Filtralite® products are made of expanded clay aggregates; they are available in 3 different particles densities:

Abbreviation Definition Particle density
N Normal density 1100 kg/m3
M Medium density 1300 kg/m3
H High density 1700 kg/m3

The production process can also include a crushing phase in order to gain access to the internal pore structure of the aggregates and increase the specific surface area (SSA). Some Filtralite® products are not crushed, and available in a "round" form.

Abbreviation Definition





The production process ends with a sieving phase to obtain specific grain size fractions.

The Filtralite® products are divided into 4 groups according to their application:

  • Filtralite® PURE for drinking water solutions, including treatment prior to desalination, both for physical filtration and biological removal.
  • Filtralite® CLEAN for for wastewater treatment,both for biological process and tertiary filtration.
  • Filtralite® NATURE for onsite water remediation. Nature-P is enriched with natural dolomite to increase phosphorus removal properties.
  • Filtralite® AIR for odour treatment based on biological process.

The table below gives an overview of the Filtralite® products:

Filtralite® product Grain size [mm]* Bulk density [kg/m3] Particle density [kg/m3]** Voids

* undersize and oversize are inferior to 5%, respectively.

** Average value. Specific batch can vary +/- 15% from this value.

Our recommended solutions include:

  • Filtralite® PURE Mono-Multi which is a combination of HC material 0.8-1.6 (bottom layer) and NC 1.5-2.5. (upper layer), this dual media is analogue to sand and anthracite filters.
  • The Filtralite® PURE Mono-Multi Fine solution is similar, but a finer fraction is used for each layer.
  • The best material for carrying out the biological process in drinking water treatment (removal of NH4, NO3, Mn, Fe, ...) is Filtralite® PURE HC 2,5-5.
  • For biological wastewater treatment processes Filtralite® CLEAN HC 2,5-5 for nitrification, HR 3-6 and HR 4-8 for denitrification. Filtralite® CLEAN MC 2,5-4 for the final filtration of wastewater.


Settling velocity control is an important parameter of success of our solutions : more details can be found here.


Chemical composition of the Filtralite® products is as follows:

SiO2 Al2O3 Fe2O3 K2O CaO Na2O
63% 17% 7% 4% 2% 2%