Challenge
CPF, Inc./Northeast Hot Fill Co-op, Inc. needed to minimize the cost of their water and sewage, at their producing purified bottled water, in Ayer, Massachusetts. This facility is one of the largest bottlers in the U.S. producing 26 million cases of finished beverage annually, including eight million cases of Aquafina brand.
The company had been using two independent single-pass RO treatment trains, which fed a product water storage tank. Each RO system operated at 75 percent recovery, and the remaining 25 percent was sent to drain. They needed to reduce the amount of water going to drain, reduced their company's purchase of raw water and ideally reduce their operating cost.
Solution
To meet the plant's water quality specifications, Evoqua recommended installing two single-pass RO systems, followed by continuous electrodeionization (CEDI). To increase the efficiency, a reject recovery RO system was added to treat the reject water from the primary RO systems.
The product water from the recovery RO is producing water quality that is better than the city water supply. This recovered water is then sent to the plant's lime coagulation treatment system, and is used as ingredient water for carbonated soft drinks.
The reject recovery RO system is fed with 23 m3/hr of water from the storage tank, which contains reject water from the primary RO's. An ultraviolet (UV) sterilization loop ensures a low microbial count in the tank. Antiscalant is added upstream of the RO to prevent scaling of the membranes. The RO product water (14 m3/hr) is chlorinated and sent to the lime coagulation unit, while the RO reject water (9.1 m3/hr) is sent to drain.
According to the plant's quality control manager, they are able to use the recycled reject in carbonated beverage production since the water quality is better than the product water from their traditional lime coagulation treatment methods.
" We've been very happy with the system, since it's producing the water quality we need. I would definitely recommend reject recovery RO for a beverage plant that wants to reduce its water usage. "
Results
With the upgraded system, Northeast Hot Fill increased the water recovery rate from 75 percent to over 90 percent, and reduced the plant's water consumption by approximately 16 million gallons per year. Besides saving water, the system ensures that the plant achieves its bottled water specification for chloride. The company purchased a third primary RO system and carbon tower in 2005, and the product water from this RO is used for tea production, while the system reject is sent to the recovery RO system.