A predictive model for N2O production in anammox-granular sludge reactors: Combined effects of nitrite/ammonium ratio and organic matter concentration

T D S Pereira; R H Spindola; C A B S Rabelo; N C Silveira; M A T Adorno; A Kunz; E C Pires; M H R Z Damianovic

doi:10.1016/j.jenvman.2021.113295

A predictive model for N₂O production in anammox-granular sludge reactors: Combined effects of nitrite/ammonium ratio and organic matter concentration

J Environ Manage. 2021 Nov 1:297:113295. doi: 10.1016/j.jenvman.2021.113295. Epub 2021 Jul 26.

Authors

T D S Pereira¹, R H Spindola², C A B S Rabelo², N C Silveira², M A T Adorno², A Kunz³, E C Pires², M H R Z Damianovic²

Affiliations

¹ Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil. Electronic address: tiago.duarte@polimi.it.
² Laboratory of Biological Processes, Department of Hydraulics and Sanitation, São Carlos School of Engineering, University of São Paulo, Av. João Dagnone, 1100, Jd. Santa Angelina, 13563-120, São Carlos, SP, Brazil.
³ Embrapa Suínos e Aves, 89715-899, Concórdia, SC, Brazil.

PMID: 34311258
DOI: 10.1016/j.jenvman.2021.113295

Abstract

Once the use of anammox reactors has been increasing on a global scale, it is important to understand the mechanisms of N₂O emissions and how to minimise the emissions by optimising the operating conditions. In this study, the influence of chemical oxygen demand (COD) (from 0 mgO₂ L^-1 to 100 mgO₂ L^-1) and nitrite/ammonium ratio from 0.79 to 2.21 (maintaining ammonium at 100 mgN L^-1 and varying nitrite from 79 mgN L^-1 to 221 mgN L^-1) in the N₂O emissions from anammox-granular sludge reactor was investigated in two steps. Step 1 consisted of batch tests, using central composite design, and Step 2, long-term operation of a 6.5 L continuous up-flow reactor. The results showed that the N₂O emissions were minimized by controlling, in the influent, the NO₂^--N/NH₄⁺-N ratio from 1.1 to 1.3 and maintaining the COD concentration below 100 mgO₂ L^-1. TN removal efficiencies were higher than 70% in all conditions tested".

Keywords: Anammox; Heterotrophic denitrification; Modelling; Nitrite accumulation; Nitrous oxide; Wastewater.

MeSH terms

Ammonium Compounds*
Bioreactors
Denitrification
Nitrites
Nitrogen / analysis
Nitrous Oxide / analysis
Oxidation-Reduction
Sewage*

Substances

Ammonium Compounds
Nitrites
Sewage
Nitrous Oxide
Nitrogen