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A Study on the Retrieval of River Turbidity Based on KOMPSAT-3/3A Images (KOMPSAT-3/3A 영상 기반 하천의 탁도 산출 연구)

  • Kim, Dahui;Won, You Jun;Han, Sangmyung;Han, Hyangsun
    • Korean Journal of Remote Sensing
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    • v.38 no.6_1
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    • pp.1285-1300
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    • 2022
  • Turbidity, the measure of the cloudiness of water, is used as an important index for water quality management. The turbidity can vary greatly in small river systems, which affects water quality in national rivers. Therefore, the generation of high-resolution spatial information on turbidity is very important. In this study, a turbidity retrieval model using the Korea Multi-Purpose Satellite-3 and -3A (KOMPSAT-3/3A) images was developed for high-resolution turbidity mapping of Han River system based on eXtreme Gradient Boosting (XGBoost) algorithm. To this end, the top of atmosphere (TOA) spectral reflectance was calculated from a total of 24 KOMPSAT-3/3A images and 150 Landsat-8 images. The Landsat-8 TOA spectral reflectance was cross-calibrated to the KOMPSAT-3/3A bands. The turbidity measured by the National Water Quality Monitoring Network was used as a reference dataset, and as input variables, the TOA spectral reflectance at the locations of in situ turbidity measurement, the spectral indices (the normalized difference vegetation index, normalized difference water index, and normalized difference turbidity index), and the Moderate Resolution Imaging Spectroradiometer (MODIS)-derived atmospheric products(the atmospheric optical thickness, water vapor, and ozone) were used. Furthermore, by analyzing the KOMPSAT-3/3A TOA spectral reflectance of different turbidities, a new spectral index, new normalized difference turbidity index (nNDTI), was proposed, and it was added as an input variable to the turbidity retrieval model. The XGBoost model showed excellent performance for the retrieval of turbidity with a root mean square error (RMSE) of 2.70 NTU and a normalized RMSE (NRMSE) of 14.70% compared to in situ turbidity, in which the nNDTI proposed in this study was used as the most important variable. The developed turbidity retrieval model was applied to the KOMPSAT-3/3A images to map high-resolution river turbidity, and it was possible to analyze the spatiotemporal variations of turbidity. Through this study, we could confirm that the KOMPSAT-3/3A images are very useful for retrieving high-resolution and accurate spatial information on the river turbidity.

Evaluation of the Microbiological Safety for the Seawater in a Part of the South Coast, Korea (남해안 일부해역 해수의 세균학적 위생안전성 평가)

  • Park, Yeong Min;Yoon, Hyun Jin;Ham, In Tae;Yoo, Hean Jae;Choi, Jong-Duck
    • Journal of Food Hygiene and Safety
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    • v.30 no.4
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    • pp.350-358
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    • 2015
  • This study was designed to evaluate the sanitary characteristics of sea water in a part of the south coast, Korea and to check the seawater which is in compliance with the recommended bacteriological criteria for shellfish cultivation. The samples of sea water were collected at 14 sampling stations established in the survey area between March 2014 and October 2014. Food poisoning caused by seafood consumption is often associated with pathogenic microorganisms originated from fecal contamination. Therefore, fecal coliform is very important criteria for evaluating the safety of fisheries in coastal areas. The range of geometric mean (GM) and the estimated 90th percentile values of total coliform were 4.1~83.1 MPN/100 mL, and 11.7~834.1 MPN/100 mL, respectively. The GM and the estimated 90th percentile values of fecal coliform were 2.5~22.7 MPN/100 mL and 2.5~170.0 MPN/100 mL, respectively. Therefore, the bacteriological safety of seawater at this shellfish-growing area met with the Korean Shellfish Sanitation Program (KSSP) criteria for a growing area. However, the values are seasonally exceed the KSSP criteria, suggesting that the monitoring and evaluation of seawater quality is very important in shellfish-growing area.

A Study on the Charateristic of the Groundwater Quality in Seoul (서울지역의 지하수 수질특성에 관한 연구)

