• 한국물환경학회지
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• 제40권2호
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• pp.89-100
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• 2024

Climate change has a broad impact on the entire water environment, and this impact is growing. Climate adaptation in water supply systems often involves quantity and quality control, but there has been a lack of research examining the impacts of climatic factors on water supply productivity and operation conditions. Therefore, the present study focused on, first, building a database of climatic factors and water purification operating conditions, and then identifying the correlations between factors to reveal their impacts. News big data was analyzed with keywords of climatic factors and water supply systems in either nationwide or region-wide analyses. Metropolitan area exhibited more issues with cold waves whereas there were more issues with drought in the Southern Chungcheong area. A survey was conducted to seek experts' opinions on the climatic impacts leading to these effects. Pre-chlorination due to drought, high-turbidity of intake water due to rainfall, an increase of toxins in intake water due to heat waves, and low water temperature due to cold waves were expected. Pearson correlation analysis was conducted based on meteorological data and the operating data of a water purification plant. Heavy rain resulted in 13 days of high turbidity, and the subsequent low turbidity conditions required 3 days of high coagulant dosage. This insight is expected to help inform the design of operation manuals for waterworks in response to climate change.

• 상하수도학회지
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• 제12권3호
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• pp.118-124
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• 1998

To use chlorine residual as an surrogate parameter of the water quality change during the transportation in the water distribution system(WDS), the correct prediction model of chlorine residual must be established in advance. This paper shows the procedure and the result of applying the water quality model to the field WDS. To begin with, hydraulic model was calibrated and verified using fluoride as an tracer. And chlorine residual was predicted through simulation of water quality model. This predicted value was compared with the observed value. With adjusting the bulk decay coefficient(kb) and the wall decay coefficient(kw) according to the pipewall environment, the predicted chlorine residual can represent the observed value relatively well.

• Environmental Analysis Health and Toxicology
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• 제16권4호
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• pp.153-159
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• 2001

The main point source of pollution of the Keumho river in Taegu, Korea, stems from waste from the areas of industrial complexes . Although it is widely accepted that pollutants in waste water negatively effects general water quality, it is difficult to evaluate the effluent effect because of varying conditions in ambient water and inconclusive knowledge of causative pollutants. To analyze the water in relation to the industrial effluent in the area, pH. temperature, conductivity, and Microtox toxicity of various river samples were measured. Water samples were collected every 2 hours for 36 hours from Keumho river and Dalseo stream. Data from continuous monitoring for 36 hours showed that effluent in Keumho river originated from Dalseo stream, which is near adjacent to industrial complexes. Change in toxicity and other factors tested during the 36 hours indicated that continuous monitoring was necessary for a satisfactory effluent toxicity test Furthermore, in addition to water quality monitoring, it was concluded that sediment toxicity also needed to evaluate effluent effects.

• 한국해양바이오학회지
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• 제16권1호
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• pp.63-86
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• 2024

This study analyzed the distribution, diversity, and density variation of algal clusters in a freshwater reservoir from an oceanic island and a traditional inland water system to gain insights on future marine freshwater resource management. In the Paldang water system (Han River), despite the upstream Paldang Dam and the downstream Jamsil underwater reservoir being in the same meteorological zone, their algae density patterns varied inversely. The distinct algal cluster structure (diversity/dominance) of Paldang was altered in the downstream reservoir, suggesting that physical devices aid algae management in traditional water systems. In contrast, 24 out of 35 genera (63.2%) identified in the Jeolgol Reservoir (Baeknyeong Island) were unique, lacking regulatory mechanisms, and existing in a complex ecotone. The desmid Chlorophyceae Cosmarium, adapted to higher photosynthetic stress and low temperatures, dominated in January (38.04%) and August (86.45%) during the periods of extreme photosynthetic stress. Jeolgol's annual algal cluster structure (H' 2.097; D 0.259; S' 35) demonstrated higher stability than Paldang (H' 1.125; D 0.448; S' 13) and the Jamsil underwater reservoir (H' 1.078; D 0.469; S' 12), maintaining an H' above 1.5 even during midwinters. No evidence of TN/TP inflow from surrounding soils was observed, even during torrential rainfalls, with phosphorus being the limiting factor for algal growth. TOC, BOD, chlorophyll-a, and turbidity peaked during Cosmarium bloom. Future climate change is expected to cause fluctuations in algal clusters and related water quality factors. The complex transitional nature of the Jeolgol Reservoir, its algal diversity, and the interspecies interactions contribute to the high stability of its algal community.

• 한국물환경학회지
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• 제32권3호
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• pp.281-290
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• 2016

In the northernmost basin of the Bukhan River, pollution sources can have a concentrated distribution. In these basins, small streams show low flow with various and rapid water quality change in low pollutants load. Therefore, a water quality improvement plan of small streams and main stem will be necessary to establish the characteristics of small streams. This study selected a representative Hwacheon-gun in the northernmost basin of the Bukhan River. Hydro analysis was performed with GIS tools using DEM. A total of 152 small streams were listed. A total of 51 survey locations were selected after applying the selection criteria. Flow rate and water qualities were investigated. Pollution sources and pollutants loads were calculated for each basin. Pollution grade and typological classification were performed by cluster analysis using standardized environmental condition factors. As a result, G04, G01, H01 locations were found to have the worst pollution grades whereas J01, P01, and P02 had less pollution. Typological analyses were able to classify six types for the surveyed small streams. An effective water quality improvement plan was obtained based on the results of pollution grade and typological analysis using environmental condition factors of this study.

