• Title/Summary/Keyword: Groundwater depletion

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Surface Image Analysis for Evaluating Porosity and Permeability Coefficient of Permeable Concrete Block (투수 콘크리트 블록 공극률 및 투수계수 평가를 위한 표면 이미지 분석 기법 개발)

  • Jo, Sangbeom;Son, Younghwan;Kim, Donggeun;Jeon, Jihun;Kim, Taejin
    • Journal of The Korean Society of Agricultural Engineers
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    • v.65 no.2
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    • pp.47-57
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    • 2023
  • The increase of impermeable area ratio is causing hydrologic cycle problems in urban areas and groundwater depletion in rural areas, permeable pavements are getting attention to expand permeable areas. The performance of the permeable concrete block pavement, which is part of the permeable pavement, is greatly affected by the porosity. In addition, the permeability coefficient is a major factor when designing permeable concrete block pavement. Existing porosity and permeability test methods have problems such as uneconomical or poor field applicability. The object of this study was to develop a methodology for evaluating porosity and permeability coefficient using a surface image of a permeable concrete block. Specimens are manufactured with various porosity ranges and porosity and permeability tests are performed. After surface image preprocessing, normalization and binarization methods were compared. Through this, the method with the highest correlation with the lab test result was determined. From the results, the PDR (pore determined ratio) was obtained. Simple linear regression analysis is performed with PDR and lab test results. The results showed a high correlation of R2 more than 0.8, and the errors were also low.

Field Studios of In-situ Aerobic Cometabolism of Chlorinated Aliphatic Hydrocarbons

