• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1799-1808
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• 2000

To investigate the applicability of loess as a coagulant. the optimum conditions of coagulation and efficiency comparison of several coagulants (PAC, PACS, LAS) in chemical treatment of livestock wastewater were performed. As a result, the optimum mixing ratio of loess and lime(CaO) was 3:7. The optimum dosage of the mixed coagulant was 30 g/L. The optimum speed for rapid mixing of the mixed coagulant was 200 rpm at 1 min. and the optimum speed for slow mixing was 50 rpm at 10 min. The mixed coagulant showed the removal efficiency of turbidity, SS, BOD, $COD_{cr}$. T-P and TKN to 95.8%, 92.5%, 71.6%, 71.1%, 98.2% and 32.5%, respectively, which was better than other several coagulants. The mixed coagulant was possible to use as substitutional coagulants of traditional coagulant, and the producted sludge can use as a soil amendments.

• Journal of the Korean Geographical Society
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• v.44 no.4
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• pp.463-480
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• 2009

The weathering properties and provenance of loess-paleosol sequence deposited on gravel layer of river terrace in Bongdong-eup, Wangju-gun, Jeonbuk Province are examined using soil analysis, magnetic susceptibility measurement, grain size and element analysis. The Bongdong section consists of, from top to bottom, Layer 1(paleosol), Layer 2(loess), Layer 3(paleosol) and the gravel layer of river terrace. The magnetic susceptibility values show the systematic variations in the sequence and the results of grain size analysis reveal that the sequence was deposited by not fluvial or slope process, but eolian process, and that contains finer materials than the Daecheon loess and Chinese Loess Plateau. Among the results of soil analysis, organic contents indicate systematic variations similar to the magnetic susceptibility. The wet soil colors further reflect the characteristics of the sequence rather than the dry soil colors. Based on the analytical results of major and rare earth elements, the eolian materials contained in the sequence were deposited by the materials originated from the areas where the Chinese Loess Plateau has been originated or the reworked materials from the Chinese Loess Plateau, and after the depositions, the materials experienced the intensive chemical weathering under the humid-warm climatic conditions in the Korean Peninsula.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.376-382
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• 2014

The soluble loess-sulfur mixture allowed standing to remove insoluble component materials for five weeks after manufacturing. We decreased the pH level of soluble loess-sulfur mixture at pH 1.0 modified with decreasing 25% sodium hydroxide than original content. The pH ranges of soluble loess-sulfur mixture solutions were adjusted to pH 5.0-pH 11.0 (pH 1 unit) with brown rice vinegar (pH 2.8). The pH of original loess-sulfur mixture was about pH 13 and damaged the foliar parts and young leaves of tomato after twice application. These stock solutions can be diluted 500:1 with tap water to make a 0.05% working solution and were sprayed two times with 7 days interval to the leaf and stem of tomato, which were spontaneously infected with E. cichoracearum. Control efficacy of powdery mildew ranged from 85% to 90% at 7 days after first application. After second application, each loess-sulfur mixture solutions adjusted pH level significantly suppressed the powdery mildew disease in tomato. Consequently, loess-sulfur complex adjusted pH level with brown rice vinegar was suggested to be low in acute toxicity at all different pH values and suggested to use an agent for control of tomato powdery mildew in organic farming.

• Journal of the Korean Geographical Society
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• v.42 no.6
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• pp.898-913
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• 2007

