2-Logo BioSal

BioSal Anlagenbau GmbH
Gewerbegebiet: An den Angerwiesen 6
D-04651 Bad Lausick
Tel:  ++49 (0) 34345-25151
Fax:  ++49 (0) 34345-25153
e-mail: info@biosal.eu.

1-Logo BioSal

Report exhaust air treatment

System BioSal®:   Combined chemical-biological cleaning of exhaust air from mechanical-biological waste treatment plants


With various treatment processes of biogenous and other organic wastes (e.g. mechanical-biological waste treatment, sewage sludge drying, anaerobic fermentation, pig/chicken farming) beside VOC and smell-intensive substances partly larger quantities ammonia within concentration range up to 600 ppm are emitted into atmosphere.


The company BioSal Anlagenbau GmbH - among other products specialised in production of closed container biofilter units and dynamic composting plants - offers combined exhaust air treatment systems for purification of NH3-containing air for a throughput range from 100 m³/h up to > 50.000 m³/h.



Fig. 1   Configuration example of a modular BioSal® exhaust air treatment plant


These systems usually consist of several module-like linked individual components:

p            Condensate separator


p            BioSal®-AMMON scrubber with high performance filling materials and one or more scrubber stages and possibility of an on-line pH registration for direct acid / chemical dosage or liquid / product draining


p            BioSal®-FIL container biofilter from stainless steel or corrosion proof steel, alternatively in hook elevator execution, filled with layers of different exhaust air-specific filter materials


p            BioSal®-FIL-S biofilter/bioadsorber with high adsorption capacity incl.

BioSal®-SUB-S biofilter substrate for selective NH3 adsorption


p            BioSal®-UV exhaust air sterilisation module with UV-C radiation sources


p            Clean air stack


p            External or integrated frost and sound-protected BioSal® functional unit with system electrical engineering, ventilator(s), switching and control board including SPS control.


The selection of the appropriate system combination depends with consideration of the official laws as well as local and economic conditions mainly on the raw gas parameters


        * Ammonia concentration

        * Smell load

        * Concentration of further pollutants

        * Dust content

        * Input temperature

        * Input humidity                                and the appropriate target parameters.


In almost all exhaust air stream with very high input humidities the application of an upstream condensate separator is recommend in order to prevent on the one hand dilution effects of the washing liquid (BioSal®-AMMON scrubber) and on the other hand wetness pilot zones in the BioSal®-FIL biofilters.


The target of the wash process in the BioSal®-AMMON scrubber is it to let ammonia in the exhaust air react in presence of sulfuric acid to ammonium sulphate:



2 NH3 + H2SO4 à (NH4)2SO4



After scrubbing the prepurified and conditioned exhaust air can be cleaned e.g. with the help of a BioSal®-FIL biofilter system by further pollutants and smells.


During conversion process the concentration of (NH4)2SO4-solution increas and concentrated (NH4)2SO4-solution can be removed from the process.


A further use of the (NH4)2SO4-solution as liquid fertilizer (e.g. for oil fruits and other plants with high Nitrogen and Sulphur demand) or a mixture with liquid manure for the improvement of the Nitrogen content is possible.


Beside the product (NH4)2SO4 no further secondary or waste products results.


All components of the BioSal®-AMMON scrubber are made from stainless steel and high-quality plastics and frequently together with the system fans installed in a compact frost-protected and sound-absorbing external functional unit.

With the help of an on-line pH electrode configuration in a special flow assembly succeeds a delay-free determination of the respective pH value and over a metering and dosage station the optimal adjustment of the necessary H2SO4 concentration.


That ensures that only as much H2SO4 is supplied to the respective scrubber cycle, as according to the Input-NH3-Konzentration absolutely necessary.

Thus e.g. concentration peaks in the raw gas can be reliably intercepted, while with very small NH3-Konzentration no significant consumption of H2SO4 takes place.


The acid dosage (96% H2SO4) comes with magnet dosing pumps usually directly from commercial 1.000 l tanks (exchangeable after emptying - e.g. SCHUETZ® containers).



Fig. 2              Modular BioSal®-AMMON scrubber


The compact BioSal®-AMMON scrubber can be integrated due to its modular structure also problem-free into already existing exhaust air treatment plants.

