Startup of a large height-diameter ratio bioreactor by alternate feeding: performance of partial nitrification and enrichment of ammonia-oxidizing bacteria (AOB)

ABSTRACT

In order to solve the complicated control of dissolved oxygen (DO) for partial nitrification in bioreactors treating high ${\mathrm{NH}}_4^{+}-\mathrm{N}$ wastewater, a large height-diameter ratio anammox pre-reactor system was developed. And in this reactor, ${\mathrm{NO}}_2^{-}-\mathrm{N}$ accumulation rate can reach 85.76% by alternate feeding with high ${\mathrm{NH}}_4^{+}-\mathrm{N}$ wastewater (150 mg ${\mathrm{NH}}_4^{+}-\mathrm{N}/\mathrm{L}$) and low ${\mathrm{NH}}_4^{+}-\mathrm{N}$ wastewater (50 mg c) with low DO (0.19 mg/L–0.62 mg/L). Based on 16S rRNA identification technology, it was found that Nitrosomonas had a significant effect on ${\mathrm{NH}}_4^{+}-\mathrm{N}$ oxidization in this study. And when the reactor treated higher concentration wastewater (250 mg ${\mathrm{NH}}_4^{+}-\mathrm{N}/\mathrm{L}$), the growth rate of Nitrosomonas was higher than that of Nitrospira (nitrite-oxidizing bacteria, NOB), which was conducive to improving the ${\mathrm{NO}}_2^{-}-\mathrm{N}$ accumulation rate and realizing partial nitrification stably. It was also found that the material exchange frequency of the microbial flora during alternate feeding with different ${\mathrm{NH}}_4^{+}-\mathrm{N}$ concentration wastewaters was higher than that during feeding with higher ${\mathrm{NH}}_4^{+}-\mathrm{N}$ concentration wastewater (250 mg/L) by Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolism pathways analysis. This study can provide valuable insights and lay the foundation for building anammox pre-reactors.

GRAPHICAL ABSTRACT

KEYWORDS:

• Ammonium fertilizer wastewater
• KEGG
• limited oxygen aeration
• partial nitrification
• 16S rRNA

Disclosure statement

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

Additional information

Funding

The authors are grateful for the financial support from the National Natural Science Foundation of China [grant number 51308179].