• 한국물환경학회지
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• 제22권6호
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• pp.1014-1021
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• 2006

SMMIAR (Submerged Moving Media Intermittent Aeration Reactor) Process is a very efficient system which remove ammonia to nitrogen gas in one reactor. In this study, we determined the diversity of ammonia oxidizing bacteria and denitrifying bacteria using specific PCR amplification and the clone library construction. An ammonia monooxygenase gene(amoA) was analyzed to investigate the diversity of nitrifiers. Most of amoA gene fragments (27/29, 93%) were same types and they are very similar (>99%) to the sequences of Nitrosomonas europaea and other clones isolated from anoxic ammonia oxidizing reactors. ANAMMOX related bacteria have not determined by specific PCR amplification. A nitrite reductase gene(nirK) was analyzed to investigate the diversity of denitrifying bacteria. About half (9/20, 45%) of denitrifiers were clustered with Rhodobacter and most of others were clustered with Mesorhizobium (6/20, 30%) and Rhizobium (3/20, 15%). All of these nirK gene clones were clustered in alpha-Proteobacteria and this result is coincide with other system which also operate nitrification and denitrification in one reactor. The molecular monitoring of the population of nitrifiers and denitrifiers would be helpful for the system stabilization and scale-up.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.253-261
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• 2007

Molecular and cultivation techniques were used to characterize the bacterial communities of biobead reactor biofilms in a sewage treatment plant to which an Aerated Up-Flow Biobead process was applied. With this biobead process, the monthly average values of various chemical parameters in the effluent were generally kept under the regulation limits of the effluent quality of the sewage treatment plant during the operation period. Most probable number (MPN) analysis revealed that the population of denitrifying bacteria was abundant in the biobead #1 reactor, denitrifying and nitrifying bacteria coexisted in the biobead #2 reactor, and nitrifying bacteria prevailed over denitrifying bacteria in the biobead #3 reactor. The results of the MPN test suggested that the biobead #2 reactor was a transition zone leading to acclimated nitrifying biofilms in the biobead #3 reactor. Phylogenetic analysis of 16S rDNA sequences cloned from biofilms showed that the biobead #1 reactor, which received a high organic loading rate, had much diverse microorganisms, whereas the biobead #2 and #3 reactors were dominated by the members of Proteobacteria. DGGE analysis with the ammonia monooxygenase (amoA) gene supported the observation from the MPN test that the biofilms of September were fully developed and specialized for nitrification in the biobead reactor #3. All of the DNA sequences of the amoA DGGE bands were very similar to the sequence of the amoA gene of Nitrosomonas species, the presence of which is typical in the biological aerated filters. The results of this study showed that organic and inorganic nutrients were efficiently removed by both denitrifying microbial populations in the anaerobic tank and heterotrophic and nitrifying bacterial biofilms well-formed in the three functional biobead reactors in the Aerated Up-Flow Biobead process.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.843-853
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• 2014

In the context of artificial groundwater recharge, a reactive soil column at pilot-scale (4.5 m depth and 3 m in diameter) fed by treated wastewater was designed to evaluate soil filtration ability. Here, as a part of this project, the impact of treated wastewater filtration on soil bacterial communities and the soil's biological ability for wastewater treatment as well as the relevance of the use of multi-bioindicators were studied as a function of depth and time. Biomass; bacterial 16S rRNA gene diversity fingerprints; potential nitrifying, denitrifying, and sulfate-reducing activities; and functional gene (amo, nir, nar, and dsr) detection were analyzed to highlight the real and potential microbial activity and diversity within the soil column. These bioindicators show that topsoil (0 to 20 cm depth) was the more active and the more impacted by treated wastewater filtration. Nitrification was the main activity in the pilot. No sulfate-reducing activity or dsr genes were detected during the first 6 months of wastewater application. Denitrification was also absent, but genes of denitrifying bacteria were detected, suggesting that the denitrifying process may occur rapidly if adequate chemical conditions are favored within the soil column. Results also underline that a dry period (20 days without any wastewater supply) significantly impacted soil bacterial diversity, leading to a decrease of enzyme activities and biomass. Finally, our work shows that treated wastewater filtration leads to a modification of the bacterial genetic and functional structures in topsoil.

