scholarly journals Insights into interactions between vanadium (V) bio-reduction and pentachlorophenol dechlorination in synthetic groundwater

2019 ◽  
Vol 375 ◽  
pp. 121965 ◽  
Author(s):  
Baogang Zhang ◽  
Yutong Cheng ◽  
Jiaxin Shi ◽  
Xuan Xing ◽  
Yuling Zhu ◽  
...  
Keyword(s):  
Synthetic Groundwater

scholarly journals Effects of the Feeding Solution Composition on a Reductive/Oxidative Sequential Bioelectrochemical Process for Perchloroethylene Removal

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 405
Author(s):  
Edoardo Dell’Armi ◽  
Marco Zeppilli ◽  
Bruna Matturro ◽  
Simona Rossetti ◽  
Marco Petrangeli Papini ◽  
...  
Keyword(s):  
Reductive Dechlorination ◽  
Nitrate Reduction ◽  
Coulombic Efficiency ◽  
Reducing Power ◽  
Mineral Medium ◽  
Process Conditions ◽  
Microbial Electrolysis Cells ◽  
Dehalococcoides Mccartyi ◽  
In Series ◽  
Synthetic Groundwater

Chlorinated aliphatic hydrocarbons (CAHs) are common groundwater contaminants due to their improper use in several industrial activities. Specialized microorganisms are able to perform the reductive dechlorination (RD) of high-chlorinated CAHs such as perchloroethylene (PCE), while the low-chlorinated ethenes such as vinyl chloride (VC) are more susceptible to oxidative mechanisms performed by aerobic dechlorinating microorganisms. Bioelectrochemical systems can be used as an effective strategy for the stimulation of both anaerobic and aerobic microbial dechlorination, i.e., a biocathode can be used as an electron donor to perform the RD, while a bioanode can provide the oxygen necessary for the aerobic dechlorination reaction. In this study, a sequential bioelectrochemical process constituted by two membrane-less microbial electrolysis cells connected in series has been, for the first time, operated with synthetic groundwater, also containing sulphate and nitrate, to simulate more realistic process conditions due to the possible establishment of competitive processes for the reducing power, with respect to previous research made with a PCE-contaminated mineral medium (with neither sulphate nor nitrate). The shift from mineral medium to synthetic groundwater showed the establishment of sulphate and nitrate reduction and caused the temporary decrease of the PCE removal efficiency from 100% to 85%. The analysis of the RD biomarkers (i.e., Dehalococcoides mccartyi 16S rRNA and tceA, bvcA, vcrA genes) confirmed the decrement of reductive dechlorination performances after the introduction of the synthetic groundwater, also characterized by a lower ionic strength and nutrients content. On the other hand, the system self-adapted the flowing current to the increased demand for the sulphate and nitrate reduction, so that reducing power was not in defect for the RD, although RD coulombic efficiency was less.

Removing Arsenic from Synthetic Groundwater with Iron Electrocoagulation: An Fe and As K-Edge EXAFS Study

2012 ◽  
Vol 46 (2) ◽  
pp. 986-994 ◽  
Author(s):  
Case M. van Genuchten ◽  
Susan E. A. Addy ◽  
Jasquelin Peña ◽  
Ashok J. Gadgil
Keyword(s):  
Exafs Study ◽  
Synthetic Groundwater

Performance of intermittent aeration reactor on NH4-N removal from groundwater resources

2010 ◽  
Vol 61 (12) ◽  
pp. 3061-3069 ◽  
Author(s):  
W. Khanitchaidecha ◽  
T. Nakamura ◽  
T. Sumino ◽  
F. Kazama
Keyword(s):  
Removal Rate ◽  
Groundwater Resources ◽  
Ammonium Nitrogen ◽  
Total Carbon ◽  
Intermittent Aeration ◽  
Reactor Performance ◽  
Total Carbon Content ◽  
Term Operation ◽  
N Removal ◽  
Synthetic Groundwater

