• Environmental Engineering Research
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• 제15권4호
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• pp.215-223
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• 2010

This study attempted to develop and suggest a more appropriate method for the determination of event mean concentration (EMC) and pollutant removal efficiency of a stormwater best management practice (BMP) considering rainfall. The stormwater runoff and hydrologic data gathered from 22 storm events during a 28-month monitoring period on a swirl and filtration type of BMP were used to evaluate the developed methods. Based on the findings, the modified EMC method resulted in lower (average) values than the overall EMC, although the differences were not significant (P>0.05). By comparison, the developed 'Rainfall Occurrence Ratio' (ROR) method was most significantly correlated (r=0.967 to 988, P<0.009) with the other existing removal efficiency determination methods such as the 'Efficiency Ratio' (ER), 'Summation of Loads' (SOL) and 'Regression of Loads' (ROL) methods. In addition, the ROR method gave the highest efficiency values, with no significant differences with any of the pollutant parameters, unlike the other three methods. These results were obtained because the ROR method integrated both pollutant loading and rainfall, which are not considered by the other three methods. Therefore, this study proved the suitability of the modified EMC and ROR methods for application in other BMP monitoring studies.

• 한국환경과학회지
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• 제14권11호
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• pp.1057-1062
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• 2005

The present study investigated runoff characteristics of non-point pollutants and discharge load amount according to the land utilization in Yeinam river basin. The land utilization of target basin was divided into paddy field, dry field, forest, residential area and composition area. The study on the runoff characteristics of non-point pollutants by rainfall-runoff process showed that COD, SS and T-P had the first-flushing effect with relatively high concentration in early-stage of the rainfall-runoff process, but the T-P revealed similar runoff characteristics. Event Mean Concentration(EMC) of BOD and COD according to the land utilization revealed the range of $3.11\~15.50mg/L$ and $3.37\~33.42mg/L$, and the highest concentration of EMC corresponding to BOD and COD was detected in the paddy field. The EMC of SS showed $1.7\~305.02mg/L$ and it's highest concentration was found in the dry field. The EMC of T-N and T-P represented the highest concentration in the paddy field and dry field with range of $0.91\~8.76mg/L$ and $0.02\~0.44mg/L$.

• 한국물환경학회지
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• 제24권2호
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• pp.169-173
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• 2008

A field monitoring was conducted in order to find out the discharge characteristics of non-point source pollutants in the agricultural area. Event Mean Concentration (EMC) of TSS, $BOD_5$, $COD_{Mn}$, TP, TN was calculated based on the monitoring data of 10 rainfall events at agricultural watersheds. A significant relationship was observed from the correlation between EMCs and rainfall characteristics. The result shows that EMC ranges of 95% confidence intervals were 50.5~203 mg/L for TSS, 0.8~14.2 mg/L for $BOD_5$, 4.2~20.7 mg/L for $COD_{Mn}$, 2.4~4.5 mg/L for TN and 0.2~0.5 mg/L for TP, respectively. The correlation coefficients between TSS and TP and between $BOD_5$ and $COD_{Mn}$ were found to be 0.912 and 0.961. But TN was lower correlated with other EMC factors. It was also found that rainfall characteristics was not correlated with EMCs.

• 한국물환경학회지
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• 제22권2호
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• pp.294-299
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• 2006

The Ministry of Environment in Korea has introduced Total Pollution Load Management System (TPLMS) in major 4 large rivers to protect the water quality from possible pollutants. In order to successfully achieve the TPLMS, the nonpoint source should be controled by applying the best management practices in highly polluted areas. Of the various nonpoint sources, the highways are stormwater intensive landuses because of its high imperviousness and high pollutant mass emissions. The EMC (Event Mean Concentration) is an important parameter to correctly determine the pollutant mass loadings from nonpoint sources. However, it has wide ranges because of various reasons such as first flush phenomenon, rainfall and watershed characteristics. Even though the EMC is closely related to the first flush phenomenon, the relationship have not proven until present. Therefore, in this paper, the dynamic EMC method will be introduced to clearly make the relationship between EMC and first flush phenomenon. Also by applying the dynamic EMC method to monitored data, we found that the highly concentrated stormwater runoff was washed off within 20~50 minutes storm duration. The first flush criteria for economical treatment was also determined to 5~10 mm (mean=7.4 mm) as a cumulative rainfall.

