Innovation and optimization of aeration in free bubbling flat sheet MBRs

Wang, Bing, Zhang, Yan, Zhang, Guixiao, Zhang, Kaisong and Field, Robert (2021) Innovation and optimization of aeration in free bubbling flat sheet MBRs. Journal of Membrane Science, 635. p. 119522. ISSN 0376-7388

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Free bubbling in flat sheet MBRs has been widely used in water treatment to control membrane fouling, however, the associated aeration cost discourages its wider application. To counter this drawback an innovative design of the aeration system is proposed and its evaluation indicates significantly high potential. The guiding aim is the establishment of sufficient shear stress in all membrane channels at an economical specific air demand (SADm). Based upon a validated Computational Fluid Dynamics (CFD) study, hydrodynamic features including shear stress, bubble size and the distribution of bubbles across neighboring channels were predicted for two designs. For both a mini 100-sheets commercial FSMBR (size of plates 448 mm × 245 mm) and a full-scale standard unit with 1800 mm × 490 mm plates, it was shown that sufficient hydrodynamic effect is induced with our modified free aeration design in a manner that moves beyond seeking to achieve bland uniformity between channels. The optimal configuration featured a channel gap at 5 mm and an aerator with an additional large side nozzle operating at an inlet velocity of 2.6 m/s. Such an arrangement would cover 12 channels. Through optimization the air consumption was successfully reduced giving a SADm of 0.28 Nm3m-2h-1, corresponding to 46% reduction with respect to traditional industrial usage of 0.51 Nm3m-2h-1.

Item Type: Article
Additional Information: Funding information: This work was supported by grants from the National Key R&D Program of China (2018YFC1903205), Ministry of Science and Technology; the Bureau of Frontier Sciences and Education (QYZDB-SSW-DQC044); the Bureau of International Cooperation (132C35KYSB20160018); the Chinese Academy of Sciences and the Joint Project between CAS-CSIRO (132C35KYSB20170051); FJIRSM&IUE Joint Research Fund (No. RHZX-2019-002); the Fundamental Research Funds for the Central Universities, Nankai University (0085). The authors would like to thank the grant of “antifouling membranes and slug bubbling flat sheet membrane bioreactors for the next generation wastewater treatment” and Oxiamembrane Co.Ltd for technical support. RWF acknowledges the support provided by an APEX project on water reuse that has been supported by the Royal Society in partnership with the British Academy and the Royal Academy of Engineering together with generous support from the Leverhulme Trust. The authors also thank Mr. Xingbiao Chen and Dr. Olusegun Abass for their help and industrial perspective.
Uncontrolled Keywords: Flat sheet MBR, Free bubbling, CFD, Fouling control, Economical air consumption
Subjects: H300 Mechanical Engineering
Department: Faculties > Engineering and Environment > Mechanical and Construction Engineering
Depositing User: Elena Carlaw
Date Deposited: 30 Jun 2021 12:15
Last Modified: 12 Jun 2022 03:30

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