Simultaneous denitrification and antibiotic degradation of low-C/N-ratio wastewater by a three-dimensional biofilm-electrode reactor: Performance and microbial response.
Environ Res
; 210: 112856, 2022 07.
Article
en En
| MEDLINE
| ID: mdl-35150713
ABSTRACT
Three-dimensional biofilm-electrode reactors (3D-BERs) were fabricated and used to simultaneously remove nitrate and metronidazole (MNZ) from low-C/N-ratio wastewater. The results showed that 1 mg/L MNZ significantly promoted nitrate removal. After MNZ was added to the reactor, the removal efficiencies of total nitrogen (TN) and NO3--N increased significantly from 18.97% and 52.09% to 71.63% and 99.98% within 6 h, respectively. The MNZ-removal kinetics conformed to a pseudo-first-order model, and the removal rate constant reached a maximum value of 0.853 h-1, which was 4.1 and 2.8 times higher than that of pure microorganisms and pure electrochemical reactors, respectively. This indicated that the 3D-BERs constructed in this study were capable of simultaneous MNZ degradation and denitrification. In the presence of nitrate, six MNZ-degradation intermediates were identified, and four MNZ transformation pathways were proposed, including cleavage of hydroxyethyl groups, reduction of nitro groups, N-denitration, and deprotonation of side-chain hydroxyl groups. High-throughput sequencing revealed that the reactor was rich in various MNZ-degraders and denitrifiers, such as Hydrogenophaga, Methylomonas, Crenohrix, Dechloromonas, and Methylophilus. A function prediction analysis of nitrogen metabolism showed that the 3D-BER reactor with MNZ had higher denitrification activity than the other reactors tested. It was speculated that the intermediates produced by MNZ could act as carbon sources allowing denitrifying bacteria to perform denitrification, which made a nonnegligible contribution to the removal of nitrogen.
Palabras clave
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Desnitrificación
/
Aguas Residuales
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Environ Res
Año:
2022
Tipo del documento:
Article
País de afiliación:
China