To study the effect of intermittent aeration period on ammonium–nitrogen (NH4-N) removal from groundwater resources, synthetic groundwater was prepared and three reactors were operated under different conditions – “reactor A” under continuous aeration, “reactor B” under 6 h intermittent aeration, and “reactor C” under 2 h intermittent aeration. To facilitate denitrification simultaneously with nitrification, “acetate” was added as an external carbon source with step-wise increase from 0.5 to 1.5 C/N ratio, where C stands for total carbon content in the system, and N for NH4-N concentration in the synthetic groundwater. Results show that complete NH4-N removal was obtained in “reactor B” and “reactor C” at 1.3 and 1.5 C/N ratio respectively; and partial NH4-N removal in “reactor A”. These results suggest that intermittent aeration at longer interval could enhance the reactor performance on NH4-N removal in terms of efficiency and low external carbon requirement. Because of consumption of internal carbon by the process, less amount of external carbon is required. Further increase in carbon in a form of acetate (1.5 to 2.5 C/N ratios) increases removal rate (represented by reaction rate coefficient (k) of kinetic equation) as well as occurrence of free cells. It suggests that the operating condition at reactor B with 1.3 C/N ratio is more appropriate for long-term operation at a pilot-scale.

Simfuel Leaching Studies in Granitic Groundwater Under Oxidizing Conditions

1995 ◽  
Vol 412 ◽  
Author(s):  
J. Garcia-Serrano ◽  
J. A. Serrano ◽  
P. P. Diaz-Arocas ◽  
J. Quiñones ◽  
J. L. R. Almazan
Keyword(s):  
Elemental Analysis ◽  
Particle Sizes ◽  
Leaching Tests ◽  
Minor Components ◽  
High Release ◽  
Synthetic Groundwater ◽  
Granitic Groundwater ◽  
Good Agreement

AbstractSimulated high-bumup nuclear fuel (SIMFUEL) has been leached in synthetic groundwater under oxic conditions. SIMFUEL pellets were ground and sieved to two particle sizes (50–100 and 100–315 μm). An extensive solid characterization of the fragments was carried out by various techniques. Elemental analysis has also been performed prior to the leaching tests.The release of U and the minor components (Mo, Ba and Sr) was monitored during the long term dissolution experiments (350 days). These minor components exhibit a trend similar to uranium, high release at the beginning followed by a plateau. The M/U calculated ratios show different behavior although after a period of time, depending on the particle sizes, constant ratios were observed.SIMHUEL powder was used in order to simulate the physical effect of bum-up on the fuel structure. This fact seems to play an important role on the uranium release. A comparison with the results given in the literature for SIMFUEL pellet leaching tests shows good agreement with the values reported.

Influence of groundwater composition on subsurface iron and arsenic removal

2012 ◽  
Vol 66 (1) ◽  
pp. 173-178 ◽  
Author(s):  
D. H. Moed ◽  
D. van Halem ◽  
J. Q. J. C. Verberk ◽  
G. L. Amy ◽  
J. C. van Dijk
Keyword(s):  
Arsenic Removal ◽  
Iron Removal ◽  
Column Experiments ◽  
Research Project ◽  
Sand Column ◽  
Adsorption Sites ◽  
Novel Technology ◽  
Synthetic Groundwater ◽  
Subsurface Treatment ◽  
Groundwater Composition

Subsurface arsenic and iron removal (SAR/SIR) is a novel technology to remove arsenic, iron and other groundwater components by using the subsoil. This research project investigated the influence of the groundwater composition on subsurface treatment. In anoxic sand column experiments, with synthetic groundwater and virgin sand, it was found that several dissolved substances in groundwater compete for adsorption sites with arsenic and iron. The presence of 0.01 mmol L−1 phosphate, 0.2 mmol L−1 silicate, and 1 mmol L−1 nitrate greatly reduced the efficiency of SAR, illustrating the vulnerability of this technology in diverse geochemical settings. SIR was not as sensitive to other inorganic groundwater compounds, though iron retardation was limited by 1.2 mmol L−1 calcium and 0.06 mmol L−1 manganese.

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