  • Semprini, Lewts
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.04a
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    • pp.3-4
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    • 2004
  • Results will be presented from two field studies that evaluated the in-situ treatment of chlorinated aliphatic hydrocarbons (CAHs) using aerobic cometabolism. In the first study, a cometabolic air sparging (CAS) demonstration was conducted at McClellan Air Force Base (AFB), California, to treat chlorinated aliphatic hydrocarbons (CAHs) in groundwater using propane as the cometabolic substrate. A propane-biostimulated zone was sparged with a propane/air mixture and a control zone was sparged with air alone. Propane-utilizers were effectively stimulated in the saturated zone with repeated intermediate sparging of propane and air. Propane delivery, however, was not uniform, with propane mainly observed in down-gradient observation wells. Trichloroethene (TCE), cis-1, 2-dichloroethene (c-DCE), and dissolved oxygen (DO) concentration levels decreased in proportion with propane usage, with c-DCE decreasing more rapidly than TCE. The more rapid removal of c-DCE indicated biotransformation and not just physical removal by stripping. Propane utilization rates and rates of CAH removal slowed after three to four months of repeated propane additions, which coincided with tile depletion of nitrogen (as nitrate). Ammonia was then added to the propane/air mixture as a nitrogen source. After a six-month period between propane additions, rapid propane-utilization was observed. Nitrate was present due to groundwater flow into the treatment zone and/or by the oxidation of tile previously injected ammonia. In the propane-stimulated zone, c-DCE concentrations decreased below tile detection limit (1 $\mu$g/L), and TCE concentrations ranged from less than 5 $\mu$g/L to 30 $\mu$g/L, representing removals of 90 to 97%. In the air sparged control zone, TCE was removed at only two monitoring locations nearest the sparge-well, to concentrations of 15 $\mu$g/L and 60 $\mu$g/L. The responses indicate that stripping as well as biological treatment were responsible for the removal of contaminants in the biostimulated zone, with biostimulation enhancing removals to lower contaminant levels. As part of that study bacterial population shifts that occurred in the groundwater during CAS and air sparging control were evaluated by length heterogeneity polymerase chain reaction (LH-PCR) fragment analysis. The results showed that an organism(5) that had a fragment size of 385 base pairs (385 bp) was positively correlated with propane removal rates. The 385 bp fragment consisted of up to 83% of the total fragments in the analysis when propane removal rates peaked. A 16S rRNA clone library made from the bacteria sampled in propane sparged groundwater included clones of a TM7 division bacterium that had a 385bp LH-PCR fragment; no other bacterial species with this fragment size were detected. Both propane removal rates and the 385bp LH-PCR fragment decreased as nitrate levels in the groundwater decreased. In the second study the potential for bioaugmentation of a butane culture was evaluated in a series of field tests conducted at the Moffett Field Air Station in California. A butane-utilizing mixed culture that was effective in transforming 1, 1-dichloroethene (1, 1-DCE), 1, 1, 1-trichloroethane (1, 1, 1-TCA), and 1, 1-dichloroethane (1, 1-DCA) was added to the saturated zone at the test site. This mixture of contaminants was evaluated since they are often present as together as the result of 1, 1, 1-TCA contamination and the abiotic and biotic transformation of 1, 1, 1-TCA to 1, 1-DCE and 1, 1-DCA. Model simulations were performed prior to the initiation of the field study. The simulations were performed with a transport code that included processes for in-situ cometabolism, including microbial growth and decay, substrate and oxygen utilization, and the cometabolism of dual contaminants (1, 1-DCE and 1, 1, 1-TCA). Based on the results of detailed kinetic studies with the culture, cometabolic transformation kinetics were incorporated that butane mixed-inhibition on 1, 1-DCE and 1, 1, 1-TCA transformation, and competitive inhibition of 1, 1-DCE and 1, 1, 1-TCA on butane utilization. A transformation capacity term was also included in the model formation that results in cell loss due to contaminant transformation. Parameters for the model simulations were determined independently in kinetic studies with the butane-utilizing culture and through batch microcosm tests with groundwater and aquifer solids from the field test zone with the butane-utilizing culture added. In microcosm tests, the model simulated well the repetitive utilization of butane and cometabolism of 1.1, 1-TCA and 1, 1-DCE, as well as the transformation of 1, 1-DCE as it was repeatedly transformed at increased aqueous concentrations. Model simulations were then performed under the transport conditions of the field test to explore the effects of the bioaugmentation dose and the response of the system to tile biostimulation with alternating pulses of dissolved butane and oxygen in the presence of 1, 1-DCE (50 $\mu$g/L) and 1, 1, 1-TCA (250 $\mu$g/L). A uniform aquifer bioaugmentation dose of 0.5 mg/L of cells resulted in complete utilization of the butane 2-meters downgradient of the injection well within 200-hrs of bioaugmentation and butane addition. 1, 1-DCE was much more rapidly transformed than 1, 1, 1-TCA, and efficient 1, 1, 1-TCA removal occurred only after 1, 1-DCE and butane were decreased in concentration. The simulations demonstrated the strong inhibition of both 1, 1-DCE and butane on 1, 1, 1-TCA transformation, and the more rapid 1, 1-DCE transformation kinetics. Results of tile field demonstration indicated that bioaugmentation was successfully implemented; however it was difficult to maintain effective treatment for long periods of time (50 days or more). The demonstration showed that the bioaugmented experimental leg effectively transformed 1, 1-DCE and 1, 1-DCA, and was somewhat effective in transforming 1, 1, 1-TCA. The indigenous experimental leg treated in the same way as the bioaugmented leg was much less effective in treating the contaminant mixture. The best operating performance was achieved in the bioaugmented leg with about over 90%, 80%, 60 % removal for 1, 1-DCE, 1, 1-DCA, and 1, 1, 1-TCA, respectively. Molecular methods were used to track and enumerate the bioaugmented culture in the test zone. Real Time PCR analysis was used to on enumerate the bioaugmented culture. The results show higher numbers of the bioaugmented microorganisms were present in the treatment zone groundwater when the contaminants were being effective transformed. A decrease in these numbers was associated with a reduction in treatment performance. The results of the field tests indicated that although bioaugmentation can be successfully implemented, competition for the growth substrate (butane) by the indigenous microorganisms likely lead to the decrease in long-term performance.

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Properties of Permeable Block using Artificial Permeable Pipe and Polymer Powder VAE to Improve Permeability (투수성을 개선시키기 위해 인공투수관 및 분말형 폴리머 VAE를 사용한 투수블록의 특성)

  • Yoo, Beong-Young;Lee, Won-Gyu;Pyeon, Su-Jeong;Kim, Dea-Yeon;Lee, Sang-Soo
    • Journal of the Korea Institute of Building Construction
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    • v.18 no.5
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    • pp.447-453
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    • 2018
  • Since 1960, Korea the town center was developed intensively due to rapid industrial development. As a result of the development, the population was concentrated in urban areas and the green area was decreased. Due to the decrease of the green area, the circulation system of the rainwater was changed, hence the rainwater was not introduced into the groundwater., On the other hand, the water on the surface of the road was changed into the water for flowing to the river and evaporation. The changes in the water flow cause many problems, and the depletion of the groundwater does not create an environment in which microorganisms and plants can live. in Korea, permeable pavement construction is increased to solve these problems, but existing pavement blocks have many problems. The pores of the permeable block are clogged due to the accumulation of dust or whitening phenomenon, and the permeability is lost. In this study, the solution of the problems of existing permeable block were suggested by using polymer and artificial permeable pipe, and strength, permeability and service life are increased, The relationship between the substitution rate of the polymer and the mixing ratio of the artificial permeable pipe was analyzed.

