[Impact of nitrate continuous injection on N2O releases from bioreactor landfill]

A combined process comprised of ex-situ nitrification and in-situ denitrification in different bioreactors is an effective measure to nitrogen removal, but it will cause N2O, a strong greenhouse gas, emissions. This paper focused on the production characteristics and influencing factors of N2O by establishing 3 bioreactor landfill units by continuous injected different amount of nitrate leachate (50, 100 and 300 mg x L(-1)), with fresh MSW as material in an experimental scale. Experimental results showed that the production of N2O had the same regulation with different amount of NO3(-) -N injection,they all showed high at the initial period,then at a lower level, finnal at a higher level; The cumulative production is positively correlated with the amount of NO3(-) -N, the total quantity of N2O are 36 481, 44 241 and 86 264 μg respectively; However, the amount of N2O by consumption per nitrate nitrogen and N2O conversion ratio by denitrification is negatively correlation with the amount of NO3(-) -N, the average conversion ratio are 8.84 per thousand, 5.68 per thousand, 2.34 per thousand respectively; Shortage of carbon source for denitrification is the main reason for the high N2O production in each reactor in the later period.