Research on efficient denitrification system based on banana peel waste in sequencing batch reactors: Performance,...

Area of Science:

• Environmental Science
• Microbiology
• Biogeochemistry

Background:

• Nitrate pollution poses significant environmental and public health risks.
• Agricultural waste like banana peels offers a sustainable carbon source for denitrification.
• Previous studies showed feasibility but lacked long-term stability and mechanistic understanding.

Purpose of the Study:

• To investigate the long-term stability and mechanisms of banana peel-based heterotrophic denitrification.
• To elucidate the interplay between organic matter evolution and microbial communities during nitrate removal.
• To identify key microbial players and functional genes involved in the process.

Main Methods:

• A 17-cycle denitrification experiment was conducted.
• Organic matter composition was analyzed.
• Microbial community structure was assessed using 16S rRNA sequencing.
• Functional genes related to nitrogen transformation were identified.

Main Results:

• High nitrate-nitrogen removal load (164.42 mg/g) and rate (4.69 mg/(L·h)) were achieved over the long term.
• Organic matter evolution was dominated by fermenting bacteria (Anaerolineaceae), leading to humification.
• Denitrifying bacteria (Lentimicrobium) and the NirS gene were crucial for continuous nitrate removal.

Conclusions:

• Banana peels are a stable and effective carbon source for heterotrophic denitrification.
• The process involves specific microbial consortia and organic matter transformations.
• This research provides a reference for designing efficient nitrate degradation reactors using agricultural waste.