Fraction and Mobility of Heavy Metals in the Abandoned Closed Mine Near Okdong Stream Sediments (폐광산 지역 옥동천 퇴적물내에 포함된 중금속의 존재형태 및 이동성)

  • Kim Hee-Joung;Yang Jae-E;Lee Jai-Young;Jun Sang-Ho
    • Journal of Soil and Groundwater Environment
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    • v.10 no.2
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    • pp.44-51
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    • 2005
  • Fractional composition and mobility of some heavy metals in sediments from Okdong stream are investigated. The fractional scheme for heavy metals in the sediment was established for five chemically defined heavy metal forms as adsorbed fraction, carbonate fraction, reducible fraction, organic fraction, and residual fraction. The most abundant fraction heavy metals in the sediments is reducible and secondly abundant is organic fraction. Adsorbed fraction is minor part of the total heavy metals. Mobilization of heavy metals in the sediments from Okdong stream occur $19.8{\sim}56.7%$ of total cadmium concentrate. The most abundant fraction of the sediment metal is organic fraction in Cu, Pb metals investigated. Labile fraction of sediment metals are $0.5{\sim}48.5%$ of total Zn, $2.6{\sim}48.1%$ of total Pb, and $0.2{\sim}36.9%$ of total Cu, respectively. Most of labile fraction consists of reducible fraction for Cd, Zn, adsorbed fraction for Pb, reducible fraction for Cu, adsorbed fraction for Ni. The Mobilization of Zn and Cu is most likely to occur when oxygen depletes and that of Pb and Ni occurs when physical impact, oxygen depletion and pH reduction.

Geochemical evidence for K-metasomatism related to uranium enrichment in Daejeon granitic rocks near the central Ogcheon Metamorphic Belt, Korea

  • Hwang, Jeong;Moon, Sang-Ho
    • Geosciences Journal
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    • v.22 no.6
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    • pp.1001-1013
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    • 2018
  • A new type of uranium occurrence in Korea was identified in pegmatitic and hydrothermally altered granite in the Daejeon area. The U-bearing parts typically include muscovite, pink-feldspar and sericite as alteration minerals. In this study, the geochemical characteristics and alteration age of the granitic rocks were examined to provide evidence for hydrothermally-enriched uranium. The K-Ar ages of muscovite coexisting with U-bearing minerals were determined as 123 and 128 Ma. The U-bearing rocks have relatively low ($CaO+Na_2O$), high $K_2O$ contents, and high alteration index values by major element geochemistry. The trace element geochemistry shows that the uraniferous rocks have significantly low Th/U ratios and strongly differentiated features. The rare earth element patterns indicate that the uraniferous rocks have a low total REE and LREE contents with depletion of Eu. Considering the geochemical variation of the granitic rock major, trace and rare earth elements, it can be concluded that uranium enrichment in pegmatites and altered granite should be genetically related to post-magmatic hydrothermal alteration of K-metasomatism after emplacement of the two-mica granite. This is the first report for geochemical characteristics of Mesozoic granite-related U-occurrences in South Korea. This study will help further research for uranium deposits with similarities in geological setting, mineralogy and age data between South China and Korea, and can also be expected to help solve the source problems related to high uranium concentrations in some groundwater occurring in the granitic terrane.

Comparing Water Management Categories of Green Building Rating Systems for Development of Evaluation Criteria of Watersheds (유역 평가 기준 개발을 위한 그린빌딩 평가 시스템의 물관리 관련 항목 비교 연구)

  • Idrees, Muhammad Bilal;Lee, Jin-Young;Ahn, Jae-Hyun;Kim, Tae-Woong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.38 no.6
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    • pp.1013-1020
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    • 2018
  • With the rapid industrialization and increase in population, more and more people are moving to live in cities. This urbanization trend is resulting in increased construction and development activities which associates with escalation of impervious surface. This in turn causes problems like groundwater depletion, higher flood peaks, and increased rate of soil loss from the watershed. Watershed management projects are being implemented around the globe concerning with the application of soil and water resources conservation practices. It is desirable that an entire watershed be evaluated based on soil and water conservation practices applied. In this study, water management categories of green building rating systems (GBRS) of South Korea, Taiwan, and the Philippines were discussed. The water management practices rating criteria of G-SEED (South Korea), BERDE (Philippines), and EEWH (Taiwan) were explored and compared. The insights of this study are expected to be projected to establish a comprehensive rating system for the evaluation of watersheds. The quantification of watershed management practices will help future planners to identify areas of potential water-related risks and counter the hazards more effectively.

