Full Description

The application of membrane technology to drinking water treatment has been greatly limited by membrane fouling. Fouling increases operation and maintenance costs by deteriorating membrane performance and ultimately shortening membrane life. Among numerous potential foulants, colloidal particles are considered a major cause of membrane fouling in drinking water treatment. Our recent investigations into the causes and control of colloidal fouling in pressure-driven crossflow membrane filtration processes have focused on operational parameters such as flux and crossflow shear. The work presented in this paper investigates the effect of crossflow channel geometry on colloidal fouling of reverse osmosis and nanofiltration membranes, and comments on the concept of "critical flux." A series of well-controlled fouling experiments were carried out using several bench scale crossflow membrane filters, commercial flat-sheet membranes, and a suspension of silica colloids in a background electrolyte solution. The different crossflow filters afford a range of channel lengths, widths, and heights. In order to understand the effects of physical and chemical interactions, the investigation involved systematic variations of initial permeation rate, crossflow shear rate, crossflow channel height, particle feed concentration, and solution ionic strength. Results indicate that channel height has a dramatic influence on rate and extent of colloidal fouling. It is suggested that control of colloidal fouling may be achieved through determination of an optimal channel height for a given feed suspension. Includes 16 references, figures.

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Edition: Vol. - No. Published: 06/01/2001 Number of Pages: 7File Size: 1 file , 330 KB