Cascade Filterpak™

Cascade Filterpak™ Media

Veolia Water Technologies has developed a range of high-efficiency plastic media that provide the optimum effective surface area for biological growth whilst ensuring excellent gas and liquid distribution within the packed bed.


Cascade Filterpak Media are ideally suited for use in traditional trickling filter applications and further complimented with a range of neutral buoyancy media specifically designed for use in Submerged Aerated Filters (SAF) Anaerobic reactors.

Operating data from plants installed over the past three decades has enabled MTI to develop computer software that accurately calculates the required media volume for any specific municipal or industrial applications, thereby offering process security with a guaranteed high quality effluent.



  • Optimum bacterial attachment
  • Ideal effective surface area and void ratio within the packed bed
  • Guaranteed effluent quality
  • Controlled orientation within the reactor, ensuring optional three dimensional liquid distribution, increased hydraulic retention time and improved liquid film diffusion within the media bed
  • Designed for installation in a random orientation
  • Resistance to shock loadings, with fast recovery times




  • Material of manufacture: strong, lightweight, thermoplastic resin (polypropylene)
  • High aspect ratio (HAR) design
  • Robust, well-proven products
  • Suitable for wastewater treatment applications
  • Non toxic to micro-organisms
  • Immune to rot, fungus or bacterial attack
  • High resistance to ultra-violet degradation, ageing, erosion and disintegration
  • Recyclable material
  • No need for cutting or shaping to suit individual reactor profiles
  • No need for dwarf walls or expensive under drainage systems
  • Local production utilised wherever possible to ensure shipping costs are negated and money is put back into the local economy



  • 100 to 200 m2/m3
  • 95% open voidage
  • Polypropylene for long life
  • Random configuration for improved process performance and ease of installation
  • Guaranteed effluent quality



Polypropylene Properties
Cascade Filterpak is manufactured to VWS's own formulation and will meet or exceed the following material test standards :





Standard YTH1120/1150



Tensile Yield


DIN 53455



Modules of Elasticity


DIN 53452



Deflection Temp (0.46 MPa)


DIN 53461






Cascade Filterpak can optimise existing Trickling Filter applications, and is also used in Submerged Applications and in the Hyan Reactor (Hybrid Anaerobic process).


Trickling Filter Applications

Cascade Filterpak media can improve existing trickling filter installations, at a much lower cost than a full trickling filter refurbishment



Cascade Filterpak YTH1120 media with an effective surface area of 100 m2/m3 is specifically designed for use in a controlled orientation within the reactor, ensuring optimal three-dimensional liquid distribution, increased hydraulic retention time and improved liquid film diffusion within the media bed.

The media is designed for installation in a random orientation thereby eliminating the need for cutting or shaping to suit individual reactor profiles. The material of manufacture is a strong, lightweight, thermoplastic resin (polypropylene) suitable for wastewater treatment applications. It is non-toxic to micro-organisms, immune to rot, fungus or bacterial attack and has a high resistance to ultra violet degradation, ageing, erosion or disintegration.



With a surface area of 200 m2/m3, Cascade Filterpak YTH1150 random dumped polypropylene media is ideally suited for nitrification applications as well as remedial carbonaceous BOD5 removal.

The media is capable of redistributing liquid flow horizontally and throughout a 360-degree field, a minimum of 300mm per 300mm of media depth. The media are designed to orientate within the reactor bed in a manner which avoids the generation of continuous vertical or horizontal surfaces. 36,000 mixing or internal redistribution points for both liquid and air are provided per cubic metre of media. This effective internal redistribution ensures a high degree of mixing, thereby lowering diffusional resistance and maximising substrate removal rates.


Submerged Applications



Cascade Filterpak YTH1140 is a random-packed polypropylene media which has been used for over 150 years in both aerobic and anaerobic submerged reactor applications treating a wide range of municipal and industrial effluents.

Developed from MTI's unique background in submerged reactor technology, the media has been designed to provide the optimum effective surface area for biological growth, whilst addressing the specific operational requirements of submerged processes.

With a surface area of 100 m2/m3 and a void ratio of 0.95, the media is ideally suited to the treatment of high-strength wastewater. In submerged aerobic applications these media characteristics enable a high degree of endogenous biomass respiration to occur, resulting in reduced sludge yields. This minimises the need for media backwashing, ensuring process stability and lower operational costs.



Cascade Filterpak YTH1170 is a high surface area, neutral buoyancy polypropylene media specifically developed for use in submerged reactor applications.

The combination of a 200 m2/m3 surface area and a void ratio of 0.95 ensures that a high active population of biomass can be maintaned at low biomass concentrations. This significantly reduces the need for backwashing, maintains process stability and reduces operational costs.

The high porosity and minimal resistance to flow facilitiates completely mixed operation conditions within packed reactors, reducing the effects of toxic shock and ensuring even biomass development throughout the reactor volume.

Cascade Filterpak YTH1170 is ideal for the treatment of both municipal and industrial effluents in aerobic and anaerobic applications.


Hyan Reactor

The Hyan Reactor (Hybrid Anaerobic process) is a trouble-free, dependable and cost-effective treatment of high-strength effluents, using Cascade Filterpak Media.

The Hyan Reactor was designed to improve on existing anaerobic digestion processes, by reducing the excessive accumulation of inert solids and the loss of biomass through sloughing or blanket breakup. Each effect can limit system capacity and the second can throw shock loads on downstream processes.

High strength thermal conditioning liquor (or similar waste) is injected into the suspended growth zone and maintained in circulation by pumps. The geometry of the recirculation system prevents undue amounts of solids from rising to the filter zone above. It is in the suspended growth zone that the greatest burden of BOD and COD is reduced. The reactor is maintained in the 90 - 100 oF mesophilic regime and conversion proceeds at high rates.