Filtralite - Leca Norge AS

Filtralite - Leca Norge AS

Leader in Europe for expanded clay material, Leca Norge AS also manufactures products dedicated to water filtration and biological removal in drinking water and wastewater plants. With its unique porosity, Filtralite® Pure and Clean filter media offers optimum conditions for water to flow through the filter bed in order to retain more contaminants. Our products not only increase water output volumes, they also decrease operation costs. By replacing conventional sand filters with Filtralite® filter media, you can expect to get your money back in less than 3 years.

Company details

Årnesvegen 1 , Nordby , Oslo 2009 Norway
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Business Type:
Industry Type:
Water Filtration and Separation
Market Focus:
Globally (various continents)
Year Founded:


Our purpose

Whether you live in Cairo, Chicago or Copenhagen, there is an increasing influx of people to the big cities. Demographic changes and urbanisation across the globe put a strain on cities and their capacity to produce basic necessities such as drinking water.

With its unique porosity, Filtralite Pure and Clean filter media offers optimum conditions for water to flow through the filter bed in order to retain and adsorb more contaminants. This feature allows for larger volumes of water to be filtered through the same volume as contact area is increased. Water management facilities can thereby increase their output without having to rebuild and expand existing facilities simply by replacing the conventional filtering media with Filtralite.

Our products not only increase water output volumes, they also decrease operation costs. By replacing conventional sand filters with Filtralite filter media, you can expect to get your money back in less than 3 years.

Because Filtralite Pure and Clean filter media requires fewer backwashes, which means less energy and less water loss, which at the end of the day means more water out of your plant. This way, we ensure you get more out of the resources you already have.

As cities are gearing for the future, Filtralite Pure and Clean filter media is an innovative and premium filtering product tailored to meet tomorrow’s needs.

Filtralite filter media are used for a number of water treatment applications; such as drinking water treatment, wastewater treatment and on-site treatment of effluent water.


Research and Development

The development of Filtralite filter media is carried out in close cooperation with universities and research institutes both in Norway and worldwide. Many doctoral and master thesis, reports and papers have been written on various aspects of the use of Filtralite for drinking water and wastewater treatment.



Filtralite filter media is made by the burning of clay at about 1200º C, followed by crushing and sieving of the resulting expanded, clay pellets. The material has a very porous structure, and crushing exposes large surface area. Dry particle densities are in the range 500-1,600 kg/m³, and the aggregate size range is 0-20 mm. Filtralite materials are flexible and can be 'tailor-made' for specific applications. The aggregates do not release any harmful substances and the acid solubility is minimal. Despite its low density and high porosity, Filtralite has high abrasion and impact resistance.

Filtralite is manufactured by Leca Norge As, which is part of the international Saint-Gobain Group, world leader in the habitat and construction markets. The group is specialized in designing, manufacturing and distributing building materials, providing innovative solutions to meet growing demand in emerging economies, for energy efficiency and environmental protection.

Leca specialises in the manufacture of high quality expanded clay and premix products, and is one of the largest expanded clay manufacturers in the world. In addition to building sector activities, Leca develops, manufactures and sells filter media to be used for different types of water and wastewater treatment processes as well as odour treatment.


Filtralite® filter media holds international certifications for drinking water components, quality and environmental management including the European Norm EN 12905 and NSF/ANSI 61.


Leca Norge AS takes responsibility for our environment that provides us with the materials we use to create Filtralite products.


Reduction of emissions is a high-priority environmental factor

Controlling and limiting our energy consumption is an important issue, as production of lightweight expanded clay aggregates requires a great deal of energy. ISO 14001 is implemented in the entire Leca organisation in Norway, where Filtralite is produced. By working systematically with this norm, ambitious measurable environmental targets can be established and evaluated.


Transport & delivery

Leca Norge AS has a lot of experience with transporting and delivering Filtralite to almost all parts of the world. Delivery method varies from project to project, subject to the customers needs and the type of media. Most types of material qualities can be delivered in bulk or in big bags, with road or sea transport.

By using tank trucks with blowing equipment, the Filtralite products can be pneumatically discharged directly into the plant filters. Filtralite Nature P, Filtralite Pure NC 0,8-1,6 mm and Filtralite Pure NC 1,5-2,5 mm are not recommended for pneumatical discharge.

Delivery in big bags can be done for all applications and all Filtralite products. Big bags that are open at the top will normally be used. Most of the materials are normally delivered in 1,5 m3 big-bags. For deliveries to on-site wastewater treatment systems, the material is delivered in 1,0 m3 big bags. The big bags can be transported on trucks, trains or boats, or they can be stuffed into containers. Transport in containers is a good solution for smaller volumes and long sea transports.



