• Title, Summary, Keyword: first-flush

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Characteristics of Non-point Pollutants from the Road Runoff (1): Water Quality (도로노면 유출수의 비점오염원 배출 특성(1): 기본 수질 항목)

  • Park, Sangwoo;Oh, Jeill;Choi, Younghwa;Seo, Jeongwoo
    • Journal of Korean Society of Water and Wastewater
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    • v.21 no.2
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    • pp.225-233
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    • 2007
  • Road runoff water is one of the non-point sources (NPSs) of pollution negatively influencing drinking water source. Numerous road runoff NPS waters have been studied for over the last decade. However, the sources of pollution can be conditional, seasonal, or accidental. Therefore, measurement of pollutant loadings in different site is necessary to estimate the effect of road runoff water. The objective of this study was to examine the quality of road runoff water from a city bridge in Seoul, Korea. This study was conducted for two years to assess annual discharge pollution loads. In this study, key water quality parameters including chemical oxygen demand ($COD_{Cr}$), biochemcial oxygen demand ($BOD_5$), total nitrogen (T-N), total phosphorus (T-P), and suspended solid (SS) were measured at 18 different events. The results showed that typically the pollutant concentrations are higher at the beginning of each event and decrease afterwards. The first 20% of the volume of the runoff from each event is transporting 46% ($COD_{Cr}$), 48% ($BOD_5$), 50% (T-N), 34% (T-P), 30% (SS), respectively. The event mean concentrations (EMCs) were $COD_{Cr}$ (199 mg/L), $BOD_5$ (41.2 mg/L), T-N (7.97 mg/L), T-P (0.42 mg/L) and SS (113 mg/L). Although the results were consistent with the previous study (Barbosa and Hvitved-Jacobsen, 1999), $COD_{Cr}$, $BOD_5$, T-N exhibit a stronger first flush effect compared to the other contaminants.

Characteristics of Non-point Source Runoff in Housing and Industrial Area during Rainfall (강우시 주택 및 공단지역의 비점오염원 유출특성)

  • Kim, Kang Suk;Park, Jong Seok;Hong, Hyeon Seung;Rhee, Kyoung Hoon
    • Journal of Wetlands Research
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    • v.14 no.4
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    • pp.581-589
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    • 2012
  • Non-point source pollutant is exerting a serious influence on the water quality, since the characteristics of stormwater runoff is varied by the land usage pattern of an area and a basin, and all sorts of pollutants on the earth in rainfall flow into the urban stream. This study estimated EMC of each pollutant to investigate the characteristics of stormwater runoff by separating the urban area as the housing area and industrial area. As a result of the analysis, the first flush effect occurred in the non-point source pollutant of housing area and industrial area, as the runoff concentration gradually reduces after it rapidly increases in the initial rainfall, and in case of the non-point source pollutant the control of first stage rain-water. It is considered to require the continuous follow-up study such as the scale of long-term rainfall event and water quality data, land usage pattern by GIS method, database of topography and geological features, and so forth.

DJFS: Providing Highly Reliable and High-Performance File System with Small-Sized NVRAM

  • Kim, Junghoon;Lee, Minho;Song, Yongju;Eom, Young Ik
    • ETRI Journal
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    • v.39 no.6
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    • pp.820-831
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    • 2017
  • File systems and applications try to implement their own update protocols to guarantee data consistency, which is one of the most crucial aspects of computing systems. However, we found that the storage devices are substantially under-utilized when preserving data consistency because they generate massive storage write traffic with many disk cache flush operations and force-unit-access (FUA) commands. In this paper, we present DJFS (Delta-Journaling File System) that provides both a high level of performance and data consistency for different applications. We made three technical contributions to achieve our goal. First, to remove all storage accesses with disk cache flush operations and FUA commands, DJFS uses small-sized NVRAM for a file system journal. Second, to reduce the access latency and space requirements of NVRAM, DJFS attempts to journal compress the differences in the modified blocks. Finally, to relieve explicit checkpointing overhead, DJFS aggressively reflects the checkpoint transactions to file system area in the unit of the specified region. Our evaluation on TPC-C SQLite benchmark shows that, using our novel optimization schemes, DJFS outperforms Ext4 by up to 64.2 times with only 128 MB of NVRAM.

