• Title, Summary, Keyword: first-flush

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Evaluation of sound insulation performance according to aperture conditions under the flush door (세대내 플러시 도어의 하부틈새 조건에 따른 차음성능 평가)

  • An, Ji-Hyeong;Kim, Myung-Jun;Lee, Min-Joo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.153-158
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    • 2007
  • Sound insulation performance of the flush door in the apartment unit was recently decreased due to the door for the purpose of barrier free. To evaluate sound insulation, the test for 13 kinds of flush doors was performed as aperture conditions under the flush door. and the measured value was compared with the predicted values of theoretical sound transmission. The results were summarized follow; First, in case of doors with aperture by barrier free, the single number quantities ($D_{pw}$) were evaluated $21{\sim}23dB$. Whereas, in case of existing door with frame, $D_{pw}$ was evaluated $28{\sim}31dB$. And in case of sealed doors, $D_{pw}$ was evaluated $31{\sim}34dB$. Second, the measured $D_{pw}$ was good agreement with the predicted $D_{pw}$ in condition of small aperture.

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Effect of Balloonflower and Potato Cultivation on Runoff and NPS Pollution Loads (도라지와 감자 재배가 유출과 비점오염부하에 미치는 영향)

  • Shin, Jae Young;Shin, Min Hwan;Choi, Yong Hoon;Kang, Hyun Woo;Won, Chul Hee;Hwang, Moon Young;Yang, Hee Jung;Lim, Kyoung Jae;Choi, Joong Dae
    • Journal of The Korean Society of Agricultural Engineers
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    • v.54 no.6
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    • pp.89-99
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    • 2012
  • An upland monitoring was conducted for about 4 years with respect to the water and quality of rainfall-runoff. The objective was to characterize of runoff and nonpoint source (NPS) pollution from a sandy field with 4.5 % in slope under balloonflower (2008-2010) and potato (2011) cultivation. Balloonflower was cultivated without any surface cover but potato was grown under plastic mulching. Runoff rate, EMCs and NPS pollution loads were estimated. The first flush effect was evaluated, and the correlation coefficient among the selected water quality indices were analyzed. Average rainfall size was higher by 2.3 mm when balloonflower was cultivated but average runoff rate was higher by 0.02 when potato was cultivated due to the plastic mulching. EMCs monitored from balloonflower field were higher than potato field except SS and TN, but all NPS pollution loads of potato field were 2.1~22.9 times greater than balloonflower field because of larger runoff volume. As a result of first flush effects, balloonflower and potato field were more influenced by increasing of accumulated rainfall and rainfall intensity rather than first flush. In the result of correlation analysis, there were no evident correlations between runoff and water quality indices. However, there were obvious correlations between SS and the other indices except TN. As a result of this study, it was thought that perennial balloonflower crop could help reduce runoff and NPS pollution loads but annual crop with plastic mulching increase them.

Pollutants Characteristics of Surface Runoff from the Industrial Complex (산업공단에서의 지표유출수 오염물질 특성)

  • Kim, Youn-Kwon;Shin, Eung-Bai;Lee, Doo-Jin;Pae, Yo-sop;Yoon, Hyun-Sik
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.4
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    • pp.689-698
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    • 2000
  • The quality of stormwater runoff has been a major concern in water quality preservation. Characteristics of heavy metals and conventional pollutants in surface runoff from industrial complex, during the first flush, were not completely understood, Generally, separated sewer system is known for their water quality with untreated wastewater during storm events. In this study, the quality and characteristics of surface runoff from the industrial complex were investigated. The target area in the industrial complex catchment was divided 4 sub-areas, and the quality of stormwater runoff from the selected drainage areas was investigated using a grab sampling method. The petro-chemical industry and the junkyard discharged relatively high concentration of conventional pollutants, such as BOD, COD, SS, and TN through the first flush runoff samples. On the other hand, a higher level of heavy metals was found in the first flush runoff from the metal-mechanical industry and the scrap storage yard. For metals, Fe, Zn and Cu were the most prevalent species found in the first flush runoff from all sites for every surface runoff samples, while Pb, As, Cd, Cr and Ni were the least prevalent species and Hg was not found in any sample at any site. These results suggest that the nature of pollutants in surface runoff from the industrial complex was related to the type of industry, and the concentration of pollutants was determinated by the degree of exposed pollutant sources and the characteristic of rainfall events at the sites.

