• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.3
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• pp.63-70
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• 2018

This experiment was conducted to investigate nutrient leaching and mobility through soil column for application of biochar pellet during rice cultivation. For nutrient leaching through soil column experiment, it was also consisted with four treatments as control, 100% of pig manure compost pellet (PMCP), biochar pellet (pig manure compost:biochar, 6:4)(BP), and slow release fertilizer (SRF). For experimental results, it was observed that $NH_4-N$ concentration in the leachate was gradually decreased at pick of 35 days and $NO_3-N$ concentration was highest from 60 to 98 days after transplanting. $PO_4-P$ concentration in the leachate was shown to be lowest in the PMCP and BP. K concentration in the leachate was highest in the control, but lowest in SRF. For mobility of nutrient in soil depths, it shown that $NH_4-N$ concentrations were highest from 40 to 60cm and did not significantly different among treatments except the control. It was observed that the deeper depth, the higher concentration for $NH_4-N$ concentrations, but for $PO_4-P$ concentrations the deeper depth, the lower concentration. And also $PO_4-P$ concentration was highest in the control. For K mobility in soil, its pattern was appeared to be approximately same between the control and PMCP, and between BP and SRF. Therefore, it might be potential to be applied biochar pellet to reduce mobility of plant nutrients for rice cultivation.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.1
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• pp.19-29
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• 1994

The purpose of this study was to investigate the feasibility of composting of vegetable wastes containing high moisture. The parameters investigated were the effect of energy source addition, difference in bulking agent and recirculation of leachate produced during composting. Laboratory scale composting reactors were used in this study. Chinese cabbages were used as a vegetable waste. Dog food was added to the vegetable waste as a energy source. Wood chips and leaves of platan were used as bulking agents. There may be an appropriate amount of energy source to be added for composting high moisture content vegetable waste. In this study, the appropriate amount of energy source was 20% of the vegetable waste by weight basis. Recirculation of total amount of leachate produced each day on the same day may not be an appropriate approach due to the significant heat-quenching effect. When the total amount of leachate produced was equally devided and recirculated everyday through the whole composting period, the heat-quenching effect was comparatively less significant. There were no notable differences in the temperature profile and the $CO_2$ evoluation rate when leaves were used instead of wood chips as bulking agents. Considering waste recycling, it is desirable to use leaf waste as bulking agents if available, because the leaves are also wastes to be disposed of.

• Membrane Journal
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• v.21 no.4
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• pp.360-366
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• 2011

The effect of cross-flow velocity and transmembrane pressure (TMP) on membrane fouling was observed from pilot-scale operation of thermophilic anaerobic membrane bioreactor (AnMBR) treating food waste leachate. It was found that fouling rate was reduced significantly as cross-flow velocity increased at constant TMP mode of operation while this effectiveness was more pronounced at lower TMP. Higher TMP resulted in less permeable fouling layer possibly due to compressibility of foulant material on membrane surface. Particle sizes of membrane concentrate ranged from 10 to $100{\mu}m$, implying that shear-induced diffusion enhance back transport of these particle sizes away from the membrane effectively. From the continuous operation of AnMBR, it was confirmed that shear rate played an important role in the reduction of membrane fouling. Membrane autopsy works at the end of operation of AnMBR showed clearly that both organic and inorganic fouling were significant on membrane surface. Surface shear by cross-flow velocity was expected to be less effective to remove irreversible fouling which can be mainly caused by the adsorption of organic colloidal materials into membrane pores.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.49-57
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• 2000

