• Journal of the Korea Organic Resources Recycling Association
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• v.30 no.3
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• pp.13-22
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• 2022

In order to improve water quality of the water system contaminated with dyes, biochars prepared using discarded waste resources were applied in this study. Biochars with a large specific surface area were manufactured using street tree pruning products or waste wood, and were applied to remove an organic dye in synthetic water. Biochars were made by pyrolysis of typical street tree porch products (Platanas, Ginkgo, Aak) and waste wood under air-controlled conditions. Methylene blue (MB), which is widely used in phosphofibers, paper, leather, and cotton media, was selected in this study. The adsorption capacity of Platanas for MB was the highest and the q_max value obtained using the Langmuir model equation was 78.47 mg/g. In addition, the adsorption energy (E) (kJ/mol) of MB using the Dubinin-Radushkevich (D-R) model equation was 4.891 kJ/mol which was less than 8 kJ/mol (a criteria distinguishing physical adsorption from chemical adsorption). This result suggests a physical adsorption with weak interactions such as van der Waals force between the biochar and MB. In addition, the physical adsorption may resulted from that Platanas-based biohar has the largest specific surface area and pore volume. The ∆G value obtained through the adsorption experiment according to temperature variation was -3.67 to -7.68, which also suggests a physical adsorption. Considering these adsorption results, the adsorption of MB onto Platanas-based biochar seems to occur through physical adsorption. Overall, it was possible to suggest that adsorption capacity of the biochr prepared from this study was equal to or greater than that of commercial activated carbon reported in other studies.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.709-716
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• 2021

In this study, an adsorbent prepared by natural drying of iron hydroxide-based sludge collected from settling basin at a mine drainage treatment facility located in Gangneung, Gangwon-do was used to remove fluoride in an artificial fluoride solution and mine drainage, and the adsorption characteristics of the adsorbent were investigated. As a result of analyzing the chemical composition, mineralogical properties, and specific surface area of the adsorbent used in the experiment, iron oxide (Fe₂O₃) occupies 79.2 wt.% as the main constituent, and a peak related to calcite (CaCO₃) in the crystal structure analysis was analyzed. It was also identified that an irregular surface and a specific surface area of 216.78 m²·g^-1. In the indoor batch-type experiment, the effect of changes in reaction time, pH, initial fluoride concentration and temperature on the change in adsorption amount was analyzed. The adsorption of fluoride showed an adsorption amount of 3.85 mg·g^-1 16 hours after the start of the reaction, and the increase rate of the adsorption amount gradually decreased. Also, as the pH increased, the amount of fluoride adsorption decreased, and in particular, the amount of fluoride adsorption decreased rapidly around pH 5.5, the point of zero charge at which the surface charge of the adsorbent changes. Meanwhile, the results of the isotherm adsorption experiment were applied to the Langmuir and Freundlich isotherm adsorption models to infer the fluoride adsorption mechanism of the used adsorbent. To understand the thermodynamic properties of the adsorbent using the Van't Hoff equation, thermodynamic constants 𝚫H° and 𝚫G° were calculated using the adsorption amount information obtained by increasing the temperature from 25℃ to 65℃ to determine the adsorption characteristics of the adsorbent. Finally, the adsorbent was applied to the mine drainage having a fluoride concentration of about 12.8 mg·L^-1, and the fluoride removal rate was about 50%.

• Journal of the Korean GEO-environmental Society
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• v.23 no.9
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• pp.33-40
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• 2022

Sedimentation and pH neutralization has been investigated as preteatment of acid contaminate water. The settling and neutralizing process derive more effective degradation efficiency as the pre-treatment process before the removal process of adsorption, volatile, biodegradation, or oxidation. Settling velocity, uniformity coefficient, coefficient of curvature, and grain size index can define in the sedimentation process for characteristics of the soil. The stainless steel sieve has been used to separate each particle size of the dry soil by assembling in order of 4, 10, 20, 40, 80, 100, and 200 mesh sizes. The soil from Gamcheon Port in Busan drops upper side of the sieve and shakes back and forth to separate each different size of the particle. The 1L of Imhoff cone and 200 mL of the mass cylinder were used as settling tanks to calculate settling velocity. Stokes' equation was used to figure out the average density of dry soil with a value from settling velocity. In the results, the average particle density and lowest settling velocity were 1.93 g/cm³ and 0.11 cm/s, respectively. These values can detect the range of settling points of sediment to prevent chemical accidents. In pH neutralization, the initial pH of 2, 3, 4, and 5 of nitric acid and sulfuric acid are used as an acid solution; 0.1, 0.01, and 0.001 M of sodium hydroxide and calcium hydroxide are used as a base solution. The main goal of this experiment is to figure out the volume percentage of the acid solution becomes pH 7. The concentration of 0.001 M of base solution exceeds all the conditions, 0.01 M exceeds partially, and 0.1 M does not exceed 5 v/v% except pH 2. Calcium hydroxide present less volume than sodium hydroxide at pH neutralization both sulfuric and nitric acid.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.404-412
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• 2021

