• Journal of Life Science
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• v.16 no.3 s.76
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• pp.534-539
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• 2006

In the ozone disinfection unit process of a piston type batch reactor with continuous ozone analysis using a flow injection analysis (FIA) system, the CT values for 1 log inactivation of Cryptosporidium parvum by viability assays of DAPI/PI and excystation were $1.8{\sim}2.2\;mg/L{\cdot}min$ at $25^{\circ}C$ and $9.1mg/L{\cdot}min$ at $5^{\circ}C$, respectively. At the low temperature, ozone requirement rises $4{\sim}5$ times higher in order to achieve the same level of disinfection at room temperature. In a 40 L scale pilot plant with continuous flow and constant 5 minutes retention time, disinfection effects were evaluated using excystation, DAPI/PI, and cell infection method at the same time. About 0.2 log inactivation of Cryptosporidium by DAPI/PI and excystation assay, and 1.2 log inactivation by cell infectivity assay were estimated, respectively, at the CT value of about $8mg/L{\cdot}min$. The difference between DAPI/PI and excystation assay was not significant in evaluating CT values of Cryptosporidium by ozone in both experiment of the piston and the pilot reactors. However, there was significant difference between viability assay based on the intact cell wall structure and function and infectivity assay based on the developing oocysts to sporozoites and merozoites in the pilot study. The stage of development should be more sensitive to ozone oxidation than cell wall intactness of oocysts. The difference of CT values estimated by viability assay between two studies may partly come from underestimation of the residual ozone concentration due to the manual monitoring in the pilot study, or the difference of the reactor scale (50 mL vs 40 L) and types (batch vs continuous). Adequate If value to disinfect 1 and 2 log scale of Cryptosporidium in UV irradiation process was 25 $mWs/cm^2$ and 50 $mWs/cm^2$, respectively, at $25^{\circ}C$ by DAPI/PI. At $5^{\circ}C$, 40 $mWs/cm^2$ was required for disinfecting 1 log Cryptosporidium, and 80 $mWs/cm^2$ for disinfecting 2 log Cryptosporidium. It was thought that about 60% increase of If value requirement to compensate for the $20^{\circ}C$ decrease in temperature was due to the low voltage low output lamp letting weaker UV rays occur at lower temperatures.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.12
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• pp.1147-1153
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• 2010

To evaluate the solar photocatalytic degradation efficiency of chloroform in a real solar-light driven compound parabolic concentrators (CPCs) system, $TiO_2$ was irradiated with a metalhalide lamp (1000 W), which has a similar wavelength to sunlight. The results were applied to a pilot scale reactor system by converting the data to a standardized illumination time. In addition, the effects of initial pH and the $TiO_2$ dose on the photocatalytic degradation of chloroform were investigated. The results were compared with the specific surface area (S.S.A) and particle size of $TiO_2$, which changed according to the pH, to determine the relationship between the S.S.A, particle size and the photocatalytic degradation of chloroform. The experiment was carried out at pH 4~7 using 0.1, 0.2, 0.4 g/L of $TiO_2$. The particle size and specific surface area of $TiO_2$ were measured. There was no significant difference between the variables. However, pH affects the particle size distribution and specific surface area of $TiO_2$. Inaddition, the activation of a photocatalyst did not show a linear relationship with the specific surface area of $TiO_2$ in the photocatalytic degradation of chloroform.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.5
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• pp.41-48
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• 2019

Our daily lives are changing at a rapid pace and the concept of smart city is spreading, as the information communication technologies apply to various fields. However, efforts to prepare for changes in society due to technological evolution are insufficient in the field of landscape architecture. The purposes of this study are to explore the concept of smart parks, to investigate how smart technology has been applied to parks, and to identify the users' perception and satisfaction on smart park services. To this end, we conducted literature review, focus group interviews with experts, and a questionnaire survey with 180 users of the IoT See pilot smart park in Daegu. Smart parks can, as a result, be defined as sustainable parks that improve users' experience in parks and solve social and environmental problems faced by utilizing various high technology. Smart technologies introduced at the park so far have been mostly focused on safety and environmental areas, including AI CCTV, smart street lamp, and fine dust warning devices. The results of survey showed that not many users were aware of the smart services the park provided due to the lack of public communication as well as the nature of maintenance-oriented smart services. The survey also found that AR services for the education of historic parks were the least utilized, while solar power benches and WiFi service were most preferred by the park users. In conclusion, smart technologies need to be integrated with diverse park contents more centered user needs, providing services to enhance safety and environmental management in order to develop user-oriented smart parks.