SWC5-4040: 4-Inch High Rejection Seawater RO Membrane

3. Technical Parameters

• Membrane dimension: 4-inch diameter × 40-inch length (4040 standard size)

• Effective membrane area: 85ft² (7.9m²)

• Membrane material: Modified aromatic polyamide thin-film composite seawater special membrane

• Structure: Spiral wound, 34mil low-fouling biostatic feed spacer

• Standard test condition: 32000mg/L NaCl solution, 5.5MPa (800PSI) operating pressure, 25℃, 10% single element recovery, pH 6.5–7.0

• Standard permeate flow rate: 1900 GPD (7.2m³/d), flow deviation ±15%

• Nominal salt rejection ≥99.7%, minimum guaranteed salt rejection ≥99.5%

• Boron rejection rate ≥92.0%

• Operating pressure range: 5.0–8.27MPa (725–1200PSI), maximum withstand pressure 1200PSI

• Operating temperature: 5℃–45℃

• Continuous operating pH range: 2.0–11.0; chemical cleaning pH range: 1.0–13.0

• Maximum inlet SDI15: 5.0; maximum inlet turbidity: 1.0NTU

• Maximum inlet residual chlorine: ≤0.1mg/L

• Single element maximum pressure drop: ≤10PSI (0.07MPa)

• Minimum brine-to-permeate flow ratio: 5:1

• Service life under standardized maintenance: 3–5 years

• Single membrane weight: 8lbs (3.63kg)

4. Product Advantages

SWC5-4040 integrates multiple optimized designs, with obvious competitive advantages compared with ordinary 4-inch seawater RO membranes:

1. Ultra-stable high desalination performance: Nominal salt rejection reaches 99.7%, boron rejection above 92%, effectively intercept NaCl, heavy metal ions, boron and soluble salts in seawater, permeate water meets national drinking water standards without secondary desalination for most small systems.

2. 4-inch modular compact design: Standard 4040 size matches all mainstream 4-inch membrane housings, flexible for small skid-mounted, mobile and containerized desalination equipment; easy single-piece replacement, low early equipment investment, suitable for distributed small projects that cannot adopt 8-inch large membrane systems.

3. Low-fouling LD optimized flow channel: 34mil thick biostatic feed spacer eliminates dead zones inside the membrane, reduces colloid, algae and microbial adhesion; suppress concentration polarization under high-salinity operation, extend chemical cleaning cycle to 7–9 months under normal raw water pretreatment.

4. Strong high-pressure & chemical resistance: Reinforced membrane support layer improves mechanical strength, stably long-term operation under 5.0–8.27MPa seawater high pressure; wide pH cleaning window supports acid & alkali cyclic cleaning, effectively restore flux after pollution.

5. Low comprehensive operation cost: Stable flux attenuation rate, slow performance decline within service life; lower chemical cleaning frequency reduces cleaning agent consumption and system downtime, with higher cost performance than imported benchmark membranes of the same specification.

6. Consistent batch performance: Strict full-flow testing before delivery, stable flux and desalination rate among different batches, no large performance fluctuation after system assembly.

5. Application Procedures

SWC5-4040 adopts standardized full-process operation flow, divided into six core steps to avoid membrane damage and performance attenuation:

1. Raw water advanced pretreatment: Must configure multi-media filtration, activated carbon filtration, precision security filter (5μm), scale inhibitor dosing and disinfection unit; strictly control inlet SDI≤5.0, turbidity≤1.0NTU, remove suspended solids, colloids and algae to prevent irreversible membrane fouling.

2. Standard membrane installation: Install 4040 membrane elements into matched membrane housing, assemble concentrated water seal ring and O-ring as supporting accessories; avoid scratching membrane surface during handling, ensure tight pipeline connection without leakage; install permeate side towards fresh water outlet direction.

3. System commissioning trial run: After installation, fill the system with clean fresh water for low-pressure flushing, then gradually boost to standard operating pressure 5.5MPa; control single element recovery at 10%, continuous trial run for 2–3 hours, record permeate TDS, flux and pressure difference to check system stability.

4. Daily real-time monitoring during formal operation: Record daily operating pressure, water temperature, membrane inlet-outlet pressure difference, permeate yield and desalination rate; track raw water salinity fluctuation, adjust scale inhibitor dosage according to seasonal seawater quality changes.

5. Timely chemical cleaning: When membrane flux drops over 20% or pressure difference rises more than 15% compared with initial state, carry out acid and alkali alternating cleaning; strictly control cleaning liquid temperature and pH to avoid membrane material degradation.

6. Regular shutdown maintenance: Long-term shutdown needs to fill the membrane housing with 0.5–1.0% sodium bisulfite protective liquid for sealed preservation; short-term daily shutdown completes low-pressure fresh water flushing to discharge concentrated salt water inside the membrane, prevent salt crystallization scaling.

