• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_3호
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• pp.97-106
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• 2001

To improve the water quality, particularly for sea bathers, the behaviour of wastewater from sewage outfalls in water adjacent to Swansea, UK, was studied using a mathematical model. The water quality in the sewage receiving basin was determined using factors like the outfall diffuser location(distance from land boundary), sewage treatment scheme, discharge time, and bacteria decay rate, etc. With respect to these factors, an optimal strategy for sewage discharge was then investigated to minimize bacteria levels along the bathing beaches. As water quality criteria, predicted faecal coliform levels were monitored along the coast adjacent to the outfall locations. The resultant values were compared with EC Mandatory(<2000, 95 % of 20 samples) and Guideline Standards(< 100, 80 % of 20 samples). For the advective-diffusion equation, the non linear advective terms were represented using the ULTIMATE algorithm and the third-order accurate QUICKEST scheme to avoid numerical diffusion. Details of the simulation results are then presented as an optimal policy for sewage discharge in the region.

• 한국물환경학회지
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• 제25권5호
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• pp.778-784
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• 2009

The purpose of this study is to figure out the differences of the inflow rates of Sewage Treatment Plants (STP), invested by public fund or public-private partnership (PPP). This paper finds that the average ratio of sewage inflow according to facility capacities (medium and small scale STP) was either nearly below 30% or above 100% in the first year. As the size of STP increased, there was decrease in the accuracy of demand assumption. This was because the operation time when the ratio of sewage inflow was uniform was different according to the size of STP, whereby the time was short when the STP were small. The design average ratio of sewage inflow was 10% larger than the real average ratio; this was considered overdesigned. In the case of a plant built by the PPP scheme, the average ratio of inflow of the STP before an abolition of MRG was larger than after the abolition of MRG. This may be explained by moral hazard from too much reliance on MRG. After the abolition of MRG, the demand risk of PPP was shifted from a PPP project to a conventional project.

• 한국물환경학회지
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• 제27권2호
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• pp.200-209
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• 2011

The purpose of the study is to optimally manage sewage treatment plant with analysis of phosphorus contribution and improvement of water quality contributing rate in the effect of inflowing point of effluent and Pal-Dang lake after reducing T-P discharge from large scale public sewage treatment plant at upstream of Pal-Dang lake. Also, this study, for enforcement of T-P in effluent, plans optimal management of effluent T-P through examining propriety of environmental, technological, and economical aspect such as water quality standard of domestic and foreign T-P and related policy. In regarding optimal management of T-P discharged from public sewage treatment plant located in upstream of Pal-Dang lake, the study drew following conclusions. With the optimal management of public sewage treatment plant, it showed that a pollution level became higher in the order of Sumgang E in South-Han river, C in Dalcheon, B1 B2, A in North-Han river, and J in Kyungancheon, and it is required reduction of T-P first. The highest value in analysis of benefit-costs from sewage treatment plant in the selected research area was Kyungan B, and the others are with the order of Jojong A, Bokha A, Kyungan A, and Yanghwa A. With result of this study, all 14 areas are required more enforced phosphorus treatment. The study resulted that the most top priority areas were Hangang F, Sumgang B, and Gyungan A, top priority areas were Bokha A, Dalcheon B, and Cheongmi A, priority areas were Hangang E, Heukcheon A, Gyungan B, and Jojong A, and potential areas were Sumgang A, Yanghwa A, Dalcheon A, and Hangang D. It seems to be appropriate to apply 0.2 mg/L of T-P treatment for water supply source reservation, 0.5 mg/L for the other areas by locally, and 0.2~0.5 mg/L for biological nitrogen phosphorus treatment method and 0.5~1 mg/L for Conventional Activated Sludge by technologically. Also, it may be appropriate to apply 0.2 mg/L for the most top priority area(I), 0.3 mg/L for the top priority area(II), 0.4 mg/L for priority area(III), and 0.5 mg/L for potential area(IV) by the separation of priority area.

• International Journal of Control, Automation, and Systems
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• 제1권1호
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• pp.101-110
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• 2003

This paper introduces an identification method for nonlinear models in the form of rule-based Fuzzy-Neural Networks (FNN). In this study, the development of the rule-based fuzzy neural networks focuses on the technologies of Computational Intelligence (CI), namely fuzzy sets, neural networks, and genetic algorithms. The FNN modeling and identification environment realizes parameter identification through synergistic usage of clustering techniques, genetic optimization and a complex search method. We use a HCM (Hard C-Means) clustering algorithm to determine initial apexes of the membership functions of the information granules used in this fuzzy model. The parameters such as apexes of membership functions, learning rates, and momentum coefficients are then adjusted using the identification algorithm of a GA hybrid scheme. The proposed GA hybrid scheme effectively combines the GA with the improved com-plex method to guarantee both global optimization and local convergence. An aggregate objective function (performance index) with a weighting factor is introduced to achieve a sound balance between approximation and generalization of the model. According to the selection and adjustment of the weighting factor of this objective function, we reveal how to design a model having sound approximation and generalization abilities. The proposed model is experimented with using several time series data (gas furnace, sewage treatment process, and NOx emission process data from gas turbine power plants).

