• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2010년도 학술발표회
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• pp.1026-1030
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• 2010

The Geum river being used as drinking water sources has contaminated due to inflow of inadequately treated wastewater from the tributaries into the river. The characteristics of water quality in the upper regions showed good grade(BOD<3mg/L) in the Geum river, the Mankyung river and the Dongjin river, while that in the lower regions and the upper region of the Sapkyo river did not achieve the good grade. This resulted in the inflow of domestic, industrial and livestock wastewater not adequately treated by wastewater treatment systems. For lakes, the mouth of the kyungchun lake, the Sapkyo lake and the Yedane lake showed the eutrophication phenaminon with higher COD concentration. In particular, total phosphorus and chlorophyll-a concentration were higher in the Sapkyo lake than other lake.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제40권1호
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• pp.127-133
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• 2020

Most sewage treatment plants located offshore are discharged to the shore either directly or through rivers. Therefore, the water quality of the treated water discharged from the sewage treatment plant affects the water quality of the river water discharged to the river and the ocean. In this study, field surveys and numerical simulations were conducted to investigate the effect of treated water from the sewage treatment plant adjacent to the coastal environment. As a result of analyzing the water quality and sediment quality with the samples collected from the river and the estuary where the treated water was discharged to understand the impact on the coast, the treated water discharged from the sewage treatment plant was discharged to the river without exceeding the design criteria. However, the water quality discharged to the shore through estuaries was more contaminated than treated water. The cause of water quality deterioration of coastal effluent is due to the sedimentation of estuary temporarily by longshore sediment sransport which appeared around the estuary, the occurrence of estuary obstruction, and the increase of stagnant time in the estuary. As it was released and discharged, it was analyzed to affect the water quality, water quality and marine life around the estuary. Therefore, in the case of the east coast where the longshore sediment transport is strong, when planning the sewage treatment facility discharged to the ocean, it is necessary to closely examine the water quality change of the river water in the treated water such as the river mouth occlusion by the longshore sediment transport.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 한국환경생물학회 2004년도 학술대회
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• pp.54-54
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• 2004

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2023년도 학술발표회
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• pp.142-142
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• 2023

Humans inevitably and continuously produce wastewater in daily life worldwide. To decrease the degradation of river water bodies and aquatic ecosystem therein, humans have built systems at different scales to collect, drain, and treat household-produced wastewater. Particularly, municipal wastewater treatment plants (WWTPs) with centralized controls have played a key role in reducing loads of nutrients in domestic wastewater for the last few decades. Notwithstanding such contributions, impaired rivers regarding water quality and habitat integrity still exist at the whole river basin scale. It is highly attributable to the absence of dilution capacity of receiving streams and/or the accumulation of the pollutant loads along flow paths. To improve the perspective for individual WWTPs assessment, the first crucial step is to achieve systematic understanding on spatial distribution characteristics of all WWTPs together in a given river basin. By taking the initiative, our former study showed spatial hierarchical distributions of WWTPs in three large urbanized river basins in Germany. In this study, we uncover how municipal WWTPs in the contiguous United States are distributed along river networks in a give river basin. The extended spatial scope allows to deal with wide ranges in geomorphological attributes, hydro-climatic conditions, and socio-economic status. Furthermore, we identify the relation of the findings with multiple factors related to human activities, such as the spatial distribution of human settlements, the degree of economy development, and the fraction of communities served by WWTPs. Generalizable patterns found in this study are expected to contribute to establishing viable management plans for recent water-environmental challenges caused by WWTP-discharges to river water bodies.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제14권7호
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• pp.3570-3576
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• 2013

This paper calculated advanced sewage treatment efficiency and reduction pollution loads to estimation contribution ratio of for community sewerage in Hongcheon-gun County. The A2/O and SBR methods showed overall high treatment efficiency of 95% and 94% respectively, and SS was 80%. On the other hand, T-N and T-P showed relatively low processing efficiency of 56% and 60% respectively, but it was observed that SS showed high 96% in the MBR method. Next, by the result of yearly water change analysis on water quality of Hongcheon River which is the discharge river of community sewerage, it was observed that water quality was greatly deteriorated by COD, T-N and T-P. However, installation and operation of community sewerage showed high pollution load reduction in general water quality item by more than 80%, and in T-N and T-P by 58% and 68% respectively. It is expected that community sewerage will greatly contribute in water quality improvement of Hongcheon River.

• Journal of Environmental Health Sciences
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• 제35권4호
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• pp.334-342
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• 2009

Perfluorinated compounds (PFCs) have a wide range of domestic and industrial applications, but they are persistent in the environment. Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) are among the metabolites of PFCs and occur at high concentration in the environment. Korea is the largest importer of PFC compounds in the world, therefore, the accumulation of these compounds is possible. In this study, the concentrations of PFOS and PFOA were determined in water samples taken from sewage treatment plants (STPs) and the Han River in Seoul, Korea. After extraction with a HLB cartridge, PFCs in the samples were analyzed by HPLC with an ion trap mass spectrometry in electrospray negative mode. Limits of detection was between 1 and 1.6 ng/l. The result showed that the concentrations of PFOS and PFOA in effluent and influent of the four STPs in Seoul were 60~570 ng/l, and not detected (nd)~254 ng/l, respectively. The levels of PFOS and PFOA were higher in the effluents which passed through the treatment process than in influent water samples which was against expectation. The concentration of PFOA and PFOS in the Han River was 60~570 ng/l and nd~254 ng/l, respectively. PFOA was detected in every sample, but PFOS was only detected in the downstreams of the Han River. This result indicates that there is comprehensive contamination of PFCs in the aquatic environment in Korea.