For installation only water supply and electric power supply are necessary.


Beside the scrubbing of NH3-/H2S-containing exhaust air various BioSal® scrubbers can be operated with special absorber fluids, e.g. organic washing liquids for scrubbing of VOC containing air.

For recycling and/or sterilisation of exhausted scrubber/humidifier water we offer our BioSal®-REWA wastewater recycling technology.


The scrubber/conditioning stage following BioSal®-FIL biofilter (closed containers, alternatively hook elevator execution) are module-like structured and can be problem-free subsequently extended according to the exhaust air rates.


The sides of the biofilters are completely manufactured from stainless steel or from multilayer coated corrosion proof steel. The retaining structure of the BioSal®-FIL biofilter container usually consists of colorcoated steel.


The combined support grid for filling material and air distribution is corrosion-resistant. Special internals at the edge of filter prevent a "breaking through" of the incoming air.


The BioSal®-FIL Biofilter can be filled with different filter materials. The BioSal®-SUB standard biofilter material is brought in layers into the biofilter and consists of: wood chaff, dynamically manufactured substrate and barks.

These tried and tested substrate combination ensures an optimal settlement surface for pollutant-diminishing micro organisms, high population densities as well as a good water reservoir ability and makes the necessary trace elements available.

The input of the BioSal®-SUB biofilter material occurs in such a way that pressure drop is very low.


The service life of the BioSal®-SUB filter material amount to at least 2 years.

The natural ageing of the material is caused by sintering and microbial decomposition. Used biofilter material is free from poison or pollutants and can be problem-free disposed after use.




Fig. 3              BioSal®-FIL biofilter container as part of a modular BioSal®

exhaust air treatment plant


Usually the microbes adapt after an adaptation time of approximately 2-3 weeks of the respective contamination of the exhaust air stream.

Beyond that an initial inoculation of the bio filter material with an bioactive nutritive solution is possible.


Beside our standard BioSal®-SUB biofilter material we offer different part-synthetic organic and also multicomponent biofilter material.

With certain applications or operation or weather statuses it can come on the part of the emission sources briefly to increased pollutant concentrations (concentration peaks), which can break through the standard biofilter bed in weakened form.

The installation of a BioSal®-FIL-S biofilter/bioadsorber with high adsorption capacity downstream into the BioSal®-FIL biofilter plant ensures reliable interception of such concentration peaks.


The service life of the used BioSal®-SUB-S biofilter material with high adsorption capacity usually is thereby above that of the standard BioSal®-SUB biofilter material.


In the next years the germ situation / biological degree of purity of the cleaned exhaust air will come to public interest.

For this reason we offer already today the compact air sterilisation system BioSal®-UV, which can be connected problem-free at the outlet side the BioSal®-FIL biofilters. For the air germ reduction in the modular BioSal®-UV system Hg low pressure emitters are used, which emit mainly UV light of the wavelength 253,7 Nm.

This part of the UV spectrum steps with DNA-code of micro-organisms in a photochemical interaction and destroys the cell nucleus and the genetic information.


When desired for preliminary tests a combined exhaust air treatment system, consisting of exhaust air condenser, BioSal®-AMMON scrubber, BioSal®-FIL biofilter (static or dynamic operation mode), BioSal®-FIL-S biofilter/bioadsorber with high adsorption capacity and BioSal®-UV air sterilisation reactor for throughputs up to 3.000 m³/h is put to interested users at their disposal.


Advantages of the combined BioSal®-AMMON scrubber / BioSal®-FIL biofilter

exhaust air treatment system:


p            Modular structure of components enables gradual system extension or implementation into already existing exhaust air treatment plants. For system extension only electric power and fresh water supply are necessary.


p            Good tolerance in relation to in quantities and pollutant concentration strongly varying raw gas flows as well as against high dust and moisture loads.


p            Small power requirement / favourable operating cost: Compared with thermal exhaust air treatment systems a comparatively substantially smaller specific primary energy entry is necessary.


Contact:       BioSal Anlagenbau GmbH / Fed. Rep. Germany

                                                           Fax.:               ++49 / 34345 – 251 53

                                                           e-mail:            sattler@biosal.de

                                                                       Internet:          www.biosal.de