• Journal of environmental and Sanitary engineering
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• v.17 no.3
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• pp.46-51
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• 2002

This study was performed to treat a sewage at the upper stream of dam using modified sequencing batch reactor, During the operating period, average $COD_{cr}$, removal efficiency was about 85% but average T-N and ${PO_4}^{3-}-P$ removal efficiencies were 43% and 30% respectively. Because the organic matter was very low compared with nitrogen and phosphorous in influent($BOD_{5}/{NH_4}^{+}-N{\;}={\;}2,{\;}BOD_{5}/{PO_4}^{3-}-P{\;}={\;}15.6$), nitrogen and phosphorus removal efficiency was relatively low. Average nitrogen removal efficiency was 50 % at $10^{\circ}C$ or above and it was 36 % at $10^{\circ}C$ or below. As reactor was located in outdoor without any thermostat, temperature decreased at least $2.4^{\circ}C$ in the winter season. Therefore, if we would apply this modified sequencing batch reactor to sewage which concentration of organic matter was very low compared with nitrogen and phosphorous, we have to addition of external carbon and installation of any thermostat.

• Journal of environmental and Sanitary engineering
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• v.17 no.3
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• pp.89-98
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• 2002

The changes of conventional clarification process and an increase in treatment cost are required to meet increasingly stringent regulations related to the treated water quality. Although many enhanced coagulations have introduced to improve organic matter removal, the results to remove color, nitrogen and phosphorus as well as organic material have not been very efficient yet. The removal of waste matters such as SS, organic matter, color and turbidity contained in dyeing wastewater was carried out by using the combination of calcium hydroxide and magnesium sulfate. The flocculation was investigated as a function of coagulant dose, pH, mixing time, settling time and coagulant addition modes such as the sequential addition of the two coagulants and the simultaneous addition of them. The flocculation by the combination of calcium hydroxide and magnesium sulfate was compared with that by aluminum sulfate. The mechanism of flocculation was investigated as well. About 84% of color in dyeing watewater was removed by flocculation with combination of calcium hydroxide and magnesium sulfate.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.13-22
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• 1977

The following results were obtained in this work intended for getting more informations on features of phosphorus in Korean characteristic virgin, upland and paddy soils for knowing the ways how to evaluate the soil phosphorus availability and utilize fertilizers efficiently. 1. A large part of soil phosphorus is occupied by inorganic phosphorus in the soils of which the cultivated soils showed higher accumulation of applied phosphorus as inorganic forms than the uncultivated soils. The accumulation of organic phosphorus was indicated the highest in the paddy soils, and the lowest in the uncultivated soils. Than the cultuivated soil, the uncultivated soils have higher C/P ratio which was estimated to be related to soil fertility status essentially. 2. Iron phosphate was shown to be the most dominant form in soil phosphorus. Difference in parent rocks, from which the soils were originated, was shown to affect the carious distribution of phosphorus forms in the uncultivated soils to a large extent. The paddy soils have almost same distribution pattern of soil phosphorus forms regardless of different parent rocks. 3. The different methods for available phosphorus estimation extracted different amounts of phosphorus from the soils. Close relations between the available phosphours extracted with the different methods and the amounts of seil inorganic phosphorus were shown : e.g. between Fe-P and available-P by Olsen method. 4. Phosphorus absorption coefficient correlated negatively to soil inorganic phosphorus, and also to available phosphorus extracted with the several methods.

• Applied Biological Chemistry
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• v.17 no.3
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• pp.219-234
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• 1974

A series of experiments was conducted to study the behavior of the phosphorus added to the soils having the high phorphorus fixing capacity derived from volcanic ash in Cheju Island. Soil samples were taken from different depths of 0-10, 10-30, and 30-50cm in six citrus orchards where heavy application of phosphate fertilizer has been practised. Various forms of phosphorus were determined and phosphorus adsorption experiments were performed. The results obtained can be summarized as follows: 1. The content of inorganic phosphorus fractions determined by the method of Chang and Jackson was: water soluble P

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.753-767
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• 2013

