• 환경위생공학
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• 제12권3호
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• pp.103-109
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• 1997

As the quality of raw water deteriorates, a number of additional treatment techniques have been developed and adapted to water treatment for producing a safe and aesthetically satisfactory drinking water. So, BACFB process as pretreatment in water supply is to be effective to remove dissolved organics. This study performed to find out the effects of HRT and hydraulic characteristics on BACFB reactors in water supply. The flow type in reactor was a high dispersion with complete mixing. As superficial velocity was increased, bed expansion was closed to theoretical values. It was considered that below 30 min HRT could operated to ensure the removal of dissolved organics.

• 상하수도학회지
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• 제34권1호
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• pp.35-43
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• 2020

Turbidity has various effects on the water quality and ecosystem of a river. High turbidity during floods increases the operation cost of a drinking water supply system. Thus, the management of turbidity is essential for providing safe water to the public. There have been various efforts to estimate turbidity in river systems for proper management and early warning of high turbidity in the water supply process. Advanced data analysis technology using machine learning has been increasingly used in water quality management processes. Artificial neural networks(ANNs) is one of the first algorithms applied, where the overfitting of a model to observed data and vanishing gradient in the backpropagation process limit the wide application of ANNs in practice. In recent years, deep learning, which overcomes the limitations of ANNs, has been applied in water quality management. LSTM(Long-Short Term Memory) is one of novel deep learning algorithms that is widely used in the analysis of time series data. In this study, LSTM is used for the prediction of high turbidity(>30 NTU) in a river from the relationship of turbidity to discharge, which enables early warning of high turbidity in a drinking water supply system. The model showed 0.98, 0.99, 0.98 and 0.99 for precision, recall, F1-score and accuracy respectively, for the prediction of high turbidity in a river with 2 hour frequency data. The sensitivity of the model to the observation intervals of data is also compared with time periods of 2 hour, 8 hour, 1 day and 2 days. The model shows higher precision with shorter observation intervals, which underscores the importance of collecting high frequency data for better management of water resources in the future.

• Membrane and Water Treatment
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• 제7권4호
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• pp.313-325
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• 2016

South Africa recognises piped water as the main source of safe drinking water supply. Remote areas do not have access to this resource and they rely solely on surface water for survival, which exposes them to waterborne diseases. Interim point of use solutions are not practiced due to their laboriousness and alteration of the taste. Bio-ultra low pressure driven membrane system has been noted to be able to produce stable fluxes after one week of operation; however, there is limited literature on South African waters. This study was conducted on three rivers namely; Umgeni, Umbilo and Tugela. Three laboratory systems were setup to evaluate the performance of the technology in terms of producing stable fluxes and water that is compliant with the WHO 2008 drinking water guideline with regards to turbidity, total coliforms and E.coli. The obtained flux rate trends were similar to those noted in literature where they are referred to as stable fluxes. However, when further comparing the obtained fluxes to the normal dead-end filtration curve, it was noted that both the Umbilo and Tugela Rivers responded similarly to a normal dead-end filtration curve. The Umgeni River was noted to produce flux rates which were higher than those obtainable under normal dead-end. It can be concluded that there was no stabilisation of flux noted. However, feed water with low E.coli and turbidity concentrations enhances the flux rates. The technology was noted to produce water of less than 1 NTU and 100% removal efficiency for E.coli and total coliforms.

• 상하수도학회지
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• 제27권6호
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• pp.679-687
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• 2013

Although stable and safe drinking water supply to the customers is a basic function of multi-regional water supply systems in Korea, most systems have their vulnerabilities in emergency time due to the branch-type. Application of connections from the other water supply system can provide a solutions for these tentative problems. This paper describes reduction planning of water supply accidents that can minimize a service interruption to customers in multi-regional water supply system by connecting pipe lines between local water supply systems in Mokpo city areas. The result of this study shows that Juam dam multi-regional water supply systems can cover all of the water shortage in southern parts of Jeonnam multi-regional water supply systems by transmitting water through connected pipes between local networks. This can be effective to supply water interactively in various contingencies, when a pipe line accident occurs in southern area of Jeonnam multi-regional water supply systems. On the contrary, southern area of Jeonnam multi-regional water supply systems can cover 99.5 %($62,500m^3/day$) of the water shortage of Juam dam multi-regional water supply systems when service interruptions caused by various pipe accidents occur in the system.

• 식품보건융합연구
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• 제5권6호
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• pp.5-9
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• 2019

Desalination requires large energy. This experiment deals to desalinate brackish water through solar panels. The discharge from desalination plants is almost entirely water, and .01 percent is salt. Desalination is a process that extracts minerals from saline water. Solar-powered desalination technologies can be used to treat non-traditional water sources to increase water supplies in rural, arid areas. Water scarceness is a rising dilemma for large regions of the world. Access to safe, fresh and pure clean drinking water is one of the most important and prime troubles in different parts of the world. Among many of water cleansing technologies solar desalination/distillation/purification is one of the most sustainable and striking method engaged to congregate the supply of clean and pure drinkable water in remote areas at a very sound cost. Six types of dripper having discharge 3 - 8 lh-1 were installed one by one and measured discharge and volume of clean water indicated that at 6 lh-1 untreated water discharge have maximum evaporation and volume of clean water was 19.2 lh-1 at same temperature and radiations. Now strategy was developed that when increased the temperature the intake discharge of untreated water must be increased and salt drained water two times more than treated water.

