• Biotechnology and Bioprocess Engineering:BBE
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• 제6권2호
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• pp.95-99
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• 2001

Giardia lamblia is a parasitic protozoa which is transmitted in the form of a cyst through untreated water and also treated drinking water. Since its presence in water has led to frequent outbreaks of giardiasis and death in many countries, the removal and disinfection of this protozoan cyst from the water supply are of great concern for public health. This study examined the disinfection characteristics of G. lamblia cysts isolated from a Korean patient with giardiasis. When using sodium hypochlorite including 5 or 10 ppm chlorine, the killing rate was initially rapid, however, the disinfection slowed down and a 3log reduction could not be achieved even after 2h. The disinfection effectiveness was also reduced at a lower temperature, thereby implying that the risk o a giardiasis outbreak will be higher in the winter season. A CT (concentration$.$time) curve was constructed based on the results with sodium hypochlorite for use in designing and predicting disinfection performance. The organic chlorination disinfectant SDIS (sodium dichloroisocyanurate) produced a lower pH and a much higher residual effect than sodium hypochlorite. The disinfection of cysts by SDIC continued steadily throughout 2h of contact, although the initial killing rate was lower than that with sodium hypochlorite.

• 상하수도학회지
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• 제19권3호
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• pp.370-377
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• 2005

Dispersion of coagulant should be completed in a fraction of a second before the metal hydroxide precipitate has form. For the reason so-called pump diffusion flash mixing (PDFM) have been proposed, and PDFM is one of reasonable methods to quickly disperse the hydrolyzing metal salts. In this study, therefore, we attempt to understand the difference of removal characteristics of natural organic matter (NOM) between pump diffusion flash mixing (PDFM) and conventional rapid mixing (CRM) for coagulation in a water treatment system, and to enhance the removal of NOM through the improved mixing process. DOC and turbidity removal by PDFM higher than those by CRM, while SUVA value of water treated by PDFM was high as compared with that by CRM. Hydrophilic NOM was more effectively removed by PDFM than CRM, since charge neutralization effect increased by quick dispersion of coagulant. The DBP formation potentials due to NOM was effectively reduced by the improved mixing (i.e., PDFM) for coagulation and could be controlled through decrease in concentration of precursor rather than reduction of activity with disinfectant.

• 한국어병학회지
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• 제13권2호
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• pp.97-102
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• 2000

WSBV를 염소소독 효과를 조사하기 위하여 유효농도 5, 10, 30 ppm의 차아염소산나트륨 용액을 처리한 결과 전혀 폐사가 일어나지 않았으나, 대조구에서는 전량 폐사되었다. 포비돈 요오드 10, 20, 30 ppm에서는 불활성화를 나타내지 않았는데 이는 유기물의 다량함유나 요오드 독성에 의해 시험새우가 폐사할 가능성이 있다. 일광소독에서는 2, 4시간 처리한 시험구에서는 폐사가 일어나지 않으므로 WSBV를 불활성화 시키는 것 같다. 건조처리에서는 1, 2, 3시간 처리한 시험구에서는 WSBV가 불활성화가 되었다. 담수처리에서는 담수 60% 첨가한 시험구(비중 1.015)에서 효과가 가장 크게 나타났다.

• Journal of Korean Biological Nursing Science
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• 제23권1호
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• pp.1-10
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• 2021

Purpose: To verify the anti-microbiotic activity and to develop eco-friendly surface disinfectants using the Opuntia ficus-indica extract. Methods: The stem and fruits of the Opuntia cultivated in Jeju Island were extracted with hot water, 70% EtOH and 100% MeOH, respectively. To examine the antimicrobial activity of the extracts, gram positive bacteria (Bacillus subtilis, Staphylococcus aureus), gram negative bacteria (Escherichia coli, Salmonella typhimurium), yeast (Candida albicans), mold (Aspergillus flavus) and antibiotic resistant bacteria (E. coli, S. aureus) were measured to form a clear zone. Results: The antibacterial activity of the fruit extract was higher than that of the stem extract, and the antibacterial activity of the 100% MeOH (FM) extract and the 70% EtOH (FE) extract of the palm cactus fruit was suitable for the surface disinfectant overall, and clear-zone formed even at relatively low concentrations (250 mg/mL). The FM and FE have antibacterial activity against various bacteria, therefore they can be used as disinfectants. Conclusion: The antimicrobial activity of Opuntia ficus-indica extract from Jeju Island by stem and fruit was determined at relatively low concentrations (250 mg/mL). The Opuntia ficus-indica extract will be useful for surface disinfectants dissolving the patients' bath, oral gargling, and powdered powder in water or ethanol in appropriate concentrations.