• 상하수도학회지
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• 제20권4호
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• pp.627-635
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• 2006

Combined sewer overflow (CSOs) is a primary diffuse source degrading water quality of urban streams. In this study, CSOs caused by 5 different rainfall events at an urban watershed located in Daejeon city were monitored for the indicator microorganism concentrations. Event mean concentration (EMC) of the indicator microorganisms were: total coliform = $2.46{\times}10^6CFU/100mL$; fecal coliform = $1.01{\times}10^6CFU/100mL$; E.coli = $5.20{\times}10^5CFU/100mL$; and Fecal Streptococci = $6.08{\times}10^5CFU/100mL$. In addition, coliform concentrations were well correlated with suspended solid concentrations and the first flush effects were identified. Settling tests were carried out to estimate removal rate of indicator organisms by sedimentation from CSOs. As microorganisms are discharged in association with suspended solid, ten minutes of settlement can lower 44% of indicator microorganism leading.

• 생태와환경
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• 제44권2호
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• pp.178-186
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• 2011

본 연구는 강우 시 농촌지역에서 강우유출수와 함께 하천으로 유입되는 비점오염물질의 유출특성을 파악하기 위해 수행되었다. 유량의 증감에 따른 수질항목의 상관관계는 SS, T-P, $COD_{Mn}$, BOD, TN의 순으로 상관성이 높은 것으로 나타났고, 강우량, 강우강도, 선행무강우일수에 따라 다양한 유출 특성을 보였다. 분석된 결과를 바탕으로 EMC와 SMC를 산정한 결과 SS, T-P는 강우사상에 따라 높은 EMC 농도변화를 보였고 산술평균농도와 EMC를 비교하였는데 대체적으로 EMC가 더 높은 것으로 나타나 유량의 증감에 영향이 있는 것으로 나타났으나 T-N의 경우 영향이 없는 것으로 보였다. 또, 초기유출 특성을 살펴보면 강우 후반부의 강한 강우강도로 인해 초기세척 개념을 적용시키기 어려운 3차 이벤트와 강우량이 적고 강우강도도 약했던 5차 이벤트를 제외한 다른 이벤트에서 초기세척효과가 관찰되었고 SS > T-P > BOD > $COD_{Mn}$ > T-N 순으로 뚜렷하게 나타났다. 그리고 초기세척비율 계산 결과, 초기 유출수의 30%에 가장 많은 오염부하가 발생하고 대부분 입자형태 즉, SS, T-P의 유출이 뚜렷하므로 저류지를 통해 초기 강우유출수의 비점오염물질을 제거하는 것이 바람직하다고 판단된다. 본 연구를 통해 분석된 결과를 바탕으로 비점오염물질의 유출특성에 대한 다양한 데이터베이스를 구축하여 향후 비점오염원을 체계적으로 관리함으로써 하천 수질을 개선하려는 노력이 필요할 것으로 사료된다.

• 생태와환경
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• 제38권spc호
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• pp.67-75
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• 2005

The objectives of this study were to understand the runoff characteristics of the non-point sources originating from impervious surfaces and to assess their effect on the aquatic environment in the urban areas. The concentration of pollutants (SS, BOD, COD and T-P) except for T-N showed the highest value in runoff from road, and event mean concentration (EMC) also showed high value from road. The pollutants discharged from road showed a higher concentration in the beginning stage (0 ${\sim}$ 30%) of progressive percentage of rainfall. The contribution percentages of non-point sources by load were 44.9% for SS, 11.2% for BOD, 21.4% for COD, 11.4% for T-N and 8.1% for T-P in the total load of pollutant discharged through sewer. From our results, the road was a significant potential source that deteriorated water quality of the streams and lakes in the vicinity of the urban area during the rain period. Therefore, counter plan is required to reduce pollutant concentration on the road from non-point sources in the urban area. Also, since pollutant concentration in the beginning stage of rainfall was quite high, road cleaning seems to be one of the very useful methods to prevent inflowing of pollutants to the aquatic environment.

