• 한국환경과학회지
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• 제28권10호
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• pp.899-905
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• 2019

Recently, an innovative method for wastewater treatment and nutrient removal was developed by combining the sequence batch reactor and membrane bioreactor to overcome pollution caused by shipboard sewage. This system is a modified form of the activated sludge process and involves repeated cycles of mixing and aeration. In the present study, the bacterial diversity and dominant microbial community in this wastewater treatment system were studied using the MACROGEN next generation sequencing technique. A high diversity of bacteria was observed in anaerobic and aerobic bioreactors, with approximately 486 species. Microbial diversity and the presence of beneficial species are crucial for an effective biological shipboard wastewater treatment system. The Arcobacter genus was dominant in the anaerobic tank, which mainly contained Arcobacter lanthieri (8.24%), followed by Acinetobacter jahnsonii (5.81%). However, the dominant bacterial species in the aerobic bioreactor were Terrimonas lutea (7.24%) and Rubrivivax gelatinosus (4.95%).

• 환경영향평가
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• 제21권5호
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• pp.707-713
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• 2012

There are a lot of parameters affecting microbial acclimation/cultivation characteristics such as dynamic conditions, F/M ratio and substrate affinity. From the process control point of view, the effect of high salinity on the removal efficiencies of BOD and SS have been documented by few researchers. In this research, lab-scale CAS(Conventional Activated Sludge) process and modified $A_2O$(Anaerobic/Anoxic/Oxic) process were operated and monitored to evaluate the characteristics of microbial acclimation and cultivation under high salinity wastewater during the period of three weeks. As a result of acute microbial activity test(6hr) at various $Cl^-$ concentration, the appropriate $Cl^-$ concentration for microbial growth and acclimation ranged under 3,100 mg/l. As a result of acclimation/cultivation test, the trend of COD removal efficiency reduced gradually as time elapsed. It is considered that $NH_4$-N removal phenomenon of the conventional pollutants removal mechanisms gave little effect to the microbial acclimation/cultivation under high salinity wastewater.

• 한국환경과학회지
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• 제25권8호
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• pp.1155-1163
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• 2016

The treatment efficiencies of domestic sewage treatment processes were analysed and assessed to suggest and design a suitable technology for coal seam gas (CSG) water treatment. Two sewage treatment plants (S and G in Busan) were selected. The former operates with standard activated sludge and modified Ludzak Ettinger processes while the later uses the combination of $A_2/O$ and gravity fiber filtration. For both plants, the concentrations of BOD, $COD_{Mn}$, T-N and T-P were about 5.0, 19.0, 5.0, 11.0 and 1.0 ppm, respectively, which satisfy the discharge standards. Therefore, although sewage treatment processes seems to be applicable for CSG water treatment, additional processes to remove total dissolved solids and ionic compounds (i.e. bicarbonate) need to be introduced to produce fit-for-purpose water resources for beneficial use (in accordance with Water ACT 2013). This, for the CSG treatment process design, it is necessary to align the operating conditions with merging methods of combinable unit technology obtained from sewage treatment processes.

• Journal of Microbiology and Biotechnology
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• 제18권4호
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• pp.624-630
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• 2008

Terminal restriction fragment length polymorphism (T-RFLP) is a method that has been frequently used to survey the microbial diversity of environmental samples and to monitor changes in microbial communities. T-RFLP is a highly sensitive and reproducible procedure that combines a PCR with a labeled primer, restriction digestion of the amplified DNA, and separation of the terminal restriction fragment (T-RF). The reliable identification of T-RF requires the information of nucleotide sequences as well as the size of T-RF. However, it is difficult to obtain the information of nucleotide sequences because the T-RFs are fragmented and lack a priming site of 3'-end for efficient cloning and sequence analysis. Here, we improved on the T-RFLP method in order to analyze the nucleotide sequences of the distinct T-RFs. The first method is to selectively amplify the portion of T-RF ligated with specific oligonucleotide adapters. In the second method, the termini of T-RFs were tailed with deoxynucleotides using terminal deoxynucleotidyl transferase (TdT) and amplified by a second round of PCR. The major T-RFs generated from reference strains and from T-RFLP profiles of activated sludge samples were efficiently isolated and identified by using two modified T-RFLP methods. These methods are less time consuming and labor-intensive when compared with other methods. The T-RFLP method using TdT has the advantages of being a simple process and having no limit of restriction enzymes. Our results suggest that these methods could be useful tools for the taxonomic interpretation of T-RFs.

• 멤브레인
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• 제30권1호
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• pp.1-8
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• 2020

막 생물 반응기(MBR)에서, 활성화 된 슬러지는 생물학적 성분을 분해하고 막 공정은 이 부유 물질인 박테리아를 분리시킨다. 그러나 MBR에서의 주요 문제는 '막 오염'이다. 이 리뷰에서는 '막 오염'을 극복하기 위하여 제시된 '복합막'을 논의하고 있다. '복합막'은 탄소 또는 비탄소 재료 포함하는 막으로 분류할 수 있다. 이 복합막의 친수성은 그래핀, 산화그래핀(GO) 및 탄소 나노 튜브 또는 그들의 변형 된 부분을 깨끗한 막에 도입시킬 때 향상된다. 이산화규소(SiO₂) 또는 이산화티타늄(TiO₂)과 같은 무기 물질 또한 막의 물 흐름을 증가시키기 위해 복합막 형성에 통합된다.

• 상하수도학회지
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• 제25권1호
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• pp.95-106
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• 2011

Even though MBR processes have many advantages such as high quality effluents, a small footprint and convenience for operation compared to conventional activated sludge processes, there are some shortcomings in terms of the cost and potential fouling incident that keeps MBR (Membrane bioreactor) processes from being widely applied. To reduce these problems, PTFE (Polytetrafluoroethylene) flat sheet membranes that have excellent permeability and durability were tested instead of PVDF (Polyvinylidene fluoride) membrane which is being used widely in water treatment. Low concentration of sodium hydroxide (NaOH) was also added into the membrane modules in order to prevent the membrane fouling as well as to provide the alkalinity. With conditions mentioned above, a pilot-scale MBR system based on the MLE (Modified Ludzack Ettinger) process was operated at flux of 40 $L/m^{2}/hr$ and over 15,000 mg/L MLSS concentration for about 8 months. And coagulant(alum) was added into the membrane tank to remove phosphorus. Although the more coagulant is added the more effectively phosphorus is removed, that can lead to fouling for a long operation(Ronseca et al.,2009). By the way there is a research that fouling grow up after stopping injection of coagulant(Holbrook, 2004). Stable operation of MBR systems was achieved without major chemical cleaning and the effluent quality was found to be good enough to comply with the treated waste water quality regulations of the Korea.