The greenhouse gas nitrous oxide (N2O) can be emitted as a byproduct of nitrogen removal processes during biological waste water treatment. Up to now only few measurements of N2O emissions have been performed at Austrian waste water treatment plants (WWTP). The deficit of data hampers not only the estimation of N2O emissions but also hinders a better understanding of its formation mechanisms. The main focus of the present project is the measurement of N2O emissions at selected municipal WWTP where specific operating and loading conditions are well known. The measured N2O emissions will be correlated with the different process configurations of the treatment plants and with the waste water composition. A deeper understanding of the parameters affecting N2O production and emission shall help to implement effective measures to minimize N2O emissions e.g. by optimizing the operation and/or the design of WWTP.
On the basis of the project results a new evaluation approach (beside the IPPC approach) for N2O emissions from WWTP considering operating and loading conditions, process configuration and waste water composition will be developed. This will allow a more realistic estimation of the total contribution of municipal WWTP to N2O emissions in Austria as well as of the reduction potential of various optimization strategies.
