• Geomechanics and Engineering
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• v.15 no.4
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• pp.1005-1016
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• 2018

This paper presents an investigation on the properties of two types of cement kiln dust (CKD)-stabilized dredged sediments, silt and clay with a comparison to hydrated lime stabilization. Unconfined compressive strength (UCS) and California bearing ratio (CBR) tests were conducted to examine the optimal stabilizer content and classify the type of highway material. A strength development model of treated dredged sediments was performed. The influences of various stabilizer types and sediment types on UCS were interpreted with the aid of microstructural observations, including X-ray diffraction and scanning electron microscopy analysis. The results of the tests revealed that 6% of lime by dry weight can be suggested as optimal content for the improvement of clay and silt as selected materials. For CKD-stabilized sediment as soil cement subbase material, the use of 8% CKD was suggested as optimal content for clay, whereas 6% CKD was recommended for silt; the overall CBR value agreed with the UCS test. The reaction products calcium silicate hydrate and ettringite are the controlling mechanisms for the mechanical performance of CKD-stabilized sediments, whereas calcium aluminate hydrate is the control for lime-stabilized sediments. These results will contribute to the use of CKD as a sustainable and novel stabilizer for lime in highway material applications.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.5
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• pp.199-204
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• 2015

In this study, prevention methods of radial cracks generated inside of artificial lightweight aggregate made of reject ash and dredged soil were investigated. The reject ash and dredged soil had mixed with weight ratio of 7 : 3 and formed to spheric shape of 5~20 mm diameter, then, the aggregates were manufactured using flash sintering method at $1200^{\circ}C$ for 10 min. The formation of radial cracks in the aggregates were suppressed as the size of specimen decreased. Also, the addition of silica to aggregates had prevented generation of the radial cracks. As the size and the amount of silica powder added increased, the development of radial cracks was constrained. Therefore the artificial lightweight aggregate manufactured in this study expected to be applicable to many fields such as construction and environmental usages. Also it is expected to contribute greatly to increase the recycling rate of reject ash and dredged soil.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1C
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• pp.21-31
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• 2009

Based on the proven feasibility of bottom ash and tire shred-soil mixtures as lightweight fill materials, tire shred-bottom ash mixtures were suggested as a new lightweight fill material to replace the conventional construction material (soil) with bottom ash. Therefore, we carried out the field compaction test and performance test of large scale embankment in order to evaluate their suitability for the use of lightweight fill materials. In these tests, we could assess the settlement, earth pressure, stress-strain relation, vibration of large scale embankment which were made with tire shred-bottom ash mixture and the conventional fill material(weathered soil) respectively. The earthpressure and vibration transmission was decreased and the settlement behaviour of the 2 materials (tire shred mixture and weathered soil) was measured similarly under static/cyclic loading condition.

• Journal of Korean Society of Disaster and Security
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• v.17 no.3
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• pp.1-11
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• 2024

The purpose of this study is to develop a fluidity-improved refilling material that satisfies smooth construction and long-term durability in a low-temperature environment using special materials and field soil as a refilling material to develop technology for high-speed installation of long-term non-traditional pipelines on poor ground containing a large amount of organic soil in a low-temperature environment. To this end, a special cement material was developed, and an indoor test was conducted to determine the construction performance and durability of the fluidity improved refilling material mixed with the developed special material and field soil to meet the quality standards for field construction. The construction quality standard items of fluidity improved refill materials were set to meet the CLSM (ACI 229R-13) standard suggested by the American ACI (America Concrete Institute). In addition, in order to understand the applicability in a low-temperature environment, the test was performed with the same items at low temperature and compared with the indoor test results at room temperature.

• Korean Journal of Microbiology
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• v.49 no.4
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• pp.328-335
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• 2013

As a result of conducting a cultural experiment of tomato using chicken feather protein hydrolysate (CPH) which was mass produced by keratin protein degrading bacterium Chryseobacterium sp. FBF-7 (KACC 91463P), we found that the stem and the root of tomato showed significant improvement in growth. For the purpose of phylogenic interpretation, a comparison was drawn between the effect of CPH, a treated CPH and untreated, on the changes of bacterial populations by 454 pyrosequencing based on 16S rRNA gene sequences. Tomato rhizosphere soil untreated with CPH (NCPH) showed 6.54 Shannon index from 3,281 sequence reads, and the rhizosphere soil treated with CPH (TCPH) showed 6.33 Shannon index from 2,167 sequence reads, displaying that it does not affect the diversity. Bacterial populations were composed of 19 phyla in the rhizosphere soil, and the phylum Proteobacteria occupied 40% of total bacterial populations. Bradyrhizobium, Agromonas, Nitrobacter, and Afipia (BANA group) which belong to Bradyrhizobiaceae were abundant and commonly detected in both the treated and untreated soils, suggesting the dominance of bacterial group in rhizosphere soil. The results obtained showed that CPH treatment does not affect the indigenous bacterial populations present in the rhizosphere soil.

