David L. Brown: The town of Jupiter’s water treatment facility has a total treatment capacity of 30 million gal per day (mgd). Currently, three treatment technologies are utilized with the finished water from each blended prior to distribution. A total of 13.7 mgd can be produced from a supply originating from a deep brackish aquifer known as the Floridan Aquifer. The Floridan supply has a TDS of 5,000 ppm and is withdrawn from a production zone that exists over 1,500 ft below the ground surface. Given its relatively high TDS, the raw water is treated through reverse osmosis (RO), ultimately yielding a finished water of very high quality.
Jupiter’s service area exists on Florida’s east coast and encompasses the northernmost areas of Palm Beach County and some areas of southern Martin County. The water utility serves nearly 100,000 people in a very desirable, fast-growing region, and the community is bisected by the nationally designated “wild and scenic” Loxahatchee River.
Jupiter has a very limited supply of freshwater. The area’s freshwater supply is obtained from a shallow aquifer known as the Surficial Aquifer. This aquifer’s production zone is only 150 ft deep and is susceptible to drought. Although the area receives more than 60 in. of rainfall annually on average, the majority is wasted to tide. Aquifer over-pumping can result in saltwater intrusion into the aquifer from the Atlantic Ocean or Loxahatchee River. Furthermore, significant environmental impact can result through the drawdown of wetlands or starving the river of its minimum base flow.
The freshwater supply obtained from the Surficial Aquifer is presently treated in two manners. To ensure adequate finished water stabilization of the RO permeate, up to 1.8 mgd of anion exchange-treated supply is added to the mix. The balance of the treatment production is currently obtained through the conventional lime softening process. By early 2008, the utility expects to commission a new nanofiltration (NF) treatment facility that will replace the lime softening process and will remove any and all possibility of water quality concerns inherent to lime softening treatment of highly organic waters. The NF facility will result in Jupiter becoming 100% membrane treatment, an attribute valued in the industry and by the utility’s customers.
WWD: What role has membrane technology played in attaining quality drinking water in Jupiter?
Brown: In the mid-1980s, the Jupiter area was still a relatively small fishing village but was poised for tremendous growth as the community’s waterfronts, beaches and natural beauty made it a very desirable place to live. The area’s water utility was faced with the harsh reality that any further demands on the Surficial Aquifer would likely lead to environmental harm. To sustain growth, an adequate alternative water supply had to be pursued. Hence, Jupiter became the first large utility in southeast Florida to explore the use of the brackish Floridan Aquifer.
At that time, no other utility had explored the aquifer for use, and RO was thought of as a technology far too expensive to employ. Through innovative designs and operational practices, Jupiter’s utility has become a model in alternative water supply whose water rates remain significantly below industry averages. With nearly 50% of the supply membrane-treated via RO, Jupiter’s finished water quality is considered superior to most.
WWD: What role will membrane technology play in addressing future water quality and scarcity problems across the nation?
Brown: No other water treatment technology addresses water quality and quantity problems better than membrane treatment. Membrane technologies have emerged in recent decades as a viable and cost-effective treatment alternative for difficult-to-treat water, desalination, contaminant removal as well as a solution for compliance with increasingly stringent water regulations and standards. Furthermore, the application to wastewater reuse is critical to expanding sustainability of the nation’s water supplies over time. Although certainly not perceived as “old school,” membrane technologies are the best available technologies to expand or enhance your water supplies.
Case histories, such as Jupiter, Fla., can potentially assist many other communities to understand that supply issues can be tackled comprehensively in a cost-effective fashion with membranes. The technology is under constant refinement as use becomes more commonplace and applications are expanded.