High-Performance SWRO & Membrane Equipment
Pre-tested modular trains, skid-mounted seawater desalination systems, and advanced membrane degassing skids designed for rapid deployment and continuous industrial operation.
High-Pressure Membrane Concentration System
Specialized DTRO and high-pressure disc-tube setups engineered for extreme osmotic pressures and complex industrial brine concentration.
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Wholesale Compact Seawater Desalination Unit
Skid-mounted high-salinity seawater RO units designed for maritime vessels, coastal resorts, and offshore installations needing fresh water.
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High-Ratio Industrial Water Reuse Equipment
Multi-barrier wastewater reclamation trains maximizing water recovery percentages for boiler feeds and cooling towers in power utilities.
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Deoxygenation Membrane Degassing System
Ultra-low dissolved oxygen removal reaching single-digit ppb levels via gas-permeable hollow-fiber contactor membranes.
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Sanitary Food & Beverage Process Water Train
Hygienic stainless steel RO architectures built with complete automated CIP sanitization routines to maintain rigorous international food safety standards.
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Containerized SWRO Mobile Desalination Plant
Intermodal 20ft/40ft containerized SWRO units equipped with climate control, Duplex stainless metallurgy, and plug-and-play tie-ins.
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Industrial Demineralized RO + EDI Pure Water
Continuous electro-deionization (EDI) coupled with dual-pass reverse osmosis for sub-0.1 μS/cm boiler and semiconductor grade water.
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Compact Drinking Water SWRO Station
Modular drinking water reverse osmosis units with integrated mineral balancing, remineralization filters, and low-energy ERD isobaric devices.
View SpecificationsInside the Modern SWRO Plant: Thermodynamic & Mechanical Integrity
Seawater Reverse Osmosis (SWRO) demands a rigorous balance of fluid dynamics, metallurgy, membrane chemistry, and isobaric energy recovery. Our OEM engineering standards eliminate single points of failure across demanding marine environments.
Pretreatment & SDI Stabilization
Membrane longevity is dictated entirely by upstream colloidal control. Raw seawater fluctuating with algal blooms, suspended silts, and marine organics will foul SWRO membrane leaves in days if not properly conditioned.
- Ultrafiltration (UF) Integration: 0.02 μm hollow fiber PVDF modules guarantee Silt Density Index (SDI15) < 2.5 consistently.
- Dissolved Air Flotation (DAF): Integrated ahead of dual-media filters for red tide and high hydrocarbon marine spikes.
- Automated Coagulant Dosing: Proportional ferric chloride/polymer dosing matched to raw water streaming current monitors.
High-Pressure Pumping & Isobaric ERD
Overcoming the natural osmotic pressure of seawater (typically 27 to 35 bar at 35,000–45,000 ppm TDS) requires feed pressures reaching 55 to 70 bar, where energy recovery systems are crucial to commercial feasibility.
- Rotary Isobaric Exchangers: Direct pressure transfer from concentrate stream to feed, yielding >97.5% net energy recovery.
- Specific Energy Consumption: Drives SEC down to 2.8 – 3.2 kWh/m³, lowering lifecycle OPEX over 20-year lifespans.
- Booster Pumping Skids: High-efficiency variable speed auxiliary pumps compensate for membrane hydraulic friction.
Metallurgical Engineering & Corrosion Defense
Under 70 bar pressure and high chloride concentration, standard austenitic stainless steels (304/316L) suffer catastrophic pitting and crevice corrosion within months. Tongjie enforces strict metallurgical grades.
- Super Duplex 2507 (UNS S32750): PREN > 42 for all high-pressure manifolds, victaulic couplings, and pump casings.
- FRP Pressure Vessels: ASME Section X certified fiberglass housings rated up to 1200 PSI with multi-port side entries.
- Low-Pressure Piping: Schedule 80 PVC, PVDF, or high-density polyethylene (HDPE) to eliminate galvanic cells completely.
Intake & Screening
Deep seawater intake or beach wells equipped with passive wedge wire screens to minimize fish impingement and bulk silt entrainment.
Chemical Conditioning
Precise sodium hypochlorite dosing, SMBS dechlorination, acid/antiscalant infusion, and automatic pH balancing to prevent scale formation.
Cartridge Filtration
Polyester melt-blown depth filters (1–5 micron absolute) acting as a final protective barrier ahead of the expensive high-pressure membranes.
High-Pressure Desalting
High-rejection polyamide thin-film composite spiral wound elements running at 40–50% single-pass recovery with isobaric ERD recycling.
Post-Treatment & Mineralization
Calcite bed dissolution, carbon dioxide dosing, sodium hydroxide adjustment, and UV/chlorination ensuring WHO drinking water compliance.
Macro-Sector Industrial Solutions: Resolving Global Water Scarcity
Industrial giants face stricter extraction caps, increasing municipal tariffs, and aggressive ESG mandates. Our engineered SWRO architectures serve diverse global sectors with application-specific engineering.
