• Journal of Environmental Science International
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• v.26 no.3
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• pp.401-410
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• 2017

This study analyzed the changes in the concentrations of organic matters in constructed treatment wetlands, coming from discharge water from a sewage treatment plant and non-point pollutant sources during rainfall events. At the beginning of a rainfall event, a massive amount of particulate organic matter flowed in, and was removed from the sedimentation basin (S1, S2); dissolved organic matter was removed after passing through stepwise treatment processes in the wetland. During dry period in the wetland, the removal efficiency rate for COD and TOC was -21 and -7%, respectively; during the rainfall event, the removal efficiency rate for COD and TOC were 47 and 43%, respectively. The highly-concentrated organic matters that flowd in at the beginning of the rainfall event was stabilized by various structures in the wetland before water discharge. Cyanobacteria blooms annually at the confluence of the So-ok stream and Daecheong Lake. Therefore, it is expected that the wetland will contribute significantly to reducing cyanobacteria and improving water quality in the area.

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.268-278
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• 2010

This study derived the effectiveness analysis results of construction of wastewater treatment plant under climate change scenarios. Canadian Global Coupled Model (CGCM3) was used and A1B and A2 of Special Report on Emission Scenario (SRES) were selected. Regional climate change data for this application were downscaled by using Statistical Downscaling Model (SDSM) and the flow and BOD concentration durations were obtained by using Hydrological Simulation Program - Fortran (HSPF). The criteria for low flow and water quality were chosen as $Q_{99}$, $Q_{95}$, $Q_{90}$ and $C_{30}$, $C_{10}$, $C_1$. The numbers of days to satisfy the instreamflow requirements and target BOD concentration were also added to the criteria for comparison. As a results, small wastewater treatment plant improved the water cycle due to the increase of low flow and the decrease of BOD concentration. But climate change affected the reduction of effectiveness significantly. Especially in case of construction of small waste water treatment plant in the upstream region, it is necessary to take climate change impact into consideration since it is usually related to the low flow and the water quality of the stream.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.252-259
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• 2021

Numerous valley waters originating from Mt. Mudeung and flowing into Gwangju Cheon flowed into the confluence-type sewage conduit, the Gwangju Cheon became dry and water quality deteriorated. In this study, a method to create a stream was studied by using the valley water of Mt. Mudeung in the Gwangju cheon that flows into the sewage treatment plant as a water source. Flow and water quality surveys were investigated at four points with meaningful flow quantity. As a result, it showed a flow quantity was 105~2,721 m³/day at each point. And the average water quality was BOD₅ 0.3~1.6 mg/L. If a stream with a flow quantity of 1,500 m³/day is created during the dry season and then flows into the Namgwang bridge of Gwangju cheon, it is predicted that there will be improvements in BOD 7.3%, COD 6.5%, T-P 5.8%, and T-N 5.2%. In addition, it was determined that the load on the flow quantity of the sewage treatment plant due to the inflow of valley water would be reduced, the cost of sewage treatment would be reduced, and it would be the basis for BGN construction by creating waterside amenity in the city.

• Membrane and Water Treatment
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• v.15 no.4
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• pp.185-192
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• 2024

Paldang Lake is a reservoir that formed behind Paldang Dam on the Han River, and it is the largest water resource in South Korea. Thus, managing its water quality is important to secure a supply of clean drinking water. However, the amount of nonbiodegradable organic matter in Paldang Lake has been increasing. In this study, the objective was to quantitatively and qualitatively evaluate the levels of nonbiodegradable organic matter at different points along two rivers flowing into the lake. Multiple water quality indicators were measured including the total organic carbon (TOC), dissolved organic carbon (DOC), and refractory TOC and refractory DOC. The results were used to clarify how pollution patterns in the two watersheds have affected the water quality of Paldang Lake, and they are expected to help guide efforts to protect and manage this resource.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.4
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• pp.201-207
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• 2017