During delivery of Filtralite, it can sometimes be necessary to temporarily store the material. Filtralite filter medias can be stored outdoors without decrease of quality. It should be taken into consideration that the materials will absorb water during rainfalls, which will make the media heavier and may increase transport costs. To avoid degradation of the big bags they should not be stored outdoors for more than 6 months.

Filtralite Nature P should not be stored outdoors, as rainfall may wash out parts of the material, which may result in reduced efficiency of the media.


Filtralite are inert ceramic particles with a dense shell surrounding a porous core.

Filtralite is an expanded clay product with high porosity. The pores are of varying sizes from small micro pores to larger pores (1-2 mm), most of them linked in labyrinthlike structure. By crushing the expanded clay beads, their large surface area is exposed. The large porous surface makes the Filtralite aggregates perfect for different types of water treatment. Porosity and density are controlled during manufacture of Filtralite. Dry particle densities can be produced in the range of 500-1600 kg/m3, with a corresponding dry bulk density of 300-900 kg/m3.

During the burning of the clay, strong bonds are created. Consequently the beads are unnaffected by any traditional gases or liquids, and release of harmful substances is avoided. Resistance to chemical breakdown is very high, and the acid loss is minimal.

Despite its low density and high porosity Filtralite has a high abrasion and impact resistance. Material strength is dependent on particle density. When particle density is increased, resistance to abrasion and physical impacts is increased.

Filtralite is inert ceramic particles with a dense shell surrounding a porous core.This makes it suitable for use in different drinking water treatment processes, such as:

  • Physical filtration
  • Biological filtration
  • Pre-treatment for desalination

Drinking water treatment

Filtralite's large pore volumes and surface areas make it an ideal media for biological treatment of drinking water. Biofilm processes are excellent for treating raw water containing ammonia, manganese, iron etc. Tests have shown that Filtralite works perfectly in these kinds of processes. In conventional filtration processes Filtralite can be used in different ways.

In dual media filters Filtralite can be used in combination with sand. Tests have shown that Filtralite operates as well as or better than traditional filter media in these types of filters. Filtralite can not only be used in traditional drinking water treatment, but also in treatment of saline water. In desalination plants one of the most important parts is the pre-treatment process. Filtralite is an excellent filter media for use in pre-treatment filters in desalination plants.

Physical Filtration

Filtration of water is themost traditional type of watertreatment. Filtralite has the ideal properties to work as a good filter media in both mono and dual media filters for filtration of coagulated water.

Compared to traditional filter media like sand and anthracite Filtralite has much higher porosity, which gives lower initial head loss, slowe rhead loss build up and higher storage capacity. These advantages result in much longer filter runs between backwashes, which mean reduced energy and water consumption and higher water production, giving reduced operating costs.

By replacing sand with Filtralite in single mediafilters the operating timebetween backwashes can beextended by up to 500%. Fordual media filters a changefrom sand and anthraciteto the dual media FiltraliteMono-Multi, consistingof two different qualitiesof Filtralite, can give up to800% longer filter runs. Ifonly the top layer is replacedwith Filtralite and the bottomlayer of sand is kept the filterruns can be extended by upto 50%.

For existing filters withlow backwash velocities a change from sand to Filtralite will help in keeping the filters clean, as Filtralite is much lighter than sand and therefore need lower backwash rates for cleaning. Filters with Filtralite can be operated within a large range of filtration rates. The filtration rate will always be dependent of the configuration of the filter and the treatment process. Existing Filtralite filters operatefrom about 2 m/h up.

Biological filtration

In biological filters bacteria attach to the filter media and a biofilm arises on the surfaces of the filter grains. A large available surface area for biofilm growth is one ofthe most essential properties of filter media used in biofilmprocesses. The crushed Filtralite grains have a largesurface area, resulting in Filtralite being an ideal media for use in biological treatment processes.

Tests have shown that Filtralite is as good as or better than alternative carrier materials for biological treatment of drinking water. Ammonia, iron, manganese and other bio degradable substance scan be effectively removed in biological treatment using Filtralite as a carrier media. An important factor for an efficient biological treatment process is the time the wateris in contact with the biofilm. The most common way to quantify the contact time is the Empty Bed Contact Time (EBCT), which is defined as the time the water needs forpassing through the entire filter volume.

The needed EBCT vary for different water qualities and treatment systems, but about 20 minutes is quite normal for many systems. To be able to define the correct EBCT for a specific system it is recommended to run a pilot test. Existing Filtralite biofilters operate with filtration rates.