Direct filtration of natural and simulated river water withair sparging and sponge ball application for fouling control [An article from: Desalination]

This digital document is a journal article from Desalination, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Membrane filtration is increasingly used for converting surface water to drinking water. This study investigatedthe effectiveness of air sparging in reducing fouling during direct membrane filtration of river water. Air spargingvia side-stream filtration in tubular membranes at crossflow velocities (CFV) between 0.5-1.0 m/s enhanced thepermeability by up to a factor of 4.6, given that the water used showed a high propensity of fouling. Sponge ballapplication to remove fouling proved, for model solutions with silt and clay, that chemical cleaning with NaOClcannot erase fouling on the membrane surface by 100%. Residual fouling, indicated by flux increase above theinitial flux observed after sponge ball cleaning, remains. Repeated sponge ball application appears to reduce theresidual fouling. In terms of seasonal water sampling, the fouling potential declined from spring to fall due to adecrease of natural organic matter (NOM), colloids and mineral load (indicated by total organic carbon and turbidity).Air sparging (AS) effectiveness, measured by the ratio of AS-enhanced versus non-enhanced permeability, decreasedwith the dwindling fouling potential of the raw water. When model solutions were investigated (silt 5 g/L and clay10 g/L), the enhancement factor for the silt slurry was less than that for the clay.