Advanced pre-treatment for the Reverse Osmosis protection in desalination projects

Advanced pre-treatment for the Reverse Osmosis protection in desalination projects

Desalinization technology using reverse osmosis membranes require a highly restrictive feeding water quality taking into account turbidity and suspension solids.  The projects of big desalination plants in construction and/or design stage, include discs filters and ultrafiltration membranes as advanced pre-treatment for the reverse osmosis.  

The main advantage of the pre-treatment with discs filters and ultrafiltration against other conventional technologies is the achievement of a better quality of water, minimizing the use of drain water.

Recommended filtration degree
The ultrafiltration manufacturers recommend to protect the ultrafiltration membranes using discs filters with a filtration degree among 100 and 200 micron. The suspended solids of higher size could damage the membrane capillaries, so it is essential to retain them in the pre-treatment efficiently and with a mechanism able to erase the particles by the drainage of the system.

AZUD filtration systems, together with ultrafiltration membranes, guarantee an optimum pre-treatment:
1. Selection of the best materials.
AZUD HELIX AUTOMATIC SW is a range specially optimized to the filtration of sea water. The constructive material of all the components is resistant to the sea corrosion of the sea atmosphere near the coast line. The internal components in direct contact with the sea water are mainly technical plastics (polyamide, polypropylene, high density polyethylene).

2. AZUD guarantees a safe filtration.
The discs filters work as a physical barrier, retaining all the suspension particles higher than the established filtration degree. The studied design of the discs and grooved channels of AZUD create a real in-depth filtration. Once the discs are stacked, the direction of the channels of the higher side of each discs will be always opposite to the lower side of the next disc. Such configuration of the channels creates numerous intersection points along the water trajectory inside the stack of discs, guaranteeing, in this way, the retention of particles.

3. The performance of the system guarantees the saving of water and energy.
The optimized working conditions during the filtration and backflushing stage reduce the energy consumption during the filtration and the use of drainage water during the backflushing.

4. Own technology for an optimum performance and minimum frequency and intensity of the maintenance labours.
Product of a careful hydro efficient design, the patented AZUD HELIX SYSTEM is a clogging delay system and the essential element of the system. Placed in the base of the cartridge, its deflector fins, with a suitable inclination angle, create a helical effect that takes away from the discs a high percentage of the suspended particles in the water. This is translated in a less frequency and intensity of the maintenance labours, with the consequent saving of water.

5. Small footprint and maximum modularity.
AZUD has developed a series specially optimized to high flow rates, with capacities among 300-800 m3/h per module of discs filter, designed to reduce the footprint when installing several units in parallel. The modularity of the AZUD HELIX AUTOMATIC filtering element permits to adapt the filtration system to the installation conditioning of the final customer, making easier the starting-up and the post-maintenance.

6. A wide experience.
In the last decades, AZUD has developed a long number of sea water pre-filtration projects for different sectors and applications around the world. The development of an own technology has permitted the adaptation to the specifications of the desalination treatments.