• 환경영향평가
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• 제8권1호
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• pp.81-92
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• 1999

This study discussed the appropriateness of organic matter indexes such as biochemical oxygen demand(BOD) and chemical oxygen demand with potassium permanganate($COD_{Mn}$) in water quality environmental standard of streams and lakes and the applicability of the items to water quality environmental standard to add or substitute COD with potassium dichromate ($COD_{Cr}$) and total organic carbon(TOC) being used as index of organic matter. And indexes of organic matter content and organic carbon concentration were distinguished between dissolved and particulate component in water sample to estimate their effect on pollutants loading in lake and stream. The ratio of $COD_{Cr}$/BOD was 5.1 under BOD concentration 3mg/L in river water quality environmental standard II, and 2.67 above it. This ratio was diminished to 2.04 when BOD concentration was more than 8mg/L, in river quality environmental standard IV. Also the ratio of $COD_{Mn}$/BOD showed 2.16 under 3mg/L(BOD), and 1.1 above it. This ratio is also diminished to 0.84 over 8mg/L(BOD). Accordingly, we should apply this ratio depending on the concentration level to add and change organic matter index of water quality environmental standard newly. The ratio $COD_{Cr}/COD_{Mn}$ both in lake and stream shows 2.37(r=0.986, p<0.001). But the ratios showed range of 2.34~2.50, which is no much difference of this ratio according to $COD_{Mn}$ concentration.

• Membrane and Water Treatment
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• 제10권5호
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• pp.339-352
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• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• 한국물환경학회지
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• 제35권6호
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• pp.470-480
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• 2019

The Doam lake watershed was designated as a non-point pollution management area in 2007 to improve water quality based on watershed management implementation. There have been studies of non-point source reduction with respect to the watershed management impacting the pollutant transport of the reservoir. However, a little attention has been focused on the impact of water quality improvement by the management of the dam operation or the guidelines on the dam operation. In this study, the impact of in-lake management practices combined with watershed management is analyzed, and the appropriate guidelines on the operation of the dam are suggested. The integrated modeling system by coupling with the watershed model (HSPF) and reservoir water quality model (CE-QUAL-W2) was applied for analyzing the impact of water quality management practices. A scenario implemented with sedimentation basin and suspended matter barrier showed decrease in SS concentration up to 4.6%. The SS concentration increased in the scenarios adjusting withdrawal location from EL.673 m to the upper direction(EL.683 m and EL.688 m). The water quality was comparably high when the scenario implemented all in-lake practices with water intake at EL.673 m. However, there was improvement in water quality when the height of the water intake was moved to EL.688 m during the summer by preventing sediments inflow after the rainfall. Therefore, to manage water quality of the Doam lake, it is essential to control the water quality by modulating the height of water intake through consistent turbidity monitoring during rainfall.

• 대한공간정보학회지
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• 제7권2호
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• pp.101-110
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• 1999

강과 호수와 같은 넓은 지역을 대상으로 수질조사를 실시할 경우, 주기적이고 동시적인 관찰과 분석이 요구되고 있으며 인공위성 영상을 이용한 원격탐사 기법은 이러한 측면에서 매우 유용한 것으로 평가되고 있다. 그러나 인공위성 영상으로부터 수질인자를 추출하고자 할 때, 대기 산란의 영향이 포함된 위성영상의 화소 값은 분석의 정확도를 감소시키는 주된 원인이 된다. 본 연구에서는 원격탐사 기법을 이용하여 수질 인자를 분석하고자 할 때, 대기의 산란에 의한 영향을 제거하기 위한 대기 보정방법을 선택하고자 하였다. 또한 대기 보정방법 중 클로로필-a 부유물질, 투명도에 대한 상관성이 가장 높은 밴드의 조합을 선정하였다. 이러한 대기 보정방법과 밴드 조합을 사용하여 1984년, 1989년, 1993년, 1995년에 각각 관측된 인공위성 영상으로부터 수질 인자간의 시계열 변화를 분석하고자 하였다.

• 한국환경복원기술학회지
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• 제20권5호
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• pp.59-66
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• 2017

Preeminent water treatment plans are essential to preserve the water quality of aquatic biotopes. Previous studies have not been sufficient to provide cost-effective maintenance method since they focused only on the purification of deteriorated water that requires a continuous supply of clean water. This study proposes an economical method of water quality maintenance using water treatment media block constructed vertically using porous ceramics, zeolite, and river pebble. The water treatment media block does not require a separate purification area because it functions as a purifier within the ecological pond which can maximize the biotope area. To evaluate the performance of the water treatment media block, we longitudinally tracked the change of water quality indicators (pH, TDS, COND, DO, T-P, T-N, COD) suggested by Water Environment Standards, Ministry of Environment, Republic of Korea. We compared the water quality of one control (A: general ecological pond composition method of the laminated structure) and two experimental groups (B: a combination of aquatic plants and a water treatment media block, C: a water treatment media block only). As a result, we confirmed that the water treatment media block is an efficient and economical method to maintaining the water quality of the ecological pond for a long time. The water treatment media block will be a great help in providing a better aquatic biotope space for aquatic insects and fishes living in clear water.