  • 김익수;이재영;최상일
    • Journal of Soil and Groundwater Environment
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    • v.9 no.2
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    • pp.54-63
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    • 2004
  • For the purpose of finding out the distributions of groundwater uses, the effect of facilities on the parameter and the correlations among measurements, various statistical analysis were carried out with the data of groundwater quality measurements from January to December in 2002. (1) The rates of groundwater for drinking water were 10.5% in Yungcheon-Gu, 10.2% in Kangdong-Gu, and 9.9% in Eunpyung-Gu. The rates of other uses of groundwater were shown to be 58.1 %(786 wells) for civil defense emergency, 22.1% (299 wells) for contamination-concerning, 9.8%(133 wells) for water quality monitoring, consisting of 90% of all groundwater. (2) The 52.6% of groundwater for drinking were demonstrated to be appropriate while 91.9% for other uses-domestic, industrial, agricultural uses- were shown to be proper. (3) For drinking water, the maximum values of colar, turbidity, NH3-N, F, and Fe were 766.9 degree, 69.16NTU, 860.0 mg/l, 5.6 mg/l and 49.87 mg/l respectively. (4) Comparision of skewness and kurtosis for Seoul groundwater, pH was found to be 0.022 and -0.524, but the T.colony, color, turbidity, NH$_3$-N, NO$_3$-N, Fe and Mn respectively fumed out to be 11.641 and 174.324, 8.501 and 80.260, 5.675 and 32.821, 19.507 and 380.994, 3.323 and 17.436, 10.544 and 134.093 and 5.979 and 39.124. (5) In cases of drinking water wells for emergency, the results of statistical analysis showed that building year of the wells, depth and pumping rate didn't affect on whether it was proper for that use or not. It were shown that there were linear correlations between depth and NO3-N(-0.171) and F(0.332) while the correlation coefficients were 0.381 and -0.169 between the building year of well and depth and pumping rate respectively.

Sensory Evaluation and Mechanical Properties of Jellies Made by Adding Different Jelling Agent Ratio in Sypjeondaebo Extracts (십전대보 추출물에 젤화제의 첨가 비율을 달리하여 제조한 젤리의 기계적 특성 및 관능적 평가)

  • Kang, Myung-Hwa
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.10
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    • pp.1685-1688
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    • 2004
  • This study mechanically measured physical properties of jelly made by adding kappa carrageenan and agar-agar to the sipjeondaebo extract, varying the addition ratio. The sipjeondaebo extract used in the study showed 4.95 pH, 7.0 Brix$^{\circ}$, and high turbidity of more than 3.0 NTU. The sugar content was fixed at 25.2 Brix$^{\circ}$ when isomaltooligosaccharide was added in a 25-percent concentration. When the jelly was mechanically measured after it became hard in the refrigerator, the measurement results did not show any significant difference in cohesiveness between different addition ratios of agar-agar to kappa carrageenan. In the measurement of chewiness and gumminess, the jelly show a significantly decreasing tendency in both the two properties as the increase in the addition rate of agar-agar was made. Hardness was also measured lower as the more addition of agar-agar was made, and its the highest level was shown when there was the addition of kappa carrageenan only. Springiness was the highest when the ratio of kappa carrageenan to agar-agar was 0.7%:0.3%, while it was measured the lowest when agar-agar was added in a 1.0% concentration. In the measurement of the jelly's physical properties, the results showed the highest level of appearance when the ratio of kappa carrageenan to agar-agar was 0.7% but indicated that there was no significant difference in flavor. The overall Quality was evaluated to maintain the highest level at the kappa carrageenan to agar-agar ratio of 0.7%:0.3%, followed by a 0.5%:0.5% addition ratio.

A Study on the Diatomaceous Earth Filtration of Settling Basin Effluent (정수장 침전지 유출수의 규조토 여과에 관한 연구)

  • Shin Dae-Yewn;Ji Sung-Nam;Moon Ok-Ran;Kim Ji-Yeong;Suh Dong-Woo;Cho Young-Kwan
    • Journal of Environmental Health Sciences
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    • v.30 no.5 s.81
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    • pp.410-416
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    • 2004
  • The objective of this investigation was to evaluate applicability of precoat filtration that can be substituted for rapid sand filter of conventional water treatment system(CWTS). Precoat filter used in this experiment are candle filter. Element disk of candle are pore size $10{\mu}m(R),\;20{\mu}m(B)$ And diatomaceous earth are cake pore size $3.5{\mu}m$(Standard Super- Cel; A), $7{\mu}m$(Hyflo Super-Cel; B) and $17{\mu}m$(Celite 545RV; C). $2kg/m^2$ diatomaceous earth is used for precoating, it coated candle in $5{\sim}6mm$ thickness. 1. Al adsorption dosages by diatomaceous earth used in experimental we Hyflo Super-Cel 0.843mg/g, Standard Super-Cel 0.782 mg/g and Celite 545RV 0.766 mg/g. 2. Filtrate of precoat filter during 60min are R-C combination 20.7($m^3/m^2$)>B-C 18.3($m^3/m^2$)>B-B 15.0($m^3/m^2$)> R-B 12.9($m^3/m^2$)> R-A 11,093($l/m^2$). 3. Water quality of precoat filter effluent are thus. $KMnO_4$ consumption are $1.10{\sim}2.20mg/l$, removal rate are $30.9{\sim}65.6\%$. They are R-A 1.10(mg/l)(removal rate $65.6\%$). R-C(2.20 mg/l)(removal rate $30.9\%$). 4. $Al^{3+}$ are not detected with all combination, removal rate $100\%$. 5. Considering water quality and flux, continued running time of R-A combination is 7 hr. Accumulated filtrate are $74.4 m^3/m^2$, average flux is $177.2 l/m^2{\cdot}min$. And filtrate per diatomaceous earth 1g are 37.2 l. 6. R-A effluent's water quality are $KMnO_4$ Consumption 1.10(mg/l), DOC 1.161 mg/1, Al 0.0 mg/1, $UV_{254}$ 0.016/cm, Turbidity 0.1(NTU). R-A combination is suitable to precoat filtration for the settling basin effluent treatment.

