High-risk microbial pathogens are handled in a biosafety laboratory. After experiments, the pathogens may remain as contaminants. To safely manage a biosafety laboratory, disinfection of microbial contaminants is necessary. This study was carried out to evaluate the effect of UV-C irradiation for the disinfection of a high-risk plant pathogenic bacterium Erwinia amylovora in a laboratory setting. For the test, the bacterium (8.7 × 106 CFU/ml) was embedded on the surface of PDA and placed on the work surface in a biosafety cabinet (Class 2 Type A1), and on the three different surfaces of the laboratory bench, laboratory bench shelf, and the floor which were positioned in a straight line from the UV lamp installed in the ceiling of the biosafety laboratory (BSL 2 class). UV-C irradiation was administered for 10min, 30min, 1 hr, 2hr, 3 hr, and 4hr, respectively. The reduction rate of bacteria ranged from 95% to 99% in regard to 10 min irradiation, from 97% to 99% in regard to 30 min irradiation, from 99.8% to 99.9% in regard to 1 hr irradiation, and higher than 99.99% in regard to 2 hr irradiation. The bacterium was completely inactivated after 3 hr irradiation. A similar UV-C irradiation effect was obtained when the bacterium was placed at a distance of 1 m from the three different surface points. Bacterial reduction by UV-C irradiation was not significantly different among the three different surface points.

Various eco-friendly seed disinfection technologies have been developed due to the increase in the global demand for organic food. In order to produce sustainable and eco-friendly agricultural products in Korea, seed disinfection technologies for the production of wholesome seedlings have been researched in diverse ways compared to how they were examined in advanced countries. Both domestically and internationally, the eco-friendly seed disinfection technologies to secure the horticultural crops have been treated by biological or physical methods, such as hot water treatment with ultrasonic disinfection technology, or applying organic agricultural materials like organic acids in plant extracts. However, from a practical perspective, various applied technologies can be implemented in farm fields to disinfect significant agricultural crops, such as lettuce, Chinese cabbage, radish, watermelon, cucumber, paprika, red pepper, ginger, ginseng, and sesame seeds.

접목선인장은 우리나라 주요 수출 화훼 작목 중 하나이다. 접목선인장은 대부분 선박으로 수출되며 작은 병징만 나타나도 수출에 제약이 많고 경제적 손실도 발생하므로, 접목 과정에서 철저한 소독 과정이 요구된다. 현재 농가에서는 접목 칼을 토치로 소독하고 있으나, 유해가스로 인한 신체적 피해가 발생하고 있어 이를 대체할 소독 방식이 필요하다. 첫번째로 2번의 박테리아 검정 결과, 열탕 15초 소독이 가장 효과적으로 박테리아 증식을 억제하였다. R2A배지 검정 결과, 열탕 15 초 이상부터는 검출되지 않았으며, petrifilm에 분주하였을 때 는 0.33±1.29 CFU/mL이 발생하였다. 두번째로 모의 수송 과정 중 생체중 변화량의 경우, 분홍색 자구의 경우 무처리는 73.07b, 토치 소독은 92.18a, 열탕 15초 소독은 93.29a% initial 로 나타났다(p≤0.05). 세번째로 구경 변화량의 경우, 토치 소독과 열탕 15초 소독 모두 무처리보다 감소폭이 적어 품질 유지를 위해선 소독 과정이 반드시 필요하다고 판단된다. 마지막으로 소독 방식에 따른 최종 부패율은 무처리, 토치 소독, 열탕 15초 소독 각각 27.5±9.01, 28.33±11.55, 16.67±5.77% 가 나타났으므로 열탕 15초 소독이 가장 효과적이다. 따라서 열탕 15초 소독은 관행 소독 방식의 문제점을 해결할 수 있고, 접목 선인장의 품질 향상 및 부패 감소로 농가의 경제적인 이득 또한 향상시킬 수 있을 것으로 기대된다.

Water disinfection using UV-LED(Light emitting diode) has many advantages, such as smaller footprint and power consumption as well as relatively longer lifespan than those of conventional mercury-UV lamps. Moreover, UV-LED disinfection is considered an environmentally benign process due to its mercury-free nature. In this study, disinfection using an LED module emitting 275nm UV was carried out. 384 UV-LEDs were put into a cylinder tube with a capacity of 1.7 liters. The UV intensity of the UV-LED module was controlled from 1.7 to 8.4 mW/cm2. The disinfection efficiency for the model microorganism solutions(E. coli ) was monitored. As the UV intensity(I) and contact time(t) varied, inactivation of the microorganisms from 2 to 4-log-removals(i.e., 99 to 99.99% of disinfection efficiency) was achieved. Disinfection using UV-LED was followed to 1st order reaction and the reaction rate constant, k was determined. In addition, the relationship between UV intensity(I) and contact time(t) in order to obtain 99.99% of disinfection efficiency was modeled: I1.2∙𝑡= 460, which indicates that the product of UV intensity and contact time requiring 4-log-removals is always constant.