We examined soil properties and provenance of loess-paleosol sequences at the Daebo Granite area of Buan, Jeonbuk Province, South Korea. The section consists of the surface layer, Layer 1(paleosol), Layer 2(loess), Layer 3(paleosol), Layer 4(loess), and Layer 5(paleosol), from top to bottom and thickness of the exposed section is approximately 280cm. The magnetic susceptibility values show the distinct variations between the loess- and the paleosol layer. Even though pH, ORP, water content, and soil hardness do not display the obvious differences in the section, the organic content indicates the variation similar to those of the magnetic susceptibility. In the respect of the soil colors measured under 3 conditions, although the variations of the wet soil color exceedingly reflect the difference of the layers, these variations are obscure in some points in the section due to the characteristics of the Munsell color system. Based on the geomorphological properties, sedimentary structure, the difference of the major element composition and the condrite-normalized rare earth element(REE) patterns showing the clear difference from the adjacent bedrocks and stream sediments and the similarity to those of the Chinese Loess Plateau, it is suggested that the section was formed by the material originated from the Chinese Loess Plateau and peripheral areas. However, because the material experienced the alteration after sedimentation under the environment of the sediment area, it has the properties different from the material in the provenance areas. This phenomenon may result in the climatic condition of Korea, especially in precipitation.

• Korean Journal of Environmental Agriculture
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• v.34 no.1
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• pp.46-51
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• 2015

BACKGROUND: This study aimed at investigating the effects of sulfur-containing compounds widely used as environment-friendly organic fungicides against ginseng anthracnose, and determining the appropriate application concentration for lowering chemical injury to ginseng leaves. Ginseng anthracnose, caused by Colletotrichum gloeosporioides, is a destructive disease that significantly reduces the yield of ginseng. METHODS AND RESULTS: Ginseng anthracnose, caused by Colletotrichum gloeosporioides, is a destructive disease that significantly reduces the yield of ginseng. In a 2-year-old ginseng grown in a pot, treatment with loess-sulfur complex containing 0.06% sulfur and fermented loess-sulfur complex containing 0.13% sulfur did not show any chemical injuries. In order to measure the therapeutic effectiveness, various sulfur-containing compounds were applied to the plants after they were infected with ginseng anthracnose. Treatment with lime sulfur complex (400 dilution) showed the highest ginseng anthracnose control value, followed by fermented loess-sulfur complex (20 dilution), fermented loess-sulfur complex (40 dilution), and loess-sulfur complex (400 dilution) treatments. These compounds were applied before the outbreak of anthracnose disease in order to measure the preventive effectiveness, and in this case, treatment with fermented loess-sulfur complex (40 dilution) showed the highest control value and it was comparable to the value of the pesticide treatment used as the control in this experiment. CONCLUSION: Fermented loess-sulfur complex could be recommended as an environment-friendly organic material to control the occurrence of ginseng anthracnose.

• Resources Recycling
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• v.11 no.2
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• pp.45-51
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• 2002

This study was performed to investigate removal efficiency of wastewater by the prepared coagulant using waste oyster shell and loess. Waste oyster shell and loess contain respectively high CaO(55.43% by weight), $SiO_2$(45.30% by weight). Waste oyster shell was calcined to improve the purity of CaO at the calcination condition of $900^{\circ}C$ for 2hours, and then crushed 0.074 mm(200mesh) size by ball mill. Also, coagulant was prepared with calcined waste oyster shell and loess powder by hydration reaction. Calcined waste oyster shell and loess powder were combined with mixing ratio of 6 : 4, 7:3, 8:2 and 9:1. Though comparison experiment between prepared coagulant and chemical )$Ca(OH_2$, prepared coagulant was proved as having replaceable possibility of chemical )$Ca(OH_2$in wastewater treatment plant.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.266-270
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• 2000

Using the filtrate of loess suspension, we cultivated soybean sprouts and investigated its effect on growth and quality in soybean sprouts. In comparison with soybean sprouts cultivated by tap water, the soybean sprouts cultivated by the filtrate of loess suspension at $20^{\circ}C$ showed increases in its weight by 11.4% and length by 14.9%. When cultivated at $25^{\circ}C$, the soybean sprouts by filtrate of loess suspension also showed increases in its weight by 9.9% and length by 11.0%. We compared inorganic element contents and pH level between the filtrate of loess suspension and tap water. Contents of Ca, Mg, K, Na, Zn, Mn, and Cu did not show any difference, while only P was higher in the tap water. pH value did not show much difference either. Consequently, it seemed that inorganic element contents and pH in the filtrate of loess suspension did not give any effect on the growth of the soybean sprouts. And also there was no any significant difference in inorganic element and amino acid contents in two kinds of soybean sprouts. However in a sensory test, the color and overall acceptability of the soybean sprouts cultivated by the filtrate of loess suspension showed better than the soybean sprouts cultivated by the tap water.

