In a quest for high-efficiency mainstream partial nitritation-anammox (PN/A) implementation: One-stage or two-stage?

Shenbin Cao, Konrad Koch, Haoran Duan, George F. Wells, Liu Ye, Yingfen Zhao, Rui Du*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

26 Scopus citations

Abstract

Partial nitritation-anammox (PN/A) process is known as an energy-efficient technology for wastewater nitrogen removal, which possesses a great potential to bring wastewater treatment plants close to energy neutrality with reduced carbon footprint. To achieve this goal, various PN/A processes implemented in a single reactor configuration (one-stage system) or two separately dedicated reactors configurations (two-stage system) were explored over the past decades. Nevertheless, large-scale implementation of these PN/A processes for low-strength municipal wastewater treatment has a long way to go owing to the low efficiency and effectiveness in nitrogen removal. In this work, we provided a comprehensive analysis of one-stage and two-stage PN/A processes with a focus on evaluating their engineering application potential towards mainstream implementation. The difficulty for nitrite-oxidizing bacteria (NOB) out-selection was revealed as the critical operational challenge to achieve the desired effluent quality. Additionally, the operational strategies of low oxygen commonly adopted in one-stage systems for NOB suppression and facilitating anammox bacteria growth results in a low nitrogen removal rate (NRR). Introducing denitrification into anammox system was found to be necessary to improve the nitrogen removal efficiency (NRE) by reducing the produced nitrate with in-situ utilizing the organics from wastewater itself. However, this may lead to part of organics oxidized with additional oxygen consumed in one-stage system, further compromising the NRR. By applying a relatively high dissolved oxygen in PN reactor with residual ammonium control, and followed by a granules-based anammox reactor feeding with a small portion of raw municipal wastewater, it appeared that two-stage system could achieve a good effluent quality as well as a high NRR. In contrast to the widely studied one-stage system, this work provided a unique perspective that more effort should be devoted to developing a two-stage PN/A process to evaluate its application potential of high efficiency and economic benefits towards mainstream implementation.

Original languageEnglish (US)
Article number163540
JournalScience of the Total Environment
Volume883
DOIs
StatePublished - Jul 20 2023

Funding

This work was supported by the National Natural Science Foundation of China (NO. 42207420 ) and the Alexander von Humboldt Foundation (Grant number: 1216728 ), the financial support of the TUM Global Incentive Fund to host the workshop with our international partners from UQ and NU is highly appreciated.

Keywords

  • Effluent quality
  • Mainstream anammox
  • Municipal wastewater
  • Nitrogen removal rate (NRR)
  • One-stage PN/A
  • Two-stage PN/A

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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