Bioelectroventing: an electrochemical‐assisted bioremediation strategy for cleaning‐up atrazine‐polluted soils

Abstract

SummaryThe absence of suitable terminal electron acceptors (TEA) in soil might limit the oxidative metabolism of environmental microbial populations. Bioelectroventing is a bioelectrochemical strategy that aims to enhance the biodegradation of a pollutant in the environment by overcoming the electron acceptor limitation and maximizing metabolic oxidation. Microbial electroremediating cells (MERCs) are devices that can perform such a bioelectroventing. We also report an overall profile of the 14C‐ATR metabolites and 14C mass balance in response to the different treatments. The objective of this work was to use MERC principles, under different configurations, to stimulate soil bacteria to achieve the complete biodegradation of the herbicide 14C‐atrazine (ATR) to 14 CO 2 in soils. Our study concludes that using electrodes at a positive potential [+600 mV (versus Ag/AgCl)] ATR mineralization was enhanced by 20‐fold when compared to natural attenuation in electrode‐free controls. Furthermore, ecotoxicological analysis of the soil after the bioelectroventing treatment revealed an effective clean‐up in < 20 days. The impact of electrodes on soil bioremediation suggests a promising future for this emerging environmental technology.

Opportunities for groundwater microbial electro‐remediation

“…Following a similar strategy, toxicity reduction instead of full oxidation, METs have been used for azo dye orange 7 reduction into sulfanilic acid (Yun et al ., ) and the toxicity of waters containing dibenzothiophene or atrazine has also been decreased (Rodrigo et al ., ; Domínguez‐Garay et al ., ). Atrazine is an interesting example, as it has been successfully mineralized (Domínguez‐Garay et al ., ). This example shows the potential of METs over the treatment of complex aromatic compounds.…”

Electrodes boost microbial metabolism to mineralize antibiotics in manure

“…Negative potentials as low as −400 mV are typically reached in anodes buried in flooded environments due to the anoxic nature of the environment [27,29]. Although such a condition already enhanced the microbial activity, some authors have additionally reported higher bioremediation rates under a more positive anode potential by using a potentiostat as a tool for polarizing the electrode [37,28]. An electron acceptor with a higher redox potential is consistent with having a higher cell growth yield and harvesting more electrical current.…”

“…Likewise, these microorganisms can also use electrodes as electron source for reducing pollutants [23]. They have demonstrated efficient removal of nutrients such as nitrates [22], chlorinated hydrocarbons [24], antibiotics [25,26], herbicides [27][28][29], and petroleum hydrocarbons [30,31]. Furthermore, microbial electrochemistry in combination with the anaerobic digestion of livestock manures has already been used to simultaneously generate electricity, remove organic matter and recover nitrogen [31][32][33][34], while eliminating unpleasant odors [35].…”

Factors affecting the efficiency of a bioelectrochemical system: a review

“…Furthermore, based on the inexhaustible electron acceptor of the solid anode, the enhancement ability of the biocurrent is sustained, which overcomes the deciency of the electron acceptor in a contaminated medium. 16,17 However, there are still some problems to be solved in the actual application of BESs, such as improving the degradation of complex compounds, controlling the reaction process of microorganisms, and continuing to reduce costs.…”