• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.547-559
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• 2003

In this study, a mathematical model is developed for sewer rehabilitation planning by considering cost and inflow/infiltration. A sewer rehabilitation planning model is required to decide the economic life of the sewer by considering trade-off between cost and inflow/infiltration. And it is required to find the optimal rehabilitation timing, according to the cost effectiveness of each sewer rehabilitation within the budget. To solve the problem, we formulated a multiple objective mixed integer programming(MOMIP) model based on network flow optimization. The network is composed of state nodes and arcs. The state nodes represent the remaining life and the arcs represent the change of the state. The model considers multiple objectives which are cost minimization and minimization of inflow/infiltration. Using the multiple objective optimization, the trade-off between the cost and inflow/infiltration is presented to the planner so that a proper sewer rehabilitation plan can be selected.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.204-204
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• 2019

국지성 호우의 증가로 인해 도시 지역의 내수침수피해가 빈번하게 발생하고 있다. 특히 배수의 흐름이 집중되는 저지대 지역과 노후화된 하수관거가 설치된 지역에서 특히 피해가 집중되고 있으며, 이는 도로 측면에 설치된 빗물받이와 같은 하수시설에서 원활하게 배수가 되지 않기 때문에 강우 발생시 도로표면에 노면수가 정체되어 피해가 발생하고 있다. 과거 도로 노면의 형상과 강우의 임계 지속시간을 고려한 적정 우수 유출량 산정에 관한 연구가 진행된 바 있으나, 현재 발생하는 국지성 호우의 형태나 강우강도의 변화에 따른 유출량의 변화가 발생하였으며, 도달시간 산정식에 따른 매개변수의 차이와 새로운 도달시간 산정식의 개발로 도달시간의 결과가 크게 차이가 날 수 있다. 따라서 도로의 침수피해를 막고 교통 안정을 유지하기 위해서는 도로 조건을 고려한 도로 입구 및 하수관의 적절한 설계 등 다양한 연구가 주기적으로 이루어져야 한다. 본 연구에서는 강우 유출 모델인 SWMM 모형과 계산식을 이용하여 도로 표면의 폭과 길이, 도로 종횡단의 변화량, 재 산정한 강우강도에 따른 유출량을 계산하였다. 도로 표면의 폭과 길이, 경사를 다양하게 입력하였으며, 또한 각 Case에 따라 최대 유출량을 생성하는 임계지속기간을 결정하고 다양한 도달시간 산정식의 결과와 비교하여 상관관계를 분석하였다. 분석결과 도달시간은 산정식의 매개변수에 따라 차이가 발생하였으며, 도로표면의 길이와 횡단경사에 크게 영향을 받는 것으로 분석되었으며, 횡단경사보다 종단경사가 클 경우 도달시간이 길어져 유량의 집중을 막는 효과가 있는 것으로 나타났다.

• Journal of Wetlands Research
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• v.23 no.1
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• pp.7-13
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• 2021

Due to rapid industrial development, population growth, and improvement of living standards, the amount of sewage and wastewater, including nutrients, is increasing every year. In addition to the increasing amount of sewage and wastewater generation, untreated linked treated water (manure, livestock manure, industrial wastewater, leachate, food waste) is also increasing, and many of the linked treated water flows directly into nearby sewage treatment plants. The associated treated water causes many problems because of its own characteristics, low flow rate with high concentration compared to existing inflow sewage. In order to solve this problem, it is necessary to investigate the quantity and quality of the connected treated water whichh is flowed into the sewage treatment plant, and a study the effect on sewage treatment. Therefore, in this paper, we would like to examine the effect of the linked treated water. Seasonal effect associated with water pollution conditions was considered. In addition, a scenario was created through the distribution and inflow of connected treated water along with the water temperature conditions. Through scenario analysis, we intend to optimize the operating conditions of linked processing.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.351-354
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• 2006

본 연구에서는 산발효산물과 하수슬러지의 혼합소화를 위한 적정 혼합비를 도출을 위하여 음식물찌꺼기 고온 산발효산물과 하수슬러지의 생분해 특성과 적정혼합비를 도출하고자 수행한 결과 음식물찌꺼기 고온 산발효액과 하수슬러지를 혼합비별로 회분식 혼합소화 실험을 실시 한 결과 혼합비 1:1에서 385ml CH$_4$/g VS$_{added}$로 가장 높은 메탄발생량을 나타내었다. 이러한 결과는 음식물찌꺼기와 하수슬러지를 1:1로 동일하게 혼합하여 비교 소화실험을 실시했을 때 의 293m1 CH$_4$/g VS$_{added}$와 비교하여 상대적으로 높은 메 탄발생량을 나타내었다.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.3
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• pp.83-90
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• 2008

The ultrasonic pre-treatment of sewage sludge (SS) was investigated to increase soluble organic material and to improve anaerobic biodegradability. Ultrasonic disintegration of SS increased the amount of soluble chemical oxygen demand (SCOD), protein and carbohydrate concentrations whereas particle size decreased due to the break-up of cell walls. In terms of anaerobic biodegradability, ultrasonic pre-treatment enhanced the anaerobic biodegradation of SS, leading to the methane gas production improvement. Biochemical methane potential (BMP) of SS was 211.3 ml $CH_4/gVS$ whereas BMP after ultrasonic pre-treatment was 294.3 ml $CH_4/gVS$. The improvement in BMP for SS treated with ultrasonic disintegration was as high as 40 %. This result indicated that disintegration of SS was efficient for enhancing anaerobic biodegradability.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1133-1143
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• 2016

