Ultrafiltration Membranes: Pressurized vs. Submerged

Produced water quality

There is no difference between the two technologies, the turbidity of the discharge is less than 0.5 and the SDI is less than 3.

Recovery rate 

Comparing the process parameters, there are two significant differences. One is gas-water backwashing and the other is discharge.

Since the pressure ultrafiltration process discharges the water in the membrane module and the submerged ultrafiltration discharges the water in the membrane cell, this significant difference is reflected in the recovery rate, which can reach 92-95% for pressure ultrafiltration and 90-92% for submerged ultrafiltration.

From the point of view of recovery rate, pressure ultrafiltration is more advantageous.

Construction cost

Pressure ultrafiltration does not need membrane pond, civil construction cost is saved; submerged ultrafiltration needs membrane pond, civil construction cost is increased.

Operating cost.

Because the gravity of water can be used, submerged ultrafiltration operation energy consumption is low, and the operation cost is greatly reduced; while completely relying on the positive pressure of the pump, pressure ultrafiltration operation energy consumption is relatively higher.

According to engineering experience, the electricity consumption of pressure type ultrafiltration is 0.2 degrees per ton of water produced, and 0.1 degrees for submerged type.

Floor space

Take a 50,000-ton membrane system water plant as an example, the pressure type ultrafiltration covers an area of 24m×8m; if the project is reconstructed into a submerged ultrafiltration process, the water filter tank and pumps and other equipment remain unchanged, the footprint only needs to be 18m×6m.

Therefore, the submerged ultrafiltration has a great advantage in terms of floor space.

It can be seen that either pressure ultrafiltration or submerged ultrafiltration can accomplish the purpose of reclaimed water reuse, but it is only necessary to choose the appropriate process according to the requirements of the project.

Pressure ultrafiltration is especially suitable for small and medium-sized projects because it is more convenient to install; if you are more concerned about the construction cost of the project, you can choose pressure ultrafiltration.

While submerged ultrafiltration operates with low energy consumption, the larger the project scale, the more obvious the advantage.

For large projects, if treating one ton of water can save 0.1 degree of electricity, it can save a considerable amount of operation cost. If you are more concerned about the project operation cost, large BOT projects, you can choose the submerged ultrafiltration process.