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Analysis of Storm Water Run-off Characteristics to Evaluate the Intercepted Volume of CSOs during Wet Weather (강우시 합류식 하수관거의 월류수 차집용량 산정을 위한 유출특성 분석)

  • Choi, Sung-Hyun;Choi, Seung-Chol;Kim, Byoung-Ug;Rim, Jay-Myoung
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.3
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    • pp.320-330
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    • 2004
  • Most of domestic city is served combined sewer system among various sewer system like as separate sanitary, combined sewer system and storm sewers. During the wet weather, sewer and rainfall have been overflowed because it is over capacity of the combined sewer system; that is called combined sewer overflows(CSOs) This research was carried out to investigate runoff characteristics of combined sewer and to evaluate the effective CSOs volume in Hong-Chun gun. During wet weather, SS load of first rainfall at H-1, H-2, and H-3 were 600kg/event, 370kg/event, and 289kg/event, respectively. 55 load of second rainfall were 216kg/event, 113kg/event, and 37.2kg/event. When the first rainfall, event mean concentrations(EMCs) at each site were 702mg/L, 816mgjL and 861.5mg/L. The second rainfall's event mean concentrations(EMCs) were 99.9gm/L, 161.9mg/L, 103.6mg/L. Rrst flush coefficient b at each site were 0.237,0.166, and 0.151. When the first rainfall, the flow containing 80% of pollutant mass of CSOs at each site were 0.55, 0.23, 0.48 in first rainfall, respectively. The case of second rainfall were 0.79, 0.83, 0.81. Most of all, characteristics of rainfall like as analysis of first-flush, CSOs volume, pollutant loadings is investigated to decide intercepted volume for control of CSOs.

Relationship between chemicals in substrates and yield of Pleurotus pulmonarius (산느타리 봉지재배시 배지의 화학성이 수량에 미치는 영향)

  • Lee, An-Soo;Lee, Jae-Hong;Won, Heon-Seop;Hwang, Se-Jeong;Jung, Tae-Sung;Hong, Dae-Ki
    • Journal of Mushroom
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    • v.18 no.2
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    • pp.135-140
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    • 2020
  • We examined the chemical properties of mixed media and the yield of Pleurotus pulmonarius using bag culture (1 kg) and also evaluated their relationship. The yield of mushrooms in the first flush appeared to be correlated with total nitrogen content. The highest yield of mushroom in the first flush occurred when the nitrogen content of the media was 1.12 %; however, when the nitrogen content was lower or higher than 1.1 %, the yield decreased. The yield of mushrooms in the second flush was highly correlated with various chemical properties including total nitrogen, total carbon, and C/N ratio; for example, higher nitrogen and carbon content produced a higher yield in the second flush. Therefore, when cultivating bottle culture, the nitrogen content of the media should be approximately 1.1 %, such that most mushrooms are harvested in the first flush. Additionally, when cultivating bag culture for harvesting two or more times, it is advantageous to have higher nitrogen and carbon contents in the media than the amount required for bottle culture media.

Analysis of First Flushing Effects for the Vineyard Storm Runoff (강우시 포도밭에 대한 초기세척효과 분석)

  • Yoon, Young-Sam;Kwon, Hun-Gak;Lee, Jae-Woon;Yu, Jay-Jung;Lee, Jae-Kwan
    • Journal of Environmental Science International
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    • v.20 no.8
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    • pp.977-986
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    • 2011
  • This study analyzed the characteristics of stormwater runoff in the orchard areas and quantitatively estimated effluence of nonpoint source pollutants for the volume of runoff. Two target areas under vine cultivation were each $2,000m^2$ and $1,800m^2$, located in Gyeongju City. Since grape was the only crop on the target area, the characteristics of stormwater runoff at vineyard could be evaluated independently. A total of 51 rainfall events in the vineyard area during two years(2008-2009) was surveyed, and 19 of them became stormwater runoff, with rainfall ranging 16.5 - 79.7 mm and antecedent dry period of 1-13 days. The pollutant runoff loads by volume of stormwater runoff showed BOD ranging 19.5 - 45.3% in 30% of runoff volume. The average pollution discharge rate was 32.4%, indicating small first flush effect of BOD. The range of SS concentrations was 5 - 52.0% in 10% of runoff volume, showing the average 28.7% of discharge rate, about 3 times more than rainfall effluent. TOC and TN appeared to be similar to the results of BOD, the average discharge rate of 30.9% and 30.6% for TOC and TN, respectively, for 30% of stormwater runoff volume. Average discharge rate of COD and TP in the same runoff volume was 35.1% and 36%, respectively, showing comparatively high discharge ratio. As the targeted vineyard area was permeable land, the pollution load ratio against rainfall-runoff volume appeared to be 1:1, implying no strong first flush effect for all the survey items.

