biological filter media

biological filter media

The filter bed constitutes the heart of the biofiltration equipment because it provides the support for microbial growth. T Weiland & Rozzi, (1991) have described the general requirements of ideal biological growth support media as:

  • High area to volume ratio
  • Porous or rough surface to permit bacteria adhesion
  • Biological inertia
  • High mechanical stability
  • Low cost per unit volume

Bioaction biological filter media has:

  • large specific surface area, which is favourable to microflora establishment and maintenance, and to gas/biofilm exchange;
  • high porosity to facilitate gas convection and to promote homogeneous distribution of gases throughout the bed
  • good water retention capacity to avoid bed desiccation
  • presence and availability of intrinsic nutrients
  • presence of a dense and diverse indigenous microflora
  • free drainage to mitigate anoxic conditions
  • low pressure drop


FiltaMin mineral is characterised by complex three-dimensional structures with large, cage like cavities that can accommodate sodium, calcium, or other cations (positively charged atoms or atomic clusters); water molecules; and even small organic molecules.

Because of its ability to interact with organic molecules it adds another dimension to biological growth media performance by absorbing chemical compounds that are used as feedstock for biological digestion. Its surface structure and its moisture retention make it a preferred host for biological colonisation.

The life expectancy of the organic media is greater than 10 years delivering an excellent return on investment.


BioMedia is a homogeneous blend of organic micropore filtration media derived from a highly renewable resource and a mineral sub-straight. The media has high adsorptive properties for efficient mass transfer of organics and oxygen from inlet gases into the liquid phase. 

It is long lasting with a high mechanical stability, has low bioavailability and a high surface area to volume ratio. This exceptionally large surface area and rough porous surface permits bacteria adhesion to promote biomass colonisation and distribution. Its porosity prevents pressure loss and maintains constant aerobic conditions throughout the life of the media. The life expectancy of the organic media is greater than 5 years delivering an excellent return on investment.

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