Tenselo WTR-003 estimates membrane elements, pressure vessels, array, feed and concentrate flows, pump duty, recovery, permeate quality and scaling risk. The calculation gives a checkable starting point for manufacturer modelling and detailed process design.
Inputs for preliminary RO sizing
Enter the required product-water flow and operating hours, then select the feed type, membrane element, pressure vessel, elements per vessel and target recovery. Add the laboratory analysis, including pH, EC or TDS, hardness, alkalinity, calcium, sulphate and the other measured ions that affect osmotic pressure, scaling and permeate quality.
A higher recovery reduces concentrate volume but increases the concentration of sparingly soluble salts. Pretreatment, temperature, fouling potential and the required product-water quality can control the design before nominal membrane capacity does.
Worked brackish-water RO example
The public WTR-003 example uses a 20 m³/h product-water duty, 20 operating hours per day, feed TDS of 660 mg/L and 75% recovery. The sample used the DuPont FilmTec BW30-400 catalogue entry and Codeline 80S vessels available to the Tenselo calculation on the run date.
| Output | Calculated value |
|---|---|
| Membrane elements | 30 |
| Pressure vessels | 5 |
| Array | 3:2 two-stage |
| Approximate vessel length | 6.6 m |
| Feed flow | 26.7 m³/h |
| Concentrate flow | 6.7 m³/h |
| Design flux | 22 LMH |
Read the array and chemistry together
Review the element and vessel count with the feed, permeate and concentrate balance. Check the predicted concentrate scaling, required pressure, energy and estimated permeate composition. Related Tenselo calculations cover RO mass balance and blending where the final supply combines permeate with a bypass stream.
Upstream iron, suspended solids, oxidants and biological fouling need separate treatment review. Low-mineral permeate may also require remineralisation or blending before distribution.
Verify the final design with the membrane manufacturer
Confirm the selected element, array, temperature, feed analysis, scaling control, pressure and cleaning assumptions in the current manufacturer projection software before equipment is ordered. The DuPont FilmTec technical manual identifies BW30 as a brackish-water membrane family and explains element naming and active area. Product ranges and data sheets can change.
Start with water-analysis interpretation. Use UF sizing when particulate or microbial removal is being assessed as RO pretreatment.
Questions
What does a reverse-osmosis design calculator size?
Tenselo WTR-003 estimates membrane elements, vessels, array, feed and concentrate flows, pressure, energy, recovery, permeate quality and scaling risk for a preliminary brackish-water RO duty.
What water analysis is needed for RO design?
Use a representative laboratory analysis with pH, conductivity or TDS, hardness, alkalinity, calcium, sulphate and the other measured ions and contaminants relevant to scaling, osmotic pressure, pretreatment and product-water quality.
Can the highest possible RO recovery be used?
Recovery must remain within scaling, fouling, pressure and product-quality constraints. A higher recovery concentrates salts in the reject stream and can make the design unsuitable.
Does Tenselo replace DuPont WAVE or Hydranautics IMSDesign?
No. Tenselo provides a preliminary, checkable design workflow. Confirm the final membrane selection and performance in the current manufacturer software before ordering equipment.