The purpose of this study is to improve project performance analysis indicators for BTL sewer rehabilitation projects. Among the assessment indicators for BTL sewer rehabilitation projects, an infiltration assessment indicator is given a high score of 17.5 points as a single assessment item. This infiltration assessment indicator is assessed focusing on the amount of infiltration, and presently calculated according to 'Nighttime Domestic Flow Evaluation' method. However, this assessment indicator's failure to reflect the geological features of Jeju region is emerging as a problem in the operational stage. Thus, this study intended to compare and analyze the calculation result depending on the assessment indicators and the actual amount of infiltration, centering on Jeju region. To this end, this study analyzed the amount of infiltration in five areas of Jeju Province calculated according to 'Nighttime Domestic Flow Evaluation' method. Also, a complete enumeration survey was carried out about the conditions for actual infiltration occurrence. According to the results of this survey, ground water level is distributed lower than the level of sewer pipes. The results of a sewer pipe function test show there was no infiltration occurrence caused by sewer pipe defect. So, it is concluded that 'Nighttime Domestic Flow Evaluation' method, which is utilized for the current assessment indicator, is not appropriate to apply to Jeju region, and it is thought that there is a need to establish infiltration criteria specialized for Jeju region.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.84-89
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• 2003

The purpose of this study was to evaluate and improve the pre-treatment facility for foodwaste and sewage sludge mixture treatment. The process of foodwaste pre-treatment consists of storage, classification with crushing, and thickening. The effluent of sewage treatment facility was used as the diluting and washing water. The panicle size of foodwaste after pre-treatment was almost under 2mm, the mixture of foodwastes and sewage sludge showed an advantage to the anaerobic digestion. The amount of gas production increased from 0.8ton/day ($CH_4$ : 0.5ton/day) to 3.5ton/day ($CH_4$ : 2.3ton/day) after the anaerobic digestion of the foodwastes and sewage sludge mixture. The amount of sludge cake increased from 11.2ton/day to 21.2ton/day. Therefore, the proper operation of the foodwaste pre-treatment facility was contributed to the efficient anaerobic digestion of foodwaste and sewage sludge mixture treatment.

• Korean Journal of Environment and Ecology
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• v.13 no.3
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• pp.209-219
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• 1999

주암호는 전라남도와 광주광역시에 약 1,180,000톤/일의 생활용수와 공업용수를 공급하는 상수원이다. 상수원수계의 생활하수, 축산폐수, 숙박업소, 식당 등 점오염원과 주거지, 농경지, 산림지역에서 우수와 함께 유출되는 비점오염원으로부터 발생하는 오염부하량으로 이들 상수원의 수질은 점점 악화되어 3급수로 전락할 우려가 높아지고 있다. 이들 상수원의 수질관리에 있어 중요한 인자의 파악과 인자들간 상호작용의 이해를 용이하게 해주는 수계수질관리 부분생태계모형을 제시하였으며 지리정보체계를 응용하여 수계의 점오염원과 비점오염원을 데이터베이스화하는 방법, 오염부하량 산출방법, 점원 및 비점오염원의 공간분석, 상수원 보호구역으로부터 완충구역분석, 위성자료 분석을통한 상수원 수계 토지이용분석과 비점오염원 부하량산출 응용 방법등을 연구하였다 분석결과 주암호수계의 BOD 부하량은 주거지. 생활하수, 축산폐수, 경작지, 식당이 차지하는 비율이 높으며 총질소 부하량은 경작지, 산림, 생활하수, 추간폐수가 높으며 그리고 총인 부하량은 생활하수, 축산폐수, 경작지가 높은 것으로 나타났다. 점오염원인 생활하수, 축산폐수, 식당 뿐만 아니라 비점오염원인 경작지도 수질오염에 상당한 영향을 미치고 있다.

• Environmental engineer
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• s.184
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• pp.64-69
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• 2001

1998년 기준으로 하수처리장에서 발생하는 슬러지는 약 144만톤/년으로 발생량 대부분을 단순매립과 해양투기로 처리하고 있어서, 각종 규제가 강화됨에 따라 처리방안에 대한 대안 마련이 시급한 실정이다. 특히 단순매립 시에는 슬러지 대부분이 유기물로 부패되어 매립지 내에서 악취, 침출수, 해충 등의 2차 환경오염을 야기시키고 있다. 따라서 본 연구개발의 목표는 자가발열 고온호기성 소화(Autothermal Thermophilic Aerobic Digest

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.258-265
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• 2009

To develop environmentally friendly constructed wetlands(CWs) for treating domestic sewage which was produced in farming and fishing village, the efficiency of water treatment at different ventilation systems in the vertical bed, depths of horizontal bed, and sewage loads was investigated. In the vertical bed, BOD and COD by duplex ventilation system were lower than those by single ventilation system. But T-N and T-P concentrations by both ventilation systems in the vertical bed were little different. In the horizontal bed, BOD, COD, T-N and T-P in 1.0 m and 1.3 m depths were little different. To reduce the CWs' area and to improve the pollutant removal efficiencies, the optimum depth of horizontal bed was 1.3 m. In single and duplex ventilation CWs, the removal rate of BOD, COD, SS, T-N and T-P decreased slightly with the sewage load increases. In same sewage load conditions, the removal rates of BOD, COD, SS, T-N and T-P by duplex ventilation CWs were higher than those by single ventilation CWs. In summary, to effectively treat domestic sewage from farming and fishing village, the optimum constructed wetlands would be the duplex ventilation CWs.