AWWA ACE68684

Low pressure membranes (LPMs), ultrafiltration (UF), and microfiltration (MF) areincreasingly being used globally for drinking water treatment to remove particulates andmicrobiological contaminants. Viruses in drinking water are smaller than the nominal pore sizeof MF and some UF membranes. Even so, laboratory studies and field experience demonstratethat enteric viruses are indeed removed by LPMs. To perform properly, membranes must remainintact. Imperfections introduced during manufacturing and handling typically cause holes ormacro-pores in membrane surfaces. Compromised membranes allow passage of viruses andother contaminants across the membrane barrier directly into permeate.A numerical particle tracking model was developed to assess the significance of holes and largemacro-pores on virus passage through LPMs. Modeling predictions are compared to the resultsof virus rejection studies using two MF and two UF flat-sheet membranes challenged with MS2and PRD1 phage. The membranes tested have different characteristics (monomer, nominal poresize, thickness, hydrophobicity, and resistance). Large hole challenge tests were conducted usingneedle-compromised membranes. A small hole challenge test was conducted on an Excimerlaser-drilled UF hydrophilic membrane. This is the first such model to assess virion passage through small holes in polymeric membranesurfaces. The implications for full-scale MF and UF systems and recommendations for futureresearch are presented in this powerpoint presentation. Includes tables, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2008

Number of Pages:

23

File Size:

1 file , 2.1 MB