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CHAPTER 13

MEMBRANE PROCESSES

Robert A. Bergman, P.E.
CH2M HILL
Gainesville, Florida

A wide variety of membrane processes can be categorized according to driving force,
membrane type and configuration, and removal capabilities and mechanisms. Membrane
processes in the drinking water industry are used for desalting, softening, dissolved or-
ganics and color removal, particle and microbial removal, and other purposes. Although
membrane technologies became commercially available more than 30 years ago, they are
experiencing rapid development and improvements.
Membranes are increasingly cost-effective with better performance characteristics, and
their applications continue to grow. For example, membrane filtration systems are now
used to remove Giardia, Cryptosporidium, and other particles from surface water supplies
and to treat backwash return waters from conventional water treatment plants.
This chapter is based on current state-of-the-art membrane system design criteria. Some
of the design data will undoubtedly change as new developments occur. The reader should
keep abreast of new developments in membranes and system components by attending
training seminars, reviewing publications and ongoing research reports, and contacting
manufacturers, consultants, and other professionals practicing in the field.

TYPES OF MEMBRANE PROCESSES

Membrane processes can be classified by the driving force used to promote the water
treatment
• Pressure
• Electrical voltage
• Temperature
• Concentration gradient
• Combinations of more than one driving force

13.1