• 대한환경공학회지
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• 제35권6호
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• pp.449-455
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• 2013

소규모 하수처리시스템에 다양한 반송비와 고정식 담체를 적용하여 합성폐수에서 질소, 인의 제거를 검토하였다. 담체를 첨가 시 질소의 제거율은 40.1%에서 65.1%로 증가하였으나 COD와 인의 제거에는 영향이 없었다(<5%). 반송을 통해 유량을 2배(2Q)로 증가시킨 경우 질소의 제거율은 7% 정도가 증가하였으나, 인 제거율은 반송비가 증가됨에 따라 31.8에서 26.6%로 감소하였다. 무산소조에서 담체에 부착된 미생물은 약 73.4 $mg/cm^2$로 존재하였으며, FISH분석 결과 탈질 미생물인 Pseudomonas aeruginosa 존재 (약 58%)를 확인하였다.

• 한국물환경학회지
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• 제24권3호
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• pp.383-390
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• 2008

Recently, the interests on economical nitrogen removal from wastewater are growing. As a method of the novel nitrogen removal technology, nitrogen removal via nitrite pathway by selective inhibition of free ammonia and free nitrous acid on nitrite oxidizing bacteria have been intensively studied. The inhibition effects of free ammonia and free nitrous acid are low when domestic wastewater is used, however, because of its relatively lower nitrogen concentration than the wastewater from industry and landfill, etc. In this study, a sequencing batch reactor (SBR) is proposed for nitrogen removal to investigate the effect of the low nitrogen concentration on nitrite accumulation. Nitrification efficiency reached almost 100% during the aerobic cycle and the maximum specific nitrification rate ($V_{max,nit}$) reached $17.8mg\;NH_4{^+}-N/g\;MLVSS{\bullet}h$. During the anoxic cycle, average denitrification efficiency reached 87% and the maximum specific denitrification rate ($V_{max,den}$) reached $9.8mg\;NO_3{^-}-N/g\;MLVSS{\bullet}h$. From the analysis the main reason of nitrite accumulation in the SBR was free nitrous acid rather than free ammonia. Nitrite accumulation increased with the decrease of organic content in the wastewater and the mechanism is not well understood yet. From the result of fluorescent in situ hybridization, the distribution of nitrite oxidizing bacteria was in equilibrium with ammonium oxidizing bacteria when nitrite accumulation did not occur.

• 미생물학회지
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• 제47권1호
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• pp.56-65
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• 2011

돼지 도축폐수를 처리하는 Rotating Activated Bacillus Contactors (RABC) 공정의 세균군집 특성을 파악하기 위하여 그람양성세균수와 총세균수를 계수하여 기존 고도폐수처리공정인 A2O (Anaerobic-Anoxic-Oxic) 공정과 비교하였다. RABC 공정의 생물막 세균군집구조는 비배양기법인 16S rDNA 염기서열결정법을 이용하여 분석하였다. RABC 공정의 총세균수에 대한 그람양성세균수 비율은 생물막(32%)에 비해 최종포기조(1282%) 및 반송슬러지(958%)에서 현저히 증가한 반면, A2O 공정의 그람양성세균수 비율은 호기조(40%)와 반송슬러지(49%) 모두에서 상대적으로 훨씬 낮았다. 총 9개 문에 해당하는 92개의 클론이 검출되었으며, 이 가운데 최우점 집단은 Proteobacteria (64.1%)와 Actinobacteria (18.4)%로서 이들 2개 문이 전체의 82.5%를 차지하였다. 3번째로 많이 검출된 것은 내생포자형성세균집단이 속하는 Firmicutes (5.4%) 문이었다. 소량 검출된 나머지 6개 문은 Bacteroidetes (3.3%), Chlorobi (2.2%), Nitrospirae (1.1%), Chlorofleix (1.1%), Acidobacteria (1.1%), Fusobacteria (1.1%)의 순이었다. Proteobacteria 문 중에서는 Betaproteobacteria 강 34.8%, Alphaproteobacteria 강 26.1%로서 대부분을 차지하였고, Gammaproteobacteria 강은 3.2%이었다. 내생포자형성세균집단의 비율은 모두 19.4%로서, Firmicutes 문 5.4%와 Actinobacteria 문의 Intrasporangiaceae과 14.0%이었다. 질화세균 및 탈질세균과 관련된 클론 비율 6.5%, 인축적세균과 관련된 클론 비율 5.4%를 기록함으로써 무기영양소 및 악취 제거능력을 가진 세균집단이 RABC 생물막에 많이 서식하고 있음이 확인되었다.