LP (low pressure) series of aromatic polyamide compound membrane elements has the following properties of low-pressure operation, high permeate flow and excellent desalination and is applicable to desalination of brackish water. Besides, it is particularly applicable to fabrication of high-purity water for the electronics industry and the electric power industry owing to its excellent performance in removing soluble salts, TOC, SiO2, etc.

XLP series of extremely low pressure aromatic polyamide compound membrane element can work under ultra low pressure to reach as high permeate flow and salt rejection as regular low-pressure membrane element can, and is applicable to desalination of surface water and underground water. It operates under approximately half the operating pressure of regular low-pressure composite membrane, and achieves a salt rejection rate of up to 98%, which can decrease the investment costs for such relevant facilities as pump, piping, and container, etc. and the operating cost for the RO system, thus increasing the economic efficiency.

Technical specifications of RO Membrane Elements

MODELLP-4021LP-4040LP-8040XLP-4021XLP-4040XLP-8040
Active membrane area, ſt 2 (m2)36 (3.3)90 (8.4)400 (37.2)36 (3.3)90 (8.4)400 (37.2)
Average permeate GPD, (m3/d)950 (3.6)2 400 (9.1) 110500 (39.7)1 000 (3.78)1 000 (3.78)12 100 (45.7)
Stable rejection rate, %99.599.599.5989898
Min. rejection rate, %99.399.399.397.597.597.5


Testing Conditions

Testing ConditionsValues
Testing pressure225 psi (1,55 MPa)
Testing solution temperature25 °C
Testing solution concentration (NaCl)2 000 ppm
Testing solution pH value7,5
Recovery rate of a single membrane element15%


Operation Limits & Conditions

Operation Limits & ConditionsValues
Max. working pressure600 psi (4,14 MPa)
Max. volume of feed water75 gpm (17 m3/h)
Max. temperature of feed water45°C
Max. feed water SDI15 5
pH range of feed water during continuous operation2 ≈ 11
pH range of feed water during chemical cleaning1 ≈ 13
Residual chlorine concentration of feed water< 0,1 ppm
Max. pressure drop on a single membrane element15 psi (0,1 MPa)
Max. pressure drop on a single pressure vessel with six RO membrane elements50 psi (0,34 MPa)


Notes and Recommendations

1. All data and information provided on this site have been obtained from a long-term experiment by the manufacturer of the membrane elements. The manufacturer assumes no liability for any outcomes caused by the user’s failure to abide by the conditions of use and maintenance specified in the product manual. It is strongly recommended that the user strictly follows the designed use and maintenance requirements and keeps relevant records.

2. The permeate value listed in the table is the average value. The permeate flow of a single membrane element has a tolerance not exceeding ±15% of the nominal value.

3. All wet-type membrane elements have been strictly tested before leaving the factory, and have been treated with 1.0% sodium hydrogen sulfite (10% glycerin antifreeze required in winter) for storage purpose, then sealed with a plastic bag in a vacuum, and further packed in cardboard boxes.

4. After being used the membrane element should remain wet. To prevent the breeding of microbes in the idle membranes, it is recommended to soak the membrane elements with a protective solution of 1.0% sodium hydrogen sulfite (foodstuff -purpose) prepared with RO-filtered water.

5. Conduct low-pressure flushing for 15-25 minutes of first use, then high-pressure flushing for 60-90 minutes when first used (with permeate volume no less than 50% of designed volume). Discard all the permeate and condensed water produced during the first hour after the system start-up.

6. During storage time and operation period, it is strictly prohibited to add any chemicals that may be harmful to membrane elements. In case of any violation in adding chemicals, the manufacturer assumes no liability for any incurred damage.

7. Along with technical development and product renovation, all information will be subject to modification without prior notification.

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