As freshwater resources become more limited in coastal regions, seawater desalination is increasingly used to supplement water supplies and support industrial production. However, treating seawater is not simply a matter of passing high-salinity water through a membrane. The membrane element must operate under demanding pressure and feed-water conditions while maintaining stable salt rejection and water production.
At Runmo, we develop membrane products for different water qualities and treatment requirements. Our seawater reverse osmosis products are designed specifically for high-salinity applications, providing an option for projects ranging from seawater desalination to industrial water reuse. Understanding where these membranes fit into a treatment system is the first step toward selecting the right configuration.
Coastal Water Supply and Seawater Desalination
Coastal communities may have abundant seawater but limited access to suitable freshwater resources. Desalination provides a way to convert seawater into usable freshwater, making membrane performance particularly important for coastal water supply projects.
Our SW Series uses aromatic polyamide composite membrane elements for seawater desalination. We optimize the membrane-element structure to increase water production, with the potential to reduce the number of elements required when the same water production target is maintained. The series is also designed around relatively low operating pressure, desalination performance, and operational stability.
For project designers, this means membrane selection should be considered together with the overall system. Feed-water quality, required capacity, pressure, recovery, pretreatment, and the desired product-water quality all influence how the desalination system should be configured.
High-Concentration Brackish Water Treatment
Not every high-salinity water source is seawater. Some inland or industrial sources can have elevated salt concentrations and may require treatment approaches similar to seawater desalination.
Our SW Series is suitable for seawater as well as high-concentration brackish water. This gives system integrators another membrane option when the feed-water salinity is beyond the typical range of lower-salinity water treatment applications.
The distinction between seawater and brackish-water applications remains important, however. We recommend evaluating the actual water analysis rather than selecting a membrane solely according to the name of the water source. TDS, temperature, pH, suspended solids, organic loading, and the required permeate flow should all be considered during membrane selection.
Industrial Applications Beyond Drinking Water
Seawater membranes are not limited to municipal desalination. Industrial facilities may also need to produce treated water, reuse wastewater, or manage high-salinity streams as part of their production processes.
Our SW membrane elements are listed for several industrial applications, including power-plant boiler feed water, wastewater reuse, and the concentration and recovery of high-value substances in food and pharmaceutical applications. The broader Runmo product portfolio also serves pure-water preparation, food processing, pharmaceutical manufacturing, electronics, chemical production, and other industrial sectors.
This makes the sea water membrane a useful consideration when the treatment challenge involves high salinity rather than simply conventional freshwater filtration. In industrial projects, the membrane should still be integrated with appropriate pretreatment and downstream processes according to the characteristics of the feed stream.
What Performance Should Buyers Evaluate?
When comparing seawater RO membrane elements, buyers often focus on rejection and permeate flow. Both are important, but they should be interpreted together with the conditions under which the values were measured.
Our SW Series currently includes two published models. RM-SW1-4040 has a membrane area of 80 ft² (7.4 m²), an average permeate flow of 1,900 GPD (7.2 m³/day), and a stable rejection of 99.7%, with a minimum rejection of 99%. RM-SW2-8040 provides 380 ft² (35.2 m²), an average permeate flow of 8,200 GPD (31 m³/day), stable rejection of 99.7%, and minimum rejection of 99%.
These figures are based on Runmo’s published testing conditions: 800 psi (5.5 MPa), 25°C, a 30,000 ppm NaCl solution, pH 7.5, and an 8% single-element recovery rate. They should therefore be used as reference performance data rather than treated as universal field results.
Operating Conditions Matter as Much as Membrane Selection
A membrane can only perform as intended when the system operates within its specified limits. For our SW Series, the maximum working pressure is 1,000 psi (6.9 MPa), while the maximum feed-water SDI15 is 5 and the maximum feed-water temperature is 45°C. The published continuous-operation pH range is 2–12. Other limits include maximum feed-water TDS of 5,000 ppm, residual chlorine below 0.1 ppm, maximum turbidity of 1.0 NTU, and a maximum single-element pressure drop of 15 psi (0.1 MPa).
These specifications highlight why pretreatment and system design cannot be separated from membrane selection. If feed water contains excessive suspended solids, oxidants, or other contaminants beyond the specified operating conditions, the system may require additional treatment before reaching the membrane stage.
How We Support Different Water Treatment Projects
At Runmo, we are Suzhou Runmo Water Treatment Technology Co., Ltd., a manufacturer specializing in reverse osmosis membranes, ultrafiltration membranes, and polymer membrane technologies. We operate an independent R&D system and automated production lines, with an annual production capacity of more than 800,000 membrane products and more than 40 patents. Our products and technical support serve customers in more than 60 countries.
Our approach goes beyond supplying individual membrane elements. We provide membrane material customization, system design, engineering implementation, and technical services for different water-treatment requirements. We also maintain vertically integrated production from membrane material preparation through finished membrane assembly, allowing us to support customized dimensions, housing designs, performance characteristics, and OEM/ODM requirements.
If you are planning a coastal water supply system, high-concentration brackish-water project, industrial reuse application, or another high-salinity treatment process, we can help you evaluate the feed-water conditions and select a suitable membrane configuration. Contact Runmo with your water analysis, required capacity, and operating requirements to discuss a practical seawater membrane solution for your project.
