The Effect of Pulsed Direct Current Field on the Membrane Flux of a New Style of Membrane Bioreactor

✍ Scribed by J.-P. Chen; C.-Z. Yang; J.-H. Zhou

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 121 KB
• Volume: 30
• Category: Article
• ISSN: 0930-7516
• DOI: 10.1002/ceat.200600266

✦ Synopsis

Abstract

The effect of a pulsed direct current electric field on the membrane flux of an antifouling Membrane Bioreactor (MBR) designed and built in the laboratory was studied. The results showed that a pulsed direct current electric field had a significant effect on the membrane flux. The average membrane flux when using a pulse direct current electric field was between that of a steady electric field and that of no electric current under a trans‐membrane pressure drop of Δ__P__ = 0.1 MPa and a pulsed direct current electric field strength of 20 V/cm. There was an optimum value of pulse intensity and pulse duration for the membrane flux. The shorter the pulse interval time was, the higher the frequency of power‐on, and the higher the average stable membrane flux of the MBR. This may have resulted from the fact that charged coarse particles and colloids account for 80 % of COD~cr~ and BOD~5~ in urban domestic sewage. These particles and colloids moved away from the membrane surface at a certain electrical field strength, gradually thinning the particle sedimentary layer, reducing the membrane filtration resistance, and increasing the membrane flux significantly. However, the formation of a sedimentary layer on the membrane surface needed a significant amount of time and an appropriate pulse frequency while the MBR is powered on. This could save energy while keeping the membrane clean.