This study was carried out to find the optimal condition to treat refractory organic matter which can’t treat clearly with biological treatment and to find the optimal division dosage and division dose timing in the modification of Fenton oxidation which is used resolve the problem that hydrogen peroxide is too expensive. The results are following; 1. The highest TOC removal efficiency was 41% and color removal efficiency was 64% when the dilution magnitude of leachate is fold. This suggests that dilution is efficiency when high concentration of leachate is treated. 2. The removal efficiency of TOC and color increased up to the molar ratio between ferrate and hydrogen peroxide was 1:1. However above that ratio, removal efficiency hardly increased. The highest removal efficiency of TOC and color were 38% and 71% when the mole ratio of ferrate to hydrogen peroxide was 1.5:1. 3. When the mole ratio between ferrate and hydrogen peroxide was fixed, the removal efficiency of TOC and color increased as the dosage of hydrogen peroxide increased. 4. pH of samples were adjusted at pH 3, 5, 7, 9, 11. After oxidation reaction, pH of samples were dropped to 2.59, 2.54, 5.34, 6.36 and 9.68. The highest color removal efficiency was 75.7% when initial pH was at pH 7. 5. The removal of TOC and color was ended within 10. min. and the removal efficiency increased logarithmically within 10min. However after 10 min., the removal efficiency of hardly increased. 6. The color removal efficiency was higher with modification of fentone oxidation than that with fentone oxidation by 5%. Optimal division dosage ratio was 1:1 and optimal dose timing ratio was 2:1. However the TOC removal efficiency was not higher with modification of Fenton oxidation than that with Fenton oxidation.7. The CO $D_{Mn}$ /BO $D_{5}$ Ratio decreased with the time went by. It meant bioresolution increased as time went by. However, after 15 min., the CO $D_{Mn}$ /BO $D_{5}$ Ratio did not decrease any more. 8. In the case of $H_2O$$_2$ Divisiom Dose experiment, the increase of bioresolution was highest at the $H_2O$$_2$ Division dosage Ratio of 3:7.3:7.

• Journal of Soil and Groundwater Environment
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• v.12 no.2
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• pp.55-64
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• 2007

An analytical method using ion-exchange chromatography was developed for simultaneous quantification of low-molecularweight organic acids ($C_1-C_6$ aliphatic carboxylic acids) and inorganic anions, and then applied to the assessment of ground water contaminated by leachates from a municipal solid waste landfill. Peak interferences of halide ions to organic acids were removed by pretreatment of water samples with Ag-containing cartridges. This method allowed accurate detection of low-molecular weight organic acids (i.e., formate, acetate, propionate, pyruvate, succinate, and oxalateas) low as 0.5 mg/L with a linear dynamic range up to 20 mg/L within 11 min run time along with typical inorganic anions. High level of pyruvate and low level of formate and acetate were detected in groundwater and landfill leachates using the analytical method. Pyruvate concentration in groundwater showed a significant correlation with concentrations of $Cl^-$ and $HCO_3^-$, and pyruvate levels decreased along the downgradient from the landfill, indicating the sources of pyruvate are landfill leachate.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.768-774
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• 2008

To evaluate the effect of the solidified/stabilized sewage sludge on landfill sites, lysimeter tests were conducted. Lysimeters (LR1, LR2, and LR3) were filled with the material(Compost : Fodder : Sand = 10 : 10 : 80) and covered with different types of the cover soils, the G solidified sludge produced from the neutral solidifying chemical agent(LR1), the A solidified sludge produced from the alkali solidifying chemical agent(LR2), and the weathered granite soil(LR3). Those lysimeters were kept at the temperature controlled room with 30 $\pm$ 2$^{\circ}C$ for about 450 days. As the results, it was appeared LR2 > LR1 > LR3 that total gas production rate(L), gas production rate(L/VS(kg)) and cumulative gas(CO$_2$ + CH$_4$) production. There were not significant differences at decrease of the COD$_{Cr}$ in the leachate from LR1 and LR3. Thus, it had been shown that the use of the G solidified sludge as cover soil did not affect the COD$_{Cr}$ in the leachate. The COD$_{Cr}$ from LR2 had been increased since around 250 days because solidified/stabilized sewage sludge became re-slurry. T-N and T-P from LR3 also were higher than LR1 and LR2. Also were, the use of the solidified/stabilized sewage sludge as a cover soil, therefore, did not affect the T-N and T-Pconcentrations in the leachate.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.10
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• pp.583-589
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• 2015

