Challenge

Increased demand led this fab to look for methods to increase available water for consumption while minimizing initial capital cost and floor space.

Solution

The system consisted of a makeup system utilizing triple pass RO, UV, degasification, mixed beds, etc.  Expanding this equipment to allow for more water availability in the loop would require a noticeable increase in the capital and operating costs, and consume a distinct amount of floor space that was not readily available.  The polishing system consisted of a UF of which 5% of the UF reject would feed back ahead of the 2nd pass RO for small particle reduction.

By installing a reject UF in the reject line, 95% of the reject flow was directed back directly to the UPW tank thereby reducing the load on the makeup system.  The remaining reject stream continued to feed back ahead of the makeup ROs.

Results

The reject UF was able to take 74 gpm of the reject stream and recover 95% (70 gpm) and direct the permeate directly back to the UPW storage tank resulting in an immediate makeup capacity boost of 70 gpm.  The ongoing makeup system expansion to handle an additional makeup demand costs about $2,300,000 ($1,350,000 equipment plus $950,000 installation) for 284 gpm ($8,100/gpm).  An additional 70 gpm at the above rates would have cost about more than $567,000 installed as compared to less than $150,000 for the reject UF installed. 

This resulted in:

• An installed equipment savings of >$417,000 (65% reduction); $230,000 in equipment savings
• Increased quality and operation reliability by reducing the makeup demand
• Reduced operating cost (power for ROs, makeup RO membrane and mixed bed resin costs, manpower for makeup maintenance, etc.)
• Minimal floor space consumption (15 sq. ft. plus access area)
• Quicker upgrade than a major makeup system expansion
• This was a very quick, simple and inexpensive way for the customer to increase makeup capacity by about 10%.  The customer is taking this concept and applying it elsewhere in their global facilities