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Published on: October 26, 2021
Oxygen uptake rate tests to evaluate integrated fixed film activated sludge processes
Carol L A Maas1, Wayne J Parker, Raymond L Legge
1Hydroxyl Systems Inc., 26 Bastion Square, Victoria BC, Canada, V8W 1H9. clamaas@gmail.com
Summary
A new oxygen uptake rate (OUR) test helps monitor integrated fixed-film activated sludge (IFAS) startup. This method reveals nitrification activity faster than traditional biofilm solids measurements.
Area of Science:
- Environmental Engineering
- Wastewater Treatment
- Microbiology
Background:
- Integrated Fixed-Film Activated Sludge (IFAS) processes combine suspended growth and biofilm treatment.
- Monitoring IFAS startup is crucial for efficient wastewater treatment plant operation.
- Traditional methods for assessing biofilm activity can be slow to reflect process changes.
Purpose of the Study:
- To develop and validate a modified oxygen uptake rate (OUR) test for IFAS performance characterization.
- To compare OUR test results with other key performance indicators during IFAS startup.
- To investigate dynamic changes in physical and microbiological parameters during IFAS process startup.
Main Methods:
- A modified oxygen uptake rate (OUR) test was implemented.
- Data collected included total biofilm solids, in-basin nitrification rates, and batch nitrification rates.
- These parameters were compared against OUR test results during the startup of a full-scale IFAS facility.
Main Results:
- Nitrification on carriers showed different trends compared to total biofilm solids during startup.
- High nitrification rates were achieved within weeks of startup.
- Biofilm total solids required over 50 days to reach a quasi-steady-state, indicating slower development than nitrification activity.
Conclusions:
- Assessing nitrifying IFAS processes requires parameters beyond just total biofilm solids.
- The modified oxygen uptake rate (OUR) test is a valuable tool for monitoring IFAS activity and startup dynamics.
- OUR measurements provide a more rapid assessment of biological activity in IFAS systems.
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