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Microbial selection on enhanced biological phosphorus removal systems fed exclusively with glucose
Shamim A Begum1, Jacimaria R Batista
1Department of Chemical Engineering, Tuskegee University, 522E Luther Foster Hall, Tuskegee, AL 36088, USA. begums@mytu.tuskegee.edu
World Journal of Microbiology & Biotechnology
|July 19, 2012
Summary
Glucose supplementation in enhanced biological phosphorus removal (EBPR) systems may favor glycogen accumulating organisms (GAOs) over polyphosphate accumulating organisms (PAOs), potentially hindering phosphorus removal efficiency.
Area of Science:
- Environmental microbiology
- Wastewater treatment
- Biotechnology
Background:
- Enhanced biological phosphorus removal (EBPR) systems are crucial for nutrient management in wastewater treatment.
- The selection of microbial communities, particularly polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs), significantly impacts EBPR efficiency.
- Carbon source availability is a key factor influencing microbial selection in EBPR systems.
Purpose of the Study:
- To investigate the microbial selection dynamics in an EBPR system when exclusively fed glucose as the carbon source.
- To assess the impact of glucose on the relative abundance of key PAOs and GAOs.
- To determine the suitability of glucose as a supplementary carbon source for EBPR systems.
Main Methods:
- A laboratory-scale sequencing batch reactor (SBR) was operated using glucose as the sole carbon source.
- Fluorescence In Situ Hybridization (FISH) was employed to quantify the relative abundance (% RA) of specific PAOs (Candidatus Accumulibacter phosphatis, Microlunatus phosphovorus) and GAOs (Candidatus Competibacter phosphatis, Micropruina glycogenica).
- Monitoring of phosphorus removal efficiency throughout the experimental period.
Main Results:
- Glucose supplementation did not consistently select for Candidatus Accumulibacter phosphatis; its % RA decreased significantly over time.
- Microlunatus phosphovorus, Candidatus Competibacter phosphatis, and Micropruina glycogenica (GAOs) showed potential for selection, with maximum % RA of 21%, 37%, and 17%, respectively.
- A dominance of GAOs over PAOs was observed, correlating with a deterioration in phosphorus removal, potentially due to low pH conditions favoring GAO glycogen utilization.
Conclusions:
- Glucose alone is not an optimal carbon source for promoting PAO dominance and efficient phosphorus removal in EBPR systems.
- GAOs appear to outcompete PAOs under glucose-fed conditions, especially at low pH.
- Supplementation with volatile fatty acids is likely more beneficial for EBPR systems than glucose.
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