21,000 SWC3 and ESPA elements are installed in the Fujairah desalination plant. Photo by Hydranautics
Click here to enlarge imagePerformance data from train A first pass depicts much better performance than the projected values. The normalised salt passage is between 70% and 90% of the projected value and the trans-membrane pressure is an average of 5-bar lower than projected. The permeate salinity value fell well below the 180-ppm requirement and under the 130-ppm TDS prediction at temperatures around 30°C.
The Tampa Bay Desalination Project in the state of Florida, the largest potable seawater desalination plant of its kind in the US, treats up to 30 mgd (113,000 m3/day) of water from the Gulf of Mexico. The plant uses more than 10,000 Hydranautics membranes in a system that comprises seven seawater trains and six second-pass brackish trains. The first pass contains 9,408 elements including the new SWC4 membrane, which offers the highest salt rejection, even at elevated seawater temperatures, along with increased boron rejection.
The RO seawater system at Tampa Bay Desalination incorporates new design features that significantly reduce capital costs and power consumption during the desalting process. The system uses Hydranautics' process configuration that takes advantage of the internal separation of permeate into low and high salinity streams, reducing the size of the second pass. The benefit is immediate and long-term because of lower capital and operational costs. During start-up testing, this plant produced up to 30 mgd (116,563 m3/d) with chloride in the range of 65 to 95 ppm (approximately 150 ppm TDS) at 60% recovery and 37° C. This exceeded expectations for the plant performance.
Hydranautics' largest installed base of membranes to date remains in the Mediterranean region -
• Almeria, Spain — 13.2 mgd (50,000 m3/d) potable water desalination plant;
• Cartagena, Spain —17.17 mgd (65,000 m3/d) of clean water for potable and irrigation use;
• Larnaca, Cyprus —13.5 mgd (51,000 m3/day) of potable water from a seawater open intake source.
• Carboneras, Spain — 32 mgd (120,000 m3/d) potable water desalination plant.
The 12-train desalination plant, located in Carboneras, the south of Spain, produces potable water containing approximately 234 ppm of TDS from a seawater open intake. Each train consists of 140 vessels with seven elements per vessel for a total of 980 elements per train. This production is at a net pressure of about 60 bar and 25 °C. The plant uses 12,096 SWC3 membranes.
Authors' Note
The Hydranautics' co-authors include: Franz Gelbenegger, Technical Consultant for the Middle East; Dr. Craig Bartels, vice president of research, development and applications technology; and Serenity Gardner, marketing supervisor. Hydranautics is based in Oceanside, California, USA.