Continuous anaerobic oxidation of methane: Impact of semi-continuous liquid operation and nitrate load on N2O production and microbial community.
Chemosphere
; 278: 130441, 2021 Sep.
Article
en En
| MEDLINE
| ID: mdl-33838410
This work proves the feasibility of employing regular secondary activated sludge for the enrichment of a microbial community able to perform the anaerobic oxidation of methane coupled to nitrate reduction (N-AOM). After 96 days of activated sludge enrichment, a clear N-AOM activity was observed in the resulting microbial community. The methane removal potential of the enriched N-AOM culture was then studied in a stirred tank reactor (STR) operated in continuous mode for methane supply and semi-continuous mode for the liquid phase. The effect of applying nitrate loads of â¼22, 44, 66, and 88 g NO3- m-3 h-1 on (i) STR methane and nitrate removal performance, (ii) N2O emission, and (iii) microbial composition was investigated. Methane elimination capacities from 21 ± 13.3 to 55 ± 12 g CH4 m-3 h-1 were recorded, coupled to nitrate removal rates ranging from 6 ± 3.2 to 43 ± 14.9 g NO3- m-3 h-1. N2O production was not detected under the three nitrate loading rates applied for the assessment of potential N2O emission in the continuous N-AOM process (i.e. â¼22-66 g NO-3 m-3 h-1). The lack of N2O emissions during the process was attributed to the N2O reducing capacity of the bacterial taxa identified and the rigorous control of dissolved O2 and pH implemented (dissolved O2 values ≤ 0.07 g m-3 and pH of 7.6 ± 0.4). Microbial characterization showed that the N-AOM process was performed in absence of putative N-AOM archaea and bacteria (ANME-2d, M. oxyfera). Instead, microbial activity was driven by methane-oxidizing bacteria and denitrifying bacteria (Bacteroidetes, α-, and γ-proteobacteria).
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Microbiota
/
Metano
Idioma:
En
Revista:
Chemosphere
Año:
2021
Tipo del documento:
Article
País de afiliación:
México
Pais de publicación:
Reino Unido