This study was performed to evaluate the feasibility of anaerobic pretreatment for the leachate solubilized from thermal hydrolysis of sewage sludge cake. Overall process for the treatment of sludge cake consists of thermal hydrolysis, crystallization of magnesium, ammonium, and phosphate (MAP) for the leachate and anaerobic digestion of supernatant from MAP crystallization. The experimental evidence showed that the optimum ratio of Mg : P for the struvite crystallization of leachate solubilized from thermal hydrolysis of sludge cake was 1.5 to 1.0 as weight basis at the pH of 9.5. With this operational condition, the removal efficiencies of ammonia nitrogen and phosphorous achieved 50% and 97%, respectively. The mesophilic batch test showed that the ultimate biodegradability of the supernatant from MAP crystallization reached 63% at S/I ratio of 0.5. The readily biodegradable fraction of 90% ($S_1$) of the MAP supernatant BVS (Biodegradable Volatile Solids, $S_0$) degraded with $k_1$ of $0.207day^{-1}$ for the initial 17 days where as the rest slowly biodegradable fraction ($S_2$) of 10% of BVS degraded with $k_2$ of $0.02day^{-1}$ for the rest of the operational period. Semi-Continuously Fed and Mixed Reactor (SCFMR) was chosen as one of the best candidates to treat the MAP supernatant because of its total solids content over 6%. Maximum average biogas production rates reached 0.45 v/v-d and TVS removal efficiency of 37~41% was achieved at an hydraulic retention time (HRT) of 20 days and its corresponding organic loading rate (OLR) of 1.43 g VS/L-d.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.317-324
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• 2007

Fluorescence measurements of dissolved organic matter(DOM) have the superior advantages over other analysis tools for applying to water quality management. A preliminary study was conducted to test the feasibility of applying synchronous fluorescence measurements for tracing and monitoring pollution sources in a small stream located in an upstream area of the Sooyoung watershed in Busan. The water quality of the small stream is affected by leachate from sawdust pile and discharge of untreated sewage. The sampling sites included an upstream site, two pipes discharging untreated sewage, leachate from sawdust, and a downstream site. Of the five field samples, the leachate was distinguished from the other samples by a high peak at a lower wavelength range and a blunt peak at 350nm, suggesting that synchronous fluorescence can be used as a discrimination tool for monitoring the pollution. The efficacy of various indices derived from the spectral features to discriminate the pollution source was tested for well-defined mixture of the sawdust leachate and the upstream stream by comparing (1)the difference between measured values and those predicted based on mass balance and the characteristics of the two samples and (2)the linear correlations between index values and mass ratios of the sample mixtures. Of various discrimination indices selected, fluorescence intensities at 276 nm$({\Delta}\lambda=30nm)$and 347 nm$({\Delta}\lambda=60nm)$ were suggested as promising potential discrimination indices for the sawdust pollution source. Despite the limited number of samples and the study area, this study illustrates the evaluation process that should be followed to develop rapid, low-cost discrimination indices to monitor pollution sources based on end member mixing analyses.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.717-724
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• 2012

Salt accumulated soil should be reclaimed to lower salt level for crop production. This study was carried out to investigate the characteristics of water flow and transport of mono and divalent solutes on salt accumulated soils with different head pressures. Saturated hydraulic conductivity was measured by constant and falling head methods with maintaining different head pressures. Saturated hydraulic conductivity was influenced by bulk density and organic matter contents in soils, but it had different elusion patterns between saline and sodic soil. While the quantity of water necessary for reclamation could be varies with soil type, it was considered that the supply of one pore volume of water was affordable and economic. Additional head pressure significantly increased the volume of leachate at a given time and it was more effective at low organic matter soils. The results indicate that additional head pressure would be one of the best irrigation practices on desalination method for salt accumulated soils.

• Journal of Korean Society on Water Environment
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• v.22 no.4
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• pp.720-726
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• 2006

Long-term monitoring results of water qualities at major lakes in Korea showed COD (chemical oxygen demand) concentrations have been increasing while BOD (biochemical oxygen demand) concentrations have been decreasing during last decades. This was mainly due to refractory organic matters have been accumulated in the water body. In this study, the possible causes of COD concentration increase were evaluated. From the statistics, it can be understood that potent pollutant sources including fertilizer consumption, population, livestock, and carbon uptake have increased. Leaching tests were carried out with soils and biomasses sampled at agricultural-forestry area. From the leaching experiments, leachate qualities as a ratio of $COD_{Cr}/BOD$ were in the range of 2.5-5.0, implying that NOM (natural organic matters) discharged from the forestry area was mainly responsible for the COD accumulation. It can be understood from this research that diffuse pollutants from forestry areas should be controlled properly to reduce COD accumulation in the lakes.