Two Cases Reports of Behcet's Disease with Arthritis Treated with Oriental Medical Treatment Including Cheongsimyeonja-tang and Cheonglijagam-tang on each (청심련자탕(淸心蓮子湯)과 청리자감탕(淸離滋坎湯)을 투여한 관절염 동반 베체트병 환자 2례에 대한 한방치료 증례보고)

  • Lim, Tae Hyung;Park, Hye Sun
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.28 no.6
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    • pp.643-649
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    • 2014
  • This study was designed to report treatment for Behcet's disease with arthritis We treated 2 Behcet's disease patients with arthritis. A 46-year-old female patient was treated with Cheongsimyeonja-tang. Another case, 44-year-old female patient was diagnosed as Sjogren's disease at first and diagnosed as The Behcet's diseases about 1 year later, treated with Cheonglijagam-tang. The progress was evaluated with the visual analogue scale for joint pain and hot flush, and length of sleeping time. There was improvement in the symptoms of visual analogue scale for joint pain and hot flush, also length of sleeping time. Cheongsimyeonja-tang, Cheonglijagam-tang can be considered as a treatment for patient diagnosed as Behcet's disease suffering from arthritis, especially.

Analysis of Suspended Solid Generation with Rainfall-Runoff Events in a Small Forest Watershed (산림 소유역에서 강우-유출에 따른 부유토사 발생 특성 분석)

  • Kim, Jae-Hoon;Choi, Hyung-Tae;Lim, Hong-Geun
    • Journal of Environmental Science International
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    • v.24 no.12
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    • pp.1617-1627
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    • 2015
  • This study was carried out to investigate the characteristics of suspended solid concentration in small forest watershed, Hwacheon, Gangwondo. For five rainfall events from July 2013 to August 2013, rainfall, discharge, and suspended solid load has been measured. The results showed that the fist flush effect was observed for suspended solid in each rainfall event, sediment rating curve was obtained with $y=30.029x^{1.573}$ at rising limb and $y=12.902x^{1.8827}$ at falling limb, and EMC (event mean concentration) of suspended solid was calculated to 9.4 mg/L. EMC was compared to the values from the watershed that has various land use types and EMC from forest watershed was much lower that from the crop, paddy or low covered forest watershed.

Characteristics and Control of Nonpoint Pollutants in Railway Station (철로 역사에서 발생 가능한 비점오염물질의 특성 및 관리방안)

  • Oa Seong Wook;Kim Lee-Hyung
    • Proceedings of the KSR Conference
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    • pp.1695-1700
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    • 2004
  • Nonpoint pollutants were monitored on railway station land use. Lots of pollutant mass were washed-off in a first hour. The 95$\%$ confidence interval of pollutant concentrations ranges from 61.6 to 115.4 mg/L for TSS(mean= 88.50 mg/L). 103.8$\∼$244.1 mg/L for COD(mean= 174 mg/L) and 7.68$\∼$17.32 mg/L for Oil & Grease(mean= 12.5 mg/L). The various metals were also washed-off during storm runoff from railway station. The ranges of 95$\%$ confidence intervals were 39.2$\∼$84.0 ug/L for total Cu(mean= 61.6 ug/L), 14.0 $\∼$ 25.8 ug/L for total Pb(mean= 19.9 ug/L) and 182.2 $\∼$ 376.1 ug/L for total Zn(mean= 279.2 ug/L). As a result of this research, we concluded that up to 50$\%$ of the total pollutant mass can be removed when first 30$\%$ of the total flow are treating, and it can be a first flush criteria for best management practices.

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Characterization of Runoff Properties of Non-point Pollutant at a Small Rural Area considering Landuse Types (토지이용 특성을 고려한 소규모 농촌유역의 비점오염물질 유출특성 해석)

  • Bae, Sang-ho;Kim, Weon-jae;Yoon, Young H.;Lim, Hyun-man;Kim, Eun-ju;Park, Jae-roh
    • Journal of Korean Society on Water Environment
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    • v.26 no.4
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    • pp.654-663
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    • 2010
  • Attention has increasingly focused on the pollutant load discharged from rural area since the enforcement of total maximum daily loads (TMDLs) in korea. As one of the methods to control the inflow of pollutant load during wet weather events, local governments are attempting to apply non-point source control facility. To design those facilities appropriately, it is essential to understand the runoff characteristics of pollutants such as TSS, $BOD_5$, $COD_{Cr}$, TP and TN. In the paper, the quantitative analyses for pollutant runoff characteristics were examined in a small rural watershed with the area of about 53 hectares. For a dry weather day and wet weather events, variation patterns of dry weather flow and runoff characteristics of wet weather flows were monitored and investigated. The runoff model using XP-SWMM reflecting the landuse types of the watershed in detail was simulated to perform the sensitivity analyses for several factors influencing on their hydrograph and pollutographs. As a result, for the case of medium and small rainfall events (i. e. total rainfall of 35.8 and 17.5 mm), the impervious area including green house, roof and road which covers relatively low portion of total area (i. e. 16%) caused substantial first flush and the majority of total runoff load. Therefore, it has been concluded that the runoff characteristics of each pollutant and distribution of impervious area should be considered for the establishment of the control strategy of non-point pollutant runoff at a rural area.

