생물학적 질소 산화물 제거에 미치는 호기적 전자 수용체의 영향 연구

Abstract

현대 사회의 경제 발전으로 인한 오염 물질 배출량이 급증하고 있다. 특히가축 배설물, 농업, 산업 유출물 등에서 발생하는 질소 화합물은 폐수와 지하수에 그 농도가 급증하고 있으며, 이 물질들이 높은 농도로 폐수나 지하수에 존재할 경우 수질 오염을 촉진하며, 환경과 사람에게 유해한 영향을 끼치게 되어 이 물질들을 제거하기 위한 여러 처리 방식들이 개발되고 있다. 폐수 처리 과정에서는 생물학적 질소 제거 공정을 통해 이 질소 화합물들을 제거한다. 이 공정은 질산화와 탈질화 두 공정으로 이루어져 있다. 두 단계로 구분 되는 이유는 질산화는 호기적 조건에서, 탈질화는 혐기적인 조건에서 미생물에 의해 잘 이루어지기 때문이다. 하지만, 폐수 처리에는 많은 비용이 들어가는 공정이기 때문에 공정의 단순화를 줄이고자 하는 노력이 지속되고 있다. 이러한 생물학적 질소 제거 통합 공정을 위한 노력 중 하나가 바로 호기적인 탈질균 분리 연구이다. 호기적 탈질균을 분리할 경우 질산화 공정의 호기적인 조건에서 탈질화까지 진행할 수 있기 때문에 하나의 단계에서 질소 제거를 이룰 수 있어 비용 절감이 가능하다. 그래서, 많은 호기적 탈질균을 분리하고자 하는 연구들이 진행되어 왔다. 하지만, 통합하려는 질산화 공정에서처럼 산소를 지속적으로 공급하면서 미생물의 탈질의 경향성을 연구한 보고는 미미한 실정이며, 산소 농도에 따른 탈질화에 대한 부분도 구체적인 연구가 필요하다. 본 연구에서는 호기성 탈질균이 존재할 수 있는 세 가지의 시료에서, 호기성 탈질 가능성이 있는 균을 분리하여, 호기적 탈질 능력 실험을 진행하여 가장 탈질이 잘 되는 JN5 발견하였다. 염기서열 분석 결과 JN5는 슈도모나스 속(Pseudomonas sp.)에 속하는 미생물이었다. 또한 지속적인 산소 공급을 위해 공기를 5 L/min의 유량으로 공급하였을 때에도, 탈질을 일으켰으며, DO 농도가 4.89~5.25 mg/l 인 호기적인 상태에서도 탈질 대사를 하는 결과가 나타났다. 이것은 호기적인 질소 제거 통합 공정에 JN5를 적용할 수 있다는 것을 나타내는 결과이다.|Recently effluents of pollutants have increased in many countries as their economic development happened. Specially, concentration of nitrogen compounds which are caused from, industrial effluents, agricultural effluents and livestock’s excrement is increasing in the wastewater and ground water. When there is high concentration of nitrogen compounds in wastewater and ground water, it will facilitate harmful effects, such as eutrophication and methemoglobinemia, to environment and humans. In wastewater treatment process, nitrogen compounds are removed through a biological nitrogen removal process. This process consists of two steps. (nitrification and denitrification) because nitrification and denitrification can be performed in aerobic and anaerobic condition respectively. So many studies have been conducted continuously for integrating of the two processes. One of these study for the purpose is isolating aerobic denitrificans. Using aerobic denitrificans in aerobic nitrogen removal process, it is possible to perform denitrification as well as nitrification in aerobic condition. For these reasons, many researchers have attempted to isolate aerobic denitrificans and study aerobic denitrification. But, there are a little reports that aerobic denitrification was conducted under condition of contiuously supplying oxygen to microorganisms like nitrification process, and studying aerobic denitrification at various concentrations of dissolved oxygen. In this study, isolation of aerobic denitrificans from three sites in which aerobic denitrifiers may exist, and we found aerobic denitrificans, JN5. According to 16S rRNA gene sequences analysis, JN5 was identified as Pseudomonas sp. We also performed the experiments to study aerobic denitrification under supplying oxygen to microorganisms like aerobic condition at the biological nitrogen removal process in wastewater treatment system. The results of this experiments showed that JN5 could perform denitrification at 4.89~5.25 mg/l of dissolved oxygen. Therefore, JN5 is able to be used as aerobic denitrifier at an intergrated nitrogen removal process at aerobic condition.; Recently effluents of pollutants have increased in many countries as their economic development happened. Specially, concentration of nitrogen compounds which are caused from, industrial effluents, agricultural effluents and livestock’s excrement is increasing in the wastewater and ground water. When there is high concentration of nitrogen compounds in wastewater and ground water, it will facilitate harmful effects, such as eutrophication and methemoglobinemia, to environment and humans. In wastewater treatment process, nitrogen compounds are removed through a biological nitrogen removal process. This process consists of two steps. (nitrification and denitrification) because nitrification and denitrification can be performed in aerobic and anaerobic condition respectively. So many studies have been conducted continuously for integrating of the two processes. One of these study for the purpose is isolating aerobic denitrificans. Using aerobic denitrificans in aerobic nitrogen removal process, it is possible to perform denitrification as well as nitrification in aerobic condition. For these reasons, many researchers have attempted to isolate aerobic denitrificans and study aerobic denitrification. But, there are a little reports that aerobic denitrification was conducted under condition of contiuously supplying oxygen to microorganisms like nitrification process, and studying aerobic denitrification at various concentrations of dissolved oxygen. In this study, isolation of aerobic denitrificans from three sites in which aerobic denitrifiers may exist, and we found aerobic denitrificans, JN5. According to 16S rRNA gene sequences analysis, JN5 was identified as Pseudomonas sp. We also performed the experiments to study aerobic denitrification under supplying oxygen to microorganisms like aerobic condition at the biological nitrogen removal process in wastewater treatment system. The results of this experiments showed that JN5 could perform denitrification at 4.89~5.25 mg/l of dissolved oxygen. Therefore, JN5 is able to be used as aerobic denitrifier at an intergrated nitrogen removal process at aerobic condition.