Effects of oxygen in the bulk of refuses on nitrification and denitrification -Study on sources of released nitrous oxide using 15N-isotope as a tracer and FISH method-

벌크의 산소농도가 폐기물(廢棄物)의 질산화(窒酸化) 및 탈질(脫窒)에 미치는 영향 -Tracer 로서의 15N 동위원소(同位元素) 및 FISH법(法)을 이용한 아산화질소발생원(亞酸化窒素發生源)의 규명(糾明)-

Nitrification and denitrification are important processes in the landfill site as they are deeply related with degradation and stabilization of refuse. Also nitrous oxide ($N_2O$) which is released from both nitrification and denitrification is known as greenhouse gas (GHG). The purpose of this study was to clarify the process by which $N_2O$ produced using $^{15}N$ isotope. Nitrate which was labeled to 10.08% with $^{15}KNO_3$ was used and $N_2O$ was analyzed with GC mass. Results was that even also when $O_2$ of bulk was 15%, $N_2O$ was released from denitrification. And as concentrations of $O_2$ increase, sum of $N_2O$ was released from denitrification. And as concentrations of $O_2$ increase, sum of $N_2O$ and $N_2$ was decreased and ratios of $N_2O$ in the reduced gases were increased. FISH technics also adaped to confirm whether which of nitrifiers existed in the substrates. When NEU was used of which the target was ammonia oxidizing bacteria, nitrifier was not detected at all. So it was confirmed that during the reaction denitrification was dominant process. Total bacteria distributions which were detected by EUB probe explained that as $O_2$ increase the number of bacteria also increase, but between the 10-15% of $O_2$ there was no any differences.