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Appropriate Fe (II) addition significantly enhances anaerobic ammonium oxidation (Anammox) activity through improving the bacterial growth rate.

Liu Y, Ni BJ - Sci Rep (2015)

Bottom Line: This work systematically studied the effects of Fe (II) addition on Anammox activity based on the kinetic analysis of specific growth rate using data from batch tests with an enriched Anammox sludge at different dosing levels.Results clearly demonstrated that appropriate Fe (II) dosing (i.e., 0.09 mM) significantly enhanced the specific Anammox growth rate up to 0.172 d(-1) compared to 0.118 d(-1) at regular Fe (II) level (0.03 mM).The relationship between Fe (II) concentration and specific Anammox growth rate was found to be well described by typical substrate inhibition kinetics, which was integrated into currently well-established Anammox model to describe the enhanced Anammox growth with Fe (II) addition.

View Article: PubMed Central - PubMed

Affiliation: Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia.

ABSTRACT
The application of anaerobic ammonium oxidation (Anammox) process is often limited by the slow growth rate of Anammox bacteria. As the essential substrate element that required for culturing Anammox sludge, Fe (II) is expected to affect Anammox bacterial growth. This work systematically studied the effects of Fe (II) addition on Anammox activity based on the kinetic analysis of specific growth rate using data from batch tests with an enriched Anammox sludge at different dosing levels. Results clearly demonstrated that appropriate Fe (II) dosing (i.e., 0.09 mM) significantly enhanced the specific Anammox growth rate up to 0.172 d(-1) compared to 0.118 d(-1) at regular Fe (II) level (0.03 mM). The relationship between Fe (II) concentration and specific Anammox growth rate was found to be well described by typical substrate inhibition kinetics, which was integrated into currently well-established Anammox model to describe the enhanced Anammox growth with Fe (II) addition. The validity of the integrated Anammox model was verified using long-term experimental data from three independent Anammox reactors with different Fe (II) dosing levels. This Fe (II)-based approach could be potentially implemented to enhance the process rate for possible mainstream application of Anammox technology, in order for an energy autarchic wastewater treatment.

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The experimental measured and kinetic fitted ammonium consumption profiles in five 4-h batch tests under different Fe (II) concentrations:(a) 0.03 mM; (b) 0.06 mM; (c) 0.09 mM; (d) 0.12 mM; and (e) 0.18 mM (symbols represent experimental measurements and lines represent kinetic fittings).
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f1: The experimental measured and kinetic fitted ammonium consumption profiles in five 4-h batch tests under different Fe (II) concentrations:(a) 0.03 mM; (b) 0.06 mM; (c) 0.09 mM; (d) 0.12 mM; and (e) 0.18 mM (symbols represent experimental measurements and lines represent kinetic fittings).

Mentions: Figure 1 presents the measured and kinetic fitted ammonium consumption profiles from the five batch tests at different Fe (II) addition levels. The ammonium concentration decreased linearly in all the five batch experiments with different reduction rates. The kinetic fittings matched well with all the experimental measurements. In general, Fe (II) addition with a concentration higher than the normal level (0.03 mM) enhanced the Anammox activity in terms of ammonium consumption rate. The estimated specific Anammox growth rates (μAN) in the five batch tests with standard errors are also shown in Figure 1. With the increase of Fe (II) concentrations from 0.03 mM (control experiment, Figure 1a) to 0.09 mM (Figure 1c), the estimated specific growth rates of Anammox microorganisms increased from 0.1184 d−1 to 0.1719 d−1. The obtained kinetic value of 0.1184 d−1 under normal Fe (II) condition (0.03 mM) was also comparable with literature reported values28. Further increasing Fe (II) concentration to 0.18 mM slightly decreased the specific Anammox growth rate to 0.1499 d−1 (Figure 1e). The results indicated that the highest specific Anammox growth rate was achieved at a Fe (II) concentration of 0.09 mM under the studied conditions, which was 45% higher than that in control test (Figure 1a). These results demonstrated that appropriate Fe (II) addition could significantly enhance the Anammox activity.


