• Journal of Environmental Health Sciences
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• v.30 no.2
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• pp.98-103
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• 2004

To evaluate the quality of drinking water and contamination sources in a rural community, this study was carried out on the summer of 2003 at Shin-Dong Myun, Chun-Cheon, Gang-Won province. Seventy three drinking water samples were collected from three different types of water supply systems. Sources of contamination were identified and the public perception of water quality area were evaluated. The findings of this study are as follows; Drinking water was mainly obtained from Local Water and Simple Piped Water Supply Systems, and pollution sources varied over the study area. Most of residents (＞63%) were satisfied with the quality of drinking water and could not identify any contamination sources. Corresponding to this perception, measured water quality parameters generally met the Drinking Water Quality Standards (＞64%). However, approximately 35.6% of samples exceeded the regulation for Nㅒ$_3$$^{-}$$_{-}$N, coliform, and general bacteria. The water quality was significantly different among the three water supply systems, and between the potentially contaminated areas and the rest of the areas (p＜0.05). In the potentially contaminated areas, the levels of coliform and general bacteria contamination were significantly higher than the rest of the areas (p＜0.05). The coliform and general bacteria values of Simple Piped Water were significantly higher than Own Piped Water＇s, and the NO$_3$$^{-}$$_{-}$N values of Own Piped Water were significantly higher than those of water＇s (p＜0.05). Based on this study, NO$_3$$^{-}$$_{-}$N, coliform, and general bacteria were identified as a major problem of drinking water. To regularly manage drinking water supply systems, to identify contamination sources, and to add drainage systems are required in the study area.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.1
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• pp.1-6
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• 2017

Surge pressure is created by rapid change of flow rate due to operation of hydraulic component or accident of pipeline. Proper control of surge pressure in distribution system is important because it can damage pipeline and may have the potential to degrade water quality by pipe leakage due to surge pressure. Surge relief valve(SRV) is one of the most widely used devices and it is important to determine proper parameters for SRV's installation and operation. In this research, determining optimum parameters affecting performance of the SRV were investigated. We proposed the methodology for finding combination of parameters for best performance of the SRV. Therefore, the objective function for evaluate fitness of candidate parameters and surge pressure simulation software was developed to validate proposed parameters for SRV. The developed software was integrated into genetic algorithm(GA) to find best combination of parameters.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1989.10a
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• pp.52-52
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• 1989

• Journal of Korean Society of Water and Wastewater
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• v.19 no.1
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• pp.31-37
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• 2005

One of the major obstacles confronted in promoting the rainwater harvesting is the concerns of acid rain and heavy metals. Although there are many data concerning the quality of rainwater precipitation for the study of acid rain, the study on the quality of stored rainwater has been limited. In this study, we monitored the quality of stored rainwater at Galmoe middle school, where a rainwater harvesting system is installed and in use for more than two years. We measured water quality parameters such as pH, Electro Conductivity(EC), Dissolved Oxygen(DO), and some metals (aluminium (Al), chromium(Cr), manganese(Mn), zinc(Zn), copper(Cu), arsenic(As), cadmium(Cd), lead(Pb)). The monitoring period was during one year from September 9th 2003 to August 5th 2004. It was observed that the average pH of stored rainwater is neutral. DO is similar to tap water and EC is lower than tap water. Metal Concentrations are within the concentration specified in Drinking Water Quality Standard. Overall, the stored rainwater quality is good enough for sundry use and there's no threat of acid rain and air pollution, if the rainwater harvesting system is well designed and maintained.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.796-801
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• 2010

Water quality index (WQI) can be a great tool that allows experts to translate large amount of complex water quality data into a format more easily understood by the public and policy makers. Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) can be calculated with the three factors (Scope: $F_1$, Frequency: $F_2$, Amplitude: $F_3$). After all, the WQI for a specific site is produced as a number between 0 to 100; the scale is also divided into five categories, i.e., Excellent, Good, Fair, Marginal and Poor. The WQI was found to be highly related to Chl-a, pH, temperature among the collected items. When the more input parameters were used, the range of variation generally became smaller. $F_3$ among the factors of WQI was influenced by algae. It showed a similar variation tendency between WQI and algal bloom in 2008.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.5
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• pp.136-146
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• 2002

Land application of manure compost is considered one of the widely-used animal waste management practices. Many livestock farms adopt composting for their animal waste disposal and apply the compost to crop fields. While standard rates have been established based on researches with respect to land application of manure compost recently, there have been few discussions on water quality impact of the application. Water quality impact should be taken into account in land applications of manure compost. In this study, management practices were proposed based on the investigation of water quality of leachate from manure compost under rainfall simulation, field studies, and monitoring runoff water quality from farm fields after land application of animal waste. The concentrations of major water quality parameters of the leachate were significantly high, whereas those of runoff from soils after tillage for soil incorporation, were not affected by the application based on a series of experiments. Runoff water from farm fields after land application also showed high concentrations of pollutants. Appropriate management practices should be employed to minimize pollutant loading from manure applied fields. Proposed major management practices include 1) application of recommended amounts, 2) proper tillage for complete soil and manure incorporation, 3) field management to prevent excessive soil erosion, 4) complete diversion of inflow into the field from outside, 5) implementation of vegetative buffer strips near boundaries, and 6) prevention of direct discharge of runoff water front fields Into streams.

