An innovative strategy for inducing Anammox from partial nitrification process in a membrane bioreactor

Area of Science:

• Environmental Science
• Microbiology
• Nanotechnology

Background:

• Anaerobic ammonium oxidation (Anammox) is a key process for biological nitrogen removal.
• Optimizing Anammox bacteria activity is crucial for efficient wastewater treatment.

Purpose of the Study:

• To investigate the feasibility of using copper oxide nanoparticles (CuO NPs) to induce Anammox in a membrane bioreactor (MBR).
• To establish an autotrophic nitrogen removal system using CuO NPs.

Main Methods:

• Step-wise addition of CuO NPs to an MBR-based partial nitrification system.
• Monitoring bacterial abundance (Nitrosomonas, Candidatus Kuenenia) and nitrogen removal rate (NRR).
• Evaluating CuO NPs removal, transformation, and adsorption within the system.

Main Results:

• Anammox was successfully induced at 5 mg L^-1 CuO NPs.
• Relative abundance of Nitrosomonas and Candidatus Kuenenia increased significantly.
• Optimal NRR of 0.56 kg m^-3 d^-1 achieved with 20 mg L^-1 CuO NPs, but higher concentrations (50 mg L^-1) were inhibitory.

Conclusions:

• Low concentrations of CuO NPs (5 mg L^-1) effectively induce Anammox and support Anammox bacteria survival.
• CuO NP aggregation facilitates attached growth of Anammox bacteria and provides a suitable MBR environment.
• CuO NPs show potential for enhancing autotrophic nitrogen removal systems.