Abstract:Nitrate groundwater contamination is an issue of global concern that has not been satisfactorily and efficiently addressed, yet. In this study, a 2-stage, sequential bioelectrochemical system (BES) was run to perform autotrophic denitrification of synthetic groundwater. The system was run at a 75.6 mgNO3−-N L−1NCC d−1 nitrate loading rate, achieving almost complete removal of nitrate (>93%) and Total Nitrogen (TN) (>93%). After treatment in the first stage reactor values of effluent nitrate compatible wi… Show more
“…In case of BES-PS, a voltage of 1.0 V was applied between anode and cathode using a laboratory power supply (LABPS3005D, Velleman, Netherlands); this voltage value had been shown suitable to achieve denitrification by previous studies [27, 38]. In case of BES-Pot, the cathode potential was poised at -0.303 V vs SHE (-0.5 V vs Ag/AgCl) using a potentiostat (NEV4, Nanoelectra, Spain), based on previous experience by the authors [39, 40, 41]. Fig.…”
Bioelectrochemical systems (BES) application was proposed for a variety of specific uses, due to these systems’ characteristics: electrodes can act as virtually inexhaustible electron acceptors/donors, offering a growth-support surface for microorganisms, and stimulating naturally-occurring microbial degradation activities.
In situ,
groundwater denitrification therefore seems to be a potential candidate for their use. In this study, buried biocathodes were operated in laboratory settings for the simulation of
in situ
groundwater denitrification. Two alternative configurations were tested: biocathode buried in sand, and biocathode buried in gravel. A control test with a biocathode in absence of sand/gravel was also performed. In all the cases, biocathodes were driven by power supply or potentiostat to guarantee a steady electron flux to the cathode. The presence of sand and gravel strongly influenced the denitrification process: in both configurations, accumulation of intermediate N-forms was detected, suggesting that the denitrification process was only partially achieved. In addition, a significant decrease (in the 20–36% range) in nitrate removal rates was measured in sand and gravel setups compared to the control reactor; this issue could be attributed to lack of recirculation that limited contact between substrate and electrode-adherent biofilm. Biocathodes buried in gravel obtained better results than those buried in sand due to the lower packing of the medium. The results of this study suggest that, in order to achieve successful in situ treatment, special design of submerged-biocathodic BESs is necessary.
“…In case of BES-PS, a voltage of 1.0 V was applied between anode and cathode using a laboratory power supply (LABPS3005D, Velleman, Netherlands); this voltage value had been shown suitable to achieve denitrification by previous studies [27, 38]. In case of BES-Pot, the cathode potential was poised at -0.303 V vs SHE (-0.5 V vs Ag/AgCl) using a potentiostat (NEV4, Nanoelectra, Spain), based on previous experience by the authors [39, 40, 41]. Fig.…”
Bioelectrochemical systems (BES) application was proposed for a variety of specific uses, due to these systems’ characteristics: electrodes can act as virtually inexhaustible electron acceptors/donors, offering a growth-support surface for microorganisms, and stimulating naturally-occurring microbial degradation activities.
In situ,
groundwater denitrification therefore seems to be a potential candidate for their use. In this study, buried biocathodes were operated in laboratory settings for the simulation of
in situ
groundwater denitrification. Two alternative configurations were tested: biocathode buried in sand, and biocathode buried in gravel. A control test with a biocathode in absence of sand/gravel was also performed. In all the cases, biocathodes were driven by power supply or potentiostat to guarantee a steady electron flux to the cathode. The presence of sand and gravel strongly influenced the denitrification process: in both configurations, accumulation of intermediate N-forms was detected, suggesting that the denitrification process was only partially achieved. In addition, a significant decrease (in the 20–36% range) in nitrate removal rates was measured in sand and gravel setups compared to the control reactor; this issue could be attributed to lack of recirculation that limited contact between substrate and electrode-adherent biofilm. Biocathodes buried in gravel obtained better results than those buried in sand due to the lower packing of the medium. The results of this study suggest that, in order to achieve successful in situ treatment, special design of submerged-biocathodic BESs is necessary.
“…However, the lack of pilot scale studies and in-situ remediation projects makes it difficult to accurately evaluate the actual cost of conducting a real BESs remedial project; increasing the distance between the anode and cathode (as in the remedial field) would cause a decrease of the MFC cell potential and reduction efficiency [88], which would result in a direct impact on the cost. Besides, mots of BESs studies at present have been conducted from days to months [47,56,59,132], while the long term operational stability of BESs for groundwater remediation is still questionable. Thereby, scaling up the BESs to an applicable size and conducting long term BESs remedial studies should be implemented in future.…”
Section: Discussion and Perspectivesmentioning
confidence: 99%
“…Groundwater denitrification [47,126,127]; Energy consumption [49]; Metals and perchlorate removal [25];…”
Section: Published Journals and Authors Analysismentioning
confidence: 99%
“…With continued innovation and advances in groundwater remedial technologies, some researchers have focused on novel technologies that are more efficient, sustainable and cost-saving [42][43][44][45]. Among these, bioelectrochemical systems (BESs) have remarkably emerged in the last two decades [25,[46][47][48][49][50][51][52][53]. BESs can be defined as microbial electrochemical systems in which electrochemically active microorganisms act as catalyzers for anode and/or cathode reactions [25,42]-specifically, the electro-active microorganisms, the electrodes, and the possible electron donor/acceptors (groundwater pollutants) consist of an electrical circuit through which the electron is transferred by the electro-active microorganisms while the pollutants are oxidized/reduced [25,[54][55][56], which means that both oxidation and reductions can occur at the anode and the cathode, respectively [25,49,57].…”
: Due to the deficiency of fresh water resources and the deterioration of groundwater quality worldwide, groundwater remedial technologies are especially crucial for preventing groundwater pollution and protecting the precious groundwater resource. Among the remedial alternatives, bioelectrochemical systems have unique advantages on both economic and technological aspects. However, it is rare to see a deep study focused on the information mining and visualization of the publications in this field, and research that can reveal and visualize the development trajectory and trends is scarce. Therefore, this study summarizes the published information in this field from the Web of Science Core Collection of the last two decades (1999–2018) and uses Citespace to quantitatively visualize the relationship of authors, published countries, organizations, funding sources, and journals and detect the research front by analyzing keywords and burst terms. The results indicate that the studies focused on bioelectrochemical systems for groundwater remediation have had a significant increase during the last two decades, especially in China, Germany and Italy. The national research institutes and universities of the USA and the countries mentioned above dominate the research. Environmental Science & Technology, Applied and Environmental Microbiology, and Water Research are the most published journals in this field. The network maps of the keywords and burst terms suggest that reductive microbial diversity, electron transfer, microbial fuel cell, etc., are the research hotspots in recent years, and studies focused on microbial enrichment culture, energy supply/recovery, combined pollution remediation, etc., should be enhanced in future.
“…− considered in the study. 35 The ODEs for mass balances of NO 3 − (eqn (1)), NO 2 − (eqn (2)) and intracellular reduced mediators (eqn (3)) are reported in eqn ( 1)-( 3): Environmental Science: Water Research & Technology Paper…”
Nitrate (NO3-) contamination of groundwater is a worldwide issue that poses great threats to human health due to the use of the groundwater source for drinking water production. Among the...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
