Long-term enhanced nitrogen removal and power generation in high-salinity ammonium-rich wastewater treatment via heterotrophic nitrifying-aerobic denitrifying bacteria-functionalized biocathodes.

Zusammenfassung

A lab-scale single-chamber microbial fuel cell (SCMFC) with a heterotrophic nitrifying-aerobic denitrifying bacteria (HNADB)-functionalized biocathode was developed to treat high-salinity ammonium-rich wastewater for the first time. Results showed that the system achieved a total nitrogen removal efficiency and rate of 92.5 % and 2.2 mg/(L∙h), respectively, far superior to autotrophic nitrifying bacteria (ANB) biocathode and platinum carbon cathode systems. The maximum power density of the HNADB-biocathode system was 1.4 times that of the ANB-biocathode system. The HNADB-biocathode SCMFC maintained stable performance throughout 350 days of operation. Microbial community analysis confirmed that electrical stimulation further enriched salt-tolerant electroactive HNADB in the HNADB-functionalized biocathode biofilm, particularly the genus Vitellibacter. This facilitated the coupling of nitrogen removal and electricity generation. Microbial metabolism and electron transfer activity tests indicated that the bidirectional incentive between extracellular electron transfer (EET) and intracellular electron transfer (IET) in the HNADB-functionalized biocathode biofilm may be the key factor driving enhanced nitrogen removal and electricity generation. Additionally, redox mediators (mainly flavin and cytochrome c) and electrode biofilm pseudocapacitance may play crucial roles in EET. This study provides a potentially effective strategy for improving the high-salinity ammonium-rich wastewater treatment.

Schlagwörter

Kennungen

DOI

41139031

PubMed

41139031

Zeitschrift

Bioresource technology

Jahr

2025