This study examined the effect of ultraviolet (UV) application on bacterial disinfection in a commercialized humidifier using ultrasonic wave (UW). To accurately examine disinfection kinetics in tap-water condition, tap-water was sterilized using a filter, and then inoculated with pure cultures of E. coli and P. putida with known viable counts. The disinfection kinetic characteristics were experimentally compared when UV alone, UW alone, and UW+UV together were applied in disinfecting the added bacteria in the commercialized humidifier. When UV alone was applied, bacterial disinfection kinetics followed a first-order decay reaction, and showed an approximately 10-time weaker disinfection compared to the typical UV disinfection in water treatment or wastewater treatment. When UW alone was applied, bacterial disinfection kinetics followed a second-order decay reaction with a low disinfection rate constant of 0.0002 min-1(CFU/mL)-1. When UV and UW were applied together, however and interestingly, the disinfection rate constant (0.0211 min-1(CFU/mL)-1) was approximately 100 times increased than that for the UW alone case. These results revealed that the co-use of UV and UW can provide synergistic effect on bacterial disinfection in a tap-water condition in household humidifiers.

인삼 뿌리썩음병균(Cylindrocarpon destructans)과 뿌리혹선충(Meloidogyne spp.)은 국내 인삼(panax ginseng C. A. Meyer) 연작장해의 주요인으로, 인삼 생산성 향상을 위해 방제가 필요하다. 본 연구는 새로 개발한 액제 훈증성 토양 소독제를 살포하며 동시에 비닐피복이 가능한 트랙터부착형 토양 소독기를 이용하여 dimethyl disulfide (DMDS)를 처리하였을 때, C. destructans와 뿌리혹선충의 방제효과를 분석하고, 시작기의 성능을 확인하기 위해 수행하였다. 토양 소독기를 이용하여 인삼 재배 포장에 DMDS를 처리한 후 비닐이 피복된 상태에서 5주간 훈증하였다. 토양 소독기의 성능은 약제 살포량 오차 2.5%, 작업능률 0.9h/10a로 40%의 노력절감 효과가 있는 것으로 나타났다. 또한, 처리 전후 C. destructans 의 밀도를 분석한결과 82.5%의 밀도 억제 효과가 있는 것으로 나타났으며, 뿌리혹선충 방제효과는 100%로 나타났다. 따라서, 본 토양 소독기 시작기를 이용하여 능률적으로 DMDS를 처리할 수 있으며, C. destructans와 뿌리혹선충의 방제효과를 볼 수 있는 것으로 판단된다.

본 연구는 고부가가치 약용작물인 잔대(Adenophora triphylla var. japonica Hara)의 종자 형태특성과 휴면 유형을 조사하고, 발아율 향상을 위한 소독제와 광질을 선발하기 위해서 수행되었다. 종자 소독은 증류수(대조구), NaClO 4%, H2O2 4%와 benomyl 500mg·L-1를 이용하여 실시하였으며, 광질처리는 암조건(control I), 형광등 (control II), LEDs[red, blue, green, RB LEDs(red:blue = 8:2, 6:4, 4:6, 2:8)]를 광주기 12/12(light/dark), 광도 150μmol·m-2·s-1 photosynthetic photon flux density로 설정 하였다. 잔대 종자는 emryo (E):seed (S) ratio가 0.4로 미숙배 종자지만 30일 이내에 발아가 되며, 침지 6시간 만에 포화상태에 도달하였다. 종자 소독 후 benomyl 처리에서 곰팡이 발생이 유의적으로 억제되었으며, 최종 발아 율이 87%로 가장 높았다. 적색광에서 최종 발아율이 92%로 가장 높았으며, 일일평균발아수는 R2B8에서 가장 적었다. 따라서 잔대 종자는 휴면이 거의 없으며, benomyl 소독제와 적색광이 발아율 향상에 효과적이여, 향후 약용작물 잔대 재배에 이용가치가 높을 것이라 판 단된다.

Chlorination and UV illumination are being widely applied to inactivate a number of pathogenic microbials in the environment. Here, we evaluated the inactivation efficiency of individual and combined treatments of chlorination and UV under various aqueous conditions. UV dosage was required higher in waste water than in phosphate buffer to achieve the similar disinfecting efficiency. Free chlorine generated by electrolysis of waste water was abundant enough to inactivate microbials. Based on these, hybrid system composed of sequential treatment of electrolysis-mediated chlorination and UV treatment was developed under waste water conditions. Compared to individual treatments, hybrid system inactivated bacteria (i.e., E. coli and S. typhimurium) and viruses (i.e., MS-2 bacteriophage, rotavirus, and norovirus) more efficiently. The hybrid system also mitigated the photo re-pair of UV-driven DNA damages of target bacteria. The combined results suggested the hybrid system would achieve high inactivation efficiency and safety on various pathogenic microbials in wastewater.

