AWWA MTC69695

The objective of this powerpoint presentation was to study membrane fouling by algae. An algal bloom was created in the laboratory, and fluorescence microscopy was used to evaluateand count phytoplankton cells. The effects of shear on cells was studied by passing cells through a valveorifice at high pressure, and monitored the cell breakup with flow cytometry. Cell number decreased over time whilesmall-particle concentration increased. Fluorescence and absorbance increased withshear. The results were similar with 100-kDa ultrafiltration. Hermia's models (1982) were used to evaluatedifferences in fouling mechanisms. The best data fit was obtained for each model ineach membrane filtration experiment. Models moved from complete blocking towardcake filtration before and after shear, respectively, and rejection of carbohydrates decreased after shear. Conclusions indicate that:algal populations have a distribution of cellstructural strength; the strength distributiondetermines breakup under shear;an increased understanding was gained of howHermia's models apply to filtration of naturalsystems; shear is detrimental to pretreatment membraneproductivity; and,shear decreases rejection of organic matter,which is detrimental to downstream ROmembranes. Includes table, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2009

Number of Pages:

25

File Size:

1 file , 2 MB