This study was conducted to investigate the characteristics of the stream current detector (SCD) and charge analyzing system (CAS), which are well known as the automatic coagulant dosage determination instruments. When the SCD system was used, the current charge value set at pH 9.3 could not be used as the coagulant dosage when the pH of the raw water decreased to 5.7, and the current charge value corresponding to pH 5.7 was required to be reset. In case of CAS system, polydadmac is stable as a cationic titrant when the pH of the raw water ranged 9.3 to 6.0. And it was effective to use polydadmac as a cationic titrant for high turbidity water. The current charge of polydadmac was almost constant between pH 5 and 11, however, the difference in charge of alum is six times in this pH range. Therefore, when the pH of the raw water was changed, it seems that the coagulant used in the actual water treatment plant was as a good cationic titrant.

• YAKHAK HOEJI
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• v.21 no.4
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• pp.200-210
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• 1977

This investigation was undertaken from February 1976 to September 1976. The detergents in municipal sewages from the Chung Kae Stream, Ahn Yang Stream, and Bong Won Stream were determined at 1.5ppm, 0.93ppm, and 3.36ppm in average respectively. The concentrations of detergents determined in the Han river were 0.013ppm of Kwang Na Ru, 0.11ppm of Duk Do, 0.370ppm of Bo Kwang Dong, and 0.285ppm of Ka Yang Dong basin respectively. And the potable waters of Sung Book Ku and Sung Dong Ku from Ku Eu water pumping station located up-stream of the Han river were less polluted at 0.045ppm and 0.037ppm in average. Young Deung Po Ku and Su Dae Moon Ku had been relatively polluted at 0.181ppm and 0.133ppm. The coagulant, alum [$Al_{2}(SO_{4})_{3}$] could eliminated the small amount of detergent by coagulation. The eliminated rates were about 13% by 5ppm and 22.7% by 20ppm of aluminum sulfate in sewage contained 10ppm of turbidity. The sand and the charcoal adsorbed some detergent as the following Langmuir's equations: For the charcoal, m/x=0.029.$\times$1/Ce-11.43 For the charcoal, m/x=2.705log1/Ce-5.46 Where m: amount of snad and active carbon used(g) x: amount of detergent adsorbed from liquid(g) Ce:concentration in the liquid at equilibrium(miles) The adsorption effect of sand would be neglected. In the low concentration of detergent solution, one gram of active carbon adsorbed 0.263g of detergent. It was determined that one gram of chlorine reduced 5.5g pf DBS om keeping up 0.2ppm of residual chlorine by disinfection process with chlorine compound.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.10
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• pp.581-590
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• 2017

For effective improvement of water quality in Seokmun reservoir, this study implemented various analyses including the tributary water quality and flowrate monitoring, contamination of sediment, investigation of pollution source, selection of priority management target tributary by stream grouping method. The COD concentration of the majority of tributaries in Seokmun reservoir watershed was relatively higher than BOD concentration. The concentration of water pollutants regardless of water quality parameters in Yeokcheon, Dangjincheon, Sigokcheon, Baekseokcheon, small stream in Jinkwanri and Janghangri were higher than the other tributaries. The pollution sources in the Seokmun reservoir watershed were mostly distributed in the population, livestock, and industry. The pollutants, which located in Yeokcheon, Dangjincheon, Baekseokcheon, and small stream in Janghangri selected as priority management target tributary, should be preferentially reduced for improving the water quality in Seokmun reservoir. As the evaluation results of water quality in Seokmun reservoir for the effect of water quality improvement according to various scenarios using water quality model, it was found that the water quality in Seokmun reservoir due to the construction of a wastewater treatment plant for management of pollutants in the watershed would be satisfied the class V of water environment standard in reservoir.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.129-135
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• 2011