The physical treatment such as chemical precipitation or adsorption was usually added after biological treatment in wastewater treatment process since it was enforced to reduce the concentration of phosphate for wastewater effluent to 0.2 mg/L as P which was well known as one of main nutrient causing eutrophication in waterbody. Therefore, the new material functioned for both adsorption and disinfection was prepared with Fe and Cu, and TiO2, respectively, by changing the ratio of concentration referred to tri-metal (TM). According to SEM-EDS, TiO2 was 30~40% composition for any TM regardless of any synthesis condition. However, the ratio of composition for Fe and Cu was dependent on the initial Fe and Cu concentration, respectively. The removal efficiency of phosphate was obtained to 15% at low initial concentration and the maximum uptake (Q) was calculated to ~11 mg/g through Langmuir isotherm model using TM1 which was synthesized at 1000 mg/L, 1000 mg/L, and 2 g (10 g/L) for Fe(NO3)3, Cu(NO3)2, TiO2, respectively. In disinfection test, the efficiency of virus removal using TM was increased with increase of dosage of TM and can be reached 98% at 0.2 g.

본 연구의 목적은 온탕침지와 pH교정석회유황합제 처리에 의한 상추 유기종자의 곰팡이와 세균의 소독효과 및 발아율에 미치는 영향을 검정하고자 하였다. 상추종자에 Alternaria sp.가 53.3% 감염되어 있었고 Aspergillus sp.와 Cladosporium sp.은 각각 14.5%와 5.4% 감염되어 있었다. 세균은 형태적으로 Pseudomonas sp., 한 종만 분리되었으며 16.5%가 감염되어 있었다. 상추종자 소독에 효과적인 온탕침지조건을 탐색하고자 온탕의 온도조건(45℃, 50℃, 55℃, 60℃)에 따른 소독효과를 조사하였다. 온탕침지 온도와 처리시간이 증가함에 따라 곰팡이와 세균에 대한 살균효과는 증가하였으나 종자의 발아율은 급격히 감소하였다. 온탕침지 단독처리는 50℃ 온탕에서 20분간 처리할 경우 상추종자의 살균효과와 발아율이 각각 91.1%로 가장 우수하였다. 상추종자 소독을 위한 온탕침지와 pH교정석회유황합제 교호처리는 50℃의 온탕침지 조건에서는 10분간 처리하는 것이 상추종자의 살균효과와 발아율이 각각 100%와 97.6%로 가장 높았다. 본 연구결과는 종자 표면뿐만 아니라 종자내의 곰팡이나 세균을 살균할 수 있는 기술개발에 기여할 수 있을 것으로 생각한다.

Water supply/intake pumps operation use 70~80% of power costs in water treatment plants. In the water treatment plant, seasonal and hourly differential electricity rates are applied, so proper pump scheduling can yield power cost savings. Accordingly, the purpose of this study was to develop an optimal water supply pump scheduling scheme. An optimal operation method of water supply pumps by using genetic algorithm was developed. Also, a method to minimize power cost for water supply pump operation based on pump performance derived from the thermodynamic pump efficiency measurement method was proposed. Water level constraints to provide sufficient disinfection performance in a clearwell and reservoirs were calibrated. In addition, continuous operation time constraints were calibrated to prevent frequent pump switching. As a result of optimization, savings ratios during 7 days in winter and summer were 4.5% and 5.1%, respectively. In this study, the method for optimal water pump operation was developed to secure disinfection performance in the clearwell and to save power cost. It is expected that it will be used as a more advanced optimal water pump operation method through further studies such as water demand forecasting and efficiency according to pump combination.

In this study, a model was developed to predict for Disinfection By-Products (DBPs) generated in water supply networks and consumer premises, before and after the introduction of advanced water purification facilities. Based on two-way ANOVA, which was carried out to statistically verify the water quality difference in the water supply network according to introduce the advanced water treatment process. The water quality before and after advanced water purification was shown to have a statistically significant difference. A multiple regression model was developed to predict the concentration of DBPs in consumer premises before and after the introduction of advanced water purification facilities. The prediction model developed for the concentration of DBPs accurately simulated the actual measurements, as its coefficients of correlation with the actual measurements were all 0.88 or higher. In addition, the prediction for the period not used in the model development to verify the developed model also showed coefficients of correlation with the actual measurements of 0.96 or higher. As the prediction model developed in this study has an advantage in that the variables that compose the model are relatively simple when compared with those of models developed in previous studies, it is considered highly usable for further study and field application. The methodology proposed in this study and the study findings can be used to meet the level of consumer requirement related to DBPs and to analyze and set the service level when establishing a master plan for development of water supply, and a water supply facility asset management plan.

