[Effects of salinity concentration on N2O production during nitrification].

The experiment investigated the production and conversion rate of N2O during nitrification using saline sewage and municipal wastewater. Different kinds of sludge were used, domesticated by saline sewage influent (salinity 7.5 g/L) and municipal wastewater (salinity 0.1 g/L), respectively. The results showed that the production of N2O using saline sewage was 2.85 times higher than that using municipal wastewater. The production and conversion rate of N2O during nitrification under different salinities were also investigated. The results showed that the production of N2O was almost the same when salinity decreased from 7.5 g/L to 5.0 g/L, even 2.5 g/L. However, specific ammonia oxidation rate was increased with the decrease of salinity. The sudden increase of salinity, from 7.5 g/L to 10 g/L, resulted in the increase of N2O production and conversion rate but decrease of specific ammonia oxidation rate. Consequently, It is important to avoid the severe fluctuation of salinity resulted in the increase of N2O production and conversion rate.