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Poster title Performance and Mechanisms of Ultrafiltration Membrane Fouling Mitigation in a Novel Electrochemical Membrane Reactor (EMR)
Poster code P 3.14
Authors
  1. Chengzhi Hu University of Chinese Academy of Sciences Presenter
Form of presentation Poster
Topics
  • 3. Solving water reuse bottlenecks
    • 3.03 Innovative treatment technologies and applications
Abstract text Effective strategies for fouling mitigation are highly desirable to improve the efficiency and applicability of ultrafiltration (UF) systems.1 Applying EC as a pretreatment step is one of the promising solutions to control UF membrane fouling. The properties of flocs generated by EC have a significant influence on the structure of membrane cake layers and the extent of membrane fouling. Oxidation of HA can effectively alleviate membrane fouling due to the decrease of the molecular weight. By applying a dimensionally stable anode in an electrochemical reactor, direct oxidation would occur on the surface of the anode. In addition, if the electrolyte contained chloride ion, the chloride ion would be transformed into active chlorine and further oxidize foulants in solution. Besides, the applied electric field has also been considered as an efficient method to reduce membrane fouling, 2 which was distributed between electrodes in electrochemical system.
A novel electrochemical membrane reactor (EMR), in which electrochemical reaction (both coagulation and oxidation) were integrated into one reactor, was designed to reduce membrane fouling. The ultrafiltration (UF) membrane module was placed in the electric field zone between the electrodes in electrochemical system. EMR showed better anti-fouling performance with higher electric field due to the formation of a more polarized cake layer. The cake layer formed under higher electric field strengths showed higher porosity and hydrophilicity. Oxidation also modulated the porosity of the cake layer by breaking up humic acid (HA) molecules (i.e., carboxylic functional groups and aromatic structures). The formation of HA-floc in EC improved the hydrophilicity of the formed cake layer, leading to the enhanced alleviation of membrane fouling. Further, we proposed a novel electro membrane bioreactor (eMBR) that coupled the electrochemical process with membrane bioreactor (MBR). The removal rate of contaminates was enhanced and the evolution of the membrane fouling was mitigated by the electrochamical reactions (electrocoagulation and electroflotation) and the effect of the electric field between the electrodes. The released iron ions effectively inhibited the evolution of membrane fouling and improved the removal rate of phosphate. The polarized cake layer under electric field on the membrane surface exhibited a higher porosity, which benefited the water permeability. The activity of the microorganism was promoted and the production of extracellular polymeric substances (EPS) were reduced due to the effect of the micro electric field.The water flux and the total phosphorus (TP) removal in eMBR was 23.1% and ~50% higher in comparison with the traditional MBR, respectively.