Appropriate Fe (II) addition significantly enhances anaerobic ammonium oxidation (Anammox) activity through improving the bacterial growth rate.

Liu Y, Ni BJ - Sci Rep (2015)

The experimental measured and kinetic fitted ammonium consumption profiles in five 4-h batch tests under different Fe (II) concentrations:(a) 0.03 mM; (b) 0.06 mM; (c) 0.09 mM; (d) 0.12 mM; and (e) 0.18 mM (symbols represent experimental measurements and lines represent kinetic fittings).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4316192&req=5

f1: The experimental measured and kinetic fitted ammonium consumption profiles in five 4-h batch tests under different Fe (II) concentrations:(a) 0.03 mM; (b) 0.06 mM; (c) 0.09 mM; (d) 0.12 mM; and (e) 0.18 mM (symbols represent experimental measurements and lines represent kinetic fittings).
Mentions: Figure 1 presents the measured and kinetic fitted ammonium consumption profiles from the five batch tests at different Fe (II) addition levels. The ammonium concentration decreased linearly in all the five batch experiments with different reduction rates. The kinetic fittings matched well with all the experimental measurements. In general, Fe (II) addition with a concentration higher than the normal level (0.03 mM) enhanced the Anammox activity in terms of ammonium consumption rate. The estimated specific Anammox growth rates (μAN) in the five batch tests with standard errors are also shown in Figure 1. With the increase of Fe (II) concentrations from 0.03 mM (control experiment, Figure 1a) to 0.09 mM (Figure 1c), the estimated specific growth rates of Anammox microorganisms increased from 0.1184 d−1 to 0.1719 d−1. The obtained kinetic value of 0.1184 d−1 under normal Fe (II) condition (0.03 mM) was also comparable with literature reported values28. Further increasing Fe (II) concentration to 0.18 mM slightly decreased the specific Anammox growth rate to 0.1499 d−1 (Figure 1e). The results indicated that the highest specific Anammox growth rate was achieved at a Fe (II) concentration of 0.09 mM under the studied conditions, which was 45% higher than that in control test (Figure 1a). These results demonstrated that appropriate Fe (II) addition could significantly enhance the Anammox activity.

Bottom Line: This work systematically studied the effects of Fe (II) addition on Anammox activity based on the kinetic analysis of specific growth rate using data from batch tests with an enriched Anammox sludge at different dosing levels.Results clearly demonstrated that appropriate Fe (II) dosing (i.e., 0.09 mM) significantly enhanced the specific Anammox growth rate up to 0.172 d(-1) compared to 0.118 d(-1) at regular Fe (II) level (0.03 mM).The relationship between Fe (II) concentration and specific Anammox growth rate was found to be well described by typical substrate inhibition kinetics, which was integrated into currently well-established Anammox model to describe the enhanced Anammox growth with Fe (II) addition.

View Article: PubMed Central - PubMed

Affiliation: Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, Queensland 4072, Australia.

ABSTRACT
The application of anaerobic ammonium oxidation (Anammox) process is often limited by the slow growth rate of Anammox bacteria. As the essential substrate element that required for culturing Anammox sludge, Fe (II) is expected to affect Anammox bacterial growth. This work systematically studied the effects of Fe (II) addition on Anammox activity based on the kinetic analysis of specific growth rate using data from batch tests with an enriched Anammox sludge at different dosing levels. Results clearly demonstrated that appropriate Fe (II) dosing (i.e., 0.09 mM) significantly enhanced the specific Anammox growth rate up to 0.172 d(-1) compared to 0.118 d(-1) at regular Fe (II) level (0.03 mM). The relationship between Fe (II) concentration and specific Anammox growth rate was found to be well described by typical substrate inhibition kinetics, which was integrated into currently well-established Anammox model to describe the enhanced Anammox growth with Fe (II) addition. The validity of the integrated Anammox model was verified using long-term experimental data from three independent Anammox reactors with different Fe (II) dosing levels. This Fe (II)-based approach could be potentially implemented to enhance the process rate for possible mainstream application of Anammox technology, in order for an energy autarchic wastewater treatment.

Show MeSH