Reverse osmosis membranes construction
Most commonly used RO membranes are typically composed by a thin film composite membrane consisting of three layers: a polyester support web, a microporous polysulfone interlayer and an ultra think polyamide barrier layer on the top surface.
Figure 1 – Schematic cross-section of a Filmtec thin film composite membrane
Thin film composite membranes are packed in a spiral wound configuration. Such element contains from one to more than 30 sheets, depending on the element diameter and element type.
In membrane systems the elements are placed in series inside of a pressure vessel.
The concentrate of the first element becomes the feed to the second element and so on. The permeate tubes are connected with interconnectors (also called coupler), and the combines total permeate exits the pressure vessel at one side of the vessel.
Figure 2 – Construction of a spiral wound TFC RO element
The membranes are wound around a perforated permeate pipe.
Two membrane sheets are glued together on three sides, only with an opening towards the permeate pipe. The feed water flows across the membrane surface from one side to the other. Due to the high pressure in the vessel, a part of the water penetrates the membrane and this permeate water can only leave the PV through the permeate pipe, while the rest of the water - now more concentrated - leaves on the other side of the membrane , just flowing across the sheet.
Figure 3 – transversal cut of a membrane
Lenntech will design and select the membrane that most adapts to the customer and project needs.
Lenntech provides sustainable and complete solutions with RO technology, integrating it with the pre-treatment and post treatment necessary.
Our advantages
- Engineered and custom designed solutions for unique solutions.
- Turn-key solutions including design, engineering, manufacturing, automation, installation, maintenance and training.
- State-of-art technologies for effective water and wastewater treatment, recycling, reuse, and disposal.
- Best on-line assistance and on-site service and support.
Feedback Form or call us on +31 152 610 900