Purpose: This study examined the degree of cartilage regeneration by performing second-look arthroscopy in a group of patients who underwent high tibial osteotomy and microfractures for unicompartmental osteoarthritis of the medial knee joint and to determine the factors affecting cartilage regeneration. In addition, this study analyzed whether there is a relationship between the degree of cartilage regeneration and functional results. Materials and Methods: From 2007 to 2015, this study evaluated 81 cases who underwent second-look arthroscopy at the time of plate removal after a microfracture and high tibial osteotomy with a minimum two-year follow-up. The degree of femoral cartilage injury before surgery was classified by ICRS (International Cartilage Research Society), and all were grade III and IV. After second-look arthroscopy, cartilage regeneration was classified into a well-regenerated group (grade I, II) and a poorly regenerated group (grade III, IV). The independent factors influencing cartilage regeneration were identified through multivariate logistic regression analysis. In addition, the functional results were compared before and after surgery between the two groups using the Knee Society score (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index score (WOMAC). Results: Age, sex, body mass index, postoperative radiologic factors, and preoperative joint condition did not affect the degree of cartilage regeneration significantly. The large cartilage defect (≥2.0 cm²) (p=0.011) and the presence of kissing lesions (p=0.027) were associated with poor cartilage regeneration. No significant difference in the KSS and WOMAC scores was observed between the group with good and poor cartilage regeneration. Conclusion: The presence of a large cartilage defect and kissing lesions is associated with poor cartilage regeneration after high tibial osteotomy and microfracture. On the other hand, the degree of the regenerated cartilage did not show any correlation with the functional outcome.

• Journal of Life Science
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• v.32 no.12
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• pp.971-978
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• 2022

Sulfur-oxidizing, ammonium-oxidizing, and nitrogen-oxidizing media were used to isolate bacteria to degrade malodor gas effectively in piggery manure or soil. Twelve different strains were isolated: Paenibacillus amylolyticus, Rhodococcus jostii, Rhodococcus qingshengii, Rhodococcus opacus, Alcaligenes faecalis, Alcaligenes faecalis, Kastia adipate, Kastia adipata, Microbacterium oxydans, Halomonas campisalis, Acinetobacter oleivorans, and Micrococcus luteus. By inoculating each strain in the piggery liquid manure by 1%, the pH in most strain treatments was maintained at 8.0. Total bacterial counts were maintained at 7.3~7.9 log CFU/ml until 15 days, and then they dropped dramatically down to 5.1~5.5 log CFU/ml. On the 30th day, the treatment group inoculated with Rhodococcus opacus SK2659 showed a relatively high level of ammonium nitrogen removal, which was 39% of that of the control group. When Rhodococcus opacus SK2659 was inoculated, H2S concentration after 100 days was 3.23% compared with the control (no inoculation), suggesting that Rhodococcus opacus SK2659 is an excellent strain for removing malodor gas. The gas production of the treatments was lower than that of the control. The total accumulated amount of gas production in most strain treatments was a quarter of the gas production compared to the control throughout the experimental periods. Acinetobacter oleivorans SK2675 showed the lowest level at 12.39% compared to the control in gas production. In conclusion, the use of mixture strains, such as Rhodococcus opacus SK2659 and Acinetobacter oleivorans SK2675 isolated in this study could increase the efficacy of malodor gas reduction in the biological treatment of piggery manure.

