HUFO® modern filter media for trickling filters
Descriptionback to top
Operating principles

Feed pumps distribute the wastewater over the filter media. A population of micro-organisms form a biological slime layer on the filter media of the trickling filter and reduces the organic material in the waste water. Periodically, the micro-organisms in the anaerobic zone on the media surface lose their ability to cling to the media due to the lack of sufficient oxygen and nutrients. The wastewater flowing over the media removes the slime layer from the media bed in some places and a new slime layer begins to form. Micro-organisms develop naturally and no implantation is required. The supply of air and oxygen can be naturally or by using a fan. Properly operating filter media produces no noise and no odour.


The HUFO® filter media was designed and patented in Finland in cooperation with the University of Helsinki.

Biofilters with HUFO®filter media operate in over 8000 wastewater treatment plants in 22 countries around the world. The largest one (volume 50.000 m3) is located in Ryadh, Saudi Arabia. The HUFO® filter media is mainly used in the BIOCLERE® wastewater plants. HUFO® has been manufactured in Poland since 1997.


  • as replacement of old filter media in existing biofilters,
  • as filter media in new biofilters including BIOCLERE®.

Replacement advantages

Many old biofilters are unservicable because of filter media clogging.
Former biofilters using stones, slag or coke can easily be clogged after some time of operation. Modern filter media guarantee problem free operation of a treatment plant for its whole operational life.
Modern technical solutions allow very high reduction of biogenic compounds.
Reactivation and modernization of old type biofilter treatment plants is much cheaper than reconstruction of the treatment plants.

Featuresback to top
Biological filter during dosing
  • low weight,
  • large active surface area,
  • excellent hydraulic permeability,
  • long durability
  • no replacement needed for operation time,
  • no clogging,
  • random media.
  • high BOD5 reduction (up to 95%) and nitrifilation,
  • extremely low operation costs, statistically 70% lower than operation costs of activated sludge,
  • high process reliability - pump and fan - the only elements that move,
  • low capital investment.

Technical databack to top
Media coated with active biomass
  • shape: round with many conical surfaces,
  • diameter/height: 180 mm/50 mm,
  • surface area: 120 m2/m3,
  • void: 97%,
  • dry weight: 48 kg/m3,
  • weight in use: 200 - 400 kg/m3,
  • height (depth) of filter: 1,0 - 8,0 m,
  • bottom screen: 10 x 10 cm,
  • surface hydraulic load: 0,6 - 1,4 m3/m2 h,
  • BOD5 - load (max): 1,2 kgO2/m3 d,
  • max working temperature: 50 °C,
  • material: polypropylene,
  • colour: black.

Operation resultsback to top
Pollution reduction

BOD5 reduction - up to 95%
Ammonia nitrogen reduction
- up to 95% using nitrification unit.

The design curve - HUFO® 120 - domestic wastewater

Food industry applications

One of the applications for the HUFO® filter media is wastewater treatment in food industry before discharging to sewage system or before the second stage of treatment.

95% - 97% total reduction

Other applications

In chemical industry in absorption, distillation, liquid cooling and aeration, water oxygenation, exhaust gas dust removal and cleaning, etc.