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Article : BW30400

DOW Filmtec™ BW30-400 Membrane Element

Dow Filmtec™ BW30-400 is a high performance membrane element for brackish water.

Dow Filmtec™ BW30-400 is the best choice to obtain the highest quality of permeate. This is the first membrane element with a surface area of ​​37 m2. It is used both in existing systems and to design new ones, in which capital investment and productivity are important.

Key advantages

  • Dow Filmtec™ membrane (USA) is the world standard for water purification

  • Dow Filmtec™ elements can be washed in wider pH range (1-13) than other reverse osmosis membranes

  • Large active surface of ​​the element provides higher productivity

  • Automated high-precision production makes it possible to obtain elements with maximum active surface

Membrane type – spiral-wound element with polyamide thin-film composite

Nominal active surface, m2

Operating pressure, bar

Permeate volume, m3/day

Stabilized salt rejection, %





  1. Permeate consumption and salt (NaCl) rejection are indicated for the following test conditions: 2 000 mg/L NaCl, 25°C, pH 8, indicated pressure and 15% permeate recovery.

  2. Flow rates of permeate for every specific element might vary, but will not fluctuate by more than 15% from the indicated values.

Operating conditions

Maximum operating water temperature, °С


Maximum operating pressure, bar


Maximum pressure drop, bar


pH range, operational mode


pH range, chemical cleaning mode


Maximum feed silt density index (SDI)

SDI < 5

Free chlorine tolerance, mg/L

< 0.1

Before launch of the reverse osmosis system preliminary preparation of the membrane, refill of the elements, adjustment of the devices and other system checks should be performed.

Avoid any major pressure or flow surges inside the spiral-wound elements in the middle of launch, stop, cleaning etc. to avoid risk of damage infliction to the membrane. During the launch it is recommended to gradually switch the system from standstill to operational mode following the steps:

  • gradually increase feed water pressure during 30-60 seconds

  • operational rate of the flows should be developed gradually during 15-20 seconds

  • permeate obtained within the first hour of operation is discharged

Important information

  • After the initial soaking always keep the elements wet.

  • To prevent biofouling during long operation breaks it is recommended to submerge the membrane elements into preservative solutions.

  • Maximum pressure drop along the full length of the housing makes 2.1 bar.