Service Philosophy
We are committed to provide dedicated, fast and credible service for our customers. Besides we are trying to give our customer a quality product with no inherent problems so they don’t have to revert back for support.
Service Including
- Help design the reverse osmosis system with correct membrane model.
- Water Quality Analysis.
- Bug Diagnosis and Analysis of Membrane System.
- Designs and Evaluations of Membrane System.
- Membrane System Maintenance and Staff Training.
Membrane Application Guide
| S.No | Type | Description | Model | TDS Range |
|---|---|---|---|---|
| 1 | Industrial and commercial use | High pressure brackish water | BR | For TDS up to 7000 ppm. Rejection 99.6% |
| 2 | Low pressure high rejection | LOW2 / LOW2 XL | For TDS up to 2500 ppm. Rejection 99.6% | |
| 3 | Low pressure medium rejection | LOW3 / LOW3 XL | For TDS up to 2500 ppm. Rejection 98.0% | |
| 4 | Ultra-low pressure high rejection | LOW4 / LOW4 XL | For TDS up to 1500 ppm. Rejection 99.5% | |
| 5 | Low fouling high rejection | FOUL | For TDS up to 6000 ppm. Rejection 99.6% | |
| 6 | Sea water high rejection | SEA | For TDS up to 40000 ppm. Rejection 99.6% | |
| 7 | High pressure brackish water | NF 1 | NaCl rejection 50%. MgSO4 rejection 99% | |
| 8 | High pressure brackish water | NF 2 | NaCl rejection 70%. MgSO4 rejection 99% |
Membrane System Design Guide*
According to water quality of feed and requirements of output, users need to design the membrane system with reasonable recovery rate and permeate flow per unit membrane area by applying suitable model membranes to achieve high efficiency.
If the designed permeate flow per unit area is much higher than the reasonable value, it will greatly increase the membrane fouling rate and reduces the permeate flow, besides, the membrane system will need more cost for maintaining the system. To extend membranes service life, the recovery rate should be designed around 15% of the flow. However, some users need to design higher recovery rate (around 18%) to improve the efficiency. Therefore, it is necessary to choose the reasonable array about membrane system to achieve higher system recovery rate. The combination of series or / and parallel design can extend the membranes service life and also save on energy.
Detailed Design Advice
- For single membrane system we advise concentrate recirculation. The system will use less water and improve total recovery. If the single membrane system has a recovery of more than 18%, without concentrate recirculation, the membranes will damage and scale the membrane in a short time.
- In single stage membrane system (Single pressure vessel), the membranes should be employed in series to achieve better system recoveries (Comparison between membranes employed in series and parallel).
- For higher recoveries a combination of membranes in parallel and series should be designed. We suggest as below:
- For 1 – 2 element per pressure vessels, recovery of membrane system can be achieved as 40 – 60 % using three stage arrays (4:2:1).
- For 3 – 5 elements per pressure vessels, recovery of membrane system can achieve up to 55 – 70% using 2 stage arrays (2:1).
- For 6 elements per pressure vessels, recovery of membrane system can achieve up to 75% by using 2 stage arrays (2:1).
- For 6 elements pressure vessels, recovery of membrane system can achieve up to 85% – 90% by using three stage arrays (4:2:1).
The last element in a tube should have a minimum flow of
- 8040 RO membrane element – 3.5 M3/Hr
- 4040 RO membrane element – 0.9 M3/Hr
- Note: It is normal for membranes to get fouled, contaminated and not give the desired results (reduces permeate flow and rejection) over a period of time in spite of good design and operational practices. Reverse osmosis membranes have a service life time.
Feed Quality Required For Ro And Nf Membrane Systems
| Suspended solids | Turbidity | < 1 NTU | Colloid | Flocculation and filtration (Coarse and fine) |
| SDI 15 | < 5 | |||
| Metal oxides | Fe (mg/L) | < 0.05 | Iron | Oxidation, precipitation / filtration |
| Mn (mg/L) | < 0.05 | Manganese contamination | Using dispersing agents | |
| Scale forming matter | CaCO3 | LSI < 0 | Calcium and Magnesium salts | Decrease recovery rate, pH value and add scale inhibitor |
| Other insoluble salt | / | |||
| Organics | Oil | 0 | Organics and oil pollution | Air flotation, adsorption |
| TOC (mg/L） | < 10 | Organics pollution | Adsorption / Filtration | |
| COD (mg/L） | < 10 | |||
| BOD5 (mg/L） | < 5 | |||
| Si (mg/L） | < 20 | Colloid pollution | Flocculation and filtration (Coarse and fine) | |
| pH | 3 – 10 | Both very low and very high pH is harmful to membrane surface and accelerates ageing / deterioration of membrane flat sheet. | Constant regulating and monitoring of acid and base dosed to the RO system. | |
| Temperature | 5 – 45 ℃ | Low temperature will require more driving force to facilitate reverse osmosis and increase scaling of undissolved solids. | Use heat exchanger wherever feasible in terms of operational cost. Ideal operating temperature 25 ⁰ C | |
| High temperature will increase salt passage through membrane surface and hasten ageing of membranes. | ||||
| Oxidation | Residual chlorine (mg/l) | < 0.1 | Membrane surface will get oxidised damaging active surface area allowing salt passage. | Reducing usage of the particular agent or use activated carbon adsorption. |
| Ozone and others | 0 | |||
*The information provided in the membrane system design guide is a merely a guide to conceiving the correct reverse osmosis system design. The guide is to caution the user of the impact various impurities like organics, heavy metals and suspended load can have on a membrane system. We do not make warranties about the reliability and accuracy of this system. Any action that you take on the basis of the information on this web site is strictly at your own risk.
Note:
- The poly amide membrane flat sheet has little resistance towards free chlorine / residual chlorine in water. Under the influence of varyingtemperature, pH and other conditions, the damage caused can speed up. It must advised that free / residual chlorine in feed water should be less than 0.1 mg/L.
- Iron and manganese should be less than 0.05mg/L in reverse osmosis feed water. If concentration of iron and manganese is higher than 0.05 mg/L, there are chances that the ions will oxidise, in presence of air, to form salts of Fe (OH)3 and Mn (OH)2 which will precipitate on the membrane surface to form scales, especially when the pH is higher than normal.
- Silica usually exists in surface water with a concentration of 1 – 100 mg/L. When the pH value is lower than 9.0, Silica exist in water as Si (OH)4. When pH value is low (Below 4) it is in colloidal form. When the pH value is higher than 9.0, it will exist in Si2O3 and combine with calcium, magnesium and iron form hydrated scales which would precipitate and settle on membrane flat sheet.
- Water alkalinity is mainly because of HCO3 1-. If the water pH is higher than 8.5, HCO3– will change to CO3 2- . The free bi carbonate and carbonate radicals will easily combine with Calcium to form CaCO3 and precipitate on membrane surface as a hard scale.
- If one or more above the above said factors are not controlled, then it may lead permanent membrane damage. Membrane elements are oxidized by residual chloride or contaminated by metal oxide. Suspended solid may choke the membrane elements etc.