Runoff Characteristics of Heavy Metals from a Parking Lot by Rainfall (주차장 지역의 강우에 의한 Pb와 Zn의 유출 특성)

  • Im, Jong-Kwon;Son, Hyun-Seok;Kim, Sung-Keun;Zoh, Kyung-Duk
    • Journal of Korean Society on Water Environment
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    • v.26 no.6
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    • pp.926-933
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    • 2010
  • Runoff from a parking lot can be highly contaminated nonpoint source due to the impermeability of rainwater. This study presented runoff characteristics of heavy metals especially Zn and Pb from a parking lot during total 17 rain events. Monitoring results showed the first flush phenomenon within 30 min was observed in all rain events, but the event mean concentration (EMC) did not clearly show the characteristics of runoff. The ranges of Pb and Zn was $4{\sim}201{\mu}g/L$ and $131{\sim}672{\mu}g/L$, respectively, and the runoff mass of Zn and Pb was highly to related with the flow rate, and runoff coefficient of rain. The runoff mass of Zn was greater than that of Pb in all events. The runoff mass of Pb was highly correlated with the amount of TSS, and TSS and DOC were was related with the mass of Zn. This result implies that Pb and Zn are mainly existed in the particulate form. The results can be used to as meaningful data in the management of nonpoint source, and in the management in the runoff catchment in the parking lot.

Effect for CSOs Storage Construction - Analysis of Storm Water Run-off Characteristics in combined sewer system (합류식 하수관거 월류수 저장 시설에 대한 효과 - 강우시 합류식 하수관거에서의 오염물질 유출특성 분석)

  • Park, Jin-Kyu;Lee, Nam-Hoon;Kim, Hae-Ryong;Lee, Woong;Lee, Chae-Young
    • Journal of Korean Society of Water and Wastewater
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    • v.25 no.6
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    • pp.949-957
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    • 2011
  • This aim of study was to investigate the characteristics of discharge of pollutants as well as the correlation between flow rate and water quality constituents in a combined sewer system according to the characteristics of rainfall. For the loading rates for each pollutant, the median concentrations of all pollutants except T-N was increased when a CSO took place. The loading rates of BOD, COD, SS, T-N, T-P, Cu and Zn at the CSOs were 328-1255, 25-129, 83-2009, 4-12, 14-51, 5-11 and 5-13 times higher than the DWF (Dry Whether Flow), respectively. Especially, SS loading rate was found to be highest in all pollutants. On the other hand, the range of the first flush coefficient, b for water quality constituents such as BOD, COD, SS, T-N, T-P, Cu and Zn were 0.537-0.878, 0.589-0.888, 0.516-1.062, 0.852-1.031, 0.649-0.954, 0.975-1.015 and 0.900-1.114, respectively. In term of correlation between flow rate and pollutant concentrations, SS concentration was highly correlated to flow rate. However, there was an inverse correlation between EC (Electrical Conductivity) and flow rate because of the high dilution of flow rate. In case of correlation between pollutants, there was a high correlation between SS and T-P.

Characteristics of Non-Point Pollution from Road Surface Runoff

  • Lee, Chun-Sik;Jang, Seong-Ho
    • Journal of Environmental Science International
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    • v.19 no.6
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    • pp.665-670
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    • 2010
  • Pollutants from urban pavement consists various kinds of substances which are originated from dry deposition, a grind out tire, corrosive action of rain to pavement and facilities and raw materials of the road etc.. These are major pollutants of urban NPS (Non-point source) during rainfall period. However there is not enough information to control such pollutants for appropriate management of natural water quality. In this study of transportation areas, three monitoring stations were set up at trunk road, urban highway and national road in Gyeongnam province. Runoff flow rate was measured at every 15minutes by automatic flow meters installed at the end of storm sewer pipe within the road catchment area for water quality analysis. Data was collected every 15 minutes for initial two hours of rainfall. Additional samples were collected 1-4 hours interval till the end of rainfall. The monitoring parameters were $COD_{Mn}$, SS, T-N & T-P and heavy metals. The average EMCs of TSS and $COD_{Mn}$ were 62.0 mg/L and 24.2 mg/L on the city trunk road, which were higher than those of urban highway and national road, indicating higher pollutant loads due to activities in the city downtown area beside the vehicle. On the other hand, the average EMC of T-N and T-P were in the range of 2.67-3.23 mg/L and 0.19-3.21 mg/L for all the sampling sites. Heavy metals from the roads were mainly Fe, Zn, Cu and Mn, showing variable EMCs by the type of road. From the TSS wash-off analysis in terms of FF(first flush) index, first flush phenomenon was clearly observed in the trunk road(FF : 0.89-1.43). However, such mass delivery behavior was not apparently shown in urban highway(FF : 0.90-1.11) and national road(FF : 0.81-1.41).