Nanofiltration for Wastewater Recovery

A U.S. medical device manufacturer wanted to expand production capacity without exceeding discharge limits that could result in crippling financial penalties. It also wanted to drastically reduce raw water requirements and waste disposal costs. The plant was producing a 375-gal-per-minute (gpm) waste stream containing organic and inorganic manufacturing byproducts. The manufacturer’s goals were: recover water stream at a higher quality than the plant’s feedwater for use as feed water; reduce a certain proprietary organic contaminant to less than 1 part per million (ppm); reduce another organic contaminant to less than 5 parts per billion (ppb); reduce bacteria to less than 100 colony-forming units per milliliter.

Solution

Evoqua provided a nanofiltration pilot system that could meet the specific organic and ionic rejection and cost-efficiency goals. The design included activated carbon, nanofiltration, a sanitization station for microbial control, water storage/distribution and ozonation for organic and microbial control. The pilot study showed that the nanofiltration system was the best technology for this wastewater stream recovery and reuse and performed exactly as designed and predicted.

Results

The new system successfully recovers 80% (300 gpm) of the 375-gpm complex waste stream, producing a new permeate stream that is superior to the plant’s feedwater stream.  This eliminates 300 gpm of feedwater requirements and the need to dispose of 300 gpm of a complex waste, thus saving the plant over 52 million gal of feedwater per year and reducing waste disposal by more than 52 million gal per year. These improvements allow the plant to achieve its mandate to reduce water consumption by 10%, while still expanding medical device production. The plant’s water reuse system saves approximately $3.36 million over a 10-year period. The success of this system has resulted in duplicate, or closely related, system designs around the globe for this progressive pharmaceutical company.