For industrial and municipal desalination applications, the efficiency and reliability of your Reverse Osmosis (RO) membranes are paramount. Among the most trusted specifications in the industry is the Dow Filmtec SW30-400 (now under the DuPont brand). Known for its high salt rejection and durability, this membrane element standard has become a benchmark for seawater desalination.
At Purecowater, we specialize in providing high-performance filtration solutions, including direct replacements and premium equivalents for the Dow Filmtec SW30-400 series. Whether you are looking for the original Filmtec engineering or a comparable membrane from manufacturers like LG or Veolia, this guide covers the critical specifications, performance metrics, and applications of these 8-inch seawater elements.
Product Overview: 8" Seawater RO Elements
The SW30-400 class membrane is an 8-inch diameter, 40-inch long element designed for Seawater Reverse Osmosis (SWRO). It features a standard active surface area of 400 square feet (37 m²), optimizing the balance between productivity (flow rate) and permeate quality (salt rejection).
These membranes are engineered to withstand the high operating pressures required to overcome the osmotic pressure of seawater, typically ranging from 800 to 1,200 psi. By utilizing advanced thin-film composite (TFC) technology, they effectively remove dissolved salts, organics, and particulates, producing potable or process-grade water.
Key Features
- High Boron Rejection: Essential for meeting World Health Organization (WHO) drinking water standards.
- Durable Construction: Designed to resist fouling and withstand harsh cleaning chemicals (pH 1-13).
- High Productivity: Maximizes water output per element to reduce the system’s capital, footprint, and energy costs.
- Interlocking Endcaps (iLEC): Many modern equivalents feature interlocking designs to reduce O-ring leaks and pressure drops.
Technical Specifications
When selecting a Dow Filmtec SW30-400 equivalent, it is crucial to match the hydraulic and chemical specifications to ensure seamless integration into your existing pressure vessels. Below are the typical performance standards for this membrane class.
| Specification | Standard Performance |
|---|---|
| Membrane Type | Polyamide Thin-Film Composite |
| Dimensions | 8.0" x 40" (201 mm x 1,016 mm) |
| Active Surface Area | 400 ft² (37 m²) |
| Salt Rejection | 99.7% – 99.8% |
| Permeate Flow Rate | 6,000 – 9,000 GPD (Depending on model variant) |
| Max Feed Pressure | 1,200 psi (83 bar) |
| Chlorine Tolerance | < 0.1 ppm |
Performance Comparison: Standard vs. Low Energy
The SW30-400 designation covers a range of sub-models tailored for specific energy or rejection needs. Understanding the differences helps in selecting the right replacement for your skid.
- SW30HR (High Rejection): Prioritizes permeate quality, achieving salt rejection up to 99.8%. Ideal for single-pass systems requiring potable water compliance.
- SW30XLE (Extra Low Energy): focus on reducing energy consumption. These elements can produce comparable flow rates at lower feed pressures, significantly reducing pump energy costs. For example, some XLE models offer up to 9,000 GPD at reduced pressure loads [filterwater.com].
- Universal Equivalents: Manufacturers like LG Chem (LG SW 400 R) and Veolia (Suez) offer drop-in replacements that often match or exceed the original Dow specifications in terms of fouling resistance and boron rejection [pureaqua.com].
Applications
The 400 square foot seawater membrane is the workhorse of the desalination industry. Its reliable performance makes it suitable for a wide array of demanding environments:
- Municipal Desalination Plants: Large-scale production of drinking water from sea sources.
- Marine & Shipboard Systems: Production of fresh water for crews and equipment on vessels and offshore platforms.
- Industrial Process Water: Providing treated water for boilers, cooling towers, and manufacturing processes where high TDS (Total Dissolved Solids) feedwater is the only source.
- Resort & Hotel Water Supply: Ensuring consistent potable water for coastal hospitality businesses.
Why Choose Reliable Equivalents?
While the Dow Filmtec brand is legendary, the market for equivalent membranes has matured significantly. Sourcing an equivalent from a reputable distributor like Purecowater offers several advantages:
- Availability: Reduced lead times for critical maintenance replacements.
- Cost-Efficiency: Competitive pricing without compromising on rejection rates or longevity.
- Modern Technology: Newer equivalents often incorporate advanced spacer designs to reduce fouling and pressure drop [purelyro.com].
Contact Purecowater for Membrane Solutions
Whether you need the specific Dow Filmtec SW30-400 or a high-performance equivalent from our range of partners like Veolia, WTS, or LG, Purecowater has the expertise to support your filtration projects. We can help you analyze your feed water quality and select the exact membrane to optimize your system’s output.