Biomedia for MBBR and IFAS applications

The technology which allows the biomass to grow attached to moving plastic supports exploits the ability of the colonies of microorganisms that are generated within  the biological process to form a biofilm  adhered to the surface of special plastic elements that are dispersed in the biological volume. These elements, called carriers or media, have the purpose of increasing the quantity of active biomass present in the system and enhance the pollutant removal capacity of a plant which, if compared to conventional solutions  designed as classic activated sludge process, , can handle higher inlet loading conditions with the same process volume or, with the same organic input, will require less volume and therefore occupy less space.

MBBR

MBBR indicates the most classic process also called “pure”, in which the carriers are confined in all treatment stages of the biological reactor and in each of them the specific growth of the biomass specific to that process takes place. Bacterial growth favors the increase in the thickness of the biofilm within the protected surface of the carrier, the excess is kept under control and removed by the natural cutting action that the elements dispersed in the aerated mixture exert against each other. Biomedia are designed to have a high contact surface/occupied volume ratio and to have a specific weight that allows them to remain, under process conditions, suspended in the mass of liquid to be purified without floating or accumulating on the surface. The quantity of air to be supplied for the endogenous respiration of the bacteria must also guarantee the maintenance in suspension and the correct movement of the “carriers” in the oxidation/nitrification volume, while in the anoxic compartments the correct agitation regime must be guaranteed by an accurate choice of mixing devices that take into account the kinetic energy to be transferred to the liquid mass and the presence of biomedia in the reaction volume.

Main characteristics:

• Possibility of implementing existing purification systems
• High compactness of process volumes
• High resilience to load variations
• Possibility of achieving high removals in terms of N and P
• Low production of excess sludge
• Elimination of sludge recirculation and internal recirculation
• Low energy consumption

IFAS

IFAS is the acronym for Integrated Fixed Film Activated Sludge and indicates a hybrid process in which the benefits of traditional activated sludge biological treatment are added with the presence of adhered biomass and which is capable of achieving high performance while occupying a larger space. restricted.

In the start-up phase, the plastic supports are dispersed in the biological reactor in which the activated sludge process has already been started, the growth of the biofilm inside the carrier favors the removal of most of the BOD and subsequently the oxidation of the ammonia.

The quantity of air to be supplied for the endogenous respiration of the bacteria must also guarantee the maintenance in suspension and the correct movement of the “carriers” in the biological volume, therefore it will be necessary to verify the quantity required to be able to carry out both tasks.

One of the main applications for the IFAS solution is the retrofitting of existing activated sludge plants where it is necessary to implement the nitrification stage and increase the BOD removal yields. This technology, however, also lends itself to being adopted in the construction of new systems, if you want to adopt a compact and efficient design at the same time.

Main characteristics:

• Possibility of implementing existing purification systems
• High compactness of the process volume
• High resilience to load variations
• High ease of installation
• Low investment cost

Carrier type

BWTX

The BWTX carrier is used as a support element in biological processes with attached biomass for both municipal and industrial applications, it can be used to support the MBBR or IFAS process. The element is constructed by extrusion in high density polyethylene (HDPE) and is composed of 9 cells in which the biofilm can grow and structure.

The protected surface, i.e. the surface available for the biofilm expressed in m2/m3 of material, is the main element that distinguishes the different biomedia and is a function of numerous aspects such as geometry, dimensions, thickness and construction material: it represents the carrier area not exposed to collisions and therefore available to host the biofilm during the biological process.

Main characteristics:

• Commercial name: BWTX™
• Weight: 134 kg/m3
• Protected surface: 650 m2/m3
• Width/length: 14.5 mm (±0.5 mm)
• Height: 8.2mm (±0.2mm)
• External perimeter: 56 mm
• Internal perimeter: 197 mm

BWT 15

The BWT15 carrier is used as a support element in biomass-based organics for both municipal and industrial applications and can be used to support the MBBR or IFAS process. The element is constructed by extrusion in high density polyethylene (HDPE) and is composed of 25 cells in which the biofilm can grow and structure.
The biomass process adhered to mobile supports is based on the use of special plastic elements designed with particular shapes and dimensions such as to allow rapid and stable growth of biological biofilm within their protected surface.

The protected surface, i.e. the surface available for the biofilm expressed in m2/m3 of material, is the main element that distinguishes the different biomedia and is a function of numerous aspects such as geometry, dimensions, thickness and construction material: it represents the carrier area not exposed to collisions and therefore available to host the biofilm during the biological process.

Main characteristics:

• Commercial name: BWT15™
• Weight: 173 kg/m3
• Protected surface: 828 m2/m3
• Width/length: 14.5 mm (±0.5 mm)
• Height: 5mm (±0.2mm)
• External perimeter: 56 mm
• Internal perimeter: 258.6 mm