Thermal & Combined-Cycle Power
Power plants located on coastal shorelines require hundreds of cubic meters per hour of boiler feedwater with ultra-low silica and conductivities below 0.1 μS/cm.
- Solution: Two-pass SWRO followed by Continuous Electrodeionization (EDI).
- Silica Removal: Reactive silicate rejection >99.2% preventing turbine blade scaling.
- Degasification: Membrane contactor degassing reduces dissolved O2 to <5 ppb without thermal deaeration loads.
Mining, Mineral Extraction & Refining
Arid extraction zones across Australia, South America, and Africa possess zero fresh surface water. Remote copper, lithium, and gold mills depend on seawater piped inland over dozens of kilometers.
- Solution: Heavy-duty containerized SWRO skids resistant to high desert ambient swings (-10°C to +50°C).
- Brine Minimization: Staged disc-tube reverse osmosis (DTRO) pushing brine salinity toward 120,000 ppm for tailings reduction.
- Automated Flushing: Solar-buffered off-grid permeate displacement preventing membrane scaling during power cuts.
Island Resorts & Municipal Utilities
Isolated island developments require silent, odor-free, vibration-damped desalination operations where water must not only be potable, but clear, odorless, and perfectly mineralized.
- Solution: Containerized acoustic-insulated plants fitted with multi-layer sound attenuation.
- Boron Compliance: Multi-pass pH shifted stages driving boron down from 4.5 ppm to <0.5 ppm (WHO Drinking Limits).
- Mineral Balance: Dual limestone beds supplying natural calcium and magnesium hardness to combat pipe leaches.
The Tongjie Engineering Advantage: Total Fluid Accountability
We do not assemble off-the-shelf catalog skids. Every OEM project commences with a comprehensive ionic balance report of the client's feed water—factoring seasonal temperature shifts, Langlier Saturation Index (LSI), Stiff & Davis Stability Index (S&DSI), and organic bio-fouling potential. This precise methodology eliminates undersized membrane surface areas and early plant replacement.
Procurement Intelligence: Risk Mitigation & International Standards
Procuring capital desalination assets internationally demands uncompromising quality assurance. EPC contractors and plant directors require transparency across code certifications, manufacturing pedigrees, and factory testing.
Standardized Factory Testing (FAT)
Eliminate expensive downtime in remote coastal territories by mandating rigorous, documented testing before export crates depart our Shanghai manufacturing facilities.
- Hydrostatic Testing: Pressure manifolds and vessels pressurized to 1.5x design pressure for a sustained 4-hour test period.
- Wet Membrane Projections: Functional wet testing of random membrane batches verifies rejection curves and pressure drop ratings.
- PLC Cold & Hot I/O Simulations: 100% loop testing of sensors, flow transmitters, automatic safety dump valves, and interlocks.
Global Certification & Compliance
Navigating cross-border installations requires strict alignment with global mechanical, structural, and electrical codes to guarantee smooth local permitting.
- CE Certification: Fully harmonized under the Machinery Directive 2006/42/EC and Pressure Equipment Directive (PED 2014/68/EU).
- ASME Code Compliance: High pressure membrane housings and piping assemblies built to ASME Section VIII & B31.3 specs.
- ISO Integrated Management: ISO 9001 (Quality), ISO 14001 (Environmental Management), and ISO 45001 (Occupational Safety).
Turnkey Containerization Benefits
Constructing civil buildings in remote marine coastal areas often inflates project budgets by 300%. Our factory-packaged container systems offer complete operational autonomy.
- Corten Steel Enclosures: Standard ISO intermodal cargo containers lined with polyurethane thermal and acoustic insulation.
- Industrial HVAC Systems: Heavy-duty corrosive-environment HVAC units maintain internal skids at optimal 20°C to 25°C.
- Minimal Civil Footprint: Requires only a simple concrete foundation slab and raw feed, permeate, and brine disposal headers.
The Future of Desalination: 2025–2035 Technology Horizon
As energy costs fluctuate and carbon taxes expand, Tongjie’s R&D engineering laboratory is actively advancing next-generation desalination architectures.
AI-Enabled Autonomous Digital Twins
Conventional SWRO operations rely on reactive manual data logging. Next-generation installations are equipped with IoT-connected edge processors running dynamic normalization algorithms.
By comparing normalized permeate flow, differential pressure (ΔP), and salt passage against ideal clean-membrane baseline models in real time, the system schedules precise CIP (Clean-in-Place) procedures automatically—preventing irreversible foulant compaction and extending element life by 2.5 years on average.
Closed-Circuit Desalination (CCRO)
Traditional plug-flow RO systems operate under constant concentration gradients, losing hydraulic efficiency. Tongjie's advanced R&D incorporates closed-circuit recirculation concepts.
By continuously recycling pressurized brine through a single-stage membrane array until a target recovery percentage is reached before purging, CCRO eliminates cross-flow stagnation, interrupts scaling crystallization kinetics, and elevates system recoveries from 45% to upwards of 60% on suitable brackish-marine transitions.
