Transformation of nitrogen and production of nitrous oxide in an estuary receiving treated wastewater

Transformation of nitrogen compounds and the production of N I D22 ii D 2 O were investigated in an estuary，the Tatara estuary in Fukuoka，receiving the load from two wastewater treatment plant.Conclusions obtained in this study are as follows：1)Loading from the wastewater treatment plants to the estuary brings severe impacts through the production of N I D 22 ii D 2 O；2)Nitrous oxide originated from treated wastewater and sediments；3)The major production sites of N I D 22 D 2 O in sediments were in the midstream of the Tatara estuary；4)Nitrifis a sible source of N I D 22 D 2 O in sediments；6)Nitrous oxides has been oversaturated in the water bodies and sediments and its flux to the atmosphere is about1.07MmolNkm I D1-2 I D 1 y i D1-1 I D 1 in this estuary；7)The emission rate of N I D 22 I D 2 O to the atmosphere is as same order of magnitude as its net production rate in the estuary；8)The temporal increases in production rate of N I D 22 D 2 O were found in duction rate in the estuary；8)The temporal increases in production rate of N i D 22 the duction rate of the water bodies and sediments and its flux to the atmosphere is about.9)When temperatures in the culture was shifted up，the temporal increase of N I D22 I D 2 O in production rates were found.

Transformation of nitrogen compounds and the production of NィイD22ィエD2O were investigated in an estuary, the Tatara estuary in Fukuoka, receiving the load from two wastewater treatment plant. Conclusions obtained in this study are as follows :1) Loading from the wastewater treatment plants to the estuary brings severe impacts through the production of NィイD22ィエD2O ;2) Nitrous oxide originated from treated wastewater and sediments ;3) The major production sites of NィイD22ィエD2O in sediments were in the midstream of the Tatara estuary ;4) Nitrification is a possible source of NィイD22ィエD2O especially in low temperature season ;5) The highest concentrations of NィイD22ィエD2O in water bodies at the observation stations raged from 1.8 to 20.9μM ;6) Nitrous oxides has been oversaturated in the water bodies and sediments and its flux to the atmosphere is about 1.07 MmolNkmィイD1-2ィエD1yィイD1-1ィエD1 in this estuary ;7) The emission rate of NィイD22ィエD2O to the atmosphere is as same order of magnitude as its net production rate in the estuary ;8) The temporal increases in production rate of NィイD22ィエD2O were found in the denitrification process following the onset of anaerobic conditions ;9) When temperatures in the culture was shifted up, the temporal increase of NィイD22ィエD2O in production rates were found.