Soil contamination has continuously increased worldwide, thus the remediation for the contaminated soils has risen steadily. However, the consideration of ecological safety for the remediated soils and their agricultural uses has been very limited. Therefore, this study was to investigate the influences of selected environmentally-friendly agricultural materials, organic by-product fertilizer (OF), charcoal (CC), and biochar (BC), as soil conditioners for improving poor chemical properties of fuel-oil removed soil by land farming technique. Two different remediated soils, remediated soil A (RSA) and remediated soil B (RSB), were selected. Soil texture of both RSA and RSB was sandy loam. The chemical properties of RSA and RSB were as follows: soil pHs of 8.5 and 8.7, soil organic matter contents of 7.4 and 5.5g $kg^{-1}$, total nitrogen contents of 0.26 and 0.10g $kg^{-1}$, available phosphorus concentrations of 7.2 and 4.4mg $kg^{-1}$, and exchangeable calcium concentrations of 14.8 and $11.7cmol_c$ $kg^{-1}$, respectively. Results of the properties were not reached for the optimal values for cultivating crops that were recommended by National Academy of Agricultural Science at Rural Development Administration in Korea. However, after applying OF, CC, and BC, the chemical properties of soils were selectively improved, which were that soil organic matter content and available phosphorus concentration increased, whereas the soil pH were not changed. In particular, the chemical properties were positively changed more with the application of 5.0% biochar. Thus, continuous management of the remediated soils with applying the eco-friendly agricultural materials can improve the quality of reme-diated soils.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.17
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• pp.135-142
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• 1974

A study on the metabolism of the chemical companents of endosperm and enbryonic othans of ginseng seeds during their germination were inverstigated and the results of the changes in the contents of nitrogen conponds, carbohydrates, lipids and phosphorus conpounds are summarized as follow; 1. When a seeding grows to 5cm the fresh weight of the embryonic organ incerases 13 times compared with that of its ripened embryo veore germination and its dry weight increases 4.5 times. On the other hand, about 65% of the dry weight of the endosperm is lost. 2. During germinarion the total nitrogen content of a sedding (endosperm+embryonic organ) decreases and when the seeding grows to 5cm there is a loss of 10% of total nitrogen content. At this time, soluble nitrogen content amounts to 40~50% of the total nitrogen, a comparatively high content. 3. When theseeding grows to 5cm, the total phosphorus content decreases by 15%. During the germination period 70~75% of the total phosphorus is distributed in the embryonic orang and 25% of it is in endosperm.In the embryonic organ 35~50% of the acid soluble phosphorus is inorganic phosphorus and in the endisperm, 20~25% of the acid soluble phosphorus is inorganic phosphorus,75~80% of the organic phosphorus is contained in the endosperm. 4.One the seedling grew to 2~3cm, carbohydrates such as soluble sugars,reducong sugars,nonreducong sugars, and crude starch interconverted remarkably. 5.After stratification (just before germination) the lipid content of the endosperm is about 54% of the total weight and lipid content of the embryo is about 61%. During germination 6.81mg of the fat contained in the endosperm per seed decreases to 4.13mg while the change of fat content in the embryonic organ is not so great.

• Journal of Ecology and Environment
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• v.43 no.2
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• pp.129-160
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• 2019

Background: Characterizing and describing soils and land use and make a suggestion for sustainable utilization of land resources in the Ethiopian Rift valley flat plain areas of Lake Chamo Sub-Basin (CSB) are essential. Objectives: To (1) characterize soils of experimental area according to World Reference Base Legend and assess the nature and extent of salinity problems; (2) characterize land use systems and their role in soil properties; and (3) identify best land use practices used for both environmental management and improve agricultural productivity. Methods: Twelve randomly collected soil samples were prepared from the above land uses into 120 composites and analyzed. Results: Organic carbon (OC) and total nitrogen (TN) were varied along different land uses and depleted from the surface soils. The soil units include Chernozems (41.67%), Kastanozems (25%), Solonchaks (16.67%), and Cambisols (16.67%). The identified land uses are annual crops (AA), perennial crops (PA), and natural forest (NF). Generally, organic carbon, total nitrogen, percentage base saturation (PBS), exchangeable (potassium, calcium, and magnesium), available phosphorus (P₂O₅), manganese, copper, and iron contents were decreased in cultivated soils. Soil salinity problem was observed in annuals. Annuals have less nutrient content compared to perennials in irrigated agriculture while it is greater in annuals under rainfed. Clay, total nitrogen, available phosphorus, and available potassium (K₂O) contents were correlated positively and highly significantly with organic carbon and electrical conductivity. Conclusion: Management practices that improve soil quality should be integrated with leguminous crops when the land is used for annual crops production.

