Desal URN test

Seawater Desalination Research ADC baseline tests reveal trends in membrane performance John MacHarg, Affordable Desalination Collaboration, Thomas F Seacord, PE, and Bradley Sessions, Carollo Engineers, PC he Affordable Desalination Collaboration (ADC) has completed a major milestone in its test program that profiles the state-ofthe-art performance for seawater reverseosmosis (SWRO) technology. This testing ran over two years and involved operating seven sets of standard 8 in diameter membranes in seven-element pressure-vessels including: • FilmTec SW30HR-380, SW30XLE400i, SW30HRLE-400i, Internally Staged Design (ISD) Hybrid • Koch TFC 2822HF-400 • Hydranautics SWC5 • Toray TM820E-400. T Desalination & Water Reuse Vol. 18/2 All other associated equipment and designs used in these tests also represented state-of-the-art, off-the-shelf technology. Key system variables of recovery and flux ranged from 35-50% and 6-10 gallons per day (gpd) per square foot of membrane (gfd). The testing provides a body of data that can be used to define and project the performance of state-of-the-art SWRO for Southern California applications as well as a benchmark for the performance of new technologies and designs. 30 ADC Pilot System The ADC demonstration plant was designed to produce between 48,100 to 75,600 gpd (182-286 m3/d) of permeate flow using existing full-scale technologies that minimized power consumption. Figure 1 presents a process flow diagram for the ADC's SWRO plant located at the US Navy Seawater Desalination Test Facility in Port Hueneme, California. The process uses an open ocean intake, media filters, 5 micron bag filter, a high-efficiency positive-displacement pump and an isobaric energy-recovery device. The design criteria for these components are presented in Table 1 (see page 32). Test protocol Demonstration-scale tests of each membrane set occurred in approximately seven 9-week phases. As presented in Table 2 (see page 32), each phase of testing has the following features. The membranes were allowed to stabilize ("ripening") for two weeks at baseline conditions of 7.5 gfd and 42.5% recovery was performed. This "ripening" period ensured that the membrane and system performance were operating satisfactorily and at steadystate conditions. The ADC tested each membrane set at a predetermined matrix of 9 and 12 fluxes and recovery points for ADC I and II respectively. ADC I tested 3 sets of FilmTec membranes at flux rates of 6, 7.5 and 9 gfd and 35, 42.5 and 50% recovery. ADC II extended and optimized this test regime to include 6, 7.5, 9 and 10 gfd at 42.5, 46 and 50% recovery according to Table 2. The ADC eliminated the 35% recovery point from ADC II testing due to the results from ADC I that showed significantly higher costs at this lower recovery point . Finally, in the case of the FilmTec ISD configuration, the ADC tested a point at 9 gfd and 55% recovery, according with the manufacturer's request. ADC II SWRO Flow Diagram ADC SWRO Process i. Intake pier ii . Intake pump iii . Central seawater tank iv. Multi-media pre-filtration v. Supply pump vi. Cartridge filter 5 micron vii. Main high pressure pump viii . High pressure booster pump ix. Isobaric energy recovery x. 3 x 7 element 8" RO vessels iii Containerized 200-350 m3/day Seawater Reverse Osmosis Pilot iv F Product E vi v ii C Seawater Tank i Reverse Osmosis Process x 1.8 kWh/m3 6.8 kWh/kgal ix viii vii G D B H Reject A Typical ADC Operating Conditions Stream Seawater Boat Channel A B C D E F G H GPM 93 51 43 51 93 42 51 51 PSI 35 20 20 737 763 5 747 10 TDS 34k 34k 34k 35k 35k 103 66k 65k Figure 1. Flow Diagram - ADC's Demonstration Scale SWRO plant © 2008 FAVERSHAM HOUSE GROUP

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