• 환경영향평가
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• 제23권4호
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• pp.285-295
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• 2014

본 연구는 논으로부터 배출되는 오염물질항목별(COD, TOC, T-N, T-P, SS) 농도 분포에 적합한 확률분포모형을 분석하고 실측 평균 EMC와 확률분포 모형을 통해 추정된 중앙값 EMC(EMC50)값과 비교하였다. 이를 위해 2008년부터 2011년까지 전라남도 함평군에 위치한 논에서 모니터링을 수행하였다. 그 결과 COD는 3가지 확률분포모형(Normal, Log-Normal, Gamma), T-N은 4가지 확률분포모형(Normal, Log-Normal, Gamma, Weibull), T-P와 TOC는 3가 지 확 률 분 포 모 형 (Log-Normal, Gamma, Weibull), SS는 2가지 확률분포모형 (Log-Normal, Gamma)에서 적합한 것으로 나타났다. 특히, Log-Normal과 Gamma 확률분포모형은 모든 수질항목에 적합한 확률분포모형인 것으로 나타났다. 한편, 강우시 논 유출수의 수질항목별 평균값과 확률분포모형을 통해 추정된 EMC 중앙값과 비교한 결과 COD는 Gamma, TOC, T-N, T-P, SS는 Log-Normal 확률분포모형의 값과 비슷하게 나타났다.

• Environmental Engineering Research
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• 제13권4호
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• pp.184-191
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• 2008

Long term monitoring was conducted to investigate a surface runoff of pollution from urban highway. The monitoring data was collected for 18 rainfall events and was used to correlate pollution load to various parameters, such as rainfall intensity, antecedent dry days and total discharge flow. Runoff coefficient and seasonal variation were also evaluated. The mean runoff coefficient of the highway was 0.823(range; $0.4687{\sim}0.9884$), and wash-off ratio for $COD_{Mn}$ and SS loads was 72.6% and 64.3%, respectively. For the initial rainfall event, the runoff EMC of $COD_{Mn}$ was high in summer and the EMC of SS was high in autumn season. However the seasonal variation of T-N and T-P was not significant. The discharged $COD_{Mn}$-EMC was $147.6\;mg/L{\sim}9.0\;mg/L$ on the generated $COD_{Mn}$-EMC of $98.8\;mg/L{\sim}8.9\;mg/L$. While the generated EMC of SS was in $285.7\;mg/L{\sim}20.0\;mg/L$ and its discharged EMC was in $190.4\;mg/L{\sim}8.0\;mg/L$. EMC of pollutants was not directly related to the first flush rainfall intensity and the antecedent dry days. But the correlation was relatively high between EMC and cumulative runoff flow volume. The trend of EMC was reduced with the cumulative runoff flow volume.

• 한국물환경학회지
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• 제22권4호
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• pp.605-613
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• 2006

Discharge characteristics of non-point source pollutant and load amount of the discharge in the urban area were investigated in the Pungyeongjeong-stream basin and the Yongbong-stream basin in this present study. The land use of the studied basins were divided into paddy field, industrial complex area, combined sewage system, separate sewer system and point sources discharge. The descriptive statistics on the event mean concentrations (EMCs) of non-point pollutants by the the land use showed in the range of 4.43-32.28 mg/L for BOD and 8.27~56.17 mg/L for COD. The highest concentration was shown from the combined sewage system. The EMC of SS at the paddy field in the Pungyeongjeong-stream basin showed the highest range with the values ~ from 35.76 to 358.86 mg/L, which might have been influenced by a levee construction in the adjacent of the area. The relatively high concentration values of 4.43~32.28 mg/L and 1.617.13 mg/L emerged from TN and TP,respectively, at the discharge points of the both stream basins.