• Journal of Wetlands Research
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• v.24 no.3
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• pp.204-212
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• 2022

The LID technique began to be applied in Korea after 2009, and LID facilities are installed and operated for rainwater management in business districts such as the Ministry of Environment, the Ministry of Land, Infrastructure and Transport, and LH Corporation, public institutions, commercial land, housing, parks, and schools. However, looking at domestic cases, the application cases and operation periods are insufficient compared to those outside the country, so appropriate design standards and measures for operation and maintenance are insufficient. In particular, LID facilities constructed using LID techniques need to maintain the environment inside LID facilities because hydrological and environmental effects are expressed by material circulation and energy flow. The LID facility is designed with the treatment capacity planned for the water circulation target, and the proper maintenance, vegetation, and soil conditions are periodically identified, and the efficiency is maintained as much as possible. In other words, the soil created in LID is a very important design element because LID facilities are expected to have effects such as water pollution reduction, flood reduction, water resource acquisition, and temperature reduction while increasing water storage and penetration capacity through water circulation construction. In order to maintain and manage the functions of LID facilities accurately, the current state of the facilities and the cycle of replacement and maintenance should be accurately known through various quantitative data such as soil contamination, snow removal effects, and vegetation criteria. This study was conducted to investigate the current status of LID facilities installed in Korea from 2009 to 2020, and analyze soil changes through the continuity and current status of LID facilities applied over the past 10 years after collecting soil samples from the soil layer. Through analysis of Saturn, organic matter, hardness, water contents, pH, electrical conductivity, and salt, some vegetation-type LID facilities more than 5 to 7 years after construction showed results corresponding to the lower grade of landscape design. Facilities below the lower level can be recognized as a point of time when maintenance is necessary in a state that may cause problems in soil permeability and vegetation growth. Accordingly, it was found that LID facilities should be managed through soil replacement and replacement.

• Journal of the Korea Organic Resources Recycling Association
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• v.29 no.4
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• pp.67-76
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• 2021

Biogasification is a technology that produces environmentally friendly fuel using methane gas generated in the process of stably decomposing and processing organic waste. Biogasification is the most used method for energy conversion of organic waste with high moisture content, and is a useful method for organic waste treatment following the prohibition of direct landfill (2005) and marine dumping (2013). Due to African Swine Fever (ASF), which recently occurred in Korea, recycling of wet feed is prohibited, and consumers such as dry feed and compost are negatively recognized, making it difficult to treat food waste. Accordingly, biogasification is attracting more attention for the treatment and recycling of food waste. Korea's energy consumption amounted to 268.41 106toe, ranking 9th in the world. However, it is an energy-poor country that depends on foreign imports for about 95.8% of its energy supply. Therefore, in Korea, the Renewable Energy Portfolio Standard (RPS) is being introduced. The domestic RPS system sets the weight of the new and renewable energy certificate (REC, Renewable energy certificate) of waste energy lower than that of other renewable energy. Therefore, an additional incentive system is required for the activation of waste-to-energy. In this study, the operation of an anaerobic digester that treats food waste, food waste Leachate and various organic wastes was confirmed. It was intended to be used as basic data for preparing the waste-to-energy incentive system through precise monitoring for a certain period of time. Four sites that produce biogas from organic waste and use them for power generation and heavy gas were selected as target facilities, and field surveys and sampling were conducted. Basic properties analysis was performed on the influent sample of organic waste and the effluent sample according to the treatment process. As a result of the analysis of the properties, the total solids of the digester influent was an average of 12.11%, and the volatile solids of the total solids were confirmed to be 85.86%. BOD and CODcr removal rates were 60.8% and 64.8%. The volatile fatty acids in the influent averaged 55,716 mg/L. It can be confirmed that most of the volatile fatty acids were decomposed and removed with an average reduction rate of 92.3% after anaerobic digestion.

• Journal of Wetlands Research
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• v.25 no.3
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• pp.184-195
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• 2023

To develop an effective management plan for Ambrosia trifida L., an invasive alien plant in Korea, we assessed the potential of Ophraella communa LeSage as a biological control agent. This involved investigating the host specificity of the herbivore Ophraella communa LeSage, its annual travel distance, and the impact of this insect on the fitness of Ambrosia trifida L. We confirmed the host plant preference of Ophraella communa LeSage. The travel distance of this insect was determined by monitoring its appearance in selected Ambrosia trifida L. communities without these insects at distances of 10, 20, 30, and 100 meters, based on the locations where the presence of Ophraella communa LeSage was observed. The growth, reproductive, and physiological responses of Ambrosia trifida L. were measured according to feeding by Ophraella communa LeSage. As a result, Ophraella communa LeSage fed on only three taxa and moved short distances within a radius of 30 m per year from the host. The feeding behavior of the herbivore had a negative impact on the growth, reproductive, and physiological responses of Ambrosia trifida L. And the plant's growth and reproduction improved with increasing distance from the herbivore. Furthermore, the introduction of herbivores was able to control over 90% of Ambrosia trifida L. when the coverage of the Ambrosia trifida L. group was below 50%. However, the effectiveness of the removal decreased when the coverage exceeded 90%. These results are likely to be utilized by Ophraella communa LeSage as an ecological control agent. It is advantageous to introduce them in spring (May) when the coverage is low to maximize the effectiveness of control.