The biocidal activity of Cu(II) is greatly enhanced by the addition of H2O2 or hydroxylamine (HA), which accelerates the production of cytotoxic Cu(I) and generates a reactive oxidant (cupryl ion, Cu(III)) capable of exerting oxidative cell damages. The bimetallic Fe-Cu nanoparticles also exhibit excellent biocidal activity in the similar biocidal mechanism. These copper-based hybrid disinfection systems were assessed for their potential to inactivate surrogate bacteria and viruses. In addition, combinations of Cu(II) with HA and H2O2 (i.e., Cu(II)/HA, Cu(II)/H2O2, and Cu(II)/HA/H2O2 systems) were tested for the control of bacterial biofilms on reverse osmosis (RO) membranes. The detailed mechanisms for the cell inactivation by different copper-based disinfection systems were discussed.

Pollutants removal and disinfection effect of secondary effluent from final settling tank of sewage treatment plant of W city were investigated in Loop Reactor using ordinary granular activated carbon(GAC) and GAC coated with silver nanoparticles. The results showed that the removal efficiency of CODMn, T-N and T-P using GAC with silver nanoparticles were higher than using the ordinary GAC. The removal efficiency of T-P using GAC with silver nanoparticles is 45.4% and that of T-P using ordinary GAC is 30.9% in the same case of the input amount of 20 g/L of GAC. The total califorms is reduced according to increasing input amount of GAC with silver nanoparticles and ordinary GAC. The disinfection efficiency of total coliforms in case of GAC with silver nanoparticles is much higher than that in case of ordinary GAC. For all experiments using the silver nanoparticles, the total coliforms is under 26 cfu/mL and this shows very excellent disinfection effect.

Disinfection of microorganisms using UV light is widely used in the field of water supply and wastewater treatment plant, In spite of high germicidal effect and relatively clean by-product, UV disinfection has fundamental defeat that is accumulation of fouling materials at the interface of water and lamp sleeve. Non-contact type of UV photoreactor which can avoid this fouling generation was developed and the experimental performance evaluation of the system was carried out in this study. Log inactivation rate of E. coli was selected as a disinfection index. The concentration of E. coli of second clarifier effluent was 8.2×101 - 8.2×103 colony per mL and was well inactivated by the non-contact type of UV photoreactor. Under the UV intensity condition of 2.1 - 2.5mW/cm2, E. coli removal rate was observed in the range of 54 - 95% when the HRT was increased from 10 to 52 seconds. Experimental results showed that log inactivation of E. coli was proportional to UV dosage and 200mJ/cm2 of UV dose is expected for the 2.0 log inactivation of E. coli from the second clarifier effluent. Between the two parameters of UV intensity and contact time which are consist of UV dose, UV intensity was 4 times more effective than contact time.s

본 연구는 의료살균기술의 하나인 전극을 이용한 전기 충격 살균법을 순환식 수경재배의 배양액 재순환을 위한 배액 살균기술로 활용하고, 배액의 전기살균소독시스템을 구축하고자 할 때, 살균소독 효과가 높으며, 친환경적이고 경제적인 배양액 살균소독기술의 개발 및 전기살균소독시스템에서 사용될 전극의 최적 조건을 구명하고 전기소독의 가능성을 확인하기 위해 수행되었다. 전기살 균소독시스템 구축 시 적정 전극소재 구명을 위해 금속 전도체의 특성 조사 및 전기실험을 실시하여 배액의 pH 와 EC변화유무와 침전물 발생여부 및 배액의 원소변화 유무를 분석하였다. 새로이 개발된 전기살균소독시스템 구축 시 가장 적합한 금속 전도체 전극소재로는 전기전도도가 높고, 저항이 적으며, 소재의 수급이 용이하고, 가격이 저렴한 스테인리스 스틸임을 확인하였으며. 또한 스테인리스 스틸을 전극으로 사용하였을 때, 전기를 공급하기 전과 24V 이내의 전기를 공급한 후의 배양액내 원소변화는 거의 없는 것으로 분석되었다. 전극의 두께 보다는 넓이가 증가함에 따라 전류의 양이 증가하였으며 전극의 거리가 멀수록 목표 전류량에 도달하는 시간이 증가하였다. 적합한 전류량에 따른 주요 병원균의 살균 력을 조사한 결과 대표적 세균병인 풋마름병의 원인균인 Ralstonia solanacearum가 전류 15V-3A 170초에서 97% 가 사멸되는 것을 확인하였으며 곰팡이병인 Fusarium oxysporum은 24V-10A에서 98%의 살균력을 보였다.