• Journal of Korean Society of Environmental Engineers
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• v.30 no.6
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• pp.616-620
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• 2008

The aim of this study was to investigate the influence of phosphate on the adhesion of Escherichia coli to porous media. Column experiments were performed to examine the effect of phosphate on bacterial adhesion to quartz sand and iron-coated sand. Results showed that bacterial mass recovery in quartz sand decreased from 74.5 to 35.4% as phosphate concentration increased from 0 to 16 mg/L. This indicated that bacterial adhesion to quartz sand was enhanced with increasing phosphate concentration. This phenomenon is due to the increase of ionic strength. In contrast, the mass recovery in the coated sand increased from 2.9 to 26.0% as phosphate concentration increased. This indicated that bacterial adhesion to the coated sand was reduced with increasing phosphate concentration, due to the preoccupation of favorable adsorption sites and competitive adsorption by phosphate.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.287-293
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• 2009

This study investigated the influence of ionic strength on the adhesion and release of bacteria (Escherichia coli, Bacillus subtilis, and Staphylococcus aureus) in quartz and iron-coated sands using column experiments. Results show that the mass recovery remained constant (E. coli = 13.7${\pm}$0.5%, B. subtilis = 9.8${\pm}$1.3%, S. aureus = 13.0${\pm}$2.1%) in iron-coated sand while it decreased from 80.7 to 45.3% (S. aureus) in quartz sand with increasing ionic concentrations from 1 to 100 mM. As the ionic concentrations of leaching solution was lowered from 100 to 0.1 mM, average 39.1% of bacterial detachment was quantified from quartz sand, but no bacterial release was observed in iron-coated sand. The phenomenon observed in iron-coated sand can be attributed to the inner-sphere complexes between bacteria and coated sand, which have minimal effect from ionic strength. This study improves our knowledge regarding the bacterial interaction with surface-modified porous media.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.7
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• pp.833-838
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• 2007

In this study, adhesion and transport of bacteria in positively-charged media was investigated with batch and column experiments. Bacterial species used in this study was Escherichia coli ATCC 11105(length: 2.2 ${\mu}m$, diameter: 0.6 ${\mu}m$) and media used were quartz sand(particle size distribution: 0.5-2.0 mm, mean diameter: 1.0 mm) and iron-coated sand. Batch results indicate that bacterial adhesion increased as the content of iron-coated media increased. At iron-coated media 0%(quartz sand 100%), around 46% of bacteria was adhered to media while at iron-coated media 100%(quartz sand 0%) about 97% was attached. Column results also show that bacterial adhesion was enhanced with an increase of iron-coated media content. As the iron-coated media content increased from 0 to 100%, bacterial adhesion increased from 8 to 94%. The experimental results demonstrate that positively-charged media could influence transport of bacteria in porous media.

• Geotechnical Engineering
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• v.4 no.3
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• pp.27-34
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• 1988

Soils behave non-linearly at high strain. This study investigated the non-linear behavior of silty sands (Mixture of Ottawa Sand and Quartz Powder) by resonant column tests. The results were ·compared with Ramberg-Osgood's non-linear equation. From the tests, it was shown that the change of shear modulus and damping ratio was more sharp at low fine content, high void ratio and low confining pressure. It was also found that famberg-Osgood parameter, R was approximately 2.0, however the range of C varied from 200 to 3200.

• Horticultural Science & Technology
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• v.16 no.3
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• pp.347-349
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• 1998

Slow sand filtration was modified and applied for the determination of eliminating efficacy of various fungi and for recommending an easy approach to growers. After 1,500 liter filtration, Fusarium oxysporum was eliminated by several substrates such as activated charcoal (92.5% elimination), silica (90.8%), vermiculite (90.5%), sand (82.3%), perlite (50.4%), and hydroball (21.2%). Silica was able to eliminate several fungi by maximal ratio, which was corresponded to Fusarium oxysporum 120 cfu/mL. Collectotrichum lagenarium 98 cfu/mL. Phytophthora capsici 82 cfu/mL, Botrytis cinerea 62 cfu/mL, Pythium spp. 42 cfu/mL, and Sclerotinia ssp. 52 cfu/mL. In this case, the change of EC was minor and pH was maintained to about 7. In deep flow culture of 'Ddooksum Cheokchookmyeon' lettuce and 'Seokwang' tomato, silica-, activated charcoal-, and vermiculite-based filtration system successfully eliminated Fusarium oxysporum and Phytophthora capsici from the nutrient solution. As a result, these plants were not diseased by ten weeks after inoculation. With this system, growers can easily control the root-zone fungi in the recirculating hydroponic system.

