Characteristics of N 2 O Emission in Distilled Water and Activated Sludge Mixture

Abstract

To investigate the emission characteristics of the dissolved N 2 O in distilled water and activated sludge mixture, the total volume mass transfer coefficients of N 2 O in distilled water and activated sludge mixture were determined by batch experiments. The results indicated a difference between emission processes of N 2 O in distilled water and activated sludge mixture. At different initial N 2 O concentrations, the total volume mass transfer coefficients of N 2 O in distilled water were relatively stable, while the total volume mass transfer coefficients of N 2 O in activated sludge mixture increased with increasing initial N 2 O concentrations, due to endogenous denitrification by microorganisms in the mixture. Since N 2 O was reduced and consumed by heterotrophic bacteria in activated sludge, biochemical reactions were involved in the transfer process of N 2 O escaping from the mixture to the atmosphere. Therefore, use of distilled water was suggested to determine the total volume mass transfer coefficient in experiments calculating N 2 O emission rates for biological nitrogen removal processes.