Membrane Ultrafiltration: Waste Treatment
Application For Water Reuse
D. BHATTACHARYYA, Associate Director
K.A. GARRISON, Graduate Student
P.J.W. THE, Post Doctoral Fellow
R.B. GRIEVES, Chairman
Department of Chemical Engineering
University of Kentucky
Lexington, Kentucky 40506
INTRODUCTION
Membrane ultrafiltration has been used successfully as an effective process for the
treatment of a large number of industrial wastes. The process is appropriate for applications requiring water recycle and reuse and particularly for systems in which the very
high rejection of low-molecular-weight solutes is not warranted. Ultrafiltration is a
pressure-activated process and is generally carried out at low pressures of 105 to 106 N/m2.
The use of ultrafiltration for the separation of low-molecular-weight ionic solutes with
charged membranes (1), modest-molecular-weight (size) organic solutes (2, 3), and organic macromolecules and colloids (4) has been reported in the literature. Some of the
water reuse applications involving ultrafiltration include electrodeposition primers (5),
oil-water separation in metal cutting operations (6), and the renovation of sewage effluents (7). Porter and Nelson (4) have reviewed applications of ultrafiltration in the
chemical, food processing, and pharmaceutical industries. High pressure membrane processes such as reverse osmosis and hyperfiltration with dynamic membranes have also
been utilized in many water reuse and solute recovery systems (8, 9, 10).
The treatment of commercial laundry wastes by membrane processes for the purpose of water reuse is a very promising application. The use of reverse osmisis (11) and
ultrafiltration (3) for the treatment of laundry wastes containing anionic surfactants has
been reported in the literature. The present study primarily involves complex aqueous
suspensions containing nonionic surfactants. The objectives of this investigation are the
establishment of operating conditions to minimize concentration polarization and
membrane fouling, the achievement of adequate rejections of selected solutes, and the
development of a unique scale-up procedure involving membrane module arrangements
to obtain the high water recovery (up to 95%) essential in waste treatment. From the
experimental data obtained at very low water recovery, predictive design equations,
relating ultrafiltrate flux and the concentration of selected constituents in the ultrafil-
trate stream to the key independent variables, are generated by multiple linear regression analysis.
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