When domestic sewage and rainwater runoff are discharged into a single sewer pipe, it is called a “combined sewer system.” The sewage design standards in Korea specify the flow velocity based only on the volume of rainfall; therefore, sedimentation occurs on non-rainy days owing to the reduced flow rate and velocity. This sedimentation reduces the discharge capacity, causes unpleasant odors, and exacerbates the problem of combined sewer overflow concentration. To address this problem, the amount of sewage on non-rainy days, not just the volume of rainfall, should also be considered. There are various theories on sedimentation in sewer movement. This study introduces a self-cleansing velocity based on tractive force theory. By applying a self-cleansing velocity equivalent to the critical shear stress of a sand particle, sedimentation can be reduced on non-rainy days. The amount of sewage changes according to the water use pattern of citizens. The design hourly maximum wastewater flow was considered as a representative value, and the velocity of this flow should be more than the self-cleansing velocity. This design method requires a steeper gradient than existing design criteria. Therefore, the existing sewer pipelines need to be improved and repaired accordingly. In this study, five types of improvement and repair methods that can maximize the use of existing pipelines and minimize the depth of excavation are proposed. The key technologies utilized are trenchless sewer rehabilitation and complex cross-section pipes. Trenchless sewer rehabilitation is a popular sewage repair method. However, it is complex because the cross-section pipes do not have a universal design and require continuous research and development. In an old metropolis with a combined sewer system, it is difficult to carry out excavation work; hence, the methods presented in this study may be useful in the future.

This study is to improve the efficiency of BTL (Build Transfer Lease) project operation by comparing the infiltration rate based on the data of 5 years of infiltration of the separate sewer system and combined sewer system. In the survey site, the separate sewer system area consists of eight flowmeters in seven treatment basins, and the combined sewer system area consists of eight flowmeters in five treatment basins. The infillration rate was analyzed by night-time domestic flow evaluation method, and the average infiltration rates of the separate sewer system and combined sewer system were 13% and 16%, respectively. Combined sewer system was about 1.3 times higher than the separate sewer system. The average BOD of separate sewer system was 233 mg/L, which was about 2.4 times higher than the combined sewer system was 107 mg/L. In the comparison of the average pipe diameter-length infiltration of separate sewer system and combined sewer system, the separate sewer system and the combined sewer system were about 0.150 m3/d/mm/km and about 0.109 m3/d/mm/km, respectively. The floating population in mixed residential and commercial areas has been identified as the cause. Therefore, we propose a method to calculate the infiltration rate in consideration of the margin ratio in the area where the night active population is concentrated.

2013년 강우시 발생하는 월류수에 대한 수질배출기준이 추가됨에 따라, 효과적인 월류수의 처리공정 개발이 필요한 실정이다. 하수처리공정에서의 활성슬러지 군집(Floc)은 흡착제로써의 역할을 수행할 수 있는 물리화학적 구조를 띄고 있어, 월류수 중 오염물질을 흡착에 의해 제거할 수 있을 것으로 판단된다. 따라서, 본 연구에서는 활성슬러지의 생물흡착을 이용한 월류수 처리공정의 가능성을 평가하고자 하였다. 활성슬러지의 생물흡착성능을 평가하기 위하여, MBR공정에서의 활성슬러지를 활용하여 농도 및 흡착시간 등의 조건을 변경하여 효율평가를 진행하였다. 적정 조건에서 CODCr 및 CODMn 등의 유기물이 약 60% 이상 제거되었으며, 이를 통해 생물흡착에 의한 월류수 처리의 가능성을 확인하였다.

It follows in quality and sewage exclusion method of the investigation objective sector and the Combined Sewer Overflows which is suitable in regional characteristics and the confluence area against the rainfall initially a flow and the medulla and measurement - it analyzes the initial rainfall outflow possibility control plan which is suitable in the domestic actual condition and it proposes the monitor ring plan for the long-term flow and pollution load data accumulation. From the research which it sees the Infiltration water/Influent water and CSOs investigation it passes by the phase of hazard chain and Namwon right time 4 it does not hold reverse under selecting, Measurement it used the hazard automatic flow joint seal Sigma 910 machine and in case 15 minute interval of the I/I, it measured a flow at case 5, 15 minute standing of the CSOs. The water quality investigation for the water leakage investigation of the I/I and the sewage from the point which is identical with flow measurement during on-the-spot inspection duration against 6 items which include the BOD sampling and an analysis, when the rainfall analysis for CSOs fundamental investigation analyzed against 18 items which include the BOD sampling. Consequently, for the optimum interpretation invasion water / inflow water of the this investigation area day average․the lowest flow - water quality assessment veterinarian optimum interpretation hazard average per day - lowest flow - it averages a medulla evaluation law department one lowest flow evaluation technique and it selects, it presentation collectively from here it gets, position result with base flow analysis of invasion water / inflow water.

기상 이변과 해수 온도 상승으로 인한 국지성 집중 호우 및 돌발홍수, 대형급 태풍 빈발 등에 대비하기 위하여 홍수예보와 방재 대책에 가장 기본이 되는 각 유역 특성별 수문 기초자료의 축적 및 분석이 더욱 필요하게 되었다. 특히 홍수시 큰 피해를 가져오는 도시지역의 수문 모니터링이 부족한 실정을 고려한다면 도시하천별, 소배수구역별 수문 관측 및 제공이 필요하다. "도시홍수재해관리기술연구사업단"에서는 도시하천 유역의 수문현상 규명을 위한 기초정보 축적을 위

합류식 관거 내 고형물의 퇴적으로 인해 통수능이 감소하여 여름철 장마시 국지적인 침수가 발생하며 이로 인해 관거 내 퇴적을 더욱 초래할 수가 있다. 이와 같은 문제를 해결하고 관거의 적절한 유지관리를 위해서는 배수유역에서의 하수 및 지표면으로부터의 고형물 부하량을 산정할 필요가 있으나 많은 비용과 노력이 수반되어야 한다. 따라서 본 연구에서는 미국환경보호청에서 제시한 건조기의 합류관거 내 고형물 퇴적 부하량 산정기법과 지표면에서의 고형물 부하량 산정기법

건조기 때의 합류식 관거 내 고형물의 퇴적으로 인해 통수능이 감소하여 여름철 장마시 국지적인 침수가 발생하며 이로 인해 관거 내 퇴적을 더욱 초래할 수가 있다. 또한 관거 시스템에 퇴적된 고형물로 인해 우기시 'first-flush' 현상을 초래하기도 한다. 이와 같은 문제를 해결하기 위해서는 장기간에 걸친 관거 내 고형물 퇴적량을 관측할 필요가 있으나 많은 비용과 노력이 수반되어야 한다. 따라서 본 연구에서는 미국환경보호청에서 개발한 건조기의 합류관거