Sara Gabarrón Fernández will present her doctoral thesis "Diagnosis, assessment and optimisation of the design and operation of municipal MBRs" next 16th May at UdG Science Park. The thesis was directed by LEQUIA professors Dr Joaquim Comas and Dr Ignasi Rodríguez-Roda.
In recent years attention to wastewater treatment has increased using ever more advanced technologies such as membrane bioreactors (MBR). MBR technology provides a high quality effluent which is considered a valuable source of regenerated water. However, MBRs are still considered costly and more complex in design and operation than activated sludge systems with tertiary treatment. For this reason, further work is required in optimising MBR design and operation in order to be able to consider this technology not only technologically viable, but also economically viable.
The objective of this thesis was diagnosing, assessing and optimising the design and operation of membrane bioreactors used for treating municipal wastewater. Specifically, the thesis was carried out within the framework of a cooperation agreement with the Catalan Water Agency to study seven municipal wastewater treatment plants (WWTP) which use MBR technology in Catalonia.
Firstly, the design and operational issues of the MBRs were diagnosed together with the determination of the main operational problems related to this technology. Secondly, the optimisation strategies were applied in each full-scale MBR and the resulting costs were assessed. Once the diagnosis was completed, two of the operational problems identified in the Catalan MBRs were exhaustively evaluated: the ragging phenomenon, which consists on the textile fibre accumulation within or at the membrane channels, and the biological nitrogen removal and operational costs optimisations through model-based approaches.
The research carried out in this thesis has enabled the design and operation of the municipal MBRs in Catalonia to be assessed while, at the same time, presents several optimisation strategies which will improve the operation and costs of this technology.