The effects of magnetite on anammox performance: Phenomena to mechanisms

Chen, Hui; Zhang, Ben; Yu, Changqi; Zhang, Zhicheng; Yao, Jun; Jin, Ren‐Cun

doi:10.1016/j.biortech.2021.125470

Cited by 25 publications

(5 citation statements)

References 35 publications

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“…Denitrification, the stepwise reduction of NO 3 − to nitrogen gas (N 2 ) under anaerobic conditions, is widely recognized as the dominant biogeochemical process responsible for permanent N removal in rivers and transitional environments [5][6][7]. Anammox, the anaerobic oxidation of ammonium, can also remove inorganic N by combining ammonium (NH 4 + ) with nitrite (NO 2 − ) and releasing N 2 ; however, its occurrence is generally irrelevant if compared to denitrification in freshwater sediments [8,9].…”

Section: Introductionmentioning

confidence: 99%

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

Gervasio

Soana

Vincenzi

et al. 2022

Water

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In transitional environments, the role of sediments biogeochemistry and denitrification is crucial for establishing their buffer potential against nitrate (NO3−) pollution. The Po River (Northern Italy) is a worldwide hotspot of eutrophication. However, benthic N dynamics and the relevance of denitrification in its delta have not yet been described. The aim of the present study was to quantify the contribution of denitrification in attenuating the NO3− loading transported to the sea during summer. Benthic fluxes of dissolved inorganic nitrogen (N) and denitrification rates were measured in laboratory incubations of intact sediment cores collected, along a salinity gradient, at three sections of the Po di Goro, the southernmost arm of the Po Delta. The correlation between NO3− consumption and N2 production rates demonstrated that denitrification was the main process responsible for reactive N removal. Denitrification was stimulated by both NO3− availability in the Po River water and organic enrichment of sediment likely determined by salinity-induced flocculation of particulate organic load, and inhibited by increasing salinity, along the river–sea gradient. Overall, denitrification represented a sink of approximately 30% of the daily N loading transported in middle summer, highlighting a previously underestimated role of the Po River Delta.

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Section: Introductionmentioning

confidence: 99%

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

Gervasio

Soana

Vincenzi

et al. 2022

Water

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“…Inlet and outlet water samples were taken daily for NH 4 + -N, NO 2 − -N, and NO 3 − -N content determination. Before chemical analysis, water samples were filtered with a 0.45 µm microfilter, and water quality and MLVSS were determined according to standard methods [10]. DO was determined using a portable dissolved oxygen meter (607 A portable DO meter); pH was determined using a portable pH meter (SX-620 portable pH meter).…”

Section: Analysis Methodsmentioning

confidence: 99%

Rapid Start-Up Characteristics of Anammox under Different Inoculation Conditions

Tan

Xia

et al. 2023

IJERPH

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The long multiplication time and extremely demanding enrichment environment requirements of Anammox bacteria (AAOB) have led to difficult reactor start-ups and hindered its practical dissemination. Few feasibility studies have been reported on the recovery of AAOB activity initiation after inlet substrate disconnection caused by an unfavorable condition, and few factors, such as indicators of the recovery process, have been explored. Therefore, in this experiment, two modified expanded granular sludge bed reactors (EGSB) were inoculated with 1.5 L anaerobic granular sludge (AGS) + 1 L Anammox sludge (AMS) (R1) and 2.5 L anaerobic granular sludge (AGS) (R2), respectively. After a long-term (140 days) starvation shock at a high temperature (38 °C), the bacteria population activity recovery experiments were conducted. After 160 days, both reactors were successfully started up, and the total nitrogen removal rates exceeded 87%. Due to the experimental period, the total nitrogen removal rate of R2 was slightly higher than that of R1 in the final stage. However, it is undeniable that R2 had a relatively long activity delay during startup, while R1 had no significant activity delay during startup. The sludge obtained from R1 had a higher specific anammox activity (SAA). Analysis of the extracellular polymer substances (EPS) results showed that the extracellular polymer content in R1 was higher than that in R2 throughout the recovery process, indicating that R1 had higher sludge stability and denitrification performance. Scanning electron microscopy (SEM) analysis showed that more extracellular filamentous bacteria could be seen in the R1 reactor with better morphology of Anammox bacteria. In contrast, the R2 reactor had fewer extracellular hyphae and micropores as a percentage and higher filamentous bacteria content. The results of microbial 16SrDNA analysis showed that R1 used AAOB as inoculum to initiate Anammox, and the reactor was enriched with Anammox bacteria earlier and in much greater abundance than R2. The experimental results indicated that inoculating mixed anaerobic granular sludge and Anammox sludge to initiate an anammox reactor was more effective.

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“…This result corresponds with previous findings. Chen et al determined that the enhancement of SAA was observed when low doses of Fe (III) (less than 15 mg•L −1 ) were continuously added, whereas SAA was suppressed severely when high doses of Fe (III) (30 mg•L −1 ) were employed [47]. J et al conducted research on marine anammox and concluded that when Fe (III) concentration was lower than 2 mg•L −1 , SAA experienced a slight enhancement (8.27%).…”

Section: Kinetics Of Various Fe (Iii) Concentrations On Periodical Su...mentioning

confidence: 99%

Effects of Elevated Fe (III) on Anaerobic Ammonia Oxidation Biofilm Process: Inhibition and Recovery

Wang,

et al. 2023

Water

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To investigate the treatment performance of employing the anaerobic ammonia oxidation (anammox) biofilm process to treat the iron-containing industrial wastewater with a low carbon–nitrogen ratio and obtain an optimal condition, the effects of elevated exposure to Fe (III) (ranging from 0 to 1.5 mM) on the anammox biofilm process were explored. The findings indicated that the performance of anammox nitrogen removal remained unaffected when exposed to low levels of Fe (III) (0.1 mM and 0.3 mM). However, high concentrations (higher than 0.5 mM) showed a negative effect. The semi-inhibitory concentration (IC50) of Fe (III) was 1.32 mM. Additionally, under exposure to high levels of Fe (III), a remarkable accumulation of Fe (III) was observed within the anammox system. The total iron concentration increased from 30 mgFe·gVSS−1 to a saturation point of approximately 300 mgFe·gVSS−1. This accumulation led to a decrease in extracellular polymeric substance (EPS) from 221.4 mg·gVSS−1 to 91.3 mg·gVSS−1 and specific anammox activity (SAA) from 0.0482 gN·(gVSS·d)−1 to 0.018 gN·(gVSS·d)−1. Consequently, the activity of anammox bacteria (AnAOB) was inhibited, leading to a decline in the average total nitrogen removal efficiency (TNRE) from 86.9% to 38.3%. However, it was discovered that the inhibitory effect of continuous Fe (III) could be reversed by introducing the ferric ion complex EDTA·2Na into the system. As a result, the TNRE recovered to 60%. The findings would be useful to optimize the anammox biofilm process by adjusting the concentration of Fe (III) in the practical industrial application.

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The effects of magnetite on anammox performance: Phenomena to mechanisms

Cited by 25 publications

References 35 publications

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

Rapid Start-Up Characteristics of Anammox under Different Inoculation Conditions

Effects of Elevated Fe (III) on Anaerobic Ammonia Oxidation Biofilm Process: Inhibition and Recovery

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