EBPR using crude glycerol: assessing process resiliency and exploring metabolic anomalies

Area of Science:

• Environmental microbiology
• Biotechnology
• Wastewater treatment

Background:

• Enhanced biological phosphorus removal (EBPR) relies on cyclical anaerobic/aerobic conditions and volatile fatty acids (VFAs).
• Phosphorus accumulating organisms (PAOs) are key to EBPR, driving excess phosphorus removal.
• Crude glycerol (CG), a biodiesel byproduct, is explored as a potential VFA substitute.

Purpose of the Study:

• To investigate the efficacy of crude glycerol (CG) as a substrate for enhanced biological phosphorus removal (EBPR).
• To analyze the metabolic behavior of phosphorus accumulating organisms (PAOs) when utilizing CG under EBPR conditions.
• To determine if theoretical EBPR metabolisms are strictly required for successful phosphorus removal using CG.

Main Methods:

• Cultivating microorganisms under alternating anaerobic and aerobic conditions.
• Supplementing the growth medium with crude glycerol (CG) as the primary carbon source.
• Monitoring phosphorus uptake and release, and analyzing carbon cycling patterns.

Main Results:

• Crude glycerol (CG) supported successful enhanced biological phosphorus removal (EBPR).
• Unexpectedly, anaerobic phosphorus release was not a mandatory step for EBPR with CG.
• Carbon cycling aligned with theoretical EBPR models, indicating PAOs prioritize energy generation.
• Effective phosphorus removal was achieved with a minimal population of PAOs.

Conclusions:

• Crude glycerol (CG) is a viable and effective substrate for enhanced biological phosphorus removal (EBPR).
• The metabolic pathways of PAOs can adapt, demonstrating that traditional anaerobic phosphorus release is not always essential for EBPR.
• These findings suggest flexibility in EBPR processes and highlight CG as a promising sustainable resource for wastewater treatment.