Biological Air Cleaning


The biological air washer removes unwanted ammonia, dust and odor from the air

The principle of biological air cleaning is, that bacteria process the unwanted particles out of the air. There are no chemicals involved. Thanks to the construction and design these bacteria perform all the work and do this thoroughly.

Your farm has a long lifespan. Therefore, Dorset offers you the air washer which provides you the largest benefits for the long term: lowest running costs and high user convenience. 


Which capacities?
Which specification?
Which benefits?

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How does a biological air cleaner work?

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What is the difference between biological air cleaning and other types of air cleaning?

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Biological air washer for the poultry sector.

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Maintenance and service contracts

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Biological Air Washer

The basic biological air washer for pig farming.


BWL number

These are certificates provided by the Dutch Government for air washer designs.

Number for the Dorset Biological Air Washer:

BWL 2004.01.V3

70% ammonia reduction

View the file (pdf in Dutch, 70 kb)


Automatic data logging included

Biological Air Washer Combi

The Combi version consists of a basic biological air washer extended with an additional dust catcher.

Combi does not mean this version is combined with a chemical air washer.

BWL number

These are certificates provided by the Dutch Government for air washer designs.

Number for the Dorset Biological Air Washer Combi:

BWL 2007.02.V2

85% ammonia reduction

View the file (pdf in Dutch, 48 kb)

DLG test results

Dust reduction: 93%
Ammonia reduction: 90%
Odor reduction: 80%

DLG (Deutsche Landwirtschafts-Gesellschaft) is an independent research institute in Germany.

View the file (pdf in German, 684 kb)

Automatic data logging included


Lowest running costs

Dorset’s biological air washer has the lowest running costs. The filter is only 90cm high. Therefore the fans have little resistance to overcome, which results in low electricity costs.



With Dorset you are certain the air washer reaches its reduction values. Dorset builds only its own designs.


Dorset was the first in 1994 with a biological air cleaner for pig farmers


Barely maintenance required

The filter layer has self-cleaning capacity. The maintenance is limited to checking the sprinklers.


User friendly

The washer is easily accessible and includeds lighting.

Placement below the roof or behind the barn?

The washer can be installed inside the barn. This can be done custom-made or as a plastic container in the ridge of the barn, above the central corridor. The washing water can be stored in a silo or water tank at base level.

The washer can also be delivered with washing water storage at the top floor. In that case the barn construction requires additional attention, due to the weight of the washer. 



In the ridge Inside the barn at the back At the back in plastic container


Customized to customer specifications





The biological air scrubber operates entirely on bacteria

The bacteria live in the filter layer. Once the air goes through the filter, the bacteria feed themselves with unwanted particles in the air. By spraying water over the filter layer, the bacteria are moistened and dirt is washed away. The washing water is sprayed several times until the water it is fully saturated.

A water curtain is deployed to remove dust. The air is drawn through a curtain of sprayed water, resulting in dust remaining in the water while the air continues.


The dirty air enters the washer through openings at the side of the washer.

The air rises up through the filter layer. The bacteria live on the surface of the filter, where they feed on dirty air particles.

Water is sprayed from the nozzles above the filter. This moistens the bacteria and washes the dirt away.

Below the filter, the water is collected in a container. This water is circulated through the nozzles until it is saturated. Then it is pumped away.

Before the air leaves the washer, it goes through a demister – a thin filter pack – allowing more moisture to be kept within the washer. This reduces its water consumption.

In the Combi Washer, the dirty air passes through a dust collector – a curtain of water – before it goes into the filter packages. As a result, a higher efficiency is possible.





chemical air scrubber

biological air scrubber

chemical air scrubber biological air scrubber

How does the biological air scrubber differ from the chemical air scrubber?

The principle of chemical air washing is that if ammonia comes in contact with sulfuric acid, this results in a chemical reaction by which ammonia merges with the sulfuric acid and neutral ammonium sulphate formed.

This differs from the biological air scrubber, which operates completely on bacteria. The bacteria feed on unwanted portions in the air, such as the ammonica.

The biological washer achieves a higher odor reduction than the chemical one. The advantage of a chemical is, that it can be built more compact and is more suitable when a very high ammonia reduction should be achieved (95%). It is also better suited for air with high temperatures.

Dorset also has chemical washers available. These techniques are frequently used to wash air after drying of the digestate or manure. For washing stable air the biological air scrubber is most suitable because it has a lower air resistance.





Dorset has introduced biological air cleaning for laying and breeding hens

The basic design is the same as the Combi-Washer for pig farming. It has, however, a specially designed dust collecting that functions with washing water of the biological air washer. A normal air washer would quickly fill itself with dust and feathers, and should therefore be cleaned regularly.





Service visits and contracts

You will be assisted by technicians with many years of experience in assembling and maintaining air scrubbers.

We support you in maintaining your air scrubber. Please contact us for advice, spare parts or a service visits. We also offer service contracts.

Because our customers are located at many locations in Europe, we always look for opportunities to combine your visit with other visits in the area.