Water treatment - Reverse osmosis (RO) process

1. What can RO membranes filter?

A reverse osmosis membrane is a semi-permeable barrier that allows certain substances to pass through while preventing others from passing through. It is a key component in the RO process, which purifies water by removing dissolved solids, bacteria, viruses, and other contaminants. The semi-permeability of the membrane means it allows water molecules to pass through but blocks larger molecules and ions. This selective permeability is what makes the RO process so effective at purifying water.

2. What is RO reverse osmosis membrane?

RO reverse osmosis membranes for industrial applications are generally made of three layers of polymer materials, including: non-woven fabric, polysulfone layer, and desalination layer.

3. What is the principle of RO reverse osmosis?

Reverse osmosis is a water purification technology that uses a semi-permeable membrane to remove impurities from water. It is based on the principle of osmosis, which uses pressure to reverse the natural process of osmosis. Osmosis refers to the movement of water molecules through a semi-permeable membrane from an area with a lower solute concentration to an area with a higher solute concentration. In reverse osmosis, pressure is applied to the side with a higher solute concentration, forcing the water molecules to move in the opposite direction, from the side with the higher solute concentration to the side with the lower solute concentration. This process allows the semi-permeable membrane to effectively remove impurities and contaminants, resulting in purified water on the other side of the membrane.

4. How does reverse osmosis work?

The reverse osmosis system consists of multiple filtration stages to ensure effective purification. The process typically includes pre-filtration, membrane filtration, and post-filtration. During the pre-filtration process, sediment and larger particles are removed to protect the film. The water then passes through a semi-permeable membrane, where dissolved solids, chemicals, bacteria, viruses, and other contaminants are captured and separated from pure water.

5. The recovery rate of the RO process

Recovery rate refers to the amount of pure water produced by the RO system compared to the amount of feed water it treats. It is an important parameter that determines the efficiency of the RO process. Higher recovery means that a larger percentage of feed water is converted to pure water, while the rest is discharged as concentrated water. Achieving optimal recovery rates is crucial for striking a balance between water conservation and system performance. Firstly, it helps to conserve water and reduce waste. Secondly, it affects the efficiency of the system and its ability to remove impurities effectively. Low recovery rates can lead to high concentrations of impurities in the concentrate, reducing the overall quality of the purified water. Therefore, it is essential to design and operate RO systems with optimal recovery rates to suit specific water quality requirements and intended applications.