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Updated: May 10, 2026
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A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
pH variation and influence in an autotrophic nitrogen removing biofilm system using an efficient numerical solution
Anna Katrine Vangsgaard1, Miguel Mauricio-Iglesias, Borja Valverde-Pérez
1Computer Aided Process Engineering Center CAPEC, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Building 229, Søltofts Plads, 2800 Lyngby, Denmark.
Summary
A new pH simulator models nitritation-anammox processes in biofilms. It reveals how pH and ammonia gradients affect microbial activity within granules, crucial for wastewater treatment.
Area of Science:
- Environmental Microbiology
- Biogeochemical Modeling
- Wastewater Treatment Technologies
Background:
- Granular biofilms are key in wastewater treatment, particularly for nitrogen removal.
- Understanding micro-environmental conditions like pH is crucial for optimizing these processes.
- The nitritation-anammox process involves complex microbial interactions influenced by local chemical conditions.
Purpose of the Study:
- To develop and implement a pH simulator for granular biofilm models.
- To investigate pH profiles and their impact on the nitritation-anammox process within granules.
- To analyze the influence of operating conditions on pH and ammonia gradients.
Main Methods:
- Constructed an efficient numerical solver for nine nonlinear equations.
- Implemented the pH simulator in MATLAB and integrated it into a granular biofilm model.
- Simulated pH and ammonia profiles under various operating points.
Main Results:
- pH consistently increased with depth into the granule due to aerobic ammonium-oxidizing bacteria (AOB) near the surface.
- Higher oxygen loading led to steeper pH changes and increased ammonia availability towards the granule center.
- Initial background charge and bicarbonate concentration significantly impacted simulation outcomes.
Conclusions:
- The pH simulator provides insights into micro-environmental conditions within granular biofilms.
- pH gradients, while present, had a limited impact (≤5%) on the activity of pH-sensitive microbial groups.
- Accurate measurement of initial conditions is vital for reliable simulation results in nitritation-anammox processes.
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