• Applied Microscopy
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• v.14 no.2
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• pp.66-80
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• 1984

The organic phosphorus compounds have been widely used as an insecticide, since toxicity of these compounds is especially drastic to the insects than to men and other mammals. The organic phosphates are rapidly hydrolized and hence have little cumulative and ecologic effects. However, due to their acute toxic effects organophosphate have recorded rather high fatalities in men and domestic animals. The organic phosphorus compounds are powerful inhibitors to the carboxylic esterase enzymes such as acetylcholinesterase and pseudocholinesterase. As a result of firm binding characteristics of phosphate radicals to the active sites of enzyme, the activities of these enzymes are inhibited by the organophosphates. The organophosphates such as diazinon is easily observed from skin, gastrointestinal tract, conjunctivas and respiratory tract, and it is converted to more toxic form during metabolism in the liver The present study was carried out in order to investigate the hepatotoxicity of diazinon by observing the changes in the ultrastructure of cytoplasmic organelles of hepatic cells in albino mice. The animals were killed at 6, 12 and 24 hours after administration of 25mg/kg diazinon. The piece of hepatic tissue obtained from each animal was ultrathinly sectioned. The specimens stained by uranyl acetate and lead citrate double contrast methods were observed with JEM model 100B electron microscope. The results obtained were as follows: 1) A prominent dilatation and sacculation of the cisternae of rough endoplasmic reticulum associated with detachment of membrane bound-ribosomes, and disaggregation of the free ribosomes were recognized. 2) The hypertrophy of the smooth endoplasmic reticulum associated with depletion of the glycogen particles was observed. 3) The atrophy of cisternae of Golgi complex was observed. 4) A large number of secondary lysosomes (autophagic vacuoles and residual bodies) were formed. Consequently it is suggested that diazinon would induce disorganization of the cytoplasmic organelles of hepatocytes in albino mice.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.5-11
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• 2016

Background: As the decomposition of lignocellulosic compounds is a rate-limiting stage in the nutrient mineralization from organic matters, elucidation of the changes in soil enzyme activity can provide insight into the nutrient dynamics and ecosystem functioning. The current study aimed to assess the effect of thinning intensities on soil conditions. Un-thinned control, 20 % thinning, and 30 % thinning treatments were applied to a Larix kaempferi forest, and total carbon and nitrogen, total carbon to total nitrogen ratio, extractable nutrients (inorganic nitrogen, phosphorus, calcium, magnesium, potassium), and enzyme activities (acid phosphatase, ${\beta}$-glucosidase, ${\beta}$-xylosidase, ${\beta}$-glucosaminidase) were investigated. Results: Total carbon and nitrogen concentrations were significantly increased in the 30 % thinning treatment, whereas both the 20 and 30 % thinning treatments did not change total carbon to total nitrogen ratio. Inorganic nitrogen and extractable calcium and magnesium concentrations were significantly increased in the 20 % thinning treatment; however, no significant changes were found for extractable phosphorus and potassium concentrations either in the 20 or the 30 % thinning treatment. However, the applied thinning intensities had no significant influences on acid phosphatase, ${\beta}$-glucosidase, ${\beta}$-xylosidase, and ${\beta}$-glucosaminidase activities. Conclusions: These results indicated that thinning can elevate soil organic matter quantity and nutrient availability, and different thinning intensities may affect extractable soil nutrients inconsistently. The results also demonstrated that such inconsistent patterns in extractable nutrient concentrations after thinning might not be fully explained by the shifts in the enzyme-mediated nutrient mineralization.

• Journal of Environmental Health Sciences
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• v.37 no.1
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• pp.64-72
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• 2011

This study was performed to assess the removal efficiency on nitrogen, phosphorus and organic carbon in wastewater by spatial separation and internal recycling in a modified oxidation ditch process (modified OD). The performances of the modified OD were evaluated via laboratory-scale experiments. The process was operated at hydraulic retention times of 6-48 hours and solid retention times of 17-38 days. We found that organic carbon removal efficiency increased after the modified OD operation period. T-N removal efficiency remained stable; average T-N concentration of effluent was 8.02 mg/l after modified OD operation. In contrast, T-P concentration of effluent was over 1 mg/l. Nitrogen and phosphorus removal efficiency of modified OD at HRT 12 hr were 83.1% and 74.1%, respectively. Also, maximum efficiency was found at SRTs from 20 to 30 days. T-N removal efficiency was 83.1% at a C/N ratio from 3.0 to 3.5. However, T-N removal efficiency decreased at C/N ratios over 3.5. Also, T-P removal efficiency increased with HRT at C/P ratios in the same condition. Maximum efficiency was 74.1% at a C/P ratio from 25 to 28. T-N removal efficiency was 79.2% and T-P removal efficiency was 65.3% after M4 mode operation (added to the internal recycle line connected to the anoxic reactor). The modified OD with spatial separation and internal recycling developed in this study is, therefore, believed to be an improvement for solving problems in the nutrient removal technologies.