Biological aerated filters
Biostyr™ biofilters combine a biological reactor and a physical filter in a single structure for the removal of organic, nitrogenous and particulate pollution in the treatment of municipal and industrial wastewater. Biostyr™ biofilters are compact structures with a modular design.
It is available in several configurations, depending on the pollution to be treated:
Standard parts of the Biostyr™ module include: nozzles, air grid, filter media, a floor and insert.
The cell is made of a concrete structure divided into two areas. The lower area contains the active biomass, the filter media and an air grid laid at its base. This is separated from the upper area by a concrete ceiling fitted with nozzles, which allow the treated water to flow through and collect in a reservoir above the filter floor.
Filter beds are made with filling material Biostyrene™. This is a low-density media composed of expanded polystyrene beads. The beads are manufactured and sized according to the required result. Standard sizes for the Biostyr™ filter beds range from 2 to 230m2.
Biostyr™ reactors used are fully aerated cells. However, Biostyr™ reactors for both nitrification and denitrification can be configured with two zones, one aerated and one anoxic, and a recirculation loop of the treated water to return the nitrates.
Small module sizes are available as package stainless teel units.
Wastewater is fed at the base of the cell. Process air is also injected at the base through an air grid. Active biomass, which develops on the media, degrades the carbonaceous and nitrogenous waste. The treated water flows through the nozzles, and it is removed at the top of the cell. The upflow of influent and air raises the filter media which is blocked and compacted under the concrete ceiling and nozzle floor. The compacted filter bed retains the biomass and suspended solids.
An aeration manifold located in the lower part of the structure allows to optimise the contact time between the wastewater and the process air.
Biomass and suspended solids accumulated inside the filter medium must be removed regularly by periodic backwashes. The light weight of the material allows the system to be washed by simple gravity expansion of the filter medium using the treated water stored in the upper structure (flushing). The nozzles, located in the upper part of the filter, are only in contact with clean water and are easily accessible.