The membranes used in VSEP™ systems are made of various polymers such as polyethersulfone, polyamides, and other thin film composites. VSEP™ systems routinely employ over 200 different types of membranes.
These membranes are available in a variety of sizes and configurations. In VSEP™ systems, the membranes are affixed to a steel tray and stacked in an array, much like a traditional plate and frame configuration.
Essentially, membranes allow some things to pass through while rejecting the rest. Thus, any feed stream sent to a membrane system such as a VSEP™ will be split into two. These two streams are called permeate and concentrate (these are sometimes referred to as product water and retentate, respectively).
The part of the stream that can pass through the membrane is called the permeate. The permeate is the "clean water". The part of the stream that is rejected by the membrane is called the concentrate. In a product recovery or concentration context, the concentrate is the desirable material; in a wastewater or product clarification application, the concentrate represents a concentrated slurry of undesirable contaminants.
More information can be found on New Logic Research's website: www.vsep.com