• Membrane and Water Treatment
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• v.13 no.5
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• pp.245-257
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• 2022

Water quality characteristics and their spatial variations in the Nakdong River were statistically analyzed by multivariate techniques including correlation analysis, CA, and FA/PCA based on water quality parameters for 17 sites over 2017-2019, yielding PI values for primary factors. Site 10 indicated the highest parameter concentrations, and results of pearson's correlation analysis suggest that non-biodegradable organic matter had been distributed on the site. Five clusters were identified in order of descending pollution levels: I (Ib > Ia) > II (IIa > IIb) > III. Spatial variations started from sub-cluster Ib in which Daegu city and Geumho-river are joined. T-P, PO4-P, SS, COD, and TOC corresponded to VF 1 and 2, which were found to be principal components with strong influence on water quality. Sub-cluster Ib was strongly influenced by NO3-N and T-N compared to other clusters. According to the PIs, water quality pollution deteriorated due to non-biodegradable organic matter, nitrogen- and phosphorus-based nutrient salts in the middle and lower reaches, illustrating worsening water pollution due to inflows of anthropogenic sources on the Geumho-river, i.e., sewage and wastewater, discharged from Site 10, at which there is a concentration of urban, agricultural, and industrial areas.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.723-734
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• 2010

With a belief of high water quality production and less chemical usage, membrane technology including Microfiltration (MF), Ultrafiltration (UF), and Nanofiltration(NF) is being employed more and more in drinking water treatment process. However, due to higher energy consumption of UF and NF, MF is normally used for drinking water treatment especially in a plant of large scale. In this investigation, performance ofsand filtration and membrane filtration was compared regarding removal of various water quality parameters, such as TOC, DOC, KMnO4 consumption, THMFP, and HAAFP. Two lines of pilot plant have been operated, one of which line is a traditional advanced water treatment process which includes sedimentation, sand filtration, ozonation, and activated carbon, and the other line is an alternative treatment process which includes sedimentation with inclined plate, MF membrane, ozonation, and activated carbon. For the first about 4months of period, MF filtration showed similar or little bit higher performance than sand filtration. However, after about 4month later, sand filtration showed much higher performance in removing all parameters monitored in the investigation. It was found that sand filtration is a better option than MF filtration as far as microbial community is fully activated in sand filter bed.

• Journal of Korean Society on Water Environment
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• v.39 no.1
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• pp.46-60
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• 2023

Climate change causes fluctuations in water quality in the aquatic environment, which can cause changes in water circulation patterns and severe adverse effects on aquatic ecosystems in the future. Therefore, research is needed to predict and respond to water quality changes caused by climate change in advance. In this study, we tried to predict the dissolved oxygen (DO), chlorophyll-a, and turbidity of the Paldang reservoir for about two weeks using long short-term memory (LSTM) and gated recurrent units (GRU), which are deep learning algorithms based on recurrent neural networks. The model was built based on real-time water quality data and meteorological data. The observation period was set from July to September in the summer of 2021 (Period 1) and from March to May in the spring of 2022 (Period 2). We tried to select an algorithm with optimal predictive power for each water quality parameter. In addition, to improve the predictive power of the model, an important variable extraction technique using random forest was used to select only the important variables as input variables. In both Periods 1 and 2, the predictive power after extracting important variables was further improved. Except for DO in Period 2, GRU was selected as the best model in all water quality parameters. This methodology can be useful for preventive water quality management by identifying the variability of water quality in advance and predicting water quality in a short period.

• Journal of Korean Society of Rural Planning
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• v.9 no.1 s.18
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• pp.77-83
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• 2003

This study was carried out to provide the basic information for the water quality management of the Sumjin River Basin. The Chooryeongchon stream watershed was selected and the parameters representing water quality were investigated from May 1999 to September 2002, periodically. Yearly mean runoff ratio to the rainfall amount of the watershed was analysed as $26.6{\sim}58.8%$. Temporal variation of water quality constituents such as water temperature, pH, EC, total nitrogen, total phosphorus were analysed. The result showed that pH ranged $5.7{\sim}7.7$, EC $54{\sim}167\;{\mu}S/cm$, COD $0.8{\sim}18.1\;mg/L$, respectively. Total-N and total-P concentration ranged from 0.89 to 5.19 mg/L and from 0.0004 to 0.030 mg/L, respectively. The relationships between runoff and mass load were derived and showed high linear relationships.