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Updated: Jul 4, 2026

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities

A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities

Published on: December 25, 2015

Feast/famine growth environments and activated sludge population selection.

S C Chiesa¹, R L Irvine, J F Manning

¹Department of Civil and Mineral Engineering, University of Minnesota, Minneapolis, Minnesota 55455.

Biotechnology and Bioengineering

|May 1, 1985

Summary

Feast/famine growth conditions select for nonfilamentous activated sludge with improved settling and starvation resistance. Optimizing substrate and endogenous metabolism enhances sludge activity and settleability.

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Area of Science:

Environmental Science
Microbiology
Biotechnology

Background:

Activated sludge is a key wastewater treatment process.
Understanding microbial community dynamics is crucial for optimizing treatment efficiency.
Feast/famine growth cycles are inherent in many biological systems.

Purpose of the Study:

To investigate the impact of feast/famine growth conditions on activated sludge microbial communities.
To determine if specific operating strategies can select for desirable sludge characteristics.
To explore the relationship between sludge activity, settleability, and starvation resistance.

Main Methods:

Culturing activated sludge under controlled feast/famine conditions.
Manipulating substrate gradients and endogenous metabolism periods.
Measuring substrate and oxygen uptake activities.
Assessing sludge settling rates and starvation resistance.

Main Results:

Nonfilamentous activated sludge cultures were successfully selected under optimized feast/famine conditions.
Intermittent high substrate concentrations led to high peak activities and rapid settling.
Sludge settleability was directly influenced by controlled variations in the growth environment.
Selected cultures exhibited enhanced resistance to starvation.

Conclusions:

Feast/famine growth conditions provide a selection advantage for microbes in activated sludge.
Optimized reactor operating strategies can enhance sludge settleability and activity.
Understanding microbial selection under dynamic growth is vital for wastewater treatment.
This approach offers a method to improve activated sludge performance and resilience.