| Title |
Effects of Extrnal Carbon Source Dosage and Temperature in the 2 - Stage Denitrifying Filter |
| Authors |
윤주환(Zu Whan Yun),김경희(Kyung Hoe Kim) |
| Abstract |
A laboratory-scale 2-stage denitrifying filter plant was operated under the various dosage of methanol as an external carbon source. The methanol dosages were computed on the basis of emperical equation developed by McCarty et al. The imbalance of carbon usage for denitrification was noticed when the methanol supplied for the nitrate reduction for both 50% and 100%. Although it was primarily reasoned that the leaching of organics from the biofilm and solids trapped between the sand media, a further study is needed to confirm the findings. The organic contents in the effluent of 2-stage denitrifying filter operated with an excess methanol dosage was not as high as up to that of single stage configurations. It was probably due to the biological removal of excess organics in the second stage filter. The finding suggests that the 2-stage configuration could reduce the possible `COD-leak problem` which is an important consideration for design of the post-denitrification processes. The operating temperature has a pronounce impact on denitrification process. The nitrate reduction significantly decreased at 10℃ of operating temperature. It was also observed that the nitrous oxide(N₂O) gas was included in the denitrified gas under the normal operating conditions. The result suggested that the various nitrate reduction pathways could exist in the denitrifying filter in addition to the conventional denitrification pathway. |