Impact of dissolved oxygen and loading rate on NH3 oxidation and N2 production mechanisms in activated sludge treatment of sewage. Issue 2 (2nd June 2020)

• Record Type: Journal Article
• Authors: Zhang, Xueyu; Li, Shida; Zheng, Shaokui; Duan, Shoupeng
• Other Names: Zhou Ning‐Yi guestEditor.; Huang Wei guestEditor.; Bai Linquan guestEditor.; Yang Chen guestEditor.; Wang Hui guestEditor.
• Is Part Of: Microbial biotechnology. Volume 14:Issue 2(2021)
• Page Start: 419
• Page End: 429
• Publication Date: 2020-06-02
• Subjects: Microbial biotechnology -- Periodicals; Biotechnology; Microbiology; 660.62
• DOI: 10.1111/1751-7915.13599
• Languages: English
• ISSNs: 1751-7915

Abstract

Summary: Microaerobic activated sludge (MAS) is a one‐stage process operated at 0.5–1.0 mg l −1 dissolved oxygen (DO) aiming at simultaneous nitrification and denitrification. We used molecular techniques and a comprehensive nitrogen (N)‐transformation activity test to investigate the dominant NH3 ‐oxidizing and N2 ‐producing mechanism as well as the dominant ammonia‐oxidizing bacteria (AOB) species in sludge samples individually collected from an MAS system and a conventional anoxic/oxic (A/O) system; both systems were operated at a normal loading rate (i.e. 1.0 kg chemical oxygen demand (COD) m −3 day −1 and 0.1 kg NH4 + ‐N m −3 day −1 ) in our previous studies. The DO levels in both systems (aerobic: conventional A/O system; microaerobic: MAS system) did not affect the dominant NH3 ‐oxidizing mechanism or the dominant AOB species. This study further demonstrated the feasibility of a higher loading rate (i.e. 2.30 kg COD m −3 day −1 and 0.34 kg NH4 + ‐N m −3 day −1 ) with the MAS process during sewage treatment, which achieved a 40% reduction in aeration energy consumption than that obtained in the conventional A/O system. The increase in loading rates in the MAS system did not affect the dominant NH3 ‐oxidizing mechanism but did impact the dominant AOB species. Besides, N2 was predominantly produced by microaerobic denitrification in the MAS system at the two loading rates. Abstract : (i) The DO levels in both systems (aerobic: conventional A/O system; microaerobic: MAS system) did not affect the dominant NH3‐oxidizing mechanism or the dominant AOB species. (ii)The MAS process at a high loading rate achieved a 40% reduction in aeration energy consumption than that obtained in the conventional A/O system during sewage treatment. (iii).The increase in loading rates in the MAS system did not affect the dominant NH3‐oxidizing mechanism but did impact the dominant AOB species.