Challenge

A Biotech firm on the West Coast has found that certain cell cultures fare poorly in distilled water, yet thrive in reverse osmosis water.  Another requirement is to optimize water conservation.

Solution

USFilter, now Siemens, engineered a novel design, including reverse osmosis, service deionization, and a second pass reverse osmosis.

• The RO/SDI/RO system is hot water sanitizable to assure ultra-low microbial counts.
• The FDA has historically required two passes of reverse osmosis to produce WFI.  The first pass RO / SDI produces USP Purified Water.  A portion of this water feeds the second (single pass) RO to produce WFI.
• The second RO runs at effectively 100% recovery (the entire waste stream is recycled back to the pretreatment breaktank).   The recovery at the membrane surface is low to minimize fouling and maintenance while assuring product water quality.

Results

• Cell culture process yield is optimal
• Quality – the system consistently exceeds the requirements for WFI.
• The price of the second RO was about half of the cost of a still.
• Operating costs - Steam savings of 98% compared to that of a still
• Saves 1.3 million gallons per year in water and sewer charges compared to a still.