Effect of Nitrate and Perchlorate on Selenate Reduction in a Sequencing Batch Reactor

Kim, Hyun-Woo; Hong, Seong Hwan; Choi, Hyeoksun

doi:10.3390/pr8030344

Cited by 7 publications

(9 citation statements)

References 24 publications

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“…As a seed sludge, activated sludge was obtained from a local municipal wastewater treatment plant of I-city, South Korea. To prepare the inoculum of the FBBR, selenate reducing bacteria was selectively precultured before inoculation in a bench-scale sequencing batch reactor (SBR), following previous studies [11]. Under the anoxic condition, the acclimation period was maintained for more than a month.…”

Section: Inoculum and Culture Mediamentioning

confidence: 99%

“…Previous research demonstrated simultaneous bioreduction of selenate and nitrate in sequencing batch reactors cultivating acclimated selenate-reducing bacteria [11]. To reduce selenate at very low concentrations, a fixed-bed biofilm reactor (FBBR) might be more suitable from the engineering point of view than a suspended growth reactor because it is designed to prevent microbial washout while keeping the biocatalysts, i.e., selenate reducing bacteria, in the system longer.…”

Section: Introductionmentioning

confidence: 99%

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Carbon Source Competition in Biological Selenate Reduction under Other Oxyanions Contamination

2020

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Selenate removal in drinking water is being vigorously debated due to the various health issues concerned. As a viable treatment option, this study investigated a fixed-bed biofilm reactor (FBBR) with internal recycling. The experimental design tested how hydraulic loading rate and electron donor affect selenate reduction together with other oxyanions. The tested accompanying oxyanions were nitrate and perchlorate and experiments were designed to test how an FBBR responded to the limited electron donor condition. The results showed that the reactor achieved almost complete selenate reduction with the initial hydraulic loading rate of 12 m3/m2/day (influent concentration of 1416 µg SeO42−/L). Increasing the hydraulic loading rates to 16.24 and 48 m3/m2/day led to a gradual decline in selenate removal efficiency. A sufficient external carbon source (C:N of 3.3:1) achieved an almost complete reduction of nitrate as well as selenate. The FBBR acclimated to selenate instantaneously and reduced nitrate via synergistic denitrification. An experiment with another oxyanion addition, perchlorate (459 µg ClO4−/L), revealed that perchlorate-reducing bacteria were more strongly associated with carbon limitation than selenate-reducing bacteria, which can help us to understand parallel reactions in FBBRs. This research provides a framework to further study the use of electron donor-controlled FBBRs for simultaneous reduction of selenate and other oxyanions threatening the drinking water-related environment and public health.

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Section: Inoculum and Culture Mediamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Carbon Source Competition in Biological Selenate Reduction under Other Oxyanions Contamination

2020

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“…The initial selenate and nitrate concentrations were 0.1 mM and 0.96 mM NO 3 − -N, respectively. For that study, acetate was the electron donor, and seed sludge was activated sludge from a wastewater treatment plant [12]. However, most biological selenium reduction experiments have been limited to either pure culture or anaerobic sludge blanket methods.…”

Section: Introductionmentioning

confidence: 99%

“…However, most biological selenium reduction experiments have been limited to either pure culture or anaerobic sludge blanket methods. A relatively limited number of studies are available with a mixed microbial community and competitive anions [7,12,13].…”

Section: Introductionmentioning

confidence: 99%

Effect of Nitrate Presence on Selenium Bioremediation in Chemically Modified Zeolite Columns

Kulasekara,

Zhang,

Papelis

2023

Water

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Selenium is an essential micro-nutrient for living organisms, but elevated concentrations of it in water can adversely affect health. Nitrate is often found in selenium-contaminated water and negatively correlates with selenium removal. In this study, we investigate the effect of nitrate co-existence on selenium bioremediation in chemically modified zeolite columns. Dynamic sorption-reduction experiments were conducted using natural and iron-coated zeolite columns to remove selenite and selenate oxyanions separately, with and without nitrate anions. Anaerobic sludge was included as microbial inoculum, while lactate was the sole electron donor. The initial selenium concentration (SeIV or SeVI) was 790 µg/L, the nitrate concentration was 620 mg/L, the pH was 7.5, and the flow rate was 3 mL/min. Before introducing nitrate ions, selenium reduction in all four columns reached approximately 99%. However, after introducing nitrate ions, selenate and selenite reduction efficiencies were reduced to approximately 93% and 60%, respectively. Biofilm microbial community composition, assessed by 16S rRNA sequencing, was distinct between the communities with and without nitrate anions. Specifically, in the absence of nitrate, biofilm communities are mainly composed of selenium-reducing bacteria (Veillonella, Bacteroides and Escherichia). In contrast, the presence of nitrate led to mostly denitrifying bacteria (Anaeromusa-Anaeroarcus, Lentimicrobium, Azospirillum and Endomicrobium). Further, comparison of diversity indices (Shannon index, Faith PD and Pielou’s) shows alteration in all indices in the presence of nitrate.

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“…The effect of nitrate and perchlorate on selenate reduction in a batch reactor was investigated by Kim et al [5]. They selectively enriched selenate-reducing bacteria in bench-scale sequencing batch reactors, which were seeded with activated sludge, and operated them semi-continuously in parallel for more than one and a half months.…”

mentioning

confidence: 99%

Special Issue: Bioprocess Monitoring and Control

Hitzmann

2020

Processes

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Effect of Nitrate and Perchlorate on Selenate Reduction in a Sequencing Batch Reactor

Cited by 7 publications

References 24 publications

Carbon Source Competition in Biological Selenate Reduction under Other Oxyanions Contamination

Carbon Source Competition in Biological Selenate Reduction under Other Oxyanions Contamination

Effect of Nitrate Presence on Selenium Bioremediation in Chemically Modified Zeolite Columns

Special Issue: Bioprocess Monitoring and Control

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