Reduction of nitrous oxide emissions in municipal WWTPs by applying a bio-scrubber to treat the exhaust air from side-stream deammonification 

01.03.2022 - 30.08.2024

Federal Ministry Republic of Austria, Agriculture, Regions and Tourism

Contact Person:
Dr. Vanessa Parravicini

Project Staff:
Paul Kelterer

Brief information on the project

The research project will explore an innovative concept to reduce nitrous oxide emissions for medium-sized to large municipal sewage treatment plants with anaerobic digestion. This is based on two essential cornerstones: i) The autotrophic nitrogen removal via deammonification in the sludge dewatering effluent in side-stream and ii) the treatment of the nitrous oxide-rich exhaust-air from the deammonification basin via a denitrifying bio-scrubber with wastewater as organic carbon source. By removing nitrogen in side-stream, favourable process conditions for the reduction of N2O emissions in the activated sludge process in the main-stream waterline are created. The deammonification process in the side-stream, in which N2O is also released, exhibits more suitable conditions for the use of a bio-scrubber to remove N2O than the main-stream. 

The denitrifying bio-scrubber is the core of the new treatment concept and the object of the research work. Its suitability to treat the exhaust air from the deammonification process in the side-stream flow is to be thoroughly checked on a laboratory scale. The ecological and economic impact of the overall concept will be assessed and the reduction potential for the Austrian wastewater treatment sector will be estimated.