• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.5
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• pp.571-577
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• 2012

In this study, a small movable batch treatment system for dredging soil deposited in a rain water tube is proposed; further, a vacuum silo sorting separation device with a vacuum silo, first-stage sorting separator, and conveyor is designed. The vacuum silo sorting separation device also consists of a storage tank, transferring screw, vacuum gate, screen bar, screen bar cleaner, and vacuum discharging device. In view of the fact that the flow of drawn air in the storage tank is a major factor influencing the sorting separation performance, the optimum shape of the tank is determined by CFD flow analysis. In addition, by using CAE structure analysis, the safety of a storage tank made of boards is examined. The specifications of the vacuum silo sorting separation device are determined by conducting mechanical and dynamic simulations of the driving mechanism of the vacuum silo sorting separation device through 3D-CAD modeling. Following this study, we will design a drum-screen-type second sorter, a decanter-type dehydration device, and waste water tank and pump as a secondary device. Further, on the basis of this design, we will construct a prototype model and carry out a field test.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.115-128
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• 2008

Various human activities such as the Urbanization and Industrialization are estimated the main factors to pollute the stream. Now days, numerous studies are carried out for managing non-point sources which have un-effect on water quality of streams by land-use and livestock. In case of Korea, a matter of concern that the management of Pal dang reservoir - the main water resources of the national capital region - has been occurring. Especially, large-scale constructed-wetlands are planned and constructed at the end of Kyoung-an stream. Additionally a lot of sewage treatment plants are newly installed and extended in this watershed. According to these efforts, water quality of Kyoung-an stream is predicted that would be improved. But the more detail and scientific analysis should be carried out for the water quality improvement, because, existing water quality improvement projects are not involved to analyze root of water quality deterioration and improvement plans. Therefore, this study aims to select suitable areas for constructed-wetlands and to calculate size of the constructed-wetlands for water quality improvement in Kyoung-an stream through the geographical pollutant distribution analysis and land-use pattern analysis by high resolution satellite image and suitable area analysis of constructed-wetlands by GIS(Geographic information system). The progress of this study is (1) to select maximum pollutant loaded area by geographical analysis based on water quality data, (2) to analyze land-use patterns using high resolution satellite image, (3) to select suitable areas of constructed-wetlands, (4) to calculate area and volume of chosen constructed-wetlands using GIS. Basically, sizes of constructed-wetlands are induced through the constructed-wetlands design index based on treatment ratio(provided by Korea Water Resources Corporation). As a result of this study, two areas are selected to construct constructed-wetlands. One of the area was $127,586m^2$ near by Yong-in sewage treatment plant, and the other area was $1,647m^2$ near by Ju-buk stream and Dae-dae stream.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.7
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• pp.339-349
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• 2001

This paper suggests an optimal identification method for complex and nonlinear system modeling that is based on Fuzzy-Neural Networks(FNN). The proposed Hybrid Identification Algorithm is based on Yamakawa's FNN and uses the simplified inference as fuzzy inference method and Error Back Propagation Algorithm as learning rule. In this paper, the FNN modeling implements parameter identification using HCM algorithm and hybrid structure combined with two types of optimization theories for nonlinear systems. We use a HCM(Hard C-Means) clustering algorithm to find initial apexes of membership function. The parameters such as apexes of membership functions, learning rates, and momentum coefficients are adjusted using hybrid algorithm. The proposed hybrid identification algorithm is carried out using both a genetic algorithm and the improved complex method. Also, an aggregated objective function(performance index) with weighting factor is introduced to achieve a sound balance between approximation and generalization abilities of the model. According to the selection and adjustment of a weighting factor of an aggregate objective function which depends on the number of data and a certain degree of nonlinearity(distribution of I/O data), we show that it is available and effective to design an optimal FNN model structure with mutual balance and dependency between approximation and generalization abilities. To evaluate the performance of the proposed model, we use the time series data for gas furnace, the data of sewage treatment process and traffic route choice process.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.2
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• pp.1-14
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• 2014