Effect of Saline Concentrations on Biological Nitrification in Batch Reactor

  • Lee, Young Joon;Nguyen, Viet Hoang;Nguyen, Hong Khanh;Pham, Tuan Linh;Kim, Gi Youn
    • Journal of Integrative Natural Science
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    • v.4 no.2
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    • pp.103-112
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    • 2011
  • This study was carried out on 4 batch reactors to determine the specific ammonium oxidizing rate (SAOR), specific nitrate forming rate (SNFR) and inhibitory degree of nitrifying activities with saline concentrations. Under salt free condition ammonia was consumed during the reaction period within 200 min. When the salt level increased to 10, 20 and 30 g $NaClL^{-1}$ in reactor, ammonia depletion took 250, 300 and above 350 min, respectively. During concentration above 10 g $NaClL^{-1}$, there was nitrite accumulation. Also, at 30 g $NaClL^{-1}$ ammonia did not depleted and $NO_2{^-}$-N accumulated until the final reaction. Nitrate formation rates decreased with increasing salt concentration. SAOR and SNFR showed a decreasing trend as salinity concentrations were increased. The SAOR was reduced from 0.2 to 0.08 mg $NH_4{^+}$-N $g^{-1}VSS\;day^{-1}$ as the salt concentration increased from 0 to 30 g $NaClL^{-1}$. Similarly, the SNFR decreased from 0.26 kg $NO_3{^-}$-N $kg^{-1}VSS\;day^{-1}$ at saline free to 0.1 kg $NO_3{^-}$-N $kg^{-1}VSS\;day^{-1}$ at saline 30 g L-1. A severe inhibition of nitrifiers activity was observed at increased salt concentrations. The inhibition ratio of specific ammonium oxidation rates were 17, 47 and 60% on the reactor of 10, 20 and 30 g $NaClL^{-1}$ added, respectively. The inhibition ratio of specific nitrate forming rates also were inhibited 30, 53 and 62% on the reactor of 10, 20 and 30 g $NaClL^{-1}$ added, respectively. As the salinity concentrations increased from 0 to 30 mg $NaClL^{-1}$, the average MLSS concentration increased from 1,245 to 1,735 $mgL^{-1}$. The SS concentration of supernatant in reactor which settled about 30 minutes was not severely difference between concentration of salt free reactor and one of those high salt contained reactors.

Hydrologic and Environmental Assessment of an Infiltration Planter for Roof Runoff Use (지붕 빗물이용을 위하여 개발된 침투화분의 환경·수문학적 평가)

  • Moon, So-Yeon;Choi, Ji-Yeon;Hong, Jung-Sun;Yu, Gi-Gyung;Jeon, Je-Chan;Flores, Precious Eureka D.;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.17 no.4
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    • pp.325-331
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    • 2015
  • Due to urbanization and increase in impervious area, changes in natural water circulation system have become a cause of groundwater recharge reduction, streamflow depletion and other hydrological problems. Therefore, this study developed the infiltration planter techniques applied in an LID facility treating roof stormwater runoff such as, performance of small decentralized retention and infiltration through the reproduction of natural water circulation system and use of landscape for cleaning water. Assessment of an infiltration planter was performed through rainfall monitoring to analyze the water balance and pollutant removal efficiency. Hydrologic assessment of an infiltration planter, showed a delay in time of effluent for roof runoff for about 3 hours and on average, 79% of facilities had a runoff reduction through retention and infiltration. Based on the analysis, pollutant removal efficiency generated in the catchment area showed an average of 97% for the particulate matter, 94% for the organic matter and 86-96% and 92-93% for the nutrients and heavy metals were treated, respectively. Comparative results with other LID facilities were made. For this study, facilities compared the SA/CA to high pollutant removal efficiency for the determination to of the effectiveness of the facility when applied in an urban area.