WESSEL-UMWELTTECHNIK GMBH

Biological exhaust air cleaning is always required if exhaust air needs to be purified of volatile organic components the socalled VOCs or odorous substances. The demand for biological procedures has increased in recent years. On the one hand, biological exhaust air cleaning does not generate any climaterelevant greenhouse gases. On the other hand, it meets all legal requirements for clean gas values. With over 200 biological exhaust air cleaning processes installed, Wessel has comprehensive practical knowhow and is the technology leader in the field of biological exhaust air cleaning. The biological exhaust air cleaning systems have been continuously optimised and further developed by WesselUmwelttechnik for decades. The modern cleaning systems from WesselUmwelttechnik work efficiently. Thanks to the continuous monitoring of the plant parameters, they require only a minimum of operating effort.

Bio scrubbers are systems for the biological cleaning of exhaust air and exhaust gases and thus for the reduction of odours and polluting emissions. In this process, air polluted with a wide variety of pollutants is cleaned with the aid of a washing liquid which is loaded with microorganisms and biocatalysts (various enzymes) taken from nature. The bio scrubbers from WesselUmwelttechnik work almost without wastewater and are therefore very sustainable, regardless of the nature of the exhaust air. The basic requirement, however, is that the ingredients are watersoluble and bioavailable. WesselUmwelttechnik supplies turnkey plants like the Wessel BIOCATScrubbers in single and multistage construction.

A bio scrubber combines physical scrubbers with a biological activation unit. In this process, air polluted with a wide variety of pollutants is cleaned with the aid of a washing liquid which is loaded with microorganisms and biocatalysts (various enzymes) taken from nature. The washing water absorbs the exhaust air and pollutants from the air. Subsequently, added microorganisms oxidise them. These microorganisms use the air pollutants as substrate and nutrient medium and convert them into naturally formed decomposition products such as CO2, water, and biomass. Here, the washing water is continuously regenerated and used in a closedcircuit water treatment system. TYPICAL APPLICATION AREAS These plants are primarily used for watersoluble ingredients of the exhaust air. The usual pollutants that are filtered from the exhaust air with the help of bio scrubbers include aldehydes such as formaldehyde, alcohols, ketones and other hydrocarbon compounds.

The BIOCATDUOscrubber from WesselUmwelttechnik consists of two units. One unit is the already mentioned BIOCATscrubber. A second unit, the DLP (Dust Low Pressure) scrubber stage, is a cleaning stage for separating dust and fine fibres from the exhaust air. With the BIOCATDUOscrubbers from Wessel, gaseous pollutants as well as dust can be removed from the exhaust air at the same time. The BIOCATDUOscrubbers have two separate washing water circuits for this purpose. It is characterised by a compact design, as both units are housed in one column. COMMON USE CASES The BIOCATDUOscrubbers are used in the woodbased panels industry, for example. More precisely where MDF boards (medium density fibre) and moulded fibre parts are produced. Here the exhaust air contains fine wood fibres which have to be filtered out of the exhaust air. Furthermore, pollutants and odours must also be reduced.

Biological exhaust air cleaning is used whenever exhaust air has to be cleaned from volatile organic compounds (VOCs) and odours. Biofilters play a major role in this process. The polluted exhaust air is passed through a filter medium where the VOCs and odours are separated. Normally, this medium is an organic carrier material where microorganisms are grown on. They convert the VOCs and odours into noncritical components by means of their metabolism. Especially regarding the removal of odorous substances, biofilters are a very efficient and comparatively inexpensive way of biofiltration with an efficiency of up to 99 %. BIOCATbiofilters have a high degree of efficiency in a wide range of applications, even for exhaust air components that are difficult to dissolve in water.

When it comes to filter material, there are a few points to consider. The filter material should have a large surface area. This ensures a good exchange rate between exhaust air and filter material and provides sufficient space for microorganisms to colonise. The filter material must be designed in such a way that it has a good water holding capacity. The colonised microorganisms are only viable in a moist environment. In general, different filter materials are used in one batch. The reason for this it ensures both a good stability of the filter bed and a larger surface. In addition, the added microorganisms must be sufficiently supplied with inorganic nutrients and trace elements, unless this is provided by the composition of the exhaust air. The temperature inside the biofilter system plays a decisive role as well. Temperatures between 5 °C and 40 °C are favourable for the microorganisms to work properly.

Industrial air scrubbers are used to purify the exhaust air of pollutants, for example in the chemical or pharmaceutical industry. As soon as the exhaust air meets the legal requirements for clean gas values, it can be returned to the environment. Absorptive exhaust air purification by waste gas scrubbers is a frequently used technology. Gas scrubbers are suitable for removing pollutants, aerosols and dust from the exhaust air. Especially watersoluble exhaust air components are separated with high efficiency.

If no procedures for biological or chemical exhaiust air cleaning are to be used efficiently, the thermal treatment is regarded as method of choice. The basic thermal processes are Recuperative thermal oxidation Regenerative thermal oxidation Catalytic oxidation. The focus of our products lies particularly in the periphery of especially challenging special solutions Waste treatment Sewage sludge drying Waste water treatment Landfill aftercare Specialpurpose solutions for the chemical industry Food industry In general at corrosive media, at risk of condensation, and especially high specifications for the pure gas Since 2018 we are working close with our sister company Airprotech Srl. from Magenta/Italy in the field of thermal exhaust air cleaning. Beside our core products our range of products in the field thermal exhaust air cleaning is broadened Airprotech is specialised in the development, the manufacture and the supply of turnkey plants for thermal cleaning

In many incineration and industrial plants in various industries as well as in the municipal sector, dust emissions are produced during production processes. These emissions must be purified before they are released into the atmosphere. The dusts can be sticky, greasy, wet, dry or combustible and have different particle sizes. In general, they are between 0,1 and 1000 μm in size. Dust collection systems physically filter these dusts out of the exhaust air. WesselUmwelttechnik specialises in various methods of exhaust air cleaning, including industrial dust collector systems, to safely comply with legal requirements, e.g. the German TA Luft. In addition to dry filtering, the product range includes wet separators. This way, even humid and hot exhaust air as well as agglomerating dusts can be treated by the Wessel systems. The various exhaust air purification technologies allow the use of dust collecting systems in a wide variety of industries.

In many incineration and industrial plants of various sectors as well as in the municipal sector, dust emissions are produced during production processes. These emissions must be purified before they are released into the atmosphere The resulting dusts can be sticky, wet, dry or combustible and have different particle sizes. Often industrial dusts are between 0.1 and 1000 μm in size and vary greatly in composition. They are also present in various concentrations and combinations with other pollutants. Compared to dry separators, wet scrubbers have the great advantage that fires or explosive mixtures cannot occur. Depending on the industry and area of application, such as in incineration plants, wet separators are indispensable.