Protocol for the enrichment cultivation of anammox bacteria utilizing local resources.

Abstract

This study presents a protocol for the enrichment and immobilization of anaerobic ammonium oxidation (anammox) bacteria using local natural resources to facilitate nitrogen removal in wastewater treatment, particularly in regions where anammox seed biomass and advanced treatment facilities are not readily available. Anammox bacteria were successfully enriched from river sediments in a fixed-bed reactor using a nonwoven fabric as a support medium. Subsequently, the bacteria were immobilized onto porous polyvinyl alcohol carriers, demonstrating stable attachment and enhanced nitrogen removal efficiency. Performance evaluation experiments confirmed a high nitrogen conversion rate of 4.3 kg-N m^-3 d^-1 with stable long-term operation even under increasing nitrogen loading rates. This approach eliminates the need for external bacterial sources, enabling cost-effective and sustainable nitrogen treatment in regions where anammox technology has not yet been applied. The findings highlight the potential for localized wastewater treatment using indigenous microbial communities, with microbial analysis revealing the predominance of Candidatus Brocadia on the carriers, supporting stable nitrogen removal even under increasing loading rates. These insights emphasize the value of exploring adaptations that can enable effective operation under a broad range of temperature conditions.