Role of phosphorus in activated sludge
1Department of Civil Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
Biotechnology and Bioengineering
|August 1, 1982
Summary
Monod
Area of Science:
- Environmental Microbiology
- Biochemical Engineering
- Wastewater Treatment
Background:
- Phosphorus is a critical nutrient for microbial growth in activated sludge systems.
- Understanding phosphorus limitation is key to optimizing wastewater treatment processes.
- Activated sludge composition is significantly influenced by nutrient availability.
Purpose of the Study:
- To correlate the specific growth rate of mixed activated sludge with phosphorus limitation using Monod's kinetic model.
- To investigate the impact of phosphorus availability on sludge composition and substrate utilization in batch and continuous-flow systems.
- To establish relationships between kinetic constants derived from batch studies and cell yield in continuous-flow systems.
Main Methods:
- Application of Monod's kinetic model to batch and continuous-flow activated sludge cultures.
- Controlled variation of the COD:P ratio and temperature (25°C) in batch reactors.
- Analysis of substrate utilization, biological solids production, and sludge composition in continuous-flow systems.
Main Results:
- An inverse relationship was observed between specific growth rate and cell yield.
- Maximum specific growth rate and saturation constant were determined for phosphorus limitation.
- Phosphorus-limited sludge exhibited high carbohydrate and low protein content, with capsule formation under severe restriction.
- Substrate utilization and sludge production in continuous-flow systems were influenced by the phosphorus source.
Conclusions:
- Monod's model effectively describes phosphorus-limited growth kinetics in activated sludge.
- Sludge composition, particularly carbohydrate and protein content, is sensitive to phosphorus availability.
- Kinetic constants from batch studies can predict cell yield in continuous-flow systems, aiding process optimization.
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