Product News:  Water For Injectables (WFI)

   Applied Membranes commissioned a 2-pass RO System with an EDI (electrodeionization) to supply USP XXIV grade water for Injectables.  The system was designed with an FDA protocol and validated by a third party.  The system uses sanitary design and components.  The capacity of the system is 200,000 liters/day of WFI grade water.

     
         Applied Membranes has supplied numerous water treatment systems for various grades of USP XXIV water.

What is Nanofiltration?

Nanofiltration in concept and operation is very similar to reverse osmosis.  The key difference is the degree of removal of monovalent ions such as chlorides.  Reverse osmosis removes the monovalent ions at 98-99% level at 200 psi.  Nanofiltration membranes’ removal of monovalent ions varies from 50% to 90% depending on the material and manufacture of the membrane.  For this reason, there is a variety of nanofiltration membranes available.  Each type is specifically suited to a particular application and may not be acceptable for a different application.
    Nanofiltration membranes and systems are used for water softening, food and pharmaceutical applications.  For specifications and other information, visit the “membranes” section of our website.  www.appliedmembranes.com.  

For quantity pricing, contact our sales department.

Also available for online purchase at  www.wateranywhere.com

Technical Note By Dr. Dhawan
Suspended Solids

     Suspended solids and colloidal materials in feed water are one of the biggest problems in reverse osmosis systems.  Although most systems have some pretreatment, including 5-micron prefilters, these fine particles are responsible for the fouling of reverse osmosis membranes. 
     In order to measure the degree of this fouling problem, a concept called Silt Density Index is used.  Here filtration rates are calculated by exposing a 0.45-micron filter to the feed water under pressure.  A detailed description of the test is available at our technical website:  www.watertreatmentguide.com.
     An SDI of less than 5 is typically considered acceptable for the reverse osmosis systems.  This means membranes should foul at a very low rate at SDI values of less than 5.   Although this concept works most of the time, there are exceptions when a lower SDI (less than 3) is desirable due to the nature of the suspended solids in the feed water.
     An SDI measurement kit is available and is shown on our website. 

For more technical tips or to have your technical questions answered, visit our new technical site:  www.watertreatmentguide.com