Challenge

A medical device manufacturer in the United States wanted to expand production capacity without exceeding discharge limits that could result in crippling financial penalties. A city mandate of 10% reduction in water consumption for industrial users challenged the plant's desire to expand as the water discharged from its operations was already rapidly approaching discharge limits. Additionally, it wished to drastically reduce its raw water requirements and waste disposal cost of operation.

The plant was producing a waste stream of 375 gallons per minute (GPM) containing organic and inorganic manufacturing by-products, which contaminated the process waste stream. Historically, this process waste stream would be sent to a waste treatment and disposal process. A significant reduction of this waste stream was required to facilitate plant growth without expanding the waste discharge.

The specifics for this water system include:

• 300 GPM make-up water requirement
• Operation: 7 hrs/day, 5 days/wk, 50 wks/yr
• Feed water cost: $1.33/1,000 gallons
• Wastewater discharge cost: $2.77/1,000 gallons
• Electrical cost: $0.05 kWh

Additional project goal requirements included:

• Recover water stream at a higher quality than the plant's feed water, for use as feed water
• Reduce organic contaminant #1 (proprietary) to less than 1 part-per-million (ppm)
• Reduce organic contaminant #2 (proprietary) to less than 5 parts-per-billion (ppb)
• Reduce the bacteria to less than 100 colony forming units (cfu) per milliliter

Solution

Evoqua Water Technologies was chosen for this project based on our extensive process knowledge, piloting capacity and full complement of filtration technologies to allow a comprehensive, integrated treatment package. The Vantage® M86N Nanofiltration System was selected based on specific organic and ionic rejection characteristics and cost-efficiency of operation.

The design included the following:

• Activated carbon to remove chlorine and specific organic #2
• Nanofiltration to remove specific organic #1 without removing selective inorganic compound
• Sanitization station for microbial control
• Storage/distribution of water
• Ozonation for organic and microbial control

The design solution was piloted to verify its capability to effectively remove the organic compound, maintain acceptable operating characteristics and avoid excessive cleaning or fouling. Additionally, the system would selectively pass a specific inorganic compound that was injected upstream and utilized for manufacturing. By not removing this inorganic constituent, the company could avoid the cost and complexity of re-injecting this pretreatment chemical.​

Results

After installation and piloting, the Vantage M86N Nanofiltration System proved to be the best-suited technology for this wastewater stream recovery and reuse, performing exactly as designed and predicted. 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 feed water system. This eliminates 300 GPM of feed water requirements and saves the plant more than 52 million gallons of feed water per year, respectively lowering waste disposal.

These improvements allow the plant to achieve its requirements to reduce water consumption by 10%, while still expanding production of medical devices. The plant's water reuse system saves approximately $3.36 million over a 10-year period. These savings do not include the regulatory penalties avoided or the financial impact of the facility's inability to grow in production capacity.

The tremendous success of this system has resulted in multiple related system designs around the globe for this progressive manufacturer.