Microfiltration membrane material properties and surface water characteristics: effects on membrane fouling

Abstract

"Surface water can be challenging to treat due to high concentrations of organic matter. Membrane filtration produces high quality effluent but membrane fouling reduces system efficiency. A bench-scale, dead end filtration system was used to investigate the fouling effects of natural source waters on microfiltration flat sheet membranes. Membrane materials were selected to represent a range of surface charge characteristics and hydrophobicity. The source waters included an arctic lake, a subarctic river, as well as modified water samples, pre-filtered to include only the dissolved organics, or with deliberately changed pH values. Bench-scale results were compared with a pilot-system's seasonal performance. Resistance was shown to increase linearly over time. A resistance model was a good fit to bench scale membrane filtration runs. Membrane material was shown to be more important to membrane fouling than pH or season. Overall the charged, hydrophilic membranes performed the best, with the lowest fouling rate. Hydrophobic membranes had the highest fouling rate. Solution pH was found to affect membrane fouling rates. Influent pH adjustment improved filtration performance for some source waters and not others. The pilot system performance would have been improved by pH adjustment"--Leaf iii