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Spacer Tube RO/NF STRO / STNF

STRO/STNF Membrane Introduction




With the development of membrane technology industry, there are differentiated requirements to the performance of the membrane products, such as lower feed quality requirements, higher pressure to improve concentration ratio, longer cleaning cycle and service life. As a result, the open channel type with high pressure membrane arises at the historic moment.


High strength design, up to 120 bar operating pressure

Open feed spacer with low flow resistance and concentration  polarization 

Spiral wound structure with more membrane area 

More options for feed spacer


Industrial wastewater

High salts wastewater

Spiral wound RO/NF concentrates

Open feed spacers

STRO/STNF module

STRO/STNF membrane

High pressure vessel 

SUS center link

Inlet and outlet pipe and accessories

Comparison of STRO/STNF Membrane and conventional RO/NF Membrane

Identical Difference
High membrane area SUS center link with high strength and stability
Integrated design Uniform internal water distribution structure
Cross flow filtration Reduced impact of the membrane module flow, higher cross-flow

Open feed channel 

STRO/STNF Membrane Specifications 

Model STRO1-8035
   STRO5-8042 STNF2-8042
   Membrane type RO1 RO5 NF2
   Membrane materia Composite Polyamide
   Membrane effective area (m2)
25 27 27
   Element configuration *
Spiral, fierglass, brine seal
   Feed flux range (m3/h)
5.5-12 5.5-12
   Recommended feed flux (m3/h)
10 10
   Stable permeate flux ** (m3/d)
24 18 25
   Stable salt rejection  **(%)
98.5 99.5 98
   Min. salt rejection (%)
97.5 99 96
   Feed spacer
Special open channel
   Max. TMP (bar)
0.7 0.7
   Max. operation pressure  (bar)
120 90
   Max. operation temperature  (℃)
40 40
   Feed (SDI)
≤ 6.5
≤ 6.5
   pH  (continuous)
3-11 3-11
   pH (cleaning)
2-12 2-12
   Chlorine tolerance (ppm)
≤ 0.1
≤ 0.1

*    Salt seal installed on the end of the flow, low pressure side / permeate side.

**  Stable flux, salt rejection based on the following test conditions:

      RO1: 2000mg/l NaCl , pressure 15.5bar, recycle rate 15% , temperature 25℃, pH=8. 

      RO5:32,000 mg/l NaCl , pressure 55bar, recycle rate 8%, temperature 25℃, pH=8. 

      NF2:2000 mg/l MgSO4,  pressure 7barr, recycle rate 15% , temperature 25℃, pH=8.

Note: We can provide any flat sheet membrane to make ST module, for example: STRO4-8035, STRO5-8035, STRO1-8042, STNF1-8042, etc.

Mod                8035
Element total length (A)
890mm 1070mm
Element diameter (B)
200mm 200mm
Center tube outer diameter (C)
60.2mm 60.2mm
Membrane body length (D)
838mm 1016mm