A study on relationship of concentration of phosphorus, turbidity and pH with temperature in water and soil (물과 토양에서 pH, PO4-P, 탁도 그리고 T-P 농도에 미치는 온도의 영향에 관한 연구)

  • Min, Young-Hong;Hyun, Dae-Yoeung;Eum, Chul-Hun;Chung, Nam-Hyun;Kang, Sam-Woo;Lee, Seung-Ho
    • Analytical Science and Technology
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    • v.24 no.5
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    • pp.378-386
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    • 2011
  • The goal of this study is to understand the influence of temperature on phosphorus release rate from soil into water. As the temperature increases, $PO_4$-P reaches equilibrium more quickly and the equilibrium concentration increases, and thus the $PO_4$-P concentration increases, and pH decreases. The $PO_4$-P concentration affects pH. $PO_4$-P released from turbidity is not adsorbed onto the turbidity. $PO_4$-P was independent on the turbidity and yet $PO_4$-P was steadily increasing. However, $PO_4$-P was dependent upon the turbidity concentration as the turbidity releases $PO_4$-P. The total phosphorous (T-P) and turbidity were directly linked because T-P changed with the turbidity. T-P includes the $PO_4$-P content of water and the phosphorus content of the turbidity. As the temperature decreases, density of water increases, and the precipitation of turbidity decreases, resulting in an increases in T-P concentration. As the temperature increases, the T-P concentration decreases, but the PO4-P release rate from turbidity increases. At the same time, even at different temperatures, the T-P concentrations of the samples were about the same. When the lake gets deepened, the water temperature decreases, hence, the phosphorus release rate from soil into water was decreased. This mechanism is of great interest because phosphorus is released from soil sediment into the lake water.

Simultaneous Removal of $SO_2/NO$ using liquid Homogeneous Catalyst (액상 균일질 촉매를 이용한 $SO_2/NO$ 동시 처리 기술 개발)

  • Jung, Seung-Ho;Bae, Jin-Youl;Park, Don-Hee;Jung, Kyung-Hoon;Cha, Jin-Myeong
    • Journal of Korean Society of Environmental Engineers
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    • v.29 no.1
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    • pp.62-67
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    • 2007
  • It was investigated to develop the technology for simultaneous removal of $SO_2/NO$ in flue gas using liquid homogeneous catalyst. Test was carried out using a bench scale and a pilot scale experiment. The investigation led to the following results: 1) Removal efficiency of $SO_2$ gas showed good results regardless of operating condition. Removal efficiency of NO gas, however, proportionally increased with higher packing height, lower concentration and larger injection rate of catalyst 2) The optimum design parameters for simultaneous removal of $SO_2/NO$ gas using Fe(II)-EDTA catalyst were as follow: HTU(height of transfer unit) = 0.5 m, liquid gas ratio = 20 $L/m^3$, NTU (number of transfer unit) = 3 stages, cross dimension of scrubber=0.025 $m^2$ 3) The removal efficiencies of $SO_2$ and NO were 95% and 81%, repletely. 4) The high HTU is advantageous on removal of the NO, but the excessive HTU diminishes operating efficiency. Consequently, it is important to decide the HTU of optimum.

A study on the relationship between concentration of phosphorus, turbidity, and pH in water and soil (물과 토양에서 인의 농도, 탁도 그리고 pH와의 관계에 관한 연구)

  • Min, Young-Hong;Hyun, Dae-Yoeung;Eum, Chul-Hun;Lee, Seung-Ho
    • Analytical Science and Technology
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    • v.24 no.4
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    • pp.304-309
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    • 2011
  • In this research, behaviour of turbidity and phosphorus in water and soil dependent upon pH and a change of water was studied. Phosphorus dissolve rate from turbidity was increased for water if potential of hydrogen was less than pH 4 or more than pH 7. Turbidity release rate from soil was increased with pH. Turbidity release rate from soil was drastically increased for water if potential of hydrogen was more than pH 4. turbidity release rate from soil was stabilized more than pH 6. Dissolved phosphorus was increased from 2 hours to 24 hours and stabilized in 24 hours. Turbidity was reached the peak of 24 hours and decreased from 24 hours to 96 hours. Turbidity and dissolved phosphorus was decreased for water if these samples were changed a overlying water. Behaviour of turbidity was analogous to dissolved phosphorus when potential of hydrogen was increased from pH 6 to pH 10 and a change of overlying water was increased from 1 time to 4 times. These results suggest that phosphorus dissolve rate and turbidity were directiy correlated with pH. These results are of great importance in lakes because most lakes have a pH in the range of pH 7-10.

