• Journal of Plant Biology
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• v.6 no.3
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• pp.1-5
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• 1963

Determination of the chemical properties in some forest soils and the naked soil developed on granite in the mountains of the vicinity of Seoul, Korea are presented in this study. The soil under the broad leaved forests has a higher nutrient indicated by available nitrogen, nitrate nitrogen, and phosphorus contents, compared with that under the needle leved forests. On the contrary the content of organic matter and base exchange capacity in the needle forest soils is higher than in the broad leaved forest soils. The significant difference between two horizons of each soil appeared only to be in the content of the available phosphorus, and that of the needle and the broad leaved forest soils, and the naked soils was the nitrate nitrogen and organic matter content among the several chemical properties.

• Journal of Korean Society on Water Environment
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• v.22 no.1
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• pp.7-16
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• 2006

The present study evaluated effect of temperature on removals of organic matter (C), nitrogen (N) and phosphorus (P) in Modified-Dephanox (M-Dephanox) process, which is hybrid system, comparing with those of Modified-Ludzack Ettinger (MLE) under the suspended-growth bacteria, as control. M-Dephanox process was more stable than MLE process in the removal of C, N, P, especially in nitrification, as the temperature was decreased from $25^{\circ}C$ to $16^{\circ}C$. As the temperature was decreased from $25^{\circ}C$ to $16^{\circ}C$, the removal efficiency of $NH_4{^+}-N$ of M-Dephanox process was decreased by 3.8%, but that of MLE process decreased by 25.7%. T-N removal efficiency of M-Dephanox was higher than MLE process by 27.1% and 26.9% at $25^{\circ}C$ and $16^{\circ}C$ of temperature, respectively.

• Journal of Korean Society on Water Environment
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• v.31 no.4
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• pp.418-427
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• 2015

This study was carried out to evaluate the performance of a lab-scale novel septic tank system for improving the conventional septic tank in the developing countries of water shortages. The lab-scale novel septic tank system consists of sepetic tank, aeration tank with HBC-ring, and sand filter. Optimum HRT was reguired about 1.5days to get a total COD removal efficiency of 90%, COD, BOD and SS removal efficiency was about 70%, 60%, and 85% in sepetic tank only. The structure of sepetic tank with two stages results in the high removal efficiency of organic matter. When sepetic tank, aeration tank, and sand filter were more than HRT 1.5days, 18hrs, and 12hrs, respectively, final effluent was less than 20 mg/L of BOD, 14 mg/L of SS, so that there is a high potential of its use for reusing water in flush toilet. There is no significant effect of HRT change on nutrient removal. Total nitrogen removal efficiency was about 40%, final effluent was 30~40 mg/L of TN, total phosphorus removal efficiency was about 11~25%, final effluent was 9~12 mg/L of TP. Because there is very small amounts of organic nitrogen and phosphorus in effluent, it was possible to reuse water for agricultural use.

• Journal of Plant Biology
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• v.12 no.1
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• pp.15-21
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• 1969

In this experiment, the litters of each five species of neadle-leaf trees and broad-leaf trees were laid on each pot soils, which had same soil conditions, is the green house and the sil fertility of each pots were determined after four years. Chemical properties among each pot soils under litters of needle-laef trees showed remarkable different values in the pH, base exchange capacity, total exchangeable base, base saturation, organic matter, available phosphorus, exchangeable potassium and calcium, and that of broad-leaf trees showed respectively significant difference. The content of chemical components, such as total exchangeable base, organic matter, total nitrogen, available phosphorus and exchanbeable potassium, between pot soils under litters of the needle-leaf trees and the broad-leaf trees were significant at the 0.01 and 0.05 levels of the statistical probability. The fertility of soil under the influence of decayed fallen leaves is the highest value in the posts of broad-leaves and next to the pots of needle-leaves and the control pots the lowest. The pH value of the soil with various kinds of fallen leaves showed little difference among themselves, but it especially approached in the broad leaves plots gradually to neutral and hte non-treated plot showed acidity. Lespedeza bicolar and Castanea crenata are supposed to contribute to the fertility of soil. Pinus rigida showed excellent exchanged properties of soi. The leaves of Robinia pseudoacacia and Pinus koraiensis did not contribute much to the promotion of fertility of soil.

• Journal of The Korean Society of Agricultural Engineers
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• v.46 no.1
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• pp.107-117
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• 2004

Hourly monitoring data from Saemangeum estuary, which is expected to become freshwater, was analyzed to evaluate the water quality characteristics. Higher algal growth at spring season than winter influenced the high ratio of organic nitrogen to total nitrogen and concentration of chemical oxygen demand (COD). About 87.9％ and 59.7％ of organic nitrogen was observed at winter season and spring season, respectively. Daily salinity analysis at the mouth of two main rivers demonstrated that the Dongjin in river was more influenced by tidal effect and showed higher variation than the Mankyung river. The ratio of nitrogen to phosphorus (N/P ratio) was different with site (estuary versus sea area) and season (winter versus spring) remarkably. The N/P ratio was highest (32.74 ∼ 43.93) at estuary in winter and was lowest (1.78 ∼ 3.06) at sea in spring. The high N/P ratio at estuary area implies that phosphorus can be the limiting nutrient factor for algal growth as in general freshwater river, therefore, water quality management practice considering river characteristics rather might be needed in the Saemangeum estuary. The Saemangeum project is nationally recognized for its environmental issues, and especially water quality concern is a critical factor to make policy decision and further assessment with continued monitoring is strongly recommended.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.635-644
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• 1994

