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Updated: Jun 14, 2026
06:42
Measuring Phosphorus Release in Laboratory Microcosms for Water Quality Assessment
Published on: July 22, 2019
Uncertainty and variability in enhanced biological phosphorus removal (EBPR) stoichiometry: consequences for process
Dwight Houweling1, Yves Comeau, Imre Takács
1EnviroSim Associates, Flamborough, ON L9H 7H9, Canada. dwight@envirosim.com
Summary
Enhanced biological phosphorus removal (EBPR) is limited by volatile fatty acids (VFAs). Aerobic metabolism stoichiometry significantly impacts EBPR efficiency, more than anaerobic changes, affecting polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) competition.
Area of Science:
- Environmental Science
- Microbiology
- Biotechnology
Background:
- Enhanced biological phosphorus removal (EBPR) is crucial for wastewater treatment.
- The availability of volatile fatty acids (VFAs) is a primary constraint on EBPR.
- Polyphosphate accumulating organisms (PAOs) are key players in EBPR, utilizing VFAs.
Purpose of the Study:
- To investigate the stoichiometric factors influencing EBPR efficiency in activated sludge systems.
- To determine the relative impact of anaerobic versus aerobic metabolism on EBPR performance.
- To understand the long-term performance changes and competition dynamics between PAOs and GAOs under P-limitation.
Main Methods:
- Model-based analyses of activated sludge systems.
- Experimental studies using a sequencing batch reactor (SBR) under phosphorus (P)-limitation.
- Investigation of stoichiometric ratios governing PAO metabolism.
Main Results:
- Variability in aerobic stoichiometry was found to have the greatest impact on EBPR performance.
- Long-term EBPR deterioration under P-limitation can be predicted by PAO-GAO competition.
- A rapid decrease in phosphorus release after feed composition changes was observed, not fully explained by gradual population shifts.
Conclusions:
- Aerobic stoichiometry is a critical factor for optimizing EBPR.
- Understanding PAO-GAO competition is essential for maintaining EBPR stability.
- Further research is needed to explain rapid performance declines following feed alterations.
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