• 한국수자원학회논문집
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• 제36권5호
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• pp.863-878
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• 2003

본 연구에서는 하천의 유지용수를 확보하기 위하여 하수처리장에서 처리하여 방류하는 하수처리수를 활용하기 위한 방안을 검토하고 이를 하천유지용수로 직접 활용하기 위하여 역순환시스템의 활용을 검토하였다. 역순환시스템은 하천 하류에 위치한 하수처리장으로부터 방류되는 하수처리수를 펌핑하여 하천상류부로 이송함으로써 하천에 부족한 유지유량을 확보하는 방법으로 여러 가지 형태의 이송방안을 조합하여 하천의 특성에 맞는 최적의 시스템을 구성하고 간단한 수처리를 적용함으로서 하수처리수의 수질을 추가적으로 개선할 수 있는 특징이 있다. 또한 이송된 하수처리수를 하천에 유입시키는 방안들은 시각적으로 친수적인 경관을 제공하고 폭기 등에 의한 수질개선효과를 얻을 수 있다. 이러한 하수처리수를 활용한 역순환시스템을 하천유지용수확보에 적용하기 위하여 국내 하수처리장의 처리수 활용실태 및 수질 상태 등을 검토하였고, 국내의 하수처리수 활용 사례를 조사하였으며 외국의 유사사례 조사를 통해 국내에 적용하기 위한 방안을 마련하고 실제 하천을 대상으로 역순환시스템의 적용방안을 제시하였다.

• 한국농공학회논문집
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• 제47권1호
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• pp.93-102
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• 2005

A prototype surface flow constructed wetland was built in the upstream area of Sihwa reclaimed tidal lands to improve the water quality of Lake Sihwa by treating severely polluted stream water. In this study, we monitored hydrology, macrophyte (Phragmites communis Trin,) growth, and water quality in the Banwol and Donghwa wetlands to evaluate their performance during the initial period after the completion of wetland construction, The average removal efficiency($\%$) in each wetland was relatively low compared with the performance data from the North America Wetland Treatment System Database (NADB), which mainly includes urban sewage-treatment wetlands. However, the average removal rates per unit area ($g/m^{2}/day$) were 0.72, 0.72 and 0.51 (BOD), 2,04, 2.46 and 0.70 (SS), 0.89, 0.43 and 1.09 (TN) and 0.02, 0.02 and 0.02 (TP) in the Banwol and Donghwa wetlands and NADB, respectively. The overall performance of the Banwol and Donghwa wetlands was within the expected range of the wetland system processes contributing the reduction of the pollutant load to Lake Sihwa during the initial period of wetland operation. Considering the low influent concentration, high hydraulic loading rate, and insufficient macrophyte growth since the wetland was constructed, better performance is expected if an improved operational scheme is adopted.

• 유기물자원화
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• 제24권4호
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• pp.11-20
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• 2016

천연자원의 고갈과 온실가스의 감축은 우리가 당면하고 있는 현안이다. 이러한 이유로 폐기물의 재활용은 국제사회적으로도 큰 관심사이며, 국내에서도 비용 대비 효과적인 처리 및 재활용 기술의 개발이 지속적으로 이루어져야 하는 과제를 안고 있다. 본 연구에서는 유기성 폐기물의 처리 및 재활용에 따른 비용원단위 등을 비교 분석 함으로써 효과적인 자원화 방안에 대하여 고찰하였다. 본 연구에서 조사된 유기성 폐기물은 폐수처리오니류, 공정오니, 동 식물성 잔재물 등이며, 해당 폐기물을 배출하는 80개 사업장을 대상으로 처리현황 및 처리비용을 조사하였다. 유기성 폐기물의 경제성 있는 적정 처리방법은 퇴비화와 시멘트 부원료로 사용되는 것으로 나타났다. 유기성 폐기물의 성상, 유해물질 등에 따라 경제성 분석이 다를 수 있겠지만, 조사대상 업체로부터 현실적인 폐기물의 처리결과를 바탕으로 분석하였다. 특히, 유기성 폐기물을 퇴비화 제품으로 재활용한다면, 비료의 원료가격 등이 상승됨에 따라 비료가격은 증가 추세로 보이기 때문에 경제적인 효과가 있을 것으로 판단된다. 유기성 폐기물의 안정적인 처리 및 재활용을 위해서는 폐수처리오니 등 유해특성을 갖고 있는 폐기물과 유기성 폐기물의 재활용 처리시 기술적 어려운 점인 악취, 침출수, 이물질에 대한 기술적인 노력을 기울여야 할 것이다.

• 대한환경공학회지
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• 제36권6호
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• pp.451-459
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• 2014

본 연구에서는 2012년부터 수질오염총량관리 시행계획이 시행중인 진위천 수계의 연차별 지역개발 및 삭감계획을 평가하여 최종년도 할당부하량 및 목표수질을 만족하기 위한 방향성을 제시하고자 하였다. 진위천 수계 8개 자치단체의 시행계획을 분석한 결과, 대부분의 지자체에서 삭감계획보다 개발계획의 연차별 진행률이 빠른 경향을 보였다. 군포시, 용인시, 화성시는 2020년, 평택시는 2018년, 안성시는 2015년, 오산시는 2019년이 되어서야 삭감계획 진행율이 개발계획 진행율 보다 높거나 같아졌다. 주요 삭감방법은 하수처리시설 신증설, 방류수질 개선, 축산폐수 및 고형물의 자원화, 비점저감시설 확충 등 이었으며, 특히 축산산업이 활발한 지역의 특성이 반영되어 총 삭감률 중 가장 높은 비율을 차지하는 삭감방법은 축산폐수 및 고형물의 자원화로 삭감률은 34.1%에 해당되었다. 진위천 수계의 수질오염총량제가 성공적으로 정착하기 위해서는 삭감계획 및 지역개발계획의 체계적인 관리를 포함하여 기초자치단체의 적극적인 의지가 무엇보다 중요할 것으로 판단된다.