2026-10-31
Located on the Arabian Gulf coast at Ras Al Khair, Saudi Arabia, one of the world's largest Seawater Reverse Osmosis (SWRO) desalination plants produces over 600,000 m³ of potable water daily. The facility abstracts raw seawater from the shallow Arabian Gulf at a continuous rate of 55,000 m³/h. Gulf seawater exhibits high salinity ($TDS > 45,000\text{ mg/L}$), elevated summer temperatures ($> 38^\circ\text{C}$), high silt density index (SDI), and frequent red tide events caused by dinoflagellate blooms.
Raw seawater passes through coarse intake screens before entering primary clarification and secondary fine filtration prior to cartridge filters and high-pressure SWRO membrane racks. The original dual-cell gravity sand filters were vulnerable to severe solids breakthrough during red tides, clogging fine cartridge filters within hours and fouling SWRO membranes. To safeguard the multi-million-dollar SWRO membrane asset and ensure continuous municipal water supply, the plant owner partnered with LEFILTER to install an automated high-flow primary pre-filtration barrier.
Rapid SWRO Membrane Blinding: Red tide algae blooms ($Karenia\ brevis$) introduced high concentrations of transparent exopolymer particles (TEP) and fine silt ($10\text{--}100\,\mu\text{m}$). This caused rapid SDI spikes ($SDI_{15} > 6.5$), causing irreversible SWRO membrane organic fouling and severe flux drop.
Excessive Cartridge Filter Replacement Costs: Downstream 5 $\mu\text{m}$ polypropylene melt-blown cartridge filters blinded completely every 36 to 48 hours during turbidity spikes, consuming over 45,000 cartridge elements per year and driving up operating costs.
High Water and Energy Footprint of Sand Filters: Backwashing legacy gravity sand filters consumed massive volumes of desalinated water (over 4% of total plant production) and required large auxiliary pumping stations, increasing net energy consumption per cubic meter of desalinated water.
Extreme Saline-Thermal Corrosion Environment: The combination of 45,000 mg/L TDS seawater, 38°C operating temperature, and ambient coastal desert air caused rapid galvanic and pitting corrosion on standard stainless steel components.
LEFILTER engineered a ultra-high-capacity primary seawater filtration complex comprising twelve skid-mounted LEFILTER LF-BS Series Automatic Scraping Backwash Filters fabricated from 254 SMO super-austenitic alloy.
254 SMO Super-Alloy Metallurgy: Pressure vessel shells and internal components were fabricated from 254 SMO ($UNS\ S31254$), providing high resistance to pitting and crevice corrosion ($PREN \ge 43$) in warm Gulf seawater.
70 $\mu\text{m}$ Anti-Fouling Wedge Wire Media: The elements feature a 70 $\mu\text{m}$ slot opening manufactured from polished 254 SMO wedge wire. The smooth profile prevents TEP gelatinous matter and shell fragments from lodging within the screen matrix.
Continuous Mechanical Scraping System: Internal rotating scraper assemblies feature spring-loaded alloy blades that continuously shear away sticky organic films and algae cake from the inner screen face without interrupting main seawater flow.
Low-Water Purge Mechanism: The short-duration purge system cleans elements in 20-second bursts, discharging less than 0.1% of total incoming feed volume, preserving feed water for the downstream reverse osmosis process.
Turnkey Execution & Commissioning: LEFILTER managed direct ocean shipping to Jubail Commercial Port, inland heavy transport, civil foundation tie-in, and deployed a team of six desalination engineers for on-site commissioning and performance testing.
Following 24 months of continuous operation at the Ras Al Khair desalination plant, the LEFILTER primary pre-filtration system delivered outstanding performance metrics:
SWRO Feed Water Quality Enhancement: Consistently maintained downstream feed water Silt Density Index ($SDI_{15}$) below 2.8, protecting high-pressure SWRO membranes from particulate and organic fouling.
Cartridge Filter Life Extension: Operating lifespan of downstream 5 $\mu\text{m}$ security cartridge filters expanded from 2 days to over 42 days, reducing consumable cartridge expenditures by 94% (saving USD $680,000 annually).
Water Conservation: System backwash water loss was held under 0.08% of total intake flow, saving over 1.8 million m³ of raw seawater annually compared to backwashing sand filter beds.
Red Tide Resilience: Maintained 100% nominal water production throughout two major Gulf red tide events, preventing plant shutdowns that previously cost millions of dollars in municipal supply penalties.
Capital Payback: Lower energy consumption, reduced cartridge procurement, and extended SWRO membrane lifespans enabled the LEFILTER filtration plant to achieve complete financial payback within 7.2 months.
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