6. Quality Standards

7. Working Principle

SWC5-4040 operates based on mature reverse osmosis separation technology, optimized targeted for high-salinity seawater desalination scenarios:

Under high pressure (higher than seawater natural osmotic pressure 2.4–3.0MPa), raw seawater flows along the surface of modified polyamide semi-permeable membrane. The ultra-micro membrane pore size (0.0001–0.001μm) only allows water molecules to pass through the membrane layer to form fresh permeate water, while intercepting NaCl salt ions, boron, heavy metals, colloids, microorganisms and organic macromolecules in concentrated water side.

The membrane surface adopts negative charge hydrophilic modification technology, generating electrostatic repulsion effect on charged salt ions and colloidal pollutants, further improving interception efficiency and reducing pollutant adsorption. The 34mil wide flow channel spacer optimizes raw water turbulence state, effectively reduce concentration polarization phenomenon caused by high seawater salinity, avoid salt crystal deposition on membrane surface. The whole separation process relies on physical pressure driving, no chemical additive addition in separation stage, energy-saving and pollution-free, which is the core efficient separation technology for small seawater desalination.

8. Future Prospects

Driven by the booming market of distributed small seawater desalination, island water supply and mobile emergency water treatment equipment, market demand for compact high-performance 4-inch seawater RO membranes represented by SWC5-4040 keeps growing steadily.

In the follow-up iteration of SWC5-4040, three major technical optimization directions will be carried out:

1. Membrane material upgrading: Introduce nano-hydrophilic coating modification technology, further enhance anti-biological fouling and anti-scaling ability, extend cleaning cycle and overall service life.

2. Energy-saving low-pressure optimization: Adjust polyamide membrane layer structure, realize qualified desalination rate under lower operating pressure, reduce system energy consumption and operating cost of small desalination equipment.

3. Intelligent matching upgrading: Optimize membrane flux consistency, match with automatic monitoring desalination skids, support real-time remote data collection of membrane pressure difference, flux and desalination rate, realize automatic early warning of pollution and intelligent cleaning reminder.

Meanwhile, expand application boundaries to offshore new energy supporting water supply, marine ranch fresh water system, field military portable water treatment and other emerging fields, provide stable, cost-effective core membrane solutions for global decentralized high-salinity water resource utilization.

9. Conclusion

SWC5-4040 4-inch seawater reverse osmosis membrane, as a cost-effective alternative to Hydranautics SWC5 series benchmark products, takes 4-inch compact modular design and ≥99.7% high salt rejection as core competitiveness, thoroughly solves the drawbacks of traditional small seawater membranes including low desalination efficiency, easy fouling and short service life.

It owns standardized installation and maintenance procedures, strict full-link quality control system and wide application coverage for small desalination projects; stable performance has been verified in numerous coastal islands, ships, mobile emergency water supply and industrial high-salinity wastewater treatment projects, recognized as reliable compact seawater RO membrane element. With continuous material and structural technological upgrading, SWC5-4040 will have broader market application prospects, providing strong technical support for decentralized seawater desalination and sustainable development of limited fresh water resources.

10. Frequently Asked Questions (FAQs)

Q1: What are the core competitive strengths of SWC5-4040 compared with other 4-inch seawater RO membranes?

A1: The core advantages are three points: nominal salt rejection ≥99.7% with 92% boron removal rate; low-fouling 34mil biostatic spacer design to extend cleaning cycle; standard 4040 size compatible with all mainstream housings, lower overall procurement cost than imported equivalent SWC5-4040 membrane.

Q2: What is the effective membrane area of SWC5-4040? What is the standard daily permeate yield?

A2: Effective membrane area 85ft² (7.9m²); under standard test conditions, the permeate flow reaches 1900GPD (7.2m³/d), which meets the water demand of small household, yacht and island mini desalination equipment.

Q3: How often does SWC5-4040 need chemical cleaning under normal operation?

A3: When raw water pretreatment reaches standard SDI≤5.0, the chemical cleaning cycle is 7–9 months; if raw water turbidity and microorganism content are high, the cleaning cycle needs to be shortened appropriately according to actual operating pressure difference changes.

Q4: What is the expected service life of SWC5-4040?

A4: Under complete pretreatment, regular cleaning and standardized pressure control, the service life can reach 3–5 years; improper pretreatment or long-term overpressure operation will greatly shorten the service life.

Q5: Can SWC5-4040 be used for shipboard and island seawater desalination?

A5: Fully applicable. Its compact 4-inch size is suitable for limited space installation on ships and island skids, high pressure resistance and high salt rejection adapt to raw seawater with salinity up to 35000mg/L, and is the preferred membrane for mobile small desalination systems.

Q6: What is the single element recommended recovery rate during operation?

A6: The standard single element recovery rate is controlled at 10%. Excessively high recovery rate will aggravate concentration polarization, accelerate scaling and fouling, and lead to decreased desalination stability.