고정화 미생물 및 생물막 프로세스를 이용한 합성하수의 질소제거에 관한 연구

Abstract

본 연구에서는 질소 제거의 새로운 방법을 개발하고자 Polyethylene glycol이 주 성분인 고분자 물질에 김 등10,11)이 분리한 질소제거 박테리아 Pseudomonas aeruginosa AE-1-3과 K. pneumoniae를 포괄고정화 하여 합성하수 중의 질소제거에 영향을 주는 여러 인자들을 회분식으로 검토함과 동시에 연속적으로 질소제거 가능성을 검토하였으며. 또한 위의 2 균주를 부직포에 부착시킨 생물막 반응조를 이용하여 합성하수 중의 질소제거 가능성을 검토하였다.|The aim of this research is to develop a new process of Nitrogen removal. Whole cells of Klebsiella pneumoniae and Pseudomonas aeruginosa AE-1-3 were immobilized by entrapment with polyethlene glycol(PEG), and various factors on the removal of nitrogen from synthetic wastewater were investigated by batch and continuous reactors. also, the possibilities of the removal of nitrogen was investigated by using the biofilm process attached to a nonwoven fabric.

1. The removal of NO3-N by immobilized K. pneumoniae The removal time of NO3-N was faster with increasing of the bead amount in the reactor. The immobilized K. pneumoniae utilized glucose, acetate and methanol as carbon sources in the anoxic condition, but methanol as a carbon source was not used for removal of NO3-N under oxic condition. Until the C/N ratios of 2.5~10, the lag times are similar but at the ratios of 10 and 30, the lag time showed a tendency to getting longer. And in the case of C/N ratios of 2.5, about 41.3% were consumed because of the lack of carbon sources. The NO3-N removal efficiency of 65.3% could achieved at the low temperature(10℃) by the immobilized K. pneumoniae. It could remove more than 15% than in the case of free cells. When the NO3-N concentration was 200 mg/ℓ in the synthetic wastewater, approximately 93.1% of NO3-N was removed within 30 hours by immobilized K. pneumoniae. The immobilized K. pneumoniae could remove NO3-N under anoxic condition. NO3-N of 50 mg/ℓ was completely removed at C/N ratio of 2.5 under anoxic condition. This indicates that It is possible to remove NO3-N at a lower C/N ratio than the oxic condition. The average efficiencies of NO3-N removal of 99.9% and 99.8% were achieved during continuous treatment by immobilized K. pneumoniae at the HRT of 24 hours and 12 hours, respectively.

2. The removal of NH4-N-N and NO3-N by immobilized P. aeruginosa AE-1-3 The removal rate of NH4-N and NO3-N increased with increasing of cell concentration in the immobilized beads. A higher removal rate of NH4-N and NO3-N were observed when the smaller bead size and more visual column of the immobilized beads were used. When glucose, was added as a carbon source, 50 mg/ℓ of NH4 -N and NO3-N was completely removed in 18 hours. other carbon source, such as methanol was not utilized. NH4-N was completely consumed at C/N of 10 and 20, but C/N 5 and 2.5 the removal efficiencies of NH4-N and NO3-N ranged from 35.7%~76.9%. The removal effciencies of NH4-N and NO3-N increased with increasing of temperature and the NH4-N removal efficiency of 94.8% could achieved at the low temperature(10℃) by the immobilized P. aeruginosa AE-1-3. The average removal efficiencies of NH4-N and NO3-N at the HRT of 6 and C/N 10 was 90.5% and 93.4% respectively during continuous treatment by the immobilized P. aeruginosa AE-1-3 when NH4NO3 as a nitrogen source was used. In the case of using NH4Cl as nitrogen sources, it was assumed that operating in the condition of C/N 10 was adequate to remove effluent NH4-N at 10 mg/ℓ.

3. The process of P. aeruginosa AE-1-3 combinated with activated sludge. As a result of puttingP. aeruginosa AE-1-3 to a activated sludge in continuous system, the efficiency of the removal of NH4-N was 65.8%. But NH4-N did not convert into NO3-N. In the case of establishing activated sludge process and then establishing P. aeruginosa AE-1-3 process in continuous system, the efficiency of the removal of NH4-N and NO3-N were low. It is assumed that the frontier organic substances were almost eliminated that the amount of the organic substances influent to the latter one was too little. In the case of establishing P. aeruginosa AE-1-3 process and then establishing activated sludge process, the almost amounts of the organic substances in influent were eliminated in the frontier process. As a result, the efficiency of the removal of NH4-N and NO3-N were low because of the lack of the organic substances in the latter process.

4. The process of biological fixed film As a result of experiments of removing NH4-N and NO3-N in continuous system by using the process of attaching activated sludge process and P. aeruginosa AE-1-3 at one time to nonwoven fabric and the process of attaching just P. aeruginosa AE-1-3, each efficiencies of the removal of NH4-N were 69.8% and 63.6%. But efficiencies of the removal of NO3-N were 97.78% and 96.98%. (used NH4NO3 as a nitrogen source). As a result of continuous experiments of putting NH4Cl as nitrogen sources in the process of attaching activated sludge process and P. aeruginosa AE-1-3 at one time to nonwoven fabric and the process of attaching just P. aeruginosa AE-1-3, the efficiency of removal was 62.5%. And as the experimental time passes, the nitration appeared. As a result of continuous experiments of putting NH4-N as nitrogen sources in the process of attaching just P. aeruginosa AE-1-3 to nonwoven fabric, the efficiency of removal of NH4-N was 56.9% in anoxic condition. The efficiency of removal of NO3-N was 97.3% in anoxic condition and was 98.9% in aerobic condition.