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Updated: May 15, 2026
09:38
Updated Protocol for the Assembly and Use of the Minibioreactor Array (MBRA)
Published on: September 5, 2025
Ragging phenomenon characterisation and impact in a full-scale MBR.
S Gabarrón1, M Gómez, H Monclús
1University of Girona, Girona, Spain.
Summary
Clogging in membrane bioreactors (MBRs) is a major challenge. Manual cleaning effectively removes solids, but chemical methods are inefficient, and rapid reclogging occurs due to textile fibers.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Membrane Science
Background:
- Clogging, specifically ragging, is a significant operational challenge in membrane bioreactors (MBRs).
- Few studies address the clogging phenomenon in MBRs in peer-reviewed literature.
- This study investigates a full-scale MBR experiencing severe clogging.
Purpose of the Study:
- To evaluate the effectiveness of different cleaning methods for MBR clogging.
- To identify the primary cause of clogging in the studied MBR.
- To propose strategies for mitigating the impact of clogging.
Main Methods:
- Performance analysis of a full-scale MBR.
- Evaluation of acid and basic recovery cleaning methods.
- Assessment of manual cleaning and declogging procedures.
- Feedwater analysis for contaminants, particularly textile fibers.
Main Results:
- Acid cleaning was more effective than basic cleaning, but neither fully restored membrane permeability.
- Manual removal of accumulated solids was the only efficient cleaning method.
- Rapid reclogging occurred within 10 days after manual cleaning.
- Suspended textile fibers (>70% cotton) were identified as the main cause of ragging.
Conclusions:
- Chemical cleaning methods are largely ineffective against ragging-induced clogging in MBRs.
- Manual cleaning provides temporary relief, but rapid reclogging is a concern.
- Improving pre-treatment, manual cleaning, and reducing permeate flux are crucial for managing ragging impacts.
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