• 공업화학
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• 제33권3호
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• pp.258-271
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• 2022

Ferrate (VI) [Fe(VI)] has multi-functional features, which include potential oxidant, coagulant, and disinfectant. Because of these distinctive properties, numerous studies on the synthesis of ferrate (VI) and its possible applications in a wide research areas have been investigated. This review highlights the recent development made on different synthesis methods for ferrate including wet chemical, electrochemical, and thermal methods. The recent advancements achieved in ferrate (VI) oxidation and the synergistic effect of the oxidative properties of ferrate (VI) in the presence of various compounds or materials are also included. Moreover, this review discusses the applications of ferrate (VI) for degrading various types of water pollutants and its reaction mechanism. The optimized experimental conditions and interaction mechanisms of ferrate (VI) with micro-pollutants, dyes, and other organic compounds are also elaborated upon to provide greater insight for future studies. Lastly, the limitations and prospects of the ferrate use in the treatment of polluted water are described.

• 농업과학연구
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• 제50권4호
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• pp.817-828
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• 2023

Deteriorating soil physical properties and increasing soil pathogens due to the continuous cultivation of field crops are the leading causes of productivity deterioration. Crop rotation, soil heat treatment, and chemical control are used as pest control methods; however, each has limitations in wide application to domestic agriculture. In particular, chemical control requires improvement due to direct exposure to sterilizing solution, odor, and high-intensity work. To improve the overall domestic agricultural environment, the problems of time and cost, such as field maintenance and cultivation scale, must be addressed; therefore, mechanization technology for chemical control must be secured to derive improvement effects in a short period. Most related studies are focused on the control effect of the DMDS (dimethyl disulfide) sterilizer, and research on the performance of the sterilization spray device has been conducted after its introduction in Korea, but research on the corrosion suitability of the material is lacking. This study conducted a corrosion test to secure the corrosion resistance of a soil sterilizer injection pump, and a mechanical failure mode by corrosion by the material was established. The corrosion test comprised operation and neglect tests in which the sterilizing solution was circulated in the pump and remained in the pump, respectively. As a result of the corrosion test, damage occurred due to the weakening of the mechanical strength of the graphite material, and corrosion resistance to aluminum, stainless steel, fluororubber, and PPS (polyphenylene sulfide) materials was confirmed.

• 한국식품위생안전성학회지
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• 제22권2호
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• pp.127-131
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• 2007

본 연구는 표준 및 식품분리 V. parahaemolyticus균에 대한 주요 유형별 살균소독제의 유효성을 평가하고자 하였다. 살균소독제는 에탄올, 요오드, 염소계(무기, 유기) 각 2종, 4급 암모늄, 산, 과산화초산계, 과산화수소를 선정하였다. 시험균주는 표준균주 4종과 자연에서 분리한 10종의 V. parahaemolyticus를 정량적 현탁액 시험방법(유럽 EN 1276)으로 비교 평가하였다 에탄올(75, 95%), 요오드계 25ppm, 4급 암모늄 100 ppm,산, 과산화초산계 145 ppm은 청정조건과, 오염조건 모두에서 $5log_{10}CFU/mL$ 이상의 생균수 감소율을 보였다. 유기염소계의 시험 결과는 $5log_{10}CFU/mL$ 이상의 생균수 감소율을 보였다. 청정조건에서 요오드 15 ppm 처리구는 분리균주 4종과 표준균주 1종을 제외하고 $5log_{10}CFU/mL$ 이상의 생균수 감소율을 보였다. 또한 오염조건에서 요오드 15 ppm 처리구는 $5log_{10}CFU/mL\;(0.93{\sim}3.73log_{10}CFU/mL$ 이하의 생균수 감소율을 보였다. 1,100 ppm의 과산화수소는 모든 시험균주에 대하여 청정, 오염조건에서 $0.29{\sim}3.86 log_[10}CFU/mL$의 생균수 감소율을 보였으므로 소독력이 약한 것으로 판단된다. 결론적으로 에탄올, 요오드(25 ppm), 무기염소계, 4급 암모늄계, 산, 과산화초산계 살균소독제가 V. parahaemolyticus 제거에 효과적인 것으로 판단된다.