Applicability Evaluation of Two-stages and Dual Media Filtration System by the Small-scale Pilot Plant (이단이층 복합여과시스템의 소규모 파일롯 플랜트 적용성 평가)

  • Woo, Dal-Sik;Song, Si-Byum;Hwang, Byung-Gi
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.4
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    • pp.857-864
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    • 2009
  • This study aimed at developing the two stage and dual filtration system. It has a sand + activated carbon layer above the underdrain system and a sand layer above the middledrain system for pretreatment. When retrofitting an old filter bed or designing a new one, this technology can substitute the existing sand filter bed without requiring a new site. In order to extend the filtering duration, the upper layer of the filter bed consists of the rapid sand filtration with large particles which pre-treats and removes coarse particles and turbidity matters. The middle layer has biological activated carbon(BAC) and granular activated carbon(GAC) to eliminate dissolved organic matters, disinfection by-products precursors etc. The lower layer consists of the sand filtration for the post filtering mode. In this study, a pilot plant of two stage and dual filtration system was operated for 4 months in the S water treatment plant in Kyounggi-Do. The stability of turbidity was maintained below 1NTU. The TOC, THMFP and HAAFP were removed about 90% by two stage and dual filtration system, which is almost 2 times higher than S WTP. From analysis result of HPC along the depth of activated carbon + sand layer at 2nd stage, microorganism was mostly not detected, however, increment of HPC was shown as it becomes deeper. It indicates that growth of microorganism is occurred at activated carbon layer.

Application of coagulation pretreatment for enhancing the performance of ceramic membrane filtration (세라믹 막여과의 성능향상을 위한 응집 전처리의 적용)

  • Kang, Joon-Seok;Song, Jiyoung;Park, Seogyeong;Jeong, Ahyoung;Lee, Jeong-Jun;Seo, Inseok;Chae, Seonha;Kim, Seongsu;Kim, Han-Seung
    • Journal of Korean Society of Water and Wastewater
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    • v.31 no.6
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    • pp.501-510
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    • 2017
  • In this study, it is estimated that ceramic membrane process which can operate stably in harsh conditions replacing existing organic membrane connected with coagulation, sedimentation etc.. Jar-test was conducted by using artificial raw water containing kaolin and humic acid. It was observed that coagulant (A-PAC, 10.6%) 4mg/l is the optimal dose. As a results of evaluation of membrane single filtration process (A), coagulation-membrane filtration process (B) and coagulation-sedimentation-membrane filtration process (C), TMP variation is stable regardless of in Flux $2m^3/m^2{\cdot}day$. But in Flux $5m^3/m^2{\cdot}day$, it show change of 1-89.3 kpa by process. TMP of process (B) and (C) is increased 11.8, 0.6 kpa each. But, the (A) showed the greatest change of TMP. When evaluate (A) and (C) in Flux $10m^3/m^2{\cdot}day$, TMP of (A) stopped operation being exceeded 120 kpa in 20 minutes. On the other hand, TMP of (C) is increased only 3 kpa in 120 minutes. Through this, membrane filtration process can be operated stably by using the linkage between the pretreatment process and the ceramic membrane filtration process. Turbidity of treated water remained under 0.1 NTU regardless of flux condition and DOC and $UV_{254}$ showed a removal rate of 65-85%, 95% more each at process connected with pretreatment. Physical cleaning was carried out using water and air of 500kpa to show the recovery of pollutants formed on membrane surface by filtration. In (A) process, TMP has increased rapidly and decreased the recovery by physical cleaning as the flux rises. This means that contamination on membrane surface is irreversible fouling difficult to recover by using physical cleaning. Process (B) and (C) are observed high recovery rate of 60% more in high flux and especially recovery rate of process (B) is the highest at 95.8%. This can be judged that the coagulation flocs in the raw water formed cake layer with irreversible fouling and are favorable to physical cleaning. As a result of estimation, observe that ceramic membrane filtration connected with pretreatment improves efficiency of filtration and recovery rate of physical cleaning. And ceramic membrane which is possible to operate in the higher flux than organic membrane can be reduce the area of water purification facilities and secure a stable quantity of water by connecting the ceramic membrane with pretreatment process.