• 상하수도학회지
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• 제29권4호
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• pp.447-457
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• 2015

Water cycle within the human civilization has become important with urbanization. To date, water cycle in the eco-system has been the focus in identifying the degree of water cycle in cities, but in practicality, water cycle within the human civilization system is taking on an increasing importance. While in recent years plans to reuse water have been implemented to restore water cycle in cities, the effect that such reuse has on the entire water cycle system has not been analyzed. The analysis on the effect that water reuse has on urban areas needs to be go beyond measuring the cost-savings and look at the changes brought about in the entire city's water cycle system. This study uses a SWAT model and water balance analysis to review the effects that water reuse has on changes occurring in the urban water cycle system by linking the water cycle within the eco-system with that within the human civilization system. The SWAT model to calculate the components of water cycle in the human civilization system showed that similar to measured data, the daily changes and accumulative data can be simulated. When the amount of water reuse increases in urban areas, the surface outflow, amount of sewer discharge and the discharged amount from sewage treatment plants decrease, leading to a change in water cycle within our human civilization system. The determinant coefficients for reduced surface outflow amount and reduced sewer discharge were 0.9164 and 0.9892, respectively, while the determinant coefficient for reduced discharge of sewage treatment plants was 0.9988. This indicates that with an increase in water reuse, surface flow, sewage and discharge from sewage treatment plants all saw a linear reduction.

• 한국수자원학회논문집
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• 제48권9호
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• pp.695-709
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• 2015

지속적인 개발과 도시화로 인하여 하천으로 유입되는 비점오염원의 비율 역시 점차 증가하는 추세이며 비점오염원이 수질악화에 미치는 영향은 점점 더 커지고 있다. 하천의 수질오염을 발생시키는 비점오염원 해결방안을 모색하고 있지만 도시화에 따른 수문현상변동 및 자연현상과 관련된 문제라 연구에 어려움이 많다. 본 연구에서는 기존의 총량원단위법과 달리 유역의강우 및 도시화 특성과 처리장 운영자료를 활용하여 차별화된 비점오염원 산정 방법을 제시하였다. 하수처리장의 배수구역 내 관거시스템을 합류식으로 가정하여 강우 시 하수처리장의 배수구역별 비점 발생형태는 하수처리장 강우유 입량, 하수처리장 우회유량(bypass) 및 하천토구의 CSO의 3가지로 크게 구분하여 적용함으로써 오염부하량을 산정함으로써 오염총량 단위유역 및 하수처리구역의 관리를 위한 비교자료로 활용 가능할 것으로 판단된다.

• 한국환경과학회지
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• 제25권2호
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• pp.323-329
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• 2016

In this study, the applicability of MBR process was evaluated to improve processing of personal sewage treatment facilities of $50m^3/day$ or less. As result of the research, stable discharge water quality could be secured as result of the MBR effector operation according to rate of inflow and inflow load and treatment efficiency of 98% or higher was shown by the membrane filtering method operation for SS, $BOD_5$. it was found that high treatment efficiency of 99% or higher. It is judged that detention time can be designed until 6.9 hr when applying MBR process on personal sewage treatment facilities with high pollution load and that cutback of pollution load can be possible through this study. It was shown that MBR process application reduces an annual cost of 4,829,600 won based on the basic unit calculation results and solves burden of amount of borne by causers according to excess of discharge water quality standards.

• 한국물환경학회지
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• 제28권1호
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• pp.121-128
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• 2012

The purpose of this study is to solve the problem of nutrient removal due to rapid hydraulic retention time (HRT) variation in small size private sewage treatment facility and to have better effluent quality by using natural zeolite as a coagulant aid. The experiments were conducted by applying different conditions of HRT, coagulant, and zeolite dosages. As an experimental result, $TBOD_{5}$, TSS, and TP removal efficiencies were 64.9%, 94.5%, and 98.8% at co-injection with zeolite. Overall removal efficiencies of $TBOD_{5}$, TSS, and TP have improved 15.7, 28.7, 6.1%, respectively. This result shows that zeolite addition could improve flocculation, increase setting velocity, and thus have better treatment. Therefore the use of zeolite as a coagulant aid can be useful in small size private sewage treatment facility, where especially extra nutrient removal is required to meet the legal standard for discharge.

• 상하수도학회지
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• 제30권6호
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• pp.673-682
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• 2016

In this study, we investigated influent and effluent water pollutants in 53 Public Sewage Treatment Works (PSTWs) where industrial wastewater or landfill leachate is combined four times for two years from 2014 to 2015. Also, we analyzed the characteristics of heavy metals and volatile organic carbons at influent and effluent of these PSTWs caused by sewage treatment combined with industrial wastewater or landfill leachate. As a result, six heavy metals such as barium, copper, iron, manganese, nickel and zinc, and four volatile organic carbons (VOCs) including phenols, di(2-)ethylhexyl phthalate (DEHP), formaldehyde and toluene were observed above detection limits in most of PSTWs. Also, it was revealed that six heavy metals such as hexavalent chromium, mercury, cadmium, chromium, nickel and selenium, and four VOCs including 1,1-dichloroethylene, vinyl chloride, naphthalene, and epichlorohydrin were observed more frequently according to precipitation. As a result of reviewing the monitoring data on "Water Quality Monitoring Networks" in lower watersheds of PSTWs, both heavy metals and VOCs were below detection limits, indicating that the effluent water had little influence on the watershed. Nevertheless for the better management of influent and effluent pollutants in PSTWs, it is necessary to establish the advanced management plans for water pollutants in PSTWs, which include a list of priority substances management, monitoring plans, and guidelines for industrial wastewater and landfill leachate combined in PSTWs.