• 대한치과보철학회지
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• 제36권3호
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• pp.496-505
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• 1998

The purpose of this study was to evalute the effect of immersion disinfection on the dimensional stability of rubber impression materials. The metallic master model was made in order to simulate the intraoral arch form. Impressions were made from four impression materials (Exaflex, Extrude, Reprosil, Impregum-F) and immersed in three disinfectant solutions (Wydex, Vi-Pon, Potadine). Casts from the impressions were measured according to the interpreparation distance. The A-B and The B-D abutment distance were compared with the control group and disinfected groups. The results were as follows; 1. The measurements of the stone cast increased relative to the master model and there was a significant difference (P<0.05). 2. The relative dimensional change of the stone cast as compared with master model ranged from 0.10% to 0.56% in the A-B distance and ranged from 0.04% to 0.27% in the B-D distance. 3. The dimensional change of the disinfected groups as compared with the control group was significantly different in the three impression materials except for Impregum-F (P<0.05). 4. The relative dimensional change of the disinfected groups compared with the control group ranged from 0% to 0.20% in the A-B distance and ranged from -0.09% to 0.11% in the B-D distance. These results suggest that immersion disinfection of rubber impression materials by chemical disinfectants causes very small dimensional change and the change is clinically acceptable for prothesis fabrication

• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1114-1119
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• 2004

The biofilms on pipe walls in water distribution systems are of interest since they can lead to chlorine demand, coliform growth, pipe corrosion, and water taste and odor problems. As such, the study described in this paper is part of an AWWARF and Tampa Bay Water tailored collaboration project to determine the effect of blending different source waters on the water quality in various distribution systems. The project was based on 18 independent pilot distribution systems (PDS), each being fed by a different water blend (7 finished waters blended in different proportions). The source waters compared were groundwater, surface water, and brackish water, which were treated in a variety of pilot distribution systems, including reverse osmosis (RO) (desalination), both membrane and chemical softening, and ozonation-biological activated carbon (BAC), resulting in a total of 7 different finished waters. The observations from this study consistently demonstrated that unlined ductile iron was more heavily colonized by a biomass than galvanized steel, lined ductile iron, and PVC (in that order) and that the fixed biomass accumulation was more influenced by the nature of the supporting material than by the water quality (including the secondary residual levels). However, although the bulk liquid water cultivable bacterial counts (i.e. heterotrophic plate counts or HPCs) did not increase with a greater biofilm accumulation, the results also suggested that high HPCs corresponded to a low disinfectant residual more than a high biofilm inventory. Furthermore, temperature was found to affect the biofilms, plus the AOC was important when the residual was between 0.6 and 2.0 mg $Cl_2/l$. An additional aspect of the current study was that the potential of the exoproteolytic activity (PEPA) technique was used along with a traditional so-called destructive technique in which the biofilm was scrapped off the coupon surface, resuspended, and cultivated on an R2A agar. Both techniques indicated similar trends and relative comparisons among the PDSs, yet the culturable biofilm values for the traditional method were several orders of magnitude lower than the PEPA values.

• 식물병연구
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• 제12권3호
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• pp.278-283
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• 2006

국내 배추 재배지에서 큰 문제가 되고 있는 뿌리혹병을 석회질소로 방제하는 방법을 구명하기 위하여, 고령지농업연구소의 뿌리혹병 다발포장에서 $2002{\sim}2003 $년에 걸쳐 시험을 실시하였다. 석회질소의 처리량은 배추에 대한 질소질 비료 기비량과 같은 61 kg/10a처리할 때, 33%의 발병도를 보여 대조약제인 후루설파마이드의 77%에 비해 우수한 방제 효과를 보였다. 석회질소를 배추 정식 전 5, 10, 15, 20일에 처리한 결과, 정식 5일전 처리가 48%의 발병도를 보여 후루설파마이드 분제의 67%에 비해 발병 억제 효과가 인정되었다. 석회질소와 요소비료를 이용하여 재배한 배추의 수확기 질소 흡수량은 요소가 17.8kg/10a, 석회질소가 17.6kg/10a으로 유의성이 없었다. 이와 같은 결과로 볼 때 석회질소는 질소질 비료로서 뿐만 아니라 배추뿌리혹병을 방제하기 위한 화학약제의 대용으로서 사용될 수 있을 것으로 생각된다.