The Remarkable Power of Ultrafiltration

Ultrafiltration harnesses the force of mechanics to maintain its continuous filtering efficacy. This method of water purification stands out for its exceptional effectiveness and sustainability. The roots of ultrafiltration with membrane technology can be traced back to the healthcare sector, specifically kidney dialysis. Dialysis involves the exchange of dissolved substances in water through a semipermeable membrane, which closely resembles other filtration techniques such as microfiltration, nanofiltration, and reverse osmosis. The key distinction lies in the size of the membrane pores.

Ultrafiltration operates on the principle of a pressure differential across the membrane, spanning from the feed side to the filtrate side. The membrane is designed to retain larger particles than the size of its pores, resulting in separation based on particle size. It is, in essence, a physical separation method.

Membranes can be utilized in two main configurations: dead-end and cross-flow. In the dead-end setup, all water is compelled to pass through the membrane. Conversely, in cross-flow, the incoming raw water circulates along the membrane surface, generating speed and turbulence, which is particularly effective for treating heavily polluted water.

Periodic cleaning of the membrane surface is essential. Various cleaning methods can be employed, with backwashing using filtrate being the most commonly known. An alternative approach involves an air flush on the raw water side of the membrane, and chemical cleaning is also an option.

Ultrafiltration in the Battle Against Legionella

Ultrafiltration operates on a membrane-based technique, where water is pushed through a membrane wall under low pressure. The membrane’s pore size typically ranges from 0.015 to 0.03 μm. Supplied drinking water is forced through these pores under a pressure of at least 2 bar of pre-pressure. Viruses and bacteria are trapped within the membrane channel, while purified water flows out to the water installation. This process achieves a remarkable reduction in legionella bacteria by 99.9999% (Log 6), along with other bacteria and viruses.

Ultrafiltration’s Role in the Algae Industry

Turbin leverages ultrafiltration for algae harvesting and water purification purposes:

1. Water Purification: Turbin offers water purification solutions that effectively cleanse both fresh and saltwater for algae cultivation and production.

2. Algae Pre-concentration: Turbin provides pre-concentration solutions to increase the concentration of algae cultures before harvesting.

3. Water Recycling: Turbin offers solutions for cleaning water and media to enable efficient recycling within the algae industry.

Ultrafiltration as Pretreatment for Reverse Osmosis

Ultrafiltration serves as an excellent pretreatment step for reverse osmosis. In reverse osmosis, a semipermeable membrane is employed to remove particles from water. This filtration effect is achieved by creating a pressure difference. Solutes in the water move toward the side where the total pressure (external pressure plus osmotic pressure) is lowest. If the external pressure on the side of the concentrated solution is sufficiently high, pure solvent passes through to the other side, leaving the solute behind and yielding pure, treated water.