Relationships of pulsed frequency and anammox bacteria growth rate, at low temperatures

ABSTRACT

This study explored pulsed frequency that could enhance the anammox bacteria growth rate and TN removal rate at low temperatures (16 ± 1°C). The results showed that the growth rate of anammox bacteria in R1 (1000 Hz) was significantly higher than in R2 (30 Hz) and R3 (10⁶Hz). The relative abundance values of anammox bacteria R1 were higher by 52.21% and 172.41% than R2 and R3, while that of MLSS were as high as 241.07% and 471.36% than R2 and R3, with the nitrogen loading rate was 6.84 kg-N/m³/d. Besides, the dynamics also showed that the specific anammox activity (SAA) and the cellular yield of R1 were higher than R2 and R3. The intermediate frequency could enhance the cell division by stimulating the anammoxosome and reduce the ionic hydration layer to accelerate the ion migration rate, further improving the number of anammox bacteria even at low temperatures. The pulsed frequency could enhance the anammox growth rate and the doubling time is just 5 d.

GRAPHICAL ABSTRACT

KEYWORDS:

• Pulsed frequency
• anammox
• growth rate
• low temperature
• ionic hydration layer

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Authors’ contributions

Chi Zhang: Conceptualization, data curation, formal analysis, funding acquisition, project administration, and writing – original draft. Chao Wang: Data curation, formal analysis, and methodology. Yujia Wang: Investigation and validation. Ze Lv: Data curation and formal analysis. Xiaomin Hu: Funding acquisition and resources, investigation, methodology, supervision, and writing – review & editing.

Additional information

Funding

This research was financially supported by the Major Science and Technology Program for Water Pollution Control and Treatment (2013ZX07202-010) and the key research and development plan guidance plan project of Liaoning province(2019JH8/10300103).