Types of filters Anthracite, Silica, Volcanic Rock and Garnet
Filter products for water treatment
How is the filtration of solids in suspension carried out?
Filtration is one of the most universal processes in all types of water treatment and one that we reproduce in a controlled way when designing the bed. This process occurs in nature with the passage of water through the different layers of soil and rock. The filtration consists of the separation of solid particles suspended in a liquid, passing it through a filter with one or more layers of granular filter media of different sizes, densities and nature.
How filter products work?
The selection of raw materials that comply with the strict law in force, requires in-depth knowledge and this is our specialty.
The most common filtering medium is siliceous sand, which must be pure, with high hardness and a uniform granular size and spherical shape. Our sand meets all these criteria and we guarantee that it’s of a fluvial origin to avoid the unwanted fines and angular granules that crushed sand produces.
The apertures at the bottom of the filter can often become blocked with fine filter products and it is therefore sometimes necessary to protect them with a layer of support gravel. The coarse gravel forms a barrier between the filtering medium and the openings eliminating the risk of obstructing them.
The anthracite that we provide to our customers is a granular filtering anthracite of low density and high uniformity. It is installed on a bed of sand. This bi-layer bed can prolong the filtration cycles between counter-washes with a significant saving of energy and washing water. Our anthracite chemically meets the requirements of EN regulation: 12909.
Garnet is a high-density alumina silicate, rich in iron, also known as almandite Fe3Al2 (SiO4) 3. It is installed in thin layers (100-200mm) under the bed of sand and is used to retain very fine particles that have managed to pass through the silica bed. The granulometric size of this garnet may be slightly finer than the particle size of the silica but due to its higher density, the fine garnet will not rise through the silica bed during back-washes.
Volcanic rock is a highly-porous, amorphous alumina silicate with a low density and hardness make it an ideal material for water treatment applications. It can be used both as an economic alternative to other filter media (such as anthracite or activated clay) and as a media in bio-filtration where its rough surface makes it an excellent support for biological matter.
Filtration glass functions as an alternative to traditional silica sand for certain applications. It offers numerous advantages such as the reduction in the use of chemical agents and less energy demand given that its non-porous surface resists the adherence of bacteria and thus requires less back washing. It is also environmentally advantageous given that it is manufactured from 100% recycled glass and can be recycled again at any time, thus reducing waste.