• Korean Journal of Environment and Ecology
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• v.36 no.1
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• pp.1-29
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• 2022

This study surveyed the Mt. Teomo·Hyeolgu and surrounding areas in Ganghwa Island, located in Ganghwa-gun, Incheon, to identify vascular flora and alien plants to be used as basic data for systematic management of the remarkable plants and biodiversity conservation. The survey was carried out 13 times from March 2019 to October 2020. The identified vascular flora of Mt.Teomo·Hyeolgu was 101 families, 321 genera, 517 species, 13 subspecies, 38 varieties, 5 forms, and 573 taxa. They accounted for about 12.35% of a total of 4,641 taxa of vascular plants in Korea. The identified Northern lineage plants, endemic plants, and rare plants on the Korean Peninsula as designated by IUCN were 68 taxa, 10 taxa, and 9 taxa, respectively. 69 taxa were classified as floristic target species. Three taxa, including Maui sedge [Carex thunbergii var. appendiculata (Trautv. & C.A.Mey.) Ohwi] were identified s Class IV and 14 taxa, including Violet Stanavoi clematis (Clematis fusca var. violacea Maxim.) were identified as Class III. The naturalized plants that appeared in the study site were 63 taxa, including daisy fleabane [Erigeron annuus(L.) Pers.], common ragweed [Ambrosia artemisiifoliaL.] and Canadian fleabane [Conyza canadensis(L.) Cronquist]. The above three species were found to have spread throughout Ganghwa Island and surrounding areas such as Seokmo Island, Gyodong Island, and Gimpo city. As introduced disturbing plants like prickly lettuce [Lactuca scariola L.], bur cucumber [Sicyos angulatus L.] and field dock [Rumex acetosella L.] have been newly reported in the Mt. Teomo·Hyeolgu area, mid- to long-term conservation measures should be established for native plants, such as remarkable plants, and also management measures like physical removal should be prepared at an early stage.

• Journal of the Korean Institute of Landscape Architecture
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• v.51 no.2
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• pp.94-102
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• 2023

The Florence Charter, established in 1981 by the ICOMOS-IFLA International Commission on Historic Gardens, considered the historic garden as a plant-dominated architectural composition, a perpetual balance between the artist and the artisan's desire to remain unaltered in perpetuity. Trees, the main component of the garden, require continuous management as they repeat their creation and calling according to the cycle of the seasons and accordingly, it is suggested that management to maintain the appearance of trees in Korean palaces was an indispensable element. Although it is an important matter to historically verify the tree management techniques of the palaces of the past, research has been difficult due to the absence of historical records and the disconnection of life due to the Japanese colonial period. In addition, according to the view that trees were not generally managed in the palace, research on palace tree management techniques has not been conducted so far. Therefore, this study aimed to examine whether or not the tree management of the palaces was performed in the past through expert interviews based on photographs taken in modern times. With the identification of tree species and pruning through in-depth interviews with experts using photographs taken in the modern period, the results are as follows. First, it was found that the shapes of trees and leaves could be identified through photographs and by observing the phenomena caused by planting and pruning, it was possible to estimate whether or not the tree management was implemented in the modern palace. Second, as a result of in-depth interviews with 8 experts in 4 fields, it was possible to determine the tree species and pruning status, purpose, and method. There was no significant difference in opinions between groups, and the evidence was clearly presented. Third, the type of management of trees in the palace was mainly found to be determination of the types of tree, removal of hazardous factors of trees, and management of lower vegetation and through the photographs of Jondeokjeong and Gwanwanjeong, it was confirmed that the trees were managed even before the Japanese colonial era, considering the time of filming. Based on the photographs taken, it was possible to estimate whether the trees were managed before the Japanese colonial period through expert interviews. However, it could not be clarified due to lack of historical materials as to whether it was carried out on its own according to the circumstances of the times or by the Japanese Empire. Still, in this study, evidence was obtained to refute the view that trees of the palace were not managed in the past through the collected data. Expert opinions supporting this view were collected to make the conclusion. In addition, based on the general theory of pruning, an empirical review of expert opinions was conducted to secure the reliability of the research results.