• 한국환경과학회지
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• 제8권1호
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• pp.115-123
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• 1999

수영하수처리장 방류수의 해중방류법과 3차 처리 시설 설치의 비용분석을 한 결과는 다음과 같다. 1) 해안에서 4km 거리와 관경을 2m의 해중방류법을 이용한 수용만의 수질을 개선시키는데 소요되는 해중방류관 건설비용은 383억 원이 소요되는 것으로 산출되었다. 2) 수영하수처리장의 유출수를 해중방류관을 통해서 방류할 경우 방류수심을 32m, Diffuser의 길이를 200m로 할 경우의 초기희석배율은 유속에 따라서 56.4∼399.2으로 계산되었다. 3) 질소를 제거하기 위한 순환법의 경우의 20년 동안의 총 비용은 1,364억 원, 인을 제거하기 위한 응집제 첨가 활성슬러지법은 1,010억 원, 해중방류법은 383억 원으로 해중방류법이 3차 처리시설을 설치하는 비용보다 약 2.6∼3.5배 비용을 적게 소요하는 것으로 산출되었다. 4) 해중방류법을 이용할 경우의 수영만의 수질영향을 예측하기 위해서 물질순환모델을 이용하여 예측한 결과 수영만의 수질이 COD, 용존무기질소(DIN)와 용존무기인(DIP)의 전 항목에서 해역환경 II등급을 만족하는 것으로 예측되었다.

• 상하수도학회지
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• 제27권1호
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• pp.59-67
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• 2013

The odor occurring in the sewage system induces the displeasure, the disgust such as the headache, the vomit, etc. and increases the spiritual stress and disturbs the pleasant life of residents. These odors occur mainly in the area of combined sewage system treatment, being created in the personal sewage treatment plant such as septic tank and are incoming to sewage pipes and emitted to the outside through the manhole and the receiver, etc.; and this causes odors to the people. The Hydrogen Sulfide, the Methyl Mercaptan, the Ammonia, etc. are materials causing the odor, the more serious issue of odor is occurring since the septic tank of degradation process is being applied. The primary cause of odor is the decomposition of human feces in the septic tanks and sewage disposal facilities. The purpose of this study is reduction of hydrogen sulfide using air supplying and SOB(Sulfur-Oxidizing Bacteria). As a result of this study of the air supply system and the SOB media equipment by air supply, in case the air is injected to SOB media compared to the injection of air only, the removal efficiency the hydrogen sulfide was average 3.4 times higher.

• 상하수도학회지
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• 제30권3호
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• pp.233-240
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• 2016

Control degree and property changes of dissolved organic matter (DOM) were conducted by coagulation of chemical treatment for 2 sewage treatment plants with different technical methods. As the result, SUVA value of the second treated water (supernatant of the second settling pond after biological treatment) was increased and DOC was reduced in comparison with supplied raw water. And, SUVA value and DOC were reduced by coagulation after coagulation treatment of the second treated water. Properties of dissolved organic matter for 2 sewage treatment plants's DOC were divided. As the result, there was lots of hydrophilic component with hydrophilicity in case of plant A. In case of the second treated water, Plant A showed fulvic acid with little molecular weight was reduced among the hydrophobic component with hydrophobicity, but numic acide with lots of molecular weight was increased. However, in case of plant B, both fulvic acid with little molecular weight and humic acid with lots of molecular weight were increased among the hydrophobic components with hydrophilicity. Before the operation of phosphorus facility, properties of dissolved organic matter after biodegradation with effluent water showed hydrophilic components were reduced and hydrophobic components were increased. However, after coagulation treatment of the second treated water, hydrophilic components and hydrophobic components were outstandingly decreased or increased. During the biodegradation after coagulation treatment, hydrophilic components were significantly decreased and hydrophobic components were increased.

• 한국환경과학회지
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• 제27권4호
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• pp.261-266
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• 2018

In this study, the organic matter of effluents from sewage treatment plants, located in the Nakdong watershed was investigated. Regression equations were computed using treated sewage data to convert the chemical oxygen demand(COD) concentrations, which are mostly available from an open database, into total organic carbon(TOC) concentrations. The average concentration of organic matter in the sewage treatment plant effluents were 2.2~16.8 mg/L for COD and 3.4~14.3 mg/L for TOC. The concentrations of COD were positively correlated with the TOC concentrations. The correlation between COD and TOC was relatively high, at 0.865(p<0.01). Based on these results, regression analysis was conducted. The regression equation for TOC was $1.651{\times}COD_{Mn}-0.084$ ($R^2=0.84$). Furthermore, organic matter-related databases for more sewage treatment plants need to be built in order to establish TOC standards and manage the water quality.

• 상하수도학회지
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• 제30권3호
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• pp.241-251
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• 2016

As the Enforcement Ordinance of Environmental Policy Act was revised in 2013, total organic carbon(TOC) was added as an indicative parameter for organic matter in Water and Aquatic Ecosystem Environmental Criteria. Under these imminent circumstances, a regulatory standard is needed to achieve the proposed TOC limitation control water quality from the public sewage treatment plants(PSTWs). This study purposes to present the determination method for TOC effluent limitation at the PSTWs. Therefore we investigate the TOC effluent limitation of foreign countries such as EU, Germany and USA, and analyse the effluent water qualities of PSTWs. In using these TOC data, we review apprehensively the statistics-based, the technology-based, and the region(water quality)-based determination method of TOC effluent limitation for PSTWs.