Pressure Disc Filter as reliable protection for Ultrafiltration membrane modules
Both in the municipal drinking water treatment and in the treatment of swimming pool water, ultrafiltration has already established itself as the state of the art. Thanks to its compactness with significantly less flushing volume, very high retention rates for turbidity and ensuring sterility even with fluctuating raw water quality, ultrafiltration systems have replaced classic sand filter systems. In conventional wastewater treatment, they can either be used as a "polishing" stage after the secondary clarification, in order to improve the quality of the effluent water with regard to pathogenic microorganisms, or used directly in the aeration tank to degrade substances that are difficult to biodegrade, such as drug residues. The high selectivity of the membrane also contributes to increasing the efficiency of many industrial processes and helps to recover certain substances in the manufacturing process and thus reduce their consumption. A wide range of applications in the food and metal industry is known.
Ultrafiltration membranes are purely porous membranes, the flow through the membrane is purely convective and the driving force for mass transport is a pressure difference on both sides of the membrane. The working range of ultrafiltration is normally between 3 bar and 10 bar. In ultrafiltration, a distinction is made between static (dead-end) and dynamic (cross-flow) operation. In static operation, the membrane is flown through orthogonally, retained particles are deposited on the membrane and a filter cake is formed. In dynamic operation, the feed flows over the membrane in parallel at higher flow rates, which controls the formation of a covering layer on the membrane.
So that the ultrafiltration systems can be operated reliably and for a long time, it is important to operate them professionally and to offer them optimal protection against mechanical damage. Regular automatic permeate backflushing and chemical cleaning (CIP) including regeneration at regular intervals clear the membranes blocked by scaling and fouling and make them available for further filtration. To prevent fiber breakage, the installation of a suitable pre-filter, which acts as a physical barrier for the membranes, is required.
The AZUD HELIX AUTOMATIC disc filter systems with automatic backwashing are particularly suitable as pre-filters for ultrafiltration systems. With a standard filter fineness of 200 μm and a throughput of 20 m3/h/filtering element with a filter surface of 1,620 cm2, the pre-filters show excellent performance when it comes to removing particles. Even fibrous particles such as hair and textile fibers as well as dust and organic particles, which are often found in high concentrations in the backwash water of ultrafiltration systems, are reliably removed.
AZUD HELIX AUTOMATIC 209/8FX AA
In addition to the important protective function of the membrane modules, the pressure disc filters contribute to reducing the frequency of backwashing of the ultrafiltration systems and thus to reducing water consumption. The intervals between CIP cleaning of the ultrafiltration modules are extended thanks to the pre-filter, which significantly reduces the consumption of CIP chemicals, electricity and water. Such optimal operation leads to a significant increase in the service life of membrane modules.
Filter system AZUD WATERTECH GW DU