EBPR process dynamics under variable conditions: interaction between PAOs and the microbial community.

Area of Science:

• Environmental Microbiology
• Wastewater Treatment Engineering
• Biotechnology

Background:

• Enhanced biological phosphorus removal (EBPR) is crucial for nutrient management in wastewater treatment.
• Process conditions like carbon source, temperature, COD:P ratio, and pH significantly influence EBPR performance.
• Knowledge gaps exist regarding microbial diversity's role and the correlation between PAO/GAO communities and EBPR dynamics.

Purpose of the Study:

• To investigate the influence of different operational conditions on EBPR performance and microbial community dynamics.
• To identify the key microbial players, particularly PAOs and GAOs, involved in EBPR under varying conditions.
• To assess the relative importance of carbon source type versus other factors like temperature, COD:P ratio, and pH.

Main Methods:

• Utilized a microfluidic model biofilm system (MMBS) and a sequencing batch reactor (SBR) system.
• Evaluated EBPR performance using different carbon sources (glucose, glycerol, ethanol, amino acids).
• Analyzed microbial community composition, identifying dominant PAOs and GAOs.

Main Results:

• The type of carbon source exerted a more sensitive influence on EBPR dynamics than COD:P ratio, temperature, or pH.
• Glucose consumption led to maximal PAO activity; glycerol, ethanol, and amino acids limited EBPR performance.
• Dechloromonas was identified as the dominant PAO in both systems; Zoogloea (MMBS) and Competibacter/Contendobacter (SBR) were dominant GAOs.

Conclusions:

• Dechloromonas plays a critical role in EBPR, and carbon source selection is paramount for optimizing PAO activity.
• PAO-GAO competition appears to be overestimated, suggesting a need to re-evaluate microbial interactions in EBPR.
• Microbial diversity and community composition are highly relevant for EBPR system performance and application.