Park, Hee Deung

The integrated fixed-film activated sludge (IFAS) system is a variation of the activated sludge wastewater treatment process, in which hybrid suspended and attached biomass is used to treat wastewater. Although the function and performance of the IFAS system are well studied, little is known about its microbial community structure. In this study, the composition and diversity of the bacterial community of suspended and attached biomass samples were investigated in a full-scale IFAS system using

It is important to know the comprehensive microbial communities of fecal pollution sources and receiving water bodies for microbial source tracking. Pyrosequencing targeting the V1-V3 hypervariable regions of the 16S rRNA gene was used to investigate the characteristics of bacterial and Bacteroidales communities in major fecal sources and river waters. Diversity analysis indicated that cow feces had the highest diversities in the bacterial and Bacteroidales group followed by the pig sample, with

Nitrifying bacterial community structures of suspended and attached biomasses in a full-scale integrated fixed-film activated sludge process were investigated by analyzing 16S rRNA gene sequences obtained from pyrosequencing. The suspended biomass had a higher number of ammoniaoxidizing bacterial sequences (0.8% of total sequences)than the attached biomass (0.07%), although most of the sequences were within the Nitrosomonas oligotropha lineage in both biomasses. Nitrospira-like nitrite-oxidizing

This study compared ultrasound, ultraviolet, and catalyst processes and evaluated their respective synergistic effects. The ultrasonic frequencies in this study used 35, 283, 450, and 935 kHz, whereas short wavelength ultraviolet lamp (UVC) was used. The dose of TiO 2 was 0.3 g/L. The degradation rate constants for the sonophotolytic processes were (4.2–8.7)×10 -3 min -1 , nearly the same for the sonolytic processes. The value of the synergistic effect was 1.07. The main mechanism of this proces

Although salt is known to influence the performance of nitrification significantly, it has not been well reported on how salt affects ammonia-oxidizing bacterial (AOB) community compositions and dynamics in wastewater treatment bioreactors. In this study, these questions were evaluated in a full-scale bioreactor treating saline wastewater. Clone library analysis for the ammonia monooxygenase subunit A gene revealed that AOB belonging to the Nitrosomonas europaea and the N. oligotropha lineages i

The base sequences representing human- and cow-specific 16S rRNA gene markers identified in a T-RFLP analysis were recovered from clone libraries. The human- and cowspecific primers were designed from these sequences and their specificities were analyzed with fecal DNAs from human, cow, and pig. The AllBac primer set showed positive results for all human, cow, and pig samples, whereas the human-specific primer set showed positive result only for the human sample but not for the cow or pig sample

This study compared ultrasound, ultraviolet, and catalyst processes and evaluated their respective synergistic effects. The ultrasonic frequencies in this study used 35, 283, 450, and 935 kHz, whereas short wavelength ultraviolet lamp (UVC) was used. The dose of TiO2 was 0.3 g/L. The degradation rate constants for the sonophotolytic processes were (4.2–8.7)×10-3 min-1, nearly the same for the sonolytic processes. The value of the synergistic effect was 1.07. The main mechanism of this process wa

서로 다른 처리공정으로 운영되는 4개의 하수시설을 대상으로 16S rRNA 유전자 기반의 pyrosequencing을 이용해 활성슬러지 하수처리 생물반응기의 세균군집구조를 분석하였다. 활성슬러지에는 Rhodocyclales, Burkholderiales, Sphingobacteriales, Myxococcales, Xanthomonadales, Acidobacteria group 4,Anaerolineales, Methylococcales, Nitrospirales, Planctomycetales 목에 속하는 염기서열이 전체의 54-68%를 차지해, 소수의 세균 분류군이 활성슬러지 세균군집의 대부분을 차지하고 있었다. 이들 소수 세균 분류군의 조성은 처리장별로 차이가 있었으며, 하수처리장의 운전조건 및 환경조건에 영향을 받는 것으로 추측되었다. 또한, 활성슬러지는 매우 다양한 세균 종을 가지는 것으로 관찰되었는데 (Chao1 richness estimate: 1,374-2,902 o

호소, 하천 등에 다량의 영양염류의 유입과 수문학적, 지리학적, 생물학적 요소 등으로 인해 남조류가 대량 발생하게되며 대표적 독성물질인 마이크로시스틴-LR(MC-LR)이 증가한다. MC-LR이 포함된 지표수를 적절하게 처리하기 위하여 정수처리공정에서는 고도산화공정을 적용하고 있다. 다양한 고도산화공정 중 특히 UV, UV/H2O2, UV/O3, UV/TiO2 등에 대한연구는 꾸준히 되어왔다. 기존의 UV램프의 짧은 교체주기, 수은 폐기물 발생, 큰 열 손실 등의 단점을 보완한 UV-LED를MC-LR제거에 적용하였다. MC-LR 초기농도 100 μg/L을 280 nm의 파장인 LED-L (0.024 mW/cm 2 )와 LED-H (2.18 mW/cm 2 ) 를 이용하여 산화시켰을 때 각각 최대 약 30%, 95.9%의 MC-LR 제거율을 나타냈다. LED-H를 조사 시 자연유기물 변화는 휴믹물질, UVD, SUVA가 감소하는 경향을 보였고 방향족 유기물이 지방족 유기물로 분해되어 저분

Hetero-structured catalysts have recently attracted considerable interest from researchers in various fields, including electronics, sensing, energy, and photocatalysis. Treated water contains many harmful microorganisms and organic contaminants, which can be effectively removed through an advanced photocatalytic oxidation process. Photocatalysts with wide band gaps, such as semiconductor oxides like titanium dioxide (TiO 2 ) and zinc oxide (ZnO), are typically utilized to decompose these organi