• 농업과학연구
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• 제49권3호
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• pp.389-396
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• 2022

The purpose of this study was to investigate the safety of Houttuynia cordata Thunb extract (HCE) in Institute of Cancer Research (ICR) mice, to determine the effects of the extract on the growth performance and colony count, and to establish the optimal concentration of HCE. In total, 60 five-week-old male ICR mice with an average initial body weight (BW) of 27.24 ± 0.44 g were used in a four-week experiment. Mice were randomly allotted to four treatment groups (five replications per group, three mice per cage): 1) a control (CON) group fed with normal distilled water; 2) treatment group 1 (T1) fed with normal distilled water containing 0.05% HCE; 3) treatment group 3 (T3) fed with normal distilled water containing 0.1% HCE; and 4) treatment group 3 (T3) fed with normal distilled water containing 0.2% HCE. BW, feed intake (FI), and water intake were measured on the first, fourteenth, and eighteenth days. T2 showed a significant improvement (p < 0.05) in the feed conversion ratio (FCR) over the experimental period. However, water intake levels did not show significant differences among the groups. In the large intestine and feces, E. coli and Lactobacillus levels were significantly improved (p < 0.05) in the HCE treated group compared to the CON group. Supplying HCE via the drinking water improved the growth performance and colony count in ICR mice. Based on results of this study, utilizing HCE in livestock species is expected to be safe and feasible.

• 상하수도학회지
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• 제23권5호
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• pp.609-618
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• 2009

Repeated phenol spill in the Nakdong River has been a big issue in Korea since 1991. In this study, treatment of phenol in each water treatment process and total water treatment system is evaluated. Phenol was highly volatile, easily oxidized by ozone, and readily absorbed onto GAC. When there was phenol of 0.3mg/L in water, by ozonation of 1mg/L or by GAC adsorption with EBCT of 10minutes or longer, it could be treated to lower than 0.005mg/L, the national drinking water standard of phenol. Even when a sufficient contact time(70minutes) was allowed, only 35 to 40% of phenol could be removed by powdered activated carbon(PAC). Based on the test results, it can be concluded that 1.0mg/L or less concentration of phenol can be treated at the plants adopting the combination process of ozone and GAC down to the safe level. In this study, removal characteristics for phenol were evaluated with the existing pilot plant and demo plant in different advanced water treatment processes(AWTPs). In the future, studies on changes in oxidation and adsorption characteristics caused by competitive matters such as DOC and removal characteristics by other various AWTPs including ozone/filter adsorber need to be performed.

• 상하수도학회지
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• 제30권1호
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• pp.9-17
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• 2016

Disinfectant/oxidation process is a crucial process in water treatment for supplying safe drinking water. Chlorination is still widely used for water treatment area due to its effectiveness on microbial inactivation and economic feasibility. Recently, disinfection concern in marine environment is increasing, for example, movement of hazardous marine organism due to ballast water, marine environmental degradation due to power plant cooling water discharge, and increase of the amount of disinfectant in the offshore plant. It is needed to conduct the assessment of disinfectant behavior and the development of disinfectant prediction model in seawater. The appropriate prediction model for disinfectant behavior is not yet provided. The objective of the study is to develop chlorine decay model in seawater. Various model types were applied to develop the seawater chlorine decay model, such as first order decay model, EPA model, and two-phase model. The model simulation indicated that chlorine decay in seawater is influenced by both organic and inorganic matter in seawater. While inorganic matter has a negative correlation with the chlorine decay, organic matter has a positive correlation with the chlorine decay.

• 농업과학연구
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• 제35권1호
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• pp.53-67
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• 2008

The principle goal of environmentally-friendly agriculture is to maintain and conserve water and agriculture environment including drinking water resources by properly using agricultural materials such as agricultural chemicals, chemical fertilizers, and other agricultural materials according to act 19 of foster law of environmentally-friendly agriculture. To achieve these goals, we have to establish Integrated Nutrient Management(INM) and Integrated Pesticide Management(IPM) which are most important core technologies for environmentally-friendly rice cultivation. However, there are lack of criteria and technology for evaluation category according to soil management and its soil classes to practice an environmentally-friendly agriculture. Therefore, we should eatablish the standards to produce the safe agricultural products based on the soil physical and chemical characteristics which are basic properties of soil to accomplish the principle aims of environmentally-friendly agriculture.

• 수도
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• 제24권6호통권87호
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• pp.23-31
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• 1997

Ozonation is an effective process in providing microbiologically safe drinking water. The operation of the ozonation stage is often based on disinfection criteria which include security factors, such as the CT criterion. This type of ozonation management, which mat include large safety margins, will no longer be possible, since formation of ozonation byproducts has to be avoided. In order to reduce the security factor, a computerized tool to predict with more accuracy inactivation of micro-organisms in the ozonation process has been developed.