생물학적 탈질공정에서 외부탄소원으로 음식물류 폐기물 건조응축수의 적용성 평가

본 연구에서는 음식물류 폐기물 건조 사료화 공정에서 발생되는 건조응축수를 생물학적 탈질공정의 효율을 증대시키기 위한 외부탄소원으로 활용성을 평가하였다. 실험은 batch test의 형태로 수행되었으며, 각각의 반응기에는 건조응축수를 COD 및 T/N의 비율(C/N ratio)에 따라 주입한 후, 무산소 조건에서 5시간 동안 운영하며 1시간 간격으로 질산성 질소의 농도를 분석하였다. 음식물류 폐기물 건조응축수는 높은 유기물 함량(TCOD 21,863 mg/L) 대비 낮은 질소함량(T-N 220 mg/L)을 나타내어, 탈질공정에서의 외부탄소원의 조건을 만족하는 것으로 분석되었다. 그리고 실험 결과, C/N ratio 7.50:1에서 5시간 후 질산성 질소 제거효율이 최대 76%로, 응축수를 투입하지 않은 control (제거효율 4%)에 비해 크게 증가한 것으로 나타났다. 더욱이, 가장 낮은 효율을 나타내었던 C/N ratio 0.95:1에서도 28%의 제거효율을 나타내었다. 또한, 각 C/N ratio 별 specific denitrification rate (SDNR)을 산출한 결과, C/N ratio 7.50:1에서 0.0726 mg NO3-/mg VSS/d로, control의 0.0038 mg NO3-/mg VSS/d에 비해 크게 증가한 것으로 확인되었다. 이러한 결과를 바탕으로 음식물류 폐기물 건조응축수를 탈질공정에서의 외부탄소원으로 활용이 가능할 것으로 판단된다. In this study, the applicability of dry condensate generated from food waste dry feed conversion process was evaluated as an external carbon source to increase the efficiency of the biological denitrification process. The experiment was carried out in the form of a batch test, and dry condensate was injected into each reactor according to the COD and T/N ratio (C/N ratio). Then, the reactor was operated under anoxic conditions for 5 hours, and nitrate nitrogen was analyzed at intervals of 1 hour. The dry condensate from food waste showed a low nitrogen content (T-N 220 mg/L) compared to a high organic matter content (TCOD 21,863 mg/L), and was analyzed to satisfy the conditions of an external carbon source in the denitrification process. And as a result of the experiment, it was found that the nitrate nitrogen removal efficiency was up to 76% after 5 hours at a C/N ratio 7.50:1, which was significantly increased compared to the control which was without condensed water (removal efficiency 4%). Moreover, the removal efficiency of 28% was exhibited even at the C/N ratio 0.95:1, which exhibited the lowest efficiency. In addition, as a result of calculating the specific denitrification rate (SDNR) for each C/N ratio, 7.50:1 was found to be as 0.0726 mg NO3-/mg VSS/d, which was significantly increased than that of control as 0.0038 mg NO3-/mg VSS/d. Based on these results, it is judged that it is possible to utilize the dried condensate of food waste as an external carbon source in the denitrification process. KCI Citation Count: 0