• Korean Journal of Organic Agriculture
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• v.14 no.2
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• pp.205-217
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• 2006

This research was carried out to investigate the effects of some organic materials such as rice straw, compost, hairy vetch, phosphate rock, magnesium lime powder and ash in the organic paddy fields, and also to develope the new technique for better soil management using described materials. The results are as follows; Height and tiller of rice plants were higher in chemical fertilizer than rice straw or compost, however, those of rice plants in hairy vetch-rice cropping system reached to chemical fertilizer. The Eh value of soil has decreased consecutively since on 30th, May because of the rising of soil temperature by an increase in the activity of microbes. As a result of measuring yield and yield components, there is not significant difference between treatment. The application of organic materials enriched the contents of available phosphorus, exchangible potassium and calcium in soil, and, also improved the physical properties such as pore space rates and bulk density. From the viewpoint of soil management technology in organic paddy fields, the application of rice straw or organic compost might cause the decrease of yield compared with conventional cultivation system, chemical fertilizer, however, the application of hairy vetch residues of soil compensated for growth and yield as well as improved the physicochemical property. Therefore, it is assumed that the cultivation of hairy vetch for winter season can be one of the useful methods for organic farming system.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.861-866
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• 2013

The aim of this study was to investigate the biodegradation of dissolved organic matter derived from animal carcass disposal soil using soil inhabited bacteria and to identify the bacteria involved in the biodegradation. The two soils were obtained from the animal carcass burial sites located in Anseong, Gyeonggi-do, Korea. The results indicated that during the biodegradation experiments (56 days), 48% of dissolved organic carbon (DOC) was mineralized within 13 days in soil-derived solution 1 (initial DOC = 19.88 mgC/L), and the DOC concentration at 56 days was $8.8{\pm}0.4$ mg C/L, indicating 56% mineralization of DOC. In soil-derived solution 2 (initial DOC = 19.80 mgC/L), DOC was mineralized drastically within 13 days, and the DOC concentration was decreased to $6.0{\pm}0.4$ mg C/L at 56 days (76% mineralization of DOC). Unlike DOC value, the specific UV absorbance ($SUVA_{254}$) value, an indicator of proportion of aromatic structures in total organic carbon, tended to increase until 21 days and then decreased thereafter. The $SUVA_{254}$ values in soil-derived solutions 1 and 2 were the highest at 21 days. The microbial analysis demonstrated that Pseudomonas fluorescens, Achromobacter xylosoxidans, Nocardioides simplex, Pseudomonas mandelii, Bosea sp. were detected at 14 days of incubation, whereas Pseudomonas veronii appeared as a dominant species at 56 days.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.4
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• pp.420-426
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• 1998

This investigation was undertaken to clarify the effects of application of chemical fertilizers (Compound fertilizer and commercial compost) and organic matters (straw and clover) on changes of the composition of soil actinomycetes flora. Actinomycetes were isolated from chemical fertilizer and organic materials treated soils, and then grown on HV agar plate. The isolated strains were classified by Bergey's manual based on the morphological characteristics and color of substrate mycelium of actinomycetes. The number of actinomycetes increased 4 times in control, 36 times in clover, 20 times in straw, 5 times in chemical fertilizer and 4 times in commercial compost treated soil after 14th day of incubation. This result suggests that the application of straw or clover is more effective to increase the number of actinomycetes than compound fertilizer or commercial compost. It also showed that the application of chemical fertilizer or organic materials considerably changed the composition of soil actinomycetes flora. The proportion of streptomyces strains to the isolated total actinomycetes was 62% in control, 60% in clover, 68% in straw, 67% in chemical fertilizer and 64% in commercial compost treated soils at the 14th day.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.1
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• pp.72-81
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• 2007

This study mainly aims at suggesting plans applicable to the outdoor of environment-friendly communities in Korea by leveraging more natural conditions and materials when creating an outdoor biotop for an environment-friendly community and generating material types and development techniques enabling a natural circulation system. To this end, materials used in the outdoor of environment-friendly communities and traditional residential areas in Korea and biotop materials found in natural areas were examined. First, when the case examples of environment-friendly communities were reviewed, biotop spaces and materials that may function as habitats were hardly found. Materials used in biotop were mainly man-made structures made of artificial or processed materials, such as concrete, stones, bricks, woods and steels. Meanwhile, the outdoor space of traditional Korean villages had stone walls, soil walls, rock piles and composite piles, which composed of natural materials such as rocks, soil and plants, that naturally formed porous spaces along with the introduction of plants and provided habitats for a variety of insects. In natural areas, naturally created biotop spaces, such as rock piles, log piles, old tree deployment, branch piles, hay stacks and defoliated leaves, were found. Meanwhile, when spaces and materials available for biotop creation were reviewed to create an environment-friendly residential complex, they were divided into fences and hedges, green spaces between parks and residential buildings, ponds and waterscape spaces, zones separating pedestrian walks and roadways, breast walls and slope boundary, plant box and pergola. For each space, materials used for creating biotops and that were found in traditional Korean residential areas and natural areas were applied and suggested.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.66-74
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• 2016

Environmental pollution from abandoned metal mines has been awarded as serious problem and many techniques have been applied to remediate pollutants. Main objective of this research was to evaluate efficiency of heavy metal sorption capacity of spent mushroom media (SMM) in aqueous and soil matrix. Laboratory batch experiment was conducted and 4 different heavy metals (Cd, Pb, Cu, Zn) were evaluated. In aqueous phase, all 4 heavy metals showed high reduction efficiency ranged from 60-99% and Pb showed the highest sorption efficiency. In case of soil phase, much lower sorption efficiency was observed compared to aqueous phase. The highest reduction efficiency was observed in Cd (average of 38%). With scanning electron microscopy energy dispersive detector (SED-EDS) analysis, we confirmed sorption of heavy metals at the surface of SMM. Overall, SMM can be used as sorption materials for heavy metals in both aqueous and soil matrix and more research should be conducted to increase sorption efficiency of SMM in soil.