Implementing a completely autotrophic nitrogen removal over nitrite process using a novel umbrella basalt fiber...

Area of Science:

• Environmental biotechnology
• Wastewater treatment
• Microbial ecology

Background:

• The completely autotrophic nitrogen removal over nitrite (CANON) process faces challenges with long start-up times and unstable efficiency.
• Effective biocarriers are crucial for optimizing nitrogen removal processes in wastewater treatment.

Purpose of the Study:

• To evaluate a novel umbrella basalt fiber (BF) carrier for initiating and stabilizing the CANON process.
• To assess the efficiency and microbial community dynamics of the CANON process using BF carriers.

Main Methods:

• Implementation of the CANON process in a sequencing batch reactor using umbrella BF carriers.
• Gradual increase of influent ammonia nitrogen concentration (100–200 mg·L^-1) with controlled dissolved oxygen (< 0.8 mg L^-1).
• Analysis of nitrogen removal efficiencies and microbial community composition on the BF carriers.

Main Results:

• The CANON process initiated on day 64, achieving average ammonia nitrogen removal efficiency (ARE) of ~90% and total nitrogen removal efficiency (TNRE) of ~80%.
• Stable ARE and TNRE of 92% and 81.1% were maintained after 130 days.
• Dominant anammox genera identified as Candidatus Kuenenia and Candidatus Brocadia, with Nitrosomonas as the predominant ammonia-oxidizing bacteria.

Conclusions:

• The umbrella BF carrier provides a reliable method for rapid start-up and stable operation of the CANON process.
• The carrier supports distinct microbial populations, facilitating efficient autotrophic nitrogen removal in a single reactor.
• Novel umbrella BF carriers are highly suitable for enhancing the CANON process in wastewater treatment.