The purpose of this study is to identify the efficiency of LID technologies for controlling non-point source pollution from urban areas. The recent technical responses to managing water resource and urban areas according to the influence of climate change is an important national policy, along with green growth. Through various reference studies reasonable ways to consider a wholistic plan on urban-eco-friendly river management, the Low Impact Development (LID) as the adequate river management method is being undertaken in foreign countries to technically apply to urban plans. However, the LID is at the initial stage in Korea, with no specific studies implemented. Thus, this study explored whether LID technologies can be efficient measures to control non-point source pollution on the cost side. Ulsan's Namgu and Bukgu have been chosen as case studies that illustrate the efficiency of the LID technologies. On investigation, if LID technologies are designed properly, the efficiency of them is expected to higher than that of sewage treatment plant.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.217-219
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• 2006

This study focused an water quality response to land-based pollution loads and the appropriate pollutant load reduction in Chinhae Bay using an eco-hydrodynamic model. Land-based discharge foam urban areas, industrial complex and sewage treatment plant was the greatest contributor to cause red-tide blooms and summer hypoxia. Tidal currents velocity af the ebb tide was about 10 cm/s stronger than that of the flood tide. A residual current was simulated to. have a slightly complicated pattern with ranging from 0.1 to. 2.7 cm/s. In Masan Bay, pollutant materials cannot flaw from the inner to the outer bay easily because af residual currents flaw southward at surface and northward at the bottom. The simulation results of COD distribution showedhigh concentrations aver 3 mg/L in the inner part of Masan Bay related pollutant discharge, and charge, and lower levels less than 1.5mg/L in the central part of Chinhae Bay. For improvement water quality in Chinhae Bay, it is necessary to reduce the organic and inorganic loads from paint sources by mare than 50% and ameliorate severe polluted sediment.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.3
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• pp.50-57
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• 2000

Budgets of fresh water, salt, DIN and DIP in the Nakdong river estuary were estimated in order to clarify the characteristics of material cycling and fluxes of nutrients with a simple box model. Freshwater inflow into this system was approximately 1.1E＋10m³/y, water exchange was 3.3E＋10m³/y and water residence time was 2.03 day assumed with salinity between estuary and adjacent ocean. Nutrients loadings were 3.2E＋09mol DIN/y3.7×10³, 2.7E＋07mo1 DIP/y, respectively. net ecosystem metabolism was 2.4E＋07mo1 C/y. Although the Nakdong river discharge was the main source of nutrients but Jang-rim sewage treatment plant effluent take parts of 16% of nitrogen and 10.2% of phosphorus loadings.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.347-355
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• 2006

Anyang Stream including its main branch is the biggest branch stream of Han River in Korea. The geological and geomorphological characteristics were investigated to the affected area of Anyang Stream, in which rainfall characteristic was analyzed. The water quality surveyed that the analysis of water pollution used to biotic index and biological water pollution. The rainfall pattern in this area was like to that of typical Korea, but the rate of trigger and runoff during summer season(June~August) is more higher than mean of Korea. Before 2003, a dried stream is severe status, which was due to abundant runoff, but this status are improved. After 1997, water quality of stream is recovering status such as water pollution of stream steeply decreased. Especially after 2003, this trend is more quickly improved. Although, owing to the increasing of a T-N and SS at upstream wastewater were due to bad collection of industrial factories, livestock's and mans living, the water quality worsted at upstream. Water quality in total section of main stream was severely contaminated that water-quality limit is 5 with polysaprobic by water self-purification. That of main branch was 1~3limits with ${\alpha}$- and ${\beta}$-mesosaprobic in Anyang city area, But water quality in all area about another branch of Anyang stream except Anyang city area was almost under of 3 grades. Though trying of Anyang city for recover movement(completion of 2nd Sewage Treatment Plant and Water supply pipe system) on Anyang stream, water pollution states of upper branch in Anyang stream was not better than its of 2002 because it may be difference of control area on other cities.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.670-678
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• 2002

