Constraining nitrification by intermittent aeration to achieve methane-driven ammonia recovery of the mainstream anaerobic effluent

Xin Li; Yongze Lu; Yue Chen; Guangcan Zhu; Raymond Jianxiong Zeng

doi:10.1016/j.jenvman.2021.113103

Constraining nitrification by intermittent aeration to achieve methane-driven ammonia recovery of the mainstream anaerobic effluent

J Environ Manage. 2021 Oct 1:295:113103. doi: 10.1016/j.jenvman.2021.113103. Epub 2021 Jun 19.

Authors

Xin Li¹, Yongze Lu², Yue Chen³, Guangcan Zhu⁴, Raymond Jianxiong Zeng⁵

Affiliations

¹ School of Energy and Environment, Southeast University, Nanjing 210096, China; State Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210096, China. Electronic address: lix@seu.edu.cn.
² School of Energy and Environment, Southeast University, Nanjing 210096, China; State Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210096, China. Electronic address: yzlu@seu.edu.cn.
³ School of Energy and Environment, Southeast University, Nanjing 210096, China; Water Pollution Control and Ecological Restoration Engineering Laboratory of XiZang, Xizang Minzu University, Xianyang 712082, China. Electronic address: chenyue@seu.edu.cn.
⁴ School of Energy and Environment, Southeast University, Nanjing 210096, China; State Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing 210096, China. Electronic address: gc-zhu@seu.edu.cn.
⁵ Center of Wastewater Resource Recovery, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou 350002, China. Electronic address: rzeng@fafu.edu.cn.

PMID: 34153581
DOI: 10.1016/j.jenvman.2021.113103

Abstract

Mainstream anaerobic treatment has the potential to capture organic energy, and represents a sustainable development trend, but with the problems of low biogas quality and dissolved methane emissions. In this study, methane-driven ammonia recovery of anaerobic effluent was proposed. A 380-day long-term experiment, which was divided into four phases according to different aeration modes, was conducted. The ammonia conversion and microbial characteristics shows that ammonia oxidizing bacteria (AOB) were constrained during Phases 2 (DO: <0.2 mg L^-1) and 4 (DO: 0.1-1.6 mg L^-1), and were active during Phase 3 (DO: 2-4 mg L^-1). During phase 4, when the intermittent aeration was used, the total nitrogen removal rate was higher than during Phases 2 and 3, and nearly 100% ammonia was removed. Methylomonas, a genus of methane oxidizing bacteria (MOB), was enriched during Phase 4. The serum bottle experiment confirmed that the ammonia removal occurred through the MOB assimilation. The protein content in the CH₄-added group was 35.5%, which was higher than in the group without CH₄ (23.3%). The powerful ammonia assimilation and protein synthesis capabilities of MOB give a meaning to the anaerobic effluent for ammonia recovery and protein production. Intermittent aeration could be used to constrain AOB and improve ammonia recovery efficiency.

Keywords: Ammonia assimilation; Anaerobic effluent treatment; Methane oxidizing bacteria; Nitrification inhibition; Nitrogen recovery.

MeSH terms

Ammonia*
Anaerobiosis
Bioreactors
Methane
Nitrification*
Nitrogen
Oxidation-Reduction

Substances

Ammonia
Nitrogen
Methane