• Journal of Korean Society on Water Environment
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• 제23권6호
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• pp.837-842
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• 2007

This study was conducted to test the effect of residual Al on plankton community after dissolved air flotation (DAF) application. Growth rate of phytoplankton after DAF application ($0.37day^{-1}$) was about 2 times lower than that before DAF application ($0.70day^{-1}$). Under the condition of addition of nitrogen and phosphorus without light, growth rate phytoplankton in treatment without residual Al increased in difference with showing the negative growth rate in treatment with residual Al. Under the condition of light without addition of nutrient, growth rate of phytoplankton was no noticeable difference between the before and after DAF application. The relatively high settling rate (0.47 m/day) was observed in treatment after DAF application. Although the abundance of rotifer decreased, the abundance of copepod and cladoceran such as Daphnia galeata, Diaphanosoma sp. and Bosmina longirostris with relative higher grazing was no noticeable difference between the before and after DAF application. In the treatments before and after DAF application with zooplankton, growth rate of phytoplankton was $0.41{\pm}0.08day^{-1}$, $0.20{\pm}0.03day^{-1}$, respectively. This difference was in treatment after DAF application similar with those in treatments before and after DAF application without zooplankton. Those indicate that the filter-feeding effect of zooplankton on phytoplankton community may be not changed by residual Al after the DAF application. These results suggest that residual Al after DAF application be to improve water quality by inhibition of growth rate as well as increasing settling rate of phytoplankton.

• Journal of Korean Society on Water Environment
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• 제27권3호
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• pp.349-356
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• 2011

This study, which evaluated the contribution of the real economic value and system in the Nakdong River Basin, estimated the emergy analysis for environmental accounting of the TMDL program. And an environmental accounting for TMDL is evaluated before and after adopting TMDL program respectively. The value of emergy after adopting the TMDL was 7.90 E+20 sej/yr. Although the real yield of the river after governmental investment was high (before: 9.7118 E+20 sej/yr and after: 9.7224 E+20 sej/yr), the effects of improvement was not great, in terms of an investment cost. The benefit/cost ratio resulted from environmental accounting has decreased from 1.493 to 1.230 due to the cost of managing treatment facilities. The method of improving water quality in the Nakdong River Basin by the TMDL program should be changed into an ecological treatment facilities using resources efficiently from a control of water quality depending on expansion of the wastewater treatment facilities and advanced treatment plant using high cost and non-renewable energies.

• Journal of Ocean Engineering and Technology
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• 제17권2호
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• pp.8-13
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• 2003

Soil, ground water, and sea bed are exposed to a continuous accumulation of polluted materials, causing serious environmental damage. It has been reported that such pollution causes a massive mortality of fish stock in rivers due to the resuspension of toxic chemicals, occurring during strong wind conditions. Therefore, it becomes apparent that there is an immediate demand for the restoration treatment of polluted river bed (or sea bed) sediment layers. Pollution levels of major rivers and ports, such as Paldang, Kyungan rivers, and Masan port, are becoming of great public concern, and are posing a serious environmental threat. In particular, the pollution of the Shi-hwa river has become a nation wide issue for the last few years. In spite of such public concern, the pollution levels of such rivers or ports are worsening everyday. In this study, an environmentally sound engineering package is introduced that helps to restore the polluted river bed or sea bed sediments. This engineering package consists of a suction facility, followed by a series of mechanical, chemical, and biological treatment units. The suction facility is designed to minimize secondary pollution that occurs from the resuspension of toxic materials during suction. The sea bed cleaning engineering package is designed to be installed on the top of a floating barge. Such a combination of environmental plant and shipbuilding technology provides a cost-effective solution, minimizing the transportation between suction and treatment facilities.

• Journal of Korean Society on Water Environment
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• 제21권6호
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• pp.609-616
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• 2005

A high ammonia nitrogen ($NH_3-N$) concentration has been recursively observed every winter season in Geum River, which hindered chemical treatment processes at a water treatment plant. A flushing discharge from Daecheong Dam was often considered to dilute $NH_3-N$, but information on the quantitative effect of flushing on the downstream water quality was limited. In this study, the impact of a short-term reservoir flushing on the downstream water quality was investigated through field experiments and unsteady water quality modeling. On November 22, 2003, the reservoir discharge was increased from $30m^3/sec$ to $200m^3/sec$ within 6 hours for the purpose of the experiment. The results showed that flushing flow tends to reduce downstream $NH_3-N$ concentrations considerably, but the effectiveness was limited by flushing amount and time. An unsteady river water quality model was applied to simulate the changes of nitrogen concentrations in response to reservoir flushing. The model showed very good performance in predicting the travel time of flushing flow and the effect of flushing discharge on the reduction of downstream $NH_3-N$ concentrations at Maepo and Geumnam site, but a significant discrepancy was observed at Gongju site.