Since Korean government imposed a stricter regulation on effluent T-N and T-P concentrations from wastewater treatment plant, a new process has to be developed to meet these rules and this process should remove T-N and T-P, economically, from weak wastewater that is typical for Korea's combined sewer system sewage. In this study, a computer simulator, BioWin from EnviroSim, Inc. was used. Three processes - A2/O, Modified Johannesburg, UCT- had been simulated under same operational conditions and a new process - Parallel BNR Process - had been developed based on these simulation results. The Parallel BNR process consists of two rows of reactors: One row has anaerobic and aerobic reactors in series, and the other row has RAS anoxic1 and RAS anoxic2 reactors in series. In order to ensure anaerobic state in anaerobic tank, a part of influent is fed to RAS anoxic1 tank in second row. This process had been simulated under same conditions of other three processes and the simulation results were compared. The results showed that three existing processes could not perform biological phosphorus removal when the average influent was fed at any operation temperatures. However, the Parallel BNR process was found that biological phosphorus removal could be performed when both design and average influent were fed at any operation temperatures. This process showed the T-N concentration in effluent had a maximum value of 15mg/L when design influent was fed at $13^{\circ}C$ and a minimum value of 14mg/L when average influent was fed at $20^{\circ}C$. Also, T-P concentrations had a maximum value of 1.3mg/L when average influent was fed at $20^{\circ}C$ and a minimum value of 1.1mg/L when design influent was fed at $13^{\circ}C$. Based on these results, we found that this process can remove nitrogen and phosphorus biologically under any operational conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.486-486
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• 2023

하수처리장 내 생물반응조에서는 유기물을 제거하거나 질산화(Nitrification) 반응을 일으키기 위하여 산소를 요구하고 있으며, 필요한 산소는 송풍기 운영을 통해 공급하고 있는 상황이다. 질산화 반응을 일으키기 위해서 처리장 내 일정 이상의 산소가 수중에 공급되어야 한다. 생물반응조내 용존산소가 부족할 경우 활성슬러지의 침전성이 저해되어 오염물질 저감 효율이 떨어지게 되며, 과도한 산소가 공급되어도 수처리의 효율은 개선되지 않으며 반응에 사용되지 않은 산소들은 대기중으로 방출된다. 또한 유입수질에 따라 실시간으로 반응조 내 필요한 산소는 달라지게 되므로 유입수질에 맞는 효율적인 하수처리장 운영이 요구되고 있다. 하수처리장 내 적절한 산소를 공급하기 위하여 많은 연구들이 활발하게 진행되어 왔으나 실제생물학적 처리시 요구되는 산소의 양을 산정할 수 있는 한계점을 지니고 있으며, 하수 성분, 용량과 같은 환경에 따라 차이를 보이고 있어 범용적으로 사용하기에는 어려움이 있다. 따라서 본 연구에서는 이러한 적용 한계점을 극복하기 위하여 하수도 설계 시 사용되어지고 있는 하수도 시설기준의 산소요구량 및 공기공급량 산정식을 통하여 유입수질에 따라 실제 하수처리장에 필요한 산소요구량 & 공기공급량을 산정하는 시스템을 개발하고자 하였다. 하수도 설계기준의 여러 가지 수식을 실제 하수처리장 내 필요한 요소로 변환시켜 범용적으로 사용가능한 시스템을 개발하였다. 본 연구에서 개발한 하수처리장 송풍량 산정 시스템 적용에 따른 송풍량 절감 효율을 비교분석하기 위하여 2021년 A하수처리장의 4월 월간 데이터를 활용하여 하수처리장에서 필요한 송풍량을 산정하여 실제 사용된 송풍량과 비교 분석하여 송풍량 절감 효율을 분석하였다. 본 연구의 결과를 바탕으로 실제 하수처리장 내 송풍량 산정 시스템을 도입하게 된다면 운전자 경험에 의존하고 있는 수동적인 제어 방식에서 벗어나 자율 제어를 통한 효율적인 하수처리장을 운영할 수 있어 송풍량 절감 및 탄소중립에도 이바지 할 수 있을 것이라고 판단된다.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.189-194
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• 2012

In this study, a 3-stage biological aerated filter (BAF) system was proposed to enhance nitrogen removal in the treatment of low carbon to nitrogen ratio (C/N ratio) municipal wastewater. Laboratory experiments were conducted to evaluate the effects of dynamic-flow at the HRT of 6 h. Results of the long-term operation of 3-stage BAF systems showed that the dynamic-flow enabled the total nitrogen removal (T-N) removal efficiency of the system to be about 7 % higher than that of non-dynamic-flow system in treating domestic wastewater due to the more efficient use of organic substrates. The overall $NH_4$-N removal performance was stable during the operational period due to the unique system configuration where independent nitrification occurred. It was concluded that the 3-stage BAF system proposed in this study provided excellent performance in the removal of nitrogen by employing dynamic-flow and three columns functioning as sorption, denitrification and nitrification, respectively.