• 상하수도학회지
• /
• 제28권1호
• /
• pp.33-45
• /
• 2014

In this study, current sewer infiltration/Inflow(I/I) computation and application method was examined about improvement and adequacy relating to the main issues raised by the field for practitioners. The results of review about infiltration calculation method were considered to be in need of improvement at 'standards of minimum sewage calculation'. Furthermore, the results of review about I/I application method were considered to be in need of improvement at 'standards of seasonal infiltration application' and 'the relative decrease in the Annual evaluation standards'. In addition, annual I/I analysis at JC County for the four years(2009~2012) in respect of operation flow and rainfall data was conducted. The result of annual infiltration analysis, compared average daily sewage generated average infiltration rate was found in 21.95 %, infiltration by unit was found in $0.31m^3/day/cm/km$ and $0.12m^3/day/day$, respectively. The result of annual inflow analysis, average rainfall - Inflow equations was found $y=5.499{\times}$($R^2$ 0.793), and the average Inflow quantity by sewer extension was predicted to $0.66m^3/mm-km$.

• 상하수도학회지
• /
• 제19권2호
• /
• pp.221-227
• /
• 2005

This study has suggested the base data for decision of maintenance ranking and estimation of maintenance effect in the maintenance project of sewers as based on investigation of the defective rate in the sewer through Infiltration/Inflow(I/I) and CCTV analysis. It also analyzed the correlation between I/I and defective rate of sewer. As the result of this study, (1) Defective items of sewer was found out one item each 12.97m with an average. (2) By regression analysis, I/I has high correlation with defective rate of sewer like that $R^2$ is 0.7806. (3) The first thing in the item with bad influence on the I/I was joint badness and secondary was cross connection.

• 상하수도학회지
• /
• 제23권3호
• /
• pp.321-329
• /
• 2009

I/I(Infiltration/Inflow) characteristics should be studied to achieve I/I reduction which is a main object of sewer rehabilitation. However, The scientific and practical studies which are based on actual survey within the country are not thorough going enough. The earlier studies were limited because of a short research period and specific region. Thus, In this study, a formula is deduced by intensive correlation analysis between defective number and I/I volume in sewer pipe. It can be used as preliminary data when the project established for cost-effective pipe rehabilitation. The study shows that the researched region have a faulty point at every 9.3m on average and prove correlation between defective number and I/I volume in sewer pipes. Thus, this study can improve the investigation system and estimate the volume of the pipe rehabilitation, when site investigations for rehabilitation have been conducted.

• 상하수도학회지
• /
• 제25권2호
• /
• pp.213-221
• /
• 2011

The purpose of sewer system is to separate rain water from sewage water. Through this, it is possible to prevent the flood and preserve public water territory. For the past few years, many problems of the sewer system have been solved by the execution of sewer rehabilitation project. However, they still exist in sewer system caused by I/I, which are divided into infiltration and inflow. Infiltration means the rain water and underground water that infiltrate through breakage point on pipes, inflow means the water that flows in through misconnection on pipes. This study shows how the I/I calculation has changed according to the new standardized manual and identifies the I/I difference between the new calculation and the existing one. Through the analysis on the two calculation methods we examined the appropriacy of the new method by comparing it to the old one. The result points out that the new standardized manual is more appropriate than the old in aspect of objectivity and reproducibility(establish standardization), rationality(alteration of inflow unit).

• 상하수도학회지
• /
• 제24권5호
• /
• pp.617-628
• /
• 2010

The operation performance of sewer rehabilitation projects conducted with Build-Transfer- Lease contract in Korea will be evaluated using the index of infiltration and inflow (I/I). Though I/I obtained at the fourth year should be initially evaluated based on the I/I values observed for the previous three years after the completion of sewer construction, the concrete methodology have not been proposed to rely on the so called 'performance evaluation committee'. This study suggests two statistical methodology to evaluate the I/I performance; the confidence interval method and the hypothesis-testing method. Assumed ten I/I values in each year for 20 years are used in this study. Two cases are analyzed and compared; case I to use as control data all I/I values for all years obtained before the evaluation year and case II to use I/I values for only 3 years before the evaluation year. As a result, case II tends to have relatively higher scores than case I, reflecting the low mean I/I values at the initial years.

• 상하수도학회지
• /
• 제33권3호
• /
• pp.177-190
• /
• 2019

The purpose of this study was to analyze the effects of sewerage facilities through I/I analysis by rainfall by selecting areas where storm overflow diverging chamber is remained due to the non-maintenance drainage equipment when the sewerage system was reconstructed as a separate sewer system. Research has shown that wet weather flow(WWF) increased from 106.2% to 154.8% compared to dry weather flow(DWF) in intercepting sewers, and that the WWF increased from 122.4% to 257.6% in comparison to DWF in storm overflow diverging chamber. As a result, owing to storm overflow diverging chamber of partially separate sewer system with untreated tributary of sewage treatment plant, rainfall-derived infiltration/inflow(RDII) has been analyzed 2.7 times higher than the areas without storm overflow diverging chamber. Meanwhile, infiltration quantity of this study area was relatively higher than that of other study areas. Therefore, it is necessary to reduce infiltration quantity through sewer pipe maintenance nearby river. Drainage equipment maintenance should be performed not to operate storm overflow diverging chamber in order to handle the appropriate sewage treatment plant capacity for rainfall because it is also expected that RDII due to rain will occur after maintenance. In conclusion, it is necessary to recognize aRDII(allowance of rainfall-derived infiltration/inflow) and to be reflected it on sewage treatment plant capacity because aRDII can occur even after maintenance to the complete separate sewer system.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회 논문집
• /
• pp.1323-1327
• /
• 2005

