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Related Experiment Video

Updated: May 11, 2026

Immobilization of Multi-biocatalysts in Alginate Beads for Cofactor Regeneration and Improved Reusability

Immobilization of Multi-biocatalysts in Alginate Beads for Cofactor Regeneration and Improved Reusability

Published on: April 22, 2016

Fouling mitigation in membrane bioreactors using multivalent cations.

Mohammad Reza Mehrnia¹, Hamed Azami, Mohammad Hossein Sarrafzadeh

¹Biotechnology Group, School of Chemical Engineering, College of Engineering, University of Tehran, Tehran, Iran. mmehrnia@ut.ac.ir

Colloids and Surfaces. B, Biointerfaces

|April 30, 2013

Summary

Mineral cations significantly impact activated sludge properties and reduce membrane fouling in bioreactors. Multivalent cations enhance flocculation and settling, while monovalent cations are detrimental, offering insights for MBR optimization.

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Last Updated: May 11, 2026

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Published on: February 13, 2016

Area of Science:

Environmental Science
Water Treatment Engineering
Biotechnology

Background:

Submerged membrane bioreactors (MBRs) are crucial for wastewater treatment.
Activated sludge properties significantly influence MBR performance and membrane fouling.
Understanding cation effects is vital for optimizing MBR operations.

Purpose of the Study:

To investigate the impact of various cations on activated sludge characteristics.
To assess the influence of cations on membrane fouling in MBRs.
To develop correlations for predicting activated sludge properties and membrane fouling.

Main Methods:

Studied flocculability and settling of activated sludge with different cation concentrations (Na+, K+, Mg2+, Ca2+, Fe3+, Al3+).
Analyzed extracellular polymeric substances (EPS) ratios (tight-bound vs. loosely-bound).
Utilized 2-way ANOVA for statistical analysis and developed predictive correlations.

Main Results:

Multivalent cations (Ca2+, Al3+, Fe3+) improved activated sludge flocculability, settleability, and dewatering.
Monovalent cations (Na+, K+) negatively affected sludge flocculability.
Increased tight-bound EPS correlated with multivalent cation concentration and enhanced biosorption.
Calcium and aluminum reduced membrane fouling by approximately 30%.

Conclusions:

Multivalent cations are beneficial for activated sludge performance and mitigating membrane fouling in MBRs.
The ratio of tight-bound to loosely-bound EPS and floc size distribution are key factors in membrane fouling.
Developed correlations provide a simple method for estimating activated sludge properties and membrane fouling potential.