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Removing Pollutants from Exhaust Air

Pollutants is a collective term for all kinds of chemical compounds that pose an acute to long-term danger to humans, animals, plants, microbes and/or entire ecosystems. Very often, the quantity and composition of a pollutant that enters the environment plays a role, because not every substance is harmful in itself. The environmental situation is also decisive in determining whether a substance has a risky effect. In agriculture and industry in particular, many process-related pollutants are produced and have to be separated from the exhaust air. Only then is the exhaust air considered as clean air and may be released into the environment.


What Are Pollutants and Where Do They Arise?

Pollutants are all volatile and non-volatile organic and inorganic compounds that are often odour-intensive and have a harmful effect on humans and the environment above a certain quantity. A distinction is made between natural pollutants occurring in the environment (prussic acid, solanine, SO2, rock dust, etc.) and artificial pollutants of anthropogenic origin. The latter arise in the context of industrial processes, in agriculture, through improper storage or due to traffic.

Typical man-made pollutants include volatile substances such as formaldehyde and other aldehydes, ammonia, hydrogen sulphide (H2S) or acids (HF, HCl). Car exhaust fumes, heavy metals and particulate matter are also pollutants that play a significant role in environmental damage. Particularly critical for entire ecosystems, such as the ocean, are the so-called CMR substances (carcinogenic, mutagenic, reprotoxic). They spread through the food chain in a wide variety of living organisms, plants, and environments. These pollutants, such as formaldehyde, acetaldehyde, butadiene, O-anisidine, etc., are regulated by law with very low limits, usually below 1 mg/m³.


Why Do Pollutants Have to Be Removed from Exhaust Air?

In order not to damage the entire environment, either acutely or in the long term, proper and correct exhaust air purification is indispensable in the industrial and municipal sectors. Various plant technologies filter out a large number of pollutants from exhaust gases and vapours and then release the legally specified clean air (according to TA Luft, WGC-BREF, 30th Federal Immission Control Act (BImSchV)) into the environment.

Pollutant Removal with Systems from Wessel-Umwelttechnik

Wessel offers customised, turnkey modular plant systems. Different materials are used, tailored to the respective application (including various types of stainless steel or plastics).

Biological Exhaust Air Purification

Biological processes such as the BIOCAT bio-scrubber and the BIOCAT bio-filter are suitable for removing pollutants from the exhaust air – as long as the substances to be filtered are bio-available. In both exhaust air purification systems, microorganisms and biocatalysts are centrally involved. They break down pollutants and odours into natural, harmless products such as carbon dioxide and water.

Absorptive Exhaust Air Purification

Gas scrubbers such as the DCS scrubber (Direct Chemical Sorption) are used in chemical-absorptive exhaust air purification. DCS scrubber technology has very high efficiencies of over 90 % in the separation of pollutants as well as aerosols and dusts. The gas scrubber is particularly efficient with water-soluble components.

Adsorption Plants

Adsorption plants are an efficient way of filtering VOC (volatile organic compounds) from exhaust air, smoke gases and exhaust gases. In contrast to absorption processes, in which washing liquids bind the harmful substances, those substances are separated in an adsorption plant. This means that the pollutants are physically attached to an adsorbent such as zeolite or activated carbon.

Modular Design of Wessel Plants

Every company has different space conditions on site. Accordingly, the chosen system for pollutant cleaning must be individually adapted and customised. As a manufacturer, we at Wessel-Umwelttechnik therefore offer exhaust air purification systems that you can set up on site in a modular fashion to suit your needs. Depending on the location and the type of pollutants to be separated in the exhaust air, the various technologies and systems can be combined with each other. This means that they are always perfectly matched to the needs on site.


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