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Feast/famine ratio determined continuous flow aerobic granulation
Yewei Sun1, Bob Angelotti2, Matt Brooks2
1Occoquan Laboratory, Department of Civil and Environmental Engineering, Virginia Tech, 9408 Prince William Street, Manassas, VA 20110, USA; Hazen and Sawyer, 4035 Ridge Top Road, Suite 500, Farfax, VA 22030, USA.
The Science of the Total Environment
|August 28, 2020
Summary
Aerobic granulation in wastewater treatment requires a specific feast/famine ratio. Continuous flow aerobic granulation failed when the feast/famine ratio exceeded 0.5, indicating its critical role.
Area of Science:
- Environmental Engineering
- Biotechnology
- Wastewater Treatment
Background:
- Aerobic granules are crucial for efficient wastewater treatment.
- Plug flow reactors (PFRs) simulate feast/famine conditions essential for granulation.
- Understanding feast/famine dynamics is key to optimizing granulation processes.
Purpose of the Study:
- To investigate the impact of feast/famine ratios on aerobic granulation in continuous flow systems.
- To determine the critical feast/famine ratio for successful aerobic granulation.
- To evaluate the role of PFR configurations in modulating feast/famine conditions.
Main Methods:
- Cultivating aerobic granules in PFRs with varying numbers of completely stirred tank reactors (CSTRs) in series (4, 6, and 8 chambers).
- Applying consistent gravity selection pressure and hydraulic retention time.
- Analyzing sludge characteristics including particle size, circularity, settleability, specific gravity, zone settling velocity, and extracellular polymeric substance content.
Main Results:
- Aerobic granulation failed to establish when the feast/famine ratio was greater than 0.5.
- Different PFR configurations influenced the feast/famine patterns.
- Sludge properties were evaluated to correlate with granulation success.
Conclusions:
- The feast/famine condition is a likely prerequisite for continuous flow aerobic granulation.
- Maintaining a feast/famine ratio below 0.5 is essential for successful granulation.
- PFR design significantly impacts the feast/famine regime and granulation outcomes.
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