Institute of

Agricultural Technology

Exhaust air treatment

The exhaust air treatment is a working area which develops and evaluates technologies for an efficient separation of particulate matter, bio aerosols, ammonia and odors from livestock facilities. Operating safety and reliability, the use of residuals and cost reduction options are investigated in addition.

Different exhaust air treatment techniques to reduce emissions from livestock facilities
Different exhaust air treatment techniques to reduce emissions from livestock facilities (© Thünen-Institut)

The exhaust air treatment illustrates an effective and testable instrument for the cleaning of exhaust air from forced ventilated animal stables. Certificated operations reduce the mass flow of particulate matter and ammonia more than 70 %, in parts more than 90 %. Bio aerosols are also reduced efficiently by the exhaust air treatment systems.The reduction of odor emissions from pig keeping facilities is very efficient, while this target needs additonal research for poultry keeping. More than 1.000 exhaust air treatment systems have been installed in pig keeping facilities, but only 179 in poultry keeping (Status 2013).  The emission reduction by exhaust air treatment generates considerable investment and operation costs indeed which have to be gained by sale of products. Large air volume flows which have to be cleaned, the production of washing water coming from exhaust air scrubbers, which has to be stored and used in agriculture, and the energy consumption of pumps and vans are very important factors for the total costs. Therefore procedural improvements, especially to cut costs, are reqiured for a wider application of these techniques. Our work is focussed on the development of efficient and cost-effective exhaust air treatment systems. Main foci are the improvement of particlate matter separation in poultry keeping, the enhancement of nitrogen separation in biofilters and the production of highly enriched washing waters. Our findings are used for VDI standards, DLG information sheets, KTBL working papers and for the development of European test frames as well (

Photo gallery test facilities