N2O is a highly neglected greenhouse gas with a global warming potential 300 times higher than CO2.
Recent research, published in State of the Science Report from Global Water Research Coalition, has concluded that Wastewater Treatment Plants (WWTP) can emit extensive amounts of N2O under certain process parameters and conditions. Studies in the Netherlands, France, USA, and Australia have shown that for some WWTP’s, the N2O emission can account for up to 90% of their total carbon footprint.
Traditionally, N2O emission from WWTP’s was estimated by use of the IPCC emission factor of 3.2 g N2O/PE/year as direct emission monitoring was highly complicated and costly.
Studies suggest that in average terms, this emission factor is most likely underesti¬mated by up to ten times. Leading scientists suggest that the employment of such emission factor is inadequate, given the large variation of emission, between different WWTP and therefore recommend implementation of online measurements.