A mathematical model was developed to predict the concentrations of various nutrients in supernatants during aerobic digestion which is suitable to be employed in small wastewater treatment plants with such advantages as low capital cost and stable process. Significant reactions were determined with observing the behavior of nitrgen and phosphorus, and the model equations were built up in the form of simultaneous differential equations considering Mass Balance. Laboratory batch experiments were carried out at $20^{\circ}C$ and pH $7.5{\pm}0.5$ on the aerobic digestion of waste activated sludge at different solid levels. Nonlinear regression analysis was performed to estimate various reaction rate constants. The developed model can predict the behavior of Biomass N, dissolved organic N, $NH_4{^-}$-N, $NO_x{^-}$-N, and Biomass P, dissolved organic P, $PO_4{^-}$-P in aerobic digestion process. In this study, the results of simulation showed that dissolved nutrients had more effects on supernatants than nutrients in biomass, and phosphorus was more effective on supernatants than nitrogen.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.455-461
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• 2000

Abstract Spirulina platensis was grown in SWlUe waste to reduce inorganic compowlds and simultaneously produce feed resources. Spirulina platensis prefers nitrogenous compounds in Ibe order: $NH_4^{+}-N>NO_3^{-}-N>simple-N$ such as urea and simple amino acids. It even consumes $NH_4^{+}-N$ first when urea or nitrate are present. Therefore, the content of residual $NH_4^{+}-N$ in Spimlina platensis cultures can be determined by the relative extent of the following processes: (i) algal uptake and assimilation; (ii) ammonia stripping; and (iii) decomposition of urea to NH;-N by urease-positive bacteria. The removal rates of total nitrogen ffild total phosphorus were estimated as an indicator of the treatment effIciency. It was found that Spirulina platensis was able to reduce 70-93% of $P_4^{3-}-P$, 67-93% of inorganic nitrogen, 80-90% of COD, and 37-56% of organic nitrogen in various concentrations of swine waste over 12 days of batch cultivation. The removal of inorganic compounds from swine waste was mainly used for cell growth, however, the organic nitrogen removal was not related to cell growlb. A maximum cell density of 1.52 dry-g/l was maintained with a dilution rate of 0.2l/day in continuous cultivation by adding 30% swine waste. The nitrogen and phosphorus removal rates were correlated to the dilution rates. Based on the amino acid profile, the quality of the proteins in the Spirulina platensis grown in the waste was the same as that in a clean culture.ulture.

• Journal of Life Science
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• v.20 no.10
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• pp.1468-1475
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• 2010

Sulfate reduction rates (SRR) using $^{35}SO_4^{-2}$, sulfide producing rates (SPR) using gas chromatography, the number of sulfate reducing bacteria (SRB) using the most probable number (MPN) method, and soil components (moisture, ammonium, total nitrogen, total organic carbon, total carbon, total inorganic phosphorus, total phosphorus, and sulfate) using standard methods in the organic/conventional rice paddy soils, cleaned/polluted reservoir soils, and cleaned/polluted foreshore soils were studied with the change of seasons. The average SRR was more related to the number of SRB and soil components (especially nitrogen and phosphorus) than sulfate concentration. SRR was also recorded to be highest in October soil samples. However, SPR was higher in foreshore soils containing a high concentration sulfate than in fresh water soils, and it was also recorded to be higher in the polluted areas than in clean areas. From these results, we can conclude that the SRR and SPR of anaerobic environments were affected by the number of SRB, soil components and temperature.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.253-258
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• 2004

There have been several problems in treating shipbard sewage due to special environmental conditions of ship, such as limited space, rolling and pitching, change of temperature and so on It was suggested that Sequence Batch Reactor (SBR) might be suitable process for overcome these problems in terms of small size, high capacity of treating wastewater and full automation. In this study a SBR process was employed for biological treatment of organic wastes in the shipboard sewage. This process was able to remove nitrogen and phosphorus as well as organic matter efficiently. Afore than 95％ of chemical oxygen demand(COD) were removed. In addition, about 97％ of total nitrogen (T-N) was reduced. The total phosphorus(T-P) reduction averaged 93％. A disturbance operation caused by the treatment of Methylene Blue Active Substances(MBAS) was not observed.

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.709-717
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• 2008

The field scale experiment which is constructed with four sets (0.88 ha for each set) of wetland (0.8 ha) and pond (0.08 ha) systems was performed to examine the effect of plant coverage on the constructed wetland performance and to recommend the optimum development and management of macrophyte communities. After six growing seasons of wetlands, plant coverage was about 100%. And the concentration of DO showed low value (1.0~5.4 mg/L). This is caused by a blighted plant consumed dissolved oxygen with decay in water column. As the result, water column went to be anaerobic conditions and T-N removal rate are 58~67%. Dead vegetation increased nitrogen removal during winter because it is a source of organic carbon which is an essential parameter in denitrification. However, wetland released phosphorus caused by a blighted plant and accumulation, the removal rate of phosphorus might be decreased. To rise of DO concentration, the three open-waters were constructed in cell 3 and 4. Cell 3 has two open-waters (width 10 m, depth 1.8 m) and cell 4 has one open-water (width 20 m, depth 1.8 m). As the result, DO concentration and treatment efficiency of nutrient and BOD were improved. In case that constructed wetland is operated for a long time, physical circulation structure such as open water help continuous circulation of aerobic and anaerobic conditions. Through the constructed open-water, treatment efficiency of phosphorus and nitrogen in wetland could be improved effectively.