Biological treatments

In the field of biological treatments in recent years the biofilm treatments on plastic media have emerged, some of which are gradually replacing the activated sludge processes.

Among these treatments there are trickling filters, submerged beds and moving bed reactors, also known as MBBR reactors.

It is also emerging another technology that uses ultrafiltration membranes (MBR), that provides a high quality effluent suitable for its reuse.

Amitec has extensive experience in this area and can offer a complete range of top quality products for each of these types of treatments.

Trickling filters

The sewage to be treated, after suitable pretreatment, is distributed on the top of the trickling filter by means of rotating or static distributors, and percolates through the plastic fill. In its path, the effluent trickles on the aerobic biological film, attached on the surface of the plastic modules and capable of breaking down the organic substances. Particularly suitable for this treatment, due to the high degree of efficiency and high structural strength, is the cross-flow modular media BIOdek®, made of polypropylene.

Submerged beds

Submerged beds are reactors which are different from trickling filters, as the plastic media that carries the fixed biofilm is completely submerged and aerobic conditions are ensured by blowing air from underneath by means of diffusers. Vertical or cross-flow BIOdek® media is generally used as plastic support of the biofilm.

Moving bed reactors

In the MBBR reactors biological organisms grow on carriers dispersed and suspended in the wastewater to be treated. The biological film that forms on these carriers is a function primarily of the type of waste water supplied and of the organic load associated with it. Unlike other biofilm processes, the carriers move freely in the liquid mass, adequately aerated with medium or fine bubbles aeration systems. The support of excellence in this process is the Biomaster media, that combines a high specific surface area and a remarkable void ratio. Its structure, particularly open, allows an intense oxygenation of the attached bacterial colonies and guarantees an efficient contact with the substrate to be oxidized.
Amitec provides its customers the Biomaster range of products, available in several configurations, depending on plant needs and required treatment.

Membrane bioreactors

The membrane bioreactors or MBR represent a more advanced wastewater treatment technology than the traditional activated sludge.
The MBR system is realized by coupling a conventional activated sludge process with membrane separation process, which replaces the secondary sedimentation.
The use of ultrafiltration membranes MicroClear® and the replacement of the sedimentation tank with a membrane filtration unit has several advantages:

• high efficiency in removing suspended solids (SS)
• almost complete removal of bacteria and viruses (99,9999%)
• BOD removal close to 100%
• high nitrification
• significant reduction of the plant footprint and installation costs
• elimination of problems due to the sedimentation of the sludge and greater ease in managing the biological process, that is totally independent from the fluctuations of hydraulic load
• reduction of the sludge produced in comparison to conventional activated sludge, associated with increased sludge age
• compliance with the most stringent EU laws on concentration limits for discharges of treated wastewater
• possibilities of reuse of treated water, without additional disinfection