Maxit as is a part of the international Maxit Group, which is fully owned by the French Saint-Gobain Group.The Saint Gobain is one of the world's 100 largest industrial groups. Maxit Group has activities in about 57 countries around the world and approximately 207,000 employees.

Maxit Group specializes in the manufacture of high quality clay and premix products, and is one of the largest clay manufacturers in the world.

In addition to building sector activities, maxit as develops, manufactures and sells filter media to be used for different type of water and wastewater treatment processes as well as odour treatment.

Filtralite filter media is made by burning of clay at about 1200°C, followed by crushing and sieving.

The material has a porous structure and when crushed, a large surface area is exposed. Dry particle densities in the range 500-1600 kg/m3, and aggregate size in the range 0-20 mm, can be "tailor-made" to the specific application. The aggregates do not release harmful substances, and the acid solubility is minimal. Despite its low density and high porosity, Filtralite has high abrasion and impact resistance.

Three main types of Filtralite are available, with three different densities. For drinking water applications crushed material is used. This gives angular grains and allows the porous core to be exposed to the water. Products conform to ISO9001 quality management standard.

Filtration of is the most traditional type of water treatment. Filtralite has the ideal properties to work as a good filter media in both single- and dual media filters of filtration of coagulated water.

In dual media filters Filtralite has proved to be as good as, or better than, comparable media. By replacing the most traditional top layer filter material, anthracite, with Filtralite, time between backwashes can be increased by about 25%. This means fewer stops for backwash and reduced use of backwash water, resulting in more stable water quality and lower operational costs.

An even better filter performance can be obtained by also replacing the sand in the bottom layer with Filtralite. The so called Filtralite Mono_muti filter, consisting of a bottom layer of Filtralite HC 0.6-1.6 mm and a top layer of Filterlite NC 1.5-2.5 mm, gives extremely low head loss and good water quality. Due to the low density of both layers, the water velocity needed for backwash is much lower than for for filters using sand as bottom layer.

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 operate from about 2 m/h up to around 20 m/h.

In biological filters bacteria attach to the filter media and biofilm arises on the surfaces of the filter grains. A large available surface area for bfiofilm growth is one of the most essential properties of filter media used in biofilm processes. The crushed Filtralite grains have a large surface 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 biodegradable substances can 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 water is 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 for passing 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 rate up to about 30 m/h.

In desalination plants it is of great importance for the operation of the entire plant that the pre-treatment of the water is good before the salt is to be removed. For reverse osmosis (RO) desalination plants a good pre-treatment is essential for avoiding membrane fouling, resulting in reduced water production and increased operational costs.

Filtralite has excellent properties for use in pre-treatment filters in desalination plants, both in filters for filtration of coagulated water and in biological processes. Use of Filtralite will provide low SDI values, reduced danger for bio-fouling of membranes and long filter runs between backwashes.