Multi-layer filters are a special form of filtration system that uses several layers of different filter materials to achieve a high purification performance. This technology is often used in industrial water treatment and wastewater treatment to efficiently remove particles, turbidity and dissolved substances.
Table of contents
Structure and mode of operation
A multi-layer filter typically consists of several superimposed filter layers with different grain sizes and densities. These layers are arranged so that the water flows from coarse to finer filtration. The main components are
- Coarse layer (anthracite or quartz gravel):
- Removes larger particles such as sand or suspended matter.
- Fine layer (quartz sand):
- Filters out finer particles and turbidity.
- Support layer (coarse gravel):
- Ensures the functionality of the filter system and protects the filter nozzles.
The water passes through the layers from top to bottom, whereby the particles are retained in the respective layers. This enables staggered cleaning and extends the service life of the filter.
Photo: Our ALMA FIL multi-layer filters, which can also be operated with granulated activated carbon
Filtration process
The process comprises three main phases:
- Operating phase:
- The water flows through the various filter layers. The suspended matter and particles are retained in the appropriate layers according to their size.
- Backwash:
- To maintain the filter performance, the layers are regularly backwashed. Water is passed through the multi-layer filter in the opposite direction to remove the accumulated impurities.
- Rinse:
- After backwashing, the multi-layer filter is rinsed to remove residual impurities and prepare the filter for the next cycle.
Photo: ALMA FIL multi-layer filter with H2O2 backwash system as a 2-line pendulum system
Advantages of multilayer filters
- High filtration efficiency: Multi-layer filters can remove particles of different sizes and densities.
- Long service life: The staggered filtration distributes the dirt load over several layers, which extends the cleaning intervals.
- Flexibility: Adaptable to different water qualities and applications thanks to different combinations of filter materials.
- Energy efficiency: Low pressure loss compared to other filtration technologies.
Areas of application
Drinking water treatment:
- Multi-layer filters are able to remove particles and turbidity from raw water in order to achieve drinking water quality.
Wastewater treatment:
- Before being discharged into the sewage system or into bodies of water, wastewater is cleaned of suspended solids and organic residues in multi-layer filters.
Cooling water systems:
- Protection of heat exchangers and cooling systems from contamination.
Process water treatment & water recycling:
- Protection of membrane systems such as ultrafiltration or reverse osmosis against coarse impurities.
Photo: ALMA FIL multi-layer filter as a police filter in the outlet of our ALMA CHEM MCW CP system
Technical aspects and optimization
- Filter materials: The choice of materials depends on the water quality and the specific requirements. Typical materials are anthracite, quartz sand and activated carbon.
- Automation: Modern multi-layer filters are often equipped with automatic controls that monitor and optimize backwash cycles and flow rates.
- Scalability: Multi-layer filters have a modular structure and can be designed for small to large volumes of water.
ALMAWATECH solutions: ALMA FIL
ALMAWATECH offers customized multi-layer filter systems for the most diverse requirements in water and wastewater treatment. Our systems are characterized by high efficiency, durability and easy maintenance. With our pilot tests, we can determine the optimum filter configuration for your specific requirements.
Conclusion
Multi-layer filters are a proven and versatile solution in water treatment. Thanks to their modular design and high efficiency, they contribute to compliance with strict water quality standards and are an indispensable technology in many industrial applications.
For further information on our products, please feel free to contact us at any time!