Direct-Drive Solar Desalination
Integrating volatile photovoltaic generation with continuous membrane processes traditionally demanded costly, short-lived chemical battery banks. Our variable-frequency solar architectures bridge this gap.
Advanced VFD high-pressure pump algorithms modulate operating pressure and permeate output dynamically to track diurnal solar irradiance curves. Paired with intelligent pressure-vessel bank staging, our off-grid solar SWRO systems produce pure water directly from solar rays without intermediate grid connections.
Frequently Asked Technical & Operational Questions
Direct technical answers to the most common process, metallurgical, and economic questions posed by EPC contractors, procurement directors, and plant engineers.
What parameters are required to size a customized SWRO train accurately?
A full comprehensive laboratory water chemistry analysis is required. Essential parameters include Total Dissolved Solids (TDS), electrical conductivity, temperature range (°C), pH, turbidity or SDI15, silica (SiO2), barium, strontium, calcium, magnesium, iron, manganese, and total organic carbon (TOC). Additionally, please specify available electrical utility characteristics (Voltage/Hz) and target permeate output per 24 hours.
How does an isobaric Energy Recovery Device (ERD) affect plant economics?
Seawater reverse osmosis operates under high hydrostatic pressure where the brine concentrate departs the pressure vessel at approximately 60–65 bar. Isobaric ceramic rotary pressure exchangers transfer this hydraulic energy directly to incoming seawater feed with over 97% efficiency. This reduces the size and load of the high-pressure pump motor, lowering power draw from ~7.5 kWh/m³ down to <3.0 kWh/m³.
Why is Super Duplex 2507 stainless steel critical for high-pressure lines?
Seawater with 35,000+ ppm TDS contains dense chloride concentrations that trigger crevice corrosion and pitting in standard 304 or 316 stainless steels under high pressure. Super Duplex 2507 (UNS S32750) has a Pitting Resistance Equivalent Number (PREN) above 42, ensuring total metallurgical resilience against localized micro-pitting and stress-corrosion cracking over 25+ years of continuous marine use.
How does the system ensure compliance with WHO boron guidelines?
Natural seawater contains 4.0 to 5.5 mg/L of dissolved boron, primarily as uncharged boric acid (H3BO3) at neutral pH. Standard single-pass SWRO elements reject roughly 85–90% of boron, leaving ~0.8–1.2 mg/L in the permeate. To meet WHO drinking standards (≤0.5 mg/L), Tongjie engineers a split-stream second pass with caustic (NaOH) dosing to elevate pH above 9.5, converting boric acid to ionized borate, which is rejected at >99%.
What is the standard lead time and commissioning sequence for containerized skids?
Standard containerized SWRO units require 8 to 12 weeks for precision engineering, fabrication, assembly, and comprehensive Shanghai Factory Acceptance Testing (FAT). Upon arrival on site, plug-and-play mechanical couplings, feed pumps, and electrical drops typically allow full treated water production within 7 to 14 days under Tongjie's remote or on-site engineering supervision.
How often must SWRO membranes undergo Clean-In-Place (CIP) maintenance?
Under optimal ultrafiltration or dual-media pretreatment maintaining SDI15 < 2.5, membrane elements undergo CIP cleaning every 3 to 6 months. Tongjie systems feature fully integrated, skid-mounted CIP stations with dedicated low-pressure pumps, 1-micron cartridge polishing, chemical heater loops, and automated neutral pH flushing sequences.
High-Salinity, Oilfield & Industrial Systems
Explore our specialized industrial wastewater reuse systems, high-temperature brine crystallizer trains, off-grid solar SWRO units, and produced water fracturing skids.
Eco-Friendly Industrial Water Treatment Solutions
Comprehensive chemical-free and low-power membrane water purification plants meeting European CE directives for worldwide brand OEM supply.
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Fracturing Flowback Water Treatment Equipment
Skid-mounted oil & gas produced water systems combining coalescing oil separators, chemical softening, and heavy fouling DTRO arrays.
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Low-Conductivity Demineralized Water Station
High-efficiency double-pass reverse osmosis skids engineered for chemical processing plants requiring reliable low-conductivity process water.
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Off-Grid Solar Containerized Desalination Plant
Turnkey solar-coupled SWRO systems engineered with variable frequency drives for self-sufficient remote island and off-grid coastal communities.
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High-Efficiency Brine Concentration (ZLD)
Ultra-high pressure reverse osmosis membranes coupled with MVR thermal evaporators to achieve Zero Liquid Discharge compliance.
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Integrated Mobile Container Desalination Unit
Pre-commissioned intermodal 40ft high-cube SWRO plant with automated self-cleaning strainers and fully integrated chemical injection bays.
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Food & Beverage Hygienic Water Station
Sanitary 316L stainless steel skids designed to eliminate microbial harborage points with automated ozone and UV sterilization stages.
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High-Pressure Industrial Brine Concentrator
Advanced high-pressure membrane elements rated to 120 bar designed for coal-chemical, textile, and electroplating effluent volume reduction.
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