• Applied Biological Chemistry
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• v.14 no.3
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• pp.183-189
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• 1971

The studies reported herein were conducted to inquire the effect of fused siliceous materials which mixed with sand and quartz added calcium fertilzer on rice grown on low available silica content soil. The applied nitrogen level were examined for the two plots, nitrogen 10kg and 20kg per 10 a., and the siliceous materials(Wollastonite, Fused sand and Fused quartz) were applied as levels to 100kg, 300kg and 500kg per 10a. in the pots. The results are summerized as follows; 1. The available silica content solved in N/2 HCl solution of fused sand was more than of fused quartz but the silica solubility in 2% citric acid of fused quartz were higher than other. 2. The absorbed silica content by plant grown on the fused quartz plot was the highest among other siliceous materials and of fused sand and natural wollastonite were at almost equal. The ratio of absorbed silica of natural wollastonite was highest among them and in fused materials, the quartz was higher than sand. 3. The productivity of rice was increased by percentage of filled grain, weights of 1000 grains, and number of spikelets on account of the large quantity of the silica absorbed by plant Especially fused quartz showed the highest productive effect among siliceous materials and natural wollastonite and fused sand were similar effect. 4. From the above results. the fused quartz was selected as expelled siliceous fertilizer on rice plant among them and the fused sand was equal effect to natural wollastonite.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.185-204
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• 2024

This study was conducted for evaluation the geological, physical, and chemical properties of domestic sand by analyzing about 4,800 quality data of natural sand from river and land area surveyed until 2023 through the aggregate resource survey conducted by the Ministry of Land, Infrastructure and Transport. The average depth of the Quaternary unconsolidated sedimentary layer in Korea, which includes a sand layer, is about 10m (maximum depth 66m). The thickness of the sand layer within the sedimentary layer is most dominant in the range of 0.5m to 4.0m. This accounts for about 70% of the entire sand layer. In the sand layer, the ratio of sand, gravel, and clay is 60:20:10. Regardless of the provenance or geology, the sand is mainly composed of quartz, plagioclase, and K-feldspar, and the minor minerals are muscovite, biotite, chlorite, magnetite, epidote. The sand includes in 45~75% of quartz, 5~20% of plagioclase and K-feldspar, each other. And other minor minerals are included in 10%. The average grain size of sand is 0.5mm to 1.0mm, which accounts for 44% of sand samples. The water absorption rate and soundness are estimated to be suitable for aggregate quality standard in almost all sand, and the absolute dry density is suitable for 66%.

• Geotechnical Engineering
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• v.3 no.2
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• pp.7-16
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• 1987

The dynamic properties of soils are affected by parameters like, gradation characteristics, void ratio, confining pressure, etc. . This study mainly investigated experimentally the effect of gradation on the dynamic properties of sands with the effect of void ratio and confining pressure. Test results showed that shear modulus/damping ratio was increased/decreased with the decrease of void ratio and with the increase of confining pressure. When the fine content increased, shear modulus/damping ratio was decreased/increased. This study explained this phenomenon by the concept of the "effective number of contacts" and the "dead space".ot;dead space".uot;.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.1-7
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• 1992

Sand and silt size fractions of soils which were derived from five major rocks of granite, granite-geniss, limestone, shale, and basalt in Korea were studied. Determination of the mineralogical and chemical composition of rock-forming mineral breakdown which is accompanied by the formation of secondary minerals. The chemical composition of the fraction was largely changed with the content of weatherable and resistant soil minerals such as ferromagenesian minerals, carbonates, and guartz. In the sand fractions of the soils from the granite and granite-gneiss, chlorite-vermiculite mixed layers seem to be an intermediate weathering product prior to the weathering state of the formation of vermiculite from chlorite. Kaolin minerals in the silt fractions of the soils from the granite-gneiss are considered to be formed by the pseudomorphic transformation of plagioclase. In the sand and silt fractions of the soils derived from the limestone, large amount of calcite and dolomite seems to have been inherited from the parent rocks. The primary chloritc, micas, and feldspars are considered to be formed from the weathering remains after leaching of carbonate minerals during the soil formation. In the residual soils(Gueom series) developed from the basalt, quartz and micas were coexisted with plagioclase and augite inherited from the parent rock.

• Journal of the Korean earth science society
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• v.24 no.6
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• pp.568-577
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• 2003

The purpose of this paper is to examine the geomorphic processes of beach and sanddune development in the Chungcheong-Namdo Province. The sands consist mainly of quartz and feldspar with lesser amounts of mica and other heavy minerals. With the exception of those from the granite, the sands have a very fine texture. Another characteristic of the sand grains is low degrees of roundness and grading indicating that source areas for the material were in the vicinity of the accumulating field. Over the years, the beaches have receded as a response to the decreasing amount of depositional materials. The driving force for the formation and transformation of coastal dunes in the study area is dominant winds from the center of the Siberian High. To some extent, the erosion of coastal dunes has been a global phenomenon. The degradation process occurred most actively when spring tides attacked beaches, berms, and foredunes. The relief and shape of present-day coastal dunes is determined initially by the Pleistocene strata underneath. From the fact that the strata contained traces of frozen structure, it can be inferred that sediment once experienced the process of soil formation.