The possibility of nutrient removal during Scenedesmus sp. growth in Lake Paldang, Geongan cheon stream, and the outflow from a wastewater treatment system was examined. Scenedesmus sp. grew well in Lake Paldang water when total nitrogen (TN) and total phosphorus (TP) values were 1.9 and 0.02 mg $L^{-1}$, respectively, and 50% of the nutrients were removed. In Geongan cheon stream, the TN and TP was 3.0 mg $L^{-1}$ and 0.09 mg $L^{-1}$, respectively, chlorophyll-${\alpha}$ reached a maximum of 239~259 $m^{-3}$, and 50% of the nutrients were removed. In the wastewater treatment outflow, where Scenedesmus sp. already existed, the organism grew well without inoculation. Scenedesmus sp. can grow with proper inoculation and physical turbulence in natural waters, such as lake and stream water, and nutrients can be eliminated as phytoplankton growth occurs.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.4
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• pp.425-437
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• 2007

Flow distribution of water and sedimentation rate were investigated to understand the hydrodynamics and settling characteristics of particulate materials in a constructed wetland for treatment of non-point sources pollutants, the Sihwa constructed wetland, Korea. The Sihwa constructed wetland is divided into three sub-wetlands(the Banwol, the Donghwa and the Samhwa wetlands) to treat the polluted water from three streams, the Banwol stream, the Donghwa stream and the Samhwa stream. From the results of water flow experiment using dye(Rhodamine 50WT Red), it was found that the water flow in the wetland was prevailing at the waterway and open water. Dye was spread slowly in the closed water area planted by plants. The mean hydraulic retention time(HRT) at the upper area of high wetland and lower wetland of Banwol, was found to be 34.1 hr at the upper area and 74.6 hr at the lower area respectively, totaling approximately 108.7 hr(4.5 days). The sedimentation rate was higher at lower area(sites of B, C and D) of the wetland than upper area(site of A which is settling zone). Based on the forecast for 20 years as to the amount of sediment that can be deposited in the open water in the future, the sediment depth of each area would be like this: A: 6.3 cm, B: 8.3 cm, C: 7.0 cm, D: 9.5 cm. The contents of organic materials in the sediment deposited within the sediment trap were found to be higher overly in the first investigation period which had much rainfall, and B, C and D areas were found to have an increased COD accumulation than A area. Also, nitrogen and phosphorus were found to increase in the down-stream of the wetland. The results of this study suggest that a sustainable research and management for the characteristics of water flow pattern and sedimentation changeable as time passes is needs to maintain or improve the efficiency of water treatment in the constructed wetland.

• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.508-523
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• 2017

This study monitored the changes before and after restoration of ecological stream focusing on the places which are applied Sustainable Structured wetland Biotop (SSB) system and ecological Fish-way for restoration of Maeno stream. A total of 11 species and 191 individuals of fishes were founded out which were not verified inhabitation before restoration at SSB wetlands. Especially, it was could identified that micro habitat and healthy Fish-way was created because the restored target species, Microphysogobio yaluensis and Iksookimia koreensis were identified that habitation was monitored in SSB wetland. Amphibian have been restored to a number of Rana nigromaculata found in and around wetlands at the time of the third survey, which is highly active after restoration. Specified endangered species class 1 and natural monuments designated by the Ministry of Environment, Lutra lutra lutra, as a Mammalian, uses the wetlands and ecological Fish-way as habitat areas, and the his habitat is restored. In the case of Flora, vascular plants emerging in the survey area were increased to 7 and 13 species before restoration and 15 and 19 species directly after restoration, and 22 species and 33 species after restoration. Vegetation after restoration was found to be a basic producer of various ecosystems and a plant community that contributes to the purification of water quality such as Phragmites japonica communities. As the result of water quality monitoring, the average of treatment efficiencies were BOD 64.3%, T-N 47.2%, T-P 80.7%. Successful treatment of the nonpoint pullution source, which is a limiting factor to disturb the ecosystem, creatively restored the target species in the water quality class I, II.