Development of a single-stage mainstream anammox process using a sponge-bed trickling filter

ABSTRACT

Anaerobic ammonia oxidation to nitrogen gas using nitrite as the electron acceptor (anammox process) is considered a cost-effective solution for nitrogen removal after an anaerobic pre-treatment process. In this study, we conducted a laboratory-scale experiment to develop a single-stage partial nitritation–anammox process in a sponge-based trickling filter (STF) reactor, inoculated with anammox sludge, simulating the treatment of anaerobically pretreated concentrated domestic sewage without mechanical oxygen control. The influent ammonia concentration was 100 mg-N·L⁻¹. The K_La of the STF reactor was higher than those observed for conventional activated sludge processes. The STF reactor performed at 89.8 ± 8.2% and 42.7 ± 16.9% ammonia and TN removal efficiency, respectively, with a nitrogen loading rate of 0.55 ± 0.20 kg-N·m⁻³·day⁻¹ calculated based on sponge volume. Microbial community analysis of the STF-retained sludge indicated that both autotrophic and heterotrophic nitrogen removal occurred in the reactor.

GRAPHICAL ABSTRACT

KEYWORDS:

• Autotrophic nitrogen removal
• sponge-based trickling filter
• microbial community analysis

Acknowledgements

This research was supported financially by Grants-in-Aids for Scientific Research from the Japan Society for the Promotion of Science (PJ No. 17H06703) and the Ministry of Education, Culture, Sports, Science and Technology, Japan.

Disclosure statement

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

ORCID

Takahiro Watari http://orcid.org/0000-0003-3781-3710

Jules B. van Lier http://orcid.org/0000-0003-2607-5425

Additional information

Funding

This work was supported by Japan Society for the Promotion of Science: [Grant Number 17H06703].