Nitrogen Removal and N_2O Emission in a Full-Scale Domestic Wastewater Treatment Plant with Intermittent Aeration

概要

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Nitrous oxide(N_2O)is emitted from wastewater treatment processes. It is known as a greenhouse gas that contributes to global warming(over 200 times more per molecule than carbon dioxide)and to the destruction of the ozone layer. It is therefore of great importance to develop technology that can suppress N_2O emission. The effects of an anoxic period on N_2O emission and nitrogen removal were investigated in an actual domestic wastewater treatment plant. When operated with intermittent aeration, most of the N_2O was emitted into the atmosphere during the aerobic period. N_2O emission from the intermittent process was estimated to be 0.43-1.89 g N_2O person^<-1> year^<-1>. Maintaining a dissolved oxygen(DO) concentration of over 0.5 mg l^<-1> during the aerobic period resulted in the complete conversion of the influent NH_4-N to NO_3-N and a 60-min anoxic period was sufficient for denitrification to be completed. The findings show that an optimum combination of aerobic and anoxic conditions and their suitable control are very important for improving nitrogen removal efficiency and controlling N_2O emission.
社団法人日本生物工学会の論文
1998-08-25