Modeling granule-based completely autotrophic nitrogen removal over the nitrite (CANON) process in an SBR

Qing Cai,Jiajia Ding,Qiang He,Sheng Zhang

doi:10.2166/wrd.2021.041

Abstract

AbstractBased on the simplified activated sludge model No. 1 (ASM1), a 1D biofilm model containing autotrophic and heterotrophic microorganisms was developed to describe the microbial population dynamics and reactor dynamics of completely autotrophic nitrogen removal over the nitrite in sequencing batch reactor (CANON SBR). After sensitivity analysis and calibration for parameters, the simulation results of NH4+-N concentration and NO2−-N concentration were consistent with the measured results, while the simulated NO3−-N concentration was slightly lower than the measured. The simulation results showed that the soluble microbial products had an extremely low concentration. The aerobic ammonia oxidation bacteria and anaerobic ammonia oxidation bacteria were the dominant microbial populations of the CANON system, while nitrite oxidization bacteria and heterotrophic bacteria were eliminated completely. The optimal ratio of air aeration load to influent NH4+-N load was about 0.18 L air/mgN. The operating condition of the reactor was optimized according to the simulation results, and the total nitrogen removal rate and the total nitrogen removal efficiency increased from 0.312 ± 0.015 to 0.485 ± 0.013 kg N/m3/d and from 71.2 ± 4.3 to 85.7 ± 1.4%, respectively.

Highlights

The CANON process (Sliekers et al 2002), in which partial nitrification and anaerobic ammonia oxidation (ANAMMOX) are implemented simultaneously, has been widely applied to full-scale wastewater treatment (Joss et al 2011; Amin et al 2021) since it can save 62.5% of O2 consumption and 100% of organic carbon consumption theoretically compared to the traditional nitrification–denitrification process (Yao et al 2013)
The simultaneous growth of aerobic ammonia oxidation bacteria (AOB) and anaerobic ammonia oxidation bacteria (ANAOB) in the CANON process involves the competition on the common substrate NH4þ, the synergy transformation of substrate NO2À and the different demands for the environmental conditions (especially for dissolved oxygen (DO))
The CANON biofilm model developed by Hao et al (2002a, 2002b) revealed that the optimal DO level of maximum nitrogen removal was positively correlated with ammonia load (Hao et al 2002b), and the positive and negative changes of DO by 0.2 gO2/m3 have no significant impact on the performance of the CANON process (Hao et al 2002a)

Summary

Introduction

The CANON process (Sliekers et al 2002), in which partial nitrification and anaerobic ammonia oxidation (ANAMMOX) are implemented simultaneously, has been widely applied to full-scale wastewater treatment (Joss et al 2011; Amin et al 2021) since it can save 62.5% of O2 consumption and 100% of organic carbon consumption theoretically compared to the traditional nitrification–denitrification process (Yao et al 2013). The simultaneous growth of aerobic ammonia oxidation bacteria (AOB) and anaerobic ammonia oxidation bacteria (ANAOB) in the CANON process involves the competition on the common substrate NH4þ, the synergy transformation of substrate NO2À and the different demands for the environmental conditions (especially for dissolved oxygen (DO)). There are both anaerobic and aerobic areas in granule-based biofilm, and thereby it is suitable for one-stage autotrophic nitrogen removal (Vangsgaard et al 2013).

Methods

Results

Conclusion