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Updated: Aug 14, 2026
08:13
A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Modelling nitrification, heterotrophic growth and predation in activated sludge
M S Moussa1, C M Hooijmans, H J Lubberding
1UNESCO-IHE Institute for Water Education, P.O. Box 3015, 2601 DA Delft, Netherlands. m.moussa@delft.environment.com
Water Research
|November 30, 2005
Summary
A new mathematical model for wastewater treatment was developed, incorporating predator interactions. This model accurately predicts biomass composition and the impact of sludge age on treatment processes.
Area of Science:
- Environmental Engineering
- Microbial Ecology
- Wastewater Treatment
Background:
- Existing activated sludge models lack detailed predation mechanisms.
- Understanding microbial community dynamics is crucial for optimizing wastewater treatment.
- Predators (protozoa, metazoa) play a significant role in activated sludge systems.
Purpose of the Study:
- To develop a novel mathematical model for wastewater treatment including nitrifiers, heterotrophs, and predators.
- To investigate the effect of sludge retention time (SRT) and predation on biomass composition.
- To calibrate and validate the model using long-term experimental data.
Main Methods:
- Development of a multi-substrate, multi-species mathematical model incorporating predation.
- Calibration and validation using data from two laboratory-scale sequenced batch reactors (SBRs) operated at different SRTs (30 and 100 days) over 4 years.
- Development of a respiration-based method to assess predator activity.
Main Results:
- The model successfully described the performance of the SBR systems.
- Predicted active biomass fractions were low: 33% at 30 days SRT and 14% at 100 days SRT.
- High inert biomass fractions were consistent with microscopic observations of biomass viability.
Conclusions:
- The developed model accurately represents the complex interactions within activated sludge communities.
- Increasing sludge age significantly impacts biomass composition, favoring inert biomass.
- Predation plays a crucial role in shaping the microbial community structure and overall treatment efficiency.
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