Illinois Water Environment Association
Date/Time
3/5/2026
12:00 PM - 1:00 PM Central
12:00 PM - 1:00 PM Central
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Event Description
Elucidating the Impact of Low Dissolved Oxygen on Enhanced Biological Phosphorus Removal Under Aerobic and Anoxic Conditions at Full Scale
Thursday March 5, 2026
Noon to 1 p.m.
Zoom webinar
In this webinar, Riley Doyle will present her full-scale research on the impact of low dissolved oxygen (DO) on biological phosphorus removal. Her work at Hampton Roads Sanitation District’s (HRSD) Virginia Initiative Plant (VIP) shows that elevated aerobic DO concentrations can rapidly and persistently impair biological phosphorus removal, while sustained low-DO operation improves phosphorus removal performance, promotes polyphosphate-accumulating organisms (PAOs), and enables anoxic phosphorus uptake. Notably, improvements in effluent orthophosphate concentrations were observed even after the elimination of chemical phosphorus precipitation, highlighting the strength of the biological response. These findings challenge conventional high-DO design assumptions and identify low-DO operation as a pathway to more stable and energy-efficient nutrient removal.
Key findings presented in this webinar include:
Speaker: Riley Doyle, EIT PhD Candidate Water Engineering at Université Laval, doctoral research in collaboration with Hampton Roads Sanitation District (HRSD)
Riley Doyle is a PhD candidate in Water Engineering at Université Laval, conducting her doctoral research in collaboration with HRSD. Her PhD work is based on full-scale research at HRSD’s Virginia Initiative Plant. She holds an MS in Environmental Engineering from Virginia Tech and a BS in Environmental Engineering from Bucknell University. Her research focuses on optimizing biological phosphorus removal at full-scale facilities, the role of internally stored carbon in post-anoxic denitrification, and process modeling to evaluate CO₂ volatilization under different alkalinity addition scenarios. Riley is passionate about applying biological understanding to practical challenges in wastewater treatment, water quality, and resource recovery.
Noon to 1 p.m.
Zoom webinar
In this webinar, Riley Doyle will present her full-scale research on the impact of low dissolved oxygen (DO) on biological phosphorus removal. Her work at Hampton Roads Sanitation District’s (HRSD) Virginia Initiative Plant (VIP) shows that elevated aerobic DO concentrations can rapidly and persistently impair biological phosphorus removal, while sustained low-DO operation improves phosphorus removal performance, promotes polyphosphate-accumulating organisms (PAOs), and enables anoxic phosphorus uptake. Notably, improvements in effluent orthophosphate concentrations were observed even after the elimination of chemical phosphorus precipitation, highlighting the strength of the biological response. These findings challenge conventional high-DO design assumptions and identify low-DO operation as a pathway to more stable and energy-efficient nutrient removal.
Key findings presented in this webinar include:
- Improved Phosphorus Removal Under Low DO: Sustained low-DO operation resulted in lower and more stable effluent orthophosphate concentrations compared to higher-DO operation.
- Enhanced Biological Phosphorus Cycling: Batch testing demonstrated increased phosphorus release and aerobic uptake rates under low-DO conditions, indicating more efficient EBPR metabolism.
- Microbial Community Shifts: Reduced DO favored microbial populations associated with PAOs, directly linking operational strategy to improved biological performance.
- Anoxic Phosphorus Uptake: Measurable anoxic phosphorus uptake was observed, accounting for up to approximately 40% of aerobic uptake rates in some cases, suggesting opportunities to leverage post-anoxic processes for improved efficiency. This webinar will be particularly valuable for utilities, operators, engineers, and researchers seeking full-scale, data-driven strategies to meet increasingly stringent phosphorus limits while reducing aeration energy demand.
Speaker: Riley Doyle, EIT PhD Candidate Water Engineering at Université Laval, doctoral research in collaboration with Hampton Roads Sanitation District (HRSD)
Riley Doyle is a PhD candidate in Water Engineering at Université Laval, conducting her doctoral research in collaboration with HRSD. Her PhD work is based on full-scale research at HRSD’s Virginia Initiative Plant. She holds an MS in Environmental Engineering from Virginia Tech and a BS in Environmental Engineering from Bucknell University. Her research focuses on optimizing biological phosphorus removal at full-scale facilities, the role of internally stored carbon in post-anoxic denitrification, and process modeling to evaluate CO₂ volatilization under different alkalinity addition scenarios. Riley is passionate about applying biological understanding to practical challenges in wastewater treatment, water quality, and resource recovery.
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