도시에서 배출되는 오수나 우수를 모아서 하수처리장 또는 방류수역까지 유하시키는 역할을 하는 관거시설은 하수도 시설의 근간으로서 일반주민의 일상생활과 밀접한 관계가 있기 때문에 시설의 실태를 충분히 파악하여 적절한 유지관리를 시행하지 않으면 안된다. 그러나 지금까지 하수관거에 대한 인식부족으로 인하여 유지관리는 물론 현 실태 또한 제대로 인식 되지 않았다. 따라서 본 연구에서는 인천지역의 승기천 유역을 대상으로 I/I분석 및 예측, 이에 따른 오염 저감 방안을 연구하였다. 본 연구는 승기천 유역 내 주요지점에 대한 관거 I/I 및 하수의 누수량을 조사하기 위하여 고정식 4개 지점(풍림지점, 우성지점, 동막지점, 성주지점)에 대해 하수처리장의 유입수량 및 수질의 영향을 파악하고 해당지역의 관거 문제점을 도출하여 정비방향을 모색하고, 사업시행에 따른 효과분석에 활용하며 성과분석 목표를 수립하기 위한 기초자료를 제공하는데 연구 목적이 있다.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2006년도 학술발표회 논문집
• /
• pp.1410-1414
• /
• 2006

Infiltration and Inflow(I/I) through the old or broken sewer are caused falling efficiency of sewage treatment plants. Recently, to solve these problems maintenance work of sewer pipes is progressing and sewer flow is metered for I/I survey. In this paper, metered sewer data at GyeongGi-Do H city for two years are analyzed by ToSS program. And this paper suggest particle use of sewer flow much data for many years.

• 한국방재학회 논문집
• /
• 제8권6호
• /
• pp.7-14
• /
• 2008

하수관거시스템 개량의 주된 목적은 불명수(Inflow/Infiltration, I/I)를 제거함으로써 그 성능을 향상시키는데 있다. 이때 전체 하수관거시스템 내에서 개개 관거별 I/I 발생량을 정량화할 수 있다면, 전체 하수관거시스템 내에서 소유역별 해당 정보의 추출이 보다 명확해질 수 있다. 그러나 실제 현장에서는 예산 및 시간의 제약 때문에 개개 관거의 I/I 발생 정보의 획득은 거의 불가능하다. 본 연구에서는 하수 관거별 I/I 발생량을 AHP(Analytic Hierarch Process)를 이용하여 정량화하였으며, 산정된 관거별 I/I 발생량을 이용하여 효율적인 하수과거 개량 사업 시행을 위한 개량 우선순위 결정 모형(Rehabiliation Priority Decision Model for sewer system, RPDM)을 개발하였다. 개개 관거별 I/I 발생량 산정 결과에 기반하여 RPDM은 개량이 시행되는 기간 동안 발생하는 I/I 발생량을 최소화하는 소유역별 최적 개량 우선순위(Optimal Rehabilitation Priority, ORP)를 유전자 알고리즘을 이용하여 결정한다. 이때 최적 개량 우선순위에 따른 소유역별 개량 시행 시 발생하는 이익은 개량 기간 동안 하수처리장으로 들어가는 I/I의 하수처리비용(Waste Water Treatment Cost, WWTC)에 대한 절감을 의미한다. 본 연구에서는 개발된 RPDM에 의한 최적 개량 우선순위의 결과는 일반적인 하수관거 개량사업의 우선순위 결정 방법인 점수가중평가법(Numerical Weighting Method, NWM)과 최악의 개량순서에 따른 결과들과 비교되었으며, 개량 기간 동안의 I/I 처리비용이 점수가중평가법에 비하여 22%, 최악의 개량순서에 비하여 40% 감소하는 것으로 나타났다.

• 상하수도학회지
• /
• 제25권1호
• /
• pp.75-84
• /
• 2011

This study was conducted to provide a basic information for the establishment of operation and treatment processes in sewer system of Nakdong river basin to minimize the overall pollutants loading to water body. Sewage flowrates were regularly measured and monitored at various sampling points of newly-built separated sewer system located in G City GA sites. To assess the inflow sewage flowrate, various calculating methods such as water-use evaluation, average-minimum daily flow quality evaluation, minimum daily flow evaluation, night water-use evaluation were used. Average I/Is were calculated except water-use evaluation. Average I/Is were found to be 6.5 $m^{3}/d$, 3.5 $m^{3}/d$, 7.7 $m^{3}/d$ at GA-1, GA-2, GA-3 points respectively. I/I ratios of three areas were found to be 4.8 %, 2.0 % and 2.7 % respectively and were obviously lower than those of the other separated sewer systems as shown in the previous studies.