Washoff Characteristics of Non-point Source pollutants and Estimation of Unit Loads in Suburban Industrial Complex Areas Runoff (교외 산업단지지역 강우유출수내 비점오염물질의 유출특성 및 원단위 산정)

  • Kim, Sung-Joon;Shin, Seon-Mi;Jeon, Yong-Tae;Won, Chan-Hee
    • Journal of Environmental Impact Assessment
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    • v.21 no.2
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    • pp.315-325
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    • 2012
  • The characteristics of stormwater runoff and estimation of unit loads were examined in suburban industrial complex areas. During rainfall event, the peak concentrations occurred within the first 100 minutes after rainfall and then the highest concentration of NPS pollutants sharply decreased, showing strong first flush effect in suburban industrial complex. The cumulative load curves for NPS pollutants showed above the straight line, indicating that first flush effect occurred in suburban industrial complex. While the mean TSS, BOD, COD, TN and TP EMCs values were shown the highest values as 120.6 mg/L, 20.8 mg/L, 44.0 mg/L, 5.58 mg/L and 1.46 mg/L respectively. Unit loads estimated from the EMCs were TSS $43.86kg/km^2/day$, COD $52.45kg/km^2/day$, BOD $24.79kg/km^2/day$, T-N $6.65kg/km^2/day$, T-P $1.75kg/km^2/day$, and Pb $0.10kg/km^2/day$. Results of unit loads were compared with the unit pollutant loads from land-use in Korea and USA. The unit load of TSS was lower than that of USA. Estimated BOD and T-N and T-P unit loads were lower than that of Korea.

Pattern Analysis of CSOs Generation in a Small Rural City and Control Schemes (농촌 소도시의 CSOs 발생패턴분석 및 관리대책에 관한 연구)

  • Kim, Youngchul;An, Ik-Sung;Lee, Myung-Jae
    • Journal of Korean Society on Water Environment
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    • v.23 no.4
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    • pp.543-550
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    • 2007
  • In this study, combined sewer overflows (CSOs) from five independent rainfall events in rural city area were collected and investigated. First flush effect in sewage pumping station located near the WWTP was retarded 30 to 60 minutes from booster pumping station. The ratios between SS, COD and TP concentrations prior to rainfall and peak concentrations during the period of rainfall were highly increased but nitrogen was relatively constant, which indicates that it is not associated with particles washed off from the surface of watershed. Mass balance results show that 30% of CSO was generated from booster pump station and 66.5% of CSO was from the whole runoff area. In the area of newly constructed sewer system, CSO problem was related with pump and sewer capacities, but in other old sewer system equipped area, it was due to the collection efficiency. Finally, Log-Log pollutant rating equations were suggested.

Water Quality of the First Flushes in the Surface Runoff at an Intersection (도심 교차로 노면 지표유출수의 초기수질특성에 관한 연구)

  • Choi, Sang-Yong;Ko, Kwang-Baik;Lee, Ji-Young;Lim, Se-Ho
    • Journal of Environmental Science International
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    • v.15 no.4
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    • pp.359-364
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    • 2006
  • Two sites with different average daily traffic volume at an intersection were selected in order to investigate water quality of the first flushes in the surface runoffs. The effects of rainfall intensities and accumulated non-rainy days before rainfall events on the water quality were also delineated. Samples were collected at every 2 min. interval from each first flush from February to May, 2004 for 4 major rainfall events. $COD_{cr}$ or SS concentrations at the site with an average daily traffic volume (ADTV) of 23,000 vehicles were 2-7 times higher than those at the site with an ADTV of 1,400 vehicles. The longer the accumulated non-rainy days were, the higher the concentration of heavy metals were than those of $COD_{cr}$ and SS in the first flushes.