New insights and enhancement mechanisms of activated carbon in autotrophic denitrification system utilizing zero-valent iron as indirect electron donors.
Bioresour Technol
; 410: 131237, 2024 Oct.
Article
em En
| MEDLINE
| ID: mdl-39127355
ABSTRACT
Zero-valent iron acts as an indirect electron donor, supplying ferrous iron for the nitrate-dependent ferrous oxidation (NDFO) process. The addition of activated carbon (AC) increased the specific NDFO activity in situ and ex situ by 0.4 mg-N/(d·g VSS) and 2.2 mg-N/(d·g VSS), respectively, due to the enrichment of NDFO bacteria. Furthermore, AC reduced the nitrous oxide emission potential of the sludge, a mechanism that metagenomic analysis suggests may act as a cellular energy storage strategy. During a 196-day experiment, a total nitrogen removal efficiency of 53.7 % was achieved, which may be attributed to the upregulation of key genes involved in iron oxidation and denitrification. Based on these findings, a model involving pilin, 'nanowires,' and a cyc2/?â/(FoxEâFoxY)/?âcymA/Complex III/?-mediated pathway for extracellular electron uptake was proposed. Overall, this work provides a feasible strategy for enhancing the nitrogen removal performance of the ZVI-NDFO process.
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Base de dados:
MEDLINE
Assunto principal:
Elétrons
/
Processos Autotróficos
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Desnitrificação
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Ferro
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Nitrogênio
Idioma:
En
Ano de publicação:
2024
Tipo de documento:
Article