Nitrification mainly driven by ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in an anammox-inoculated wastewater treatment system

Jing Lu,Jiapeng Wu,Yiguo Hong,Fei Ye,Yu Wang,Ji-Dong Gu,Ying Wei,Jih-Gaw Lin

doi:10.1186/s13568-021-01321-6

Abstract

Anaerobic ammonium oxidation (anammox) process has been acknowledged as an environmentally friendly and time-saving technique capable of achieving efficient nitrogen removal. However, the community of nitrification process in anammox-inoculated wastewater treatment plants (WWTPs) has not been elucidated. In this study, ammonia oxidation (AO) and nitrite oxidation (NO) rates were analyzed with the incubation of activated sludge from Xinfeng WWTPs (Taiwan, China), and the community composition of nitrification communities were investigated by high-throughput sequencing. Results showed that both AO and NO had strong activity in the activated sludge. The average rates of AO and NO in sample A were 6.51 µmol L−1 h−1 and 6.52 µmol L−1 h−1, respectively, while the rates in sample B were 14.48 µmol L−1 h−1 and 14.59 µmol L−1 h−1, respectively. The abundance of the nitrite-oxidizing bacteria (NOB) Nitrospira was 0.89–4.95 × 1011 copies/g in both samples A and B, the abundance of ammonia-oxidizing bacteria (AOB) was 1.01–9.74 × 109 copies/g. In contrast, the abundance of ammonia-oxidizing archaea (AOA) was much lower than AOB, only with 1.28–1.53 × 105 copies/g in samples A and B. The AOA community was dominated by Nitrosotenuis, Nitrosocosmicus, and Nitrososphaera, while the AOB community mainly consisted of Nitrosomonas and Nitrosococcus. The dominant species of Nitrospira were Candidatus Nitrospira defluvii, Candidatus Nitrospira Ecomare2 and Nitrospira inopinata. In summary, the strong nitrification activity was mainly catalyzed by AOB and Nitrospira, maintaining high efficiency in nitrogen removal in the anammox-inoculated WWTPs by providing the substrates required for denitrification and anammox processes.

Highlights

The discharge of nitrogen containing wastewater into natural waters has become a global concern, resulting in problems such as acidification and eutrophication (Canfield et al 2010; Kuypers et al 2018; Bailes et al 2020; Lan et al 2011)
Lu et al AMB Express (2021) 11:158 procedures have been widely applied to ammoniumrich WWTPs (Lan et al 2011; Ali and Okabe 2015) in which ammonia is firstly transformed to nitrate via nitrification, with nitrate converted to nitrogen gas by anoxic biotransformation using organic carbon as an electron source (Yang et al 2020a, b)
The increasing need to reduce the consumption of energy and resources by treatment systems has contributed to the development of several novel nitrogen removal techniques, such as a single reactor system for high ammonium removal over nitrite (SHARON) (Hellinga et al 1998; Dongen et al 2001), completely autotrophic nitrogen removal over nitrite (CANON) (Sliekers et al 2002), oxygen-limited autotrophic nitrification–denitrification (OLAND) (Kuai et al 1998), and anaerobic ammonium oxidation (Jetten et al 1998)

Summary

Introduction

The discharge of nitrogen containing wastewater into natural waters has become a global concern, resulting in problems such as acidification and eutrophication (Canfield et al 2010; Kuypers et al 2018; Bailes et al 2020; Lan et al 2011). Lu et al AMB Express (2021) 11:158 procedures have been widely applied to ammoniumrich WWTPs (Lan et al 2011; Ali and Okabe 2015) in which ammonia is firstly transformed to nitrate via nitrification, with nitrate converted to nitrogen gas by anoxic biotransformation using organic carbon as an electron source (Yang et al 2020a, b). The anammox procedure has been proven to be more efficient than conventional nitrification–denitrification process (Yang et al 2020a, b; Ma et al 2016; Wu et al 2019; Bucci et al 2020), achieving 60% reduction in oxygen demand (e.g., aeration), 90% reduction in sludge, 100% reduction in the demand for organic carbon sources and less or no N2O emission (Kartal et al 2008; Kuenen 2008; Okabe et al 2011; Van et al 1995; Strous et al 1999). The highthroughput sequencing technique was used to further revealing the composition of the main microorganism community in WWTPs (Yang et al 2020a, b)

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