor
poluate apare la peste 250 000 din siturile prezente pe teritoriul Statelor Membre.
Acest număr este asteptat să crească. Scopul cercetării experimentale este acela de a
evalua fezabilitatea utilizării oxidării electrochimice, o tehnologie inovativă, în
vederea degradării hidrocarburilor dintr-un sol contaminat artificial. Oxidarea
electrochimică s-a dovedit a fi o tehnologie eficientă pentru remedierea solurilor
contaminate cu motorină, chiar dacă s-au obţinut eficienţe diferite pentru teste
diferite. Toate testele au fost realizate pe o perioadă de 28 de zile folosind o tensiune
specifică de 1 V/cm.
According to the European Environmental Agency, soil contamination
requiring clean up is present at approximately 250,000 sites in the EEA member
countries. And this number is expected to grow. The aim of this experimental
investigation was to assess the feasibility of using electrochemical oxidation, an
innovative technology, to degrade hydrocarbons from an artificially contaminated
soil. Electrochemical oxidation proved to be an effective technology for diesel
remediation; even tough different tests resulted in different removal efficiencies. All
tests were done for a period of 28 days using a specific voltage of 1V/cm.
... The numbers of stainless steel bars were determined based on "Basics and applications of electrokinetic re- mediation" written by Akram N. Alshawabkeh, in 2001. The idea was that when an electric current is applied, if the electrodes are bars and not plates, there remain some inactive areas ( Istrate et al. 2009;2012a;Lorenzoni et al. 2010;Andreottola et al. 2012). Because of the number of bars, larger or smaller areas, risk to remain untreated. ...
... The trend of the current variation has the tendency to increase until it reaches a maximum value after which decreases to a steady state value (usually after 21 days of treatment), similar with the one described in specific literature ( Istrate et al. 2009;Lorenzoni et al. 2010). For both types of pollution (insulating and capacitor oils) and for all studied congeners, lower concentrations of PCBs than initial ones were obtained after each treatment test. ...
This paper investigates the electrochemical treatment of polychlorinated biphenyl (PCB) contaminated soils. The research was performed within a project co-funded by the European Regional Development Fund and for the experimental part; artificially contaminated soil with PCB was used. Two reactors of different sizes were used; the smaller designed in a Ph.D. research and the larger in a research project co-funded by the European Regional Development Fund. Specific voltage, current density, redox potential, time and pH values were considered throughout the tests. The initial PCB concentration in the test soil (3.571 mg/kgdw) exceeds the intervention threshold for sensitive use according to Romanian regulations (1 mg/kgdw). Three different tests were performed: within the first one (T1) the soil was polluted with insulating oil; within the other two tests (T2 and T3) the soil was contaminated with capacitor oil. The initial PCB concentrations within the three tests (as a sum of all PCB concentrations) were: 4.4461 mg/kgdw within T1, and 3.5710 mg/kgdw within both T2 and T3. The study showed that the electrochemical treatment could achieve up to 87 % remediation efficiency for PCB polluted soils. Therefore, this treatment is relevant and a potential solution for the remediation of PCB polluted soils.
... Water Diesel remediation. Energy consumption per unit volume of soil is calculated using the following equation [13,16,17,18,19]: ...
In the present work, the results obtained after testing of two technologies that are based on the usage of an electric field to treat contaminated soil, are presented. The first technology is the electroremediation and the second one is the electro-flushing remediation. The tests were performed at laboratory scale during two different PhD researches. The treatment efficiency was up to 80% for the simple technology, while for the second one the recovery of the diesel contaminant was in proportion of 31.82%. The diesel that was not recovered and remained in soil will be removed by electrochemical processes.
... During the experiment, a continuous monitoring of the key parameters has been carried out (electric current, pH, redox potential and temperature). The soil pH represents a measure of acidity which plays an important elements and processes from soils10111213. the concentrations in the electrodes areas are smaller than the intervention threshold for sensible use mentioned in O756/1997 (removal efficiency ranged from 59% to 85%). If the attention is focused on PCB 28, the electrochemical treatment should continue for at least other 2 weeks (over 21 days of the experimental study), considering that a lower efficiency was obtained: from 53% to 83% related to the different sampling areas (anode, middle and cathode). ...
The paper presents results of laboratory experiments focused on the efficiency of polychlorinated biphenyls (PCBs) removal by electroremediation, pyrolysis and incineration decontamination methods. The experiments were carried out using soil contaminated with heavy metals and PCBs. Different process parameters were changed during the experiments in order to achieve maximum removal efficiency. Concerning the thermal methods (pyrolysis and incineration), the operating temperature and retention time were the two key parameters affecting the processes that were assessed. With regards to the electroremediation alternative for soil decontamination, the redox potential (ORP), pH, electric field and temperature were continuously monitored. Results showed that thermal treatments are the most indicated methods for removing PCBs from contaminated soils. Pyrolysis and incineration remediation methods ensured, with some exceptions, an efficiency of over 99%. The same efficiency level was attended just in case of applying the electrochemical method for removing PCB126.
La ora actuală, poluarea aerului, a apei şi a solului reprezintă o mare problemă pentru societatea umană. Scopul acestui articol este de a prezenta o evaluare a eficienţei oxidării chimice pentru înlaturarea hidrocarburilor policiclice aromatice din solurile poluate. Oxidarea chimică este o metodă de remediere ce presupune introducerea în sol a unui agent oxidant care reacţionează cu compuşii organici transformându-i în substanţe inofensive. Agenţii oxidanţi folosiţi au fost: H 2 O 2 , agentul Fenton, KMnO 4 , Na 2 S 2 O 8 , şi combinaţii între aceştia. In our days the pollution of air, water and soil represents a serous problem for human society. The aim of this work is to present an evaluation of effectiveness of chemical oxidation for the remediation of PAHs from polluted sediments. Chemical oxidation is a technique that uses chemicals to mineralize organic contaminants by changing them to harmless substances. The use of the chemical oxidation processes has been investigated for the remediation of environmental matrices contaminated by polycyclic aromatic hydrocarbons (PAHs). Laboratory experiments were conducted to assess the effects of different oxidant agents: H 2 O 2 , Fenton's Reagent, KMnO 4 , Na 2 S 2 O 8 , and combinations between them.