• Journal of environmental and Sanitary engineering
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• v.19 no.2
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• pp.15-22
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• 2004

Yellow loess, Tidal plat sediment, and mud are blown to be high in adsorption though they have great distinction according to the ratio of clay minerals content and their kinds. Thus one of the samples for this study can be obtained by drying of Yellow loess, Tidal plat sediment, and the mud which is semifinished products that are from the progress of heat treatment and making homogeneity which can be found everywhere in our county. Another sample can be prepared by reducing pollutants with the adsorbent and by homing heavy metals of their on. With the samples, noxious heavy metals such as Pb, Cd, and essential trace elements such as Cu, Fe, Mn by each concentration is tested for adsorption according to pH, the kinds of adsorbents and the amount of injection. With the help of these steps, this study shows that the adsorbents, which are green, reducing the additional pollution and low in price, can be found. It also shows that the optimal condition for removing pollutants can be found and the basic materials for treating water can be offered. The results were as follows ; Yellow loess shows the rates of adsorption by more than 50% and Tidal plat sediment and Mud show it by more than 90%. Thus Tidal plat sediment and Mud are higher than Yellow loess the rates of adsorption. The pH should be treated in natural condition because the rates of adsorption of Pb, Cd, Cu, Mn excepting Fe in mud is higher in pH 7 than in pH 3 of Yellow loess, Tidal plat sediment, and Mud. The drying adsorbents are good to use because the rates of adsorption of heavy metals has tendency to be higher in the drying method than in the burning method. It is considered that the more the mont of the injection of the adsorbent is , the higher the rates of adsorption is, and one gram is reasonable for the amount of the injection of Tidal plat sediment and mud. Yellow loess is suitable for the treatment of the water that includes low concentration of heavy metals because it has the lower rate of adsorption as the concentration of noxious heavy metals is higher. It is thought that Tidal plat sediment and Mud is proper for the treatment of the water that includes high concentration of heavy metals because the rates of adsorption has not been changed as the concentration of heavy metals increases.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.455-462
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• 2000

The objective of this study was to examine the physicochemical characteristics of coagulation reaction between loess and red tide organisms (RTO) and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea. The physicochemical characteristics of loess were examined for a particle size distribution, surface characteristics by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrothen closterium and Skeietonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various concentrations of loess, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number. A negative zeta potential of loess increased with increasing pH at $10^(-3)M$ NaCl solution and had -71.3 mV at pH 9.36. Loess had a positive zeta potential of +1,8 mV at pH 1.98, which resulted in a characteristic of material having an amphoteric surface charge. In NaCl and $CaCl_2$, solutions, loess had a decreasing negative zeta potential with increasing $Na^+\;and\;Ca^(+2)$ ion concentration and then didn't result in a charge reversal due to not occurring specific adsorption for $Na^+$ ion while resulted in a charge reversal due to occurring specific adsorption for $Ca^(+2)$ ion. In sea water, loess and RTO showed the similar zeta potential values of -112,1 and -9.2 mV, respectively and sea sand powder showed the highest zeta potential value of -25.7 mV in the clays. EDLs (electrical double-layers) of loess and RTO were extremely compressed due to high concentration of salts included in sea water, As a result, there didn't almost exist EDL repulsive force between loess and RTO approaching each other and then LVDW (London-yan der Waals) attractive force was always larger than EDL repulsive force to easily form a floe. Removal rates of RTO exponentially increased with increasing a loess concentration. The removal rates steeply increased until $800 mg/l$ of loess, and reached $100{\%}$ at 6,400 mg/l of loess. Removal rates of RTO exponentially increased with increasing a G-value. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction. Loess showed the highest RTO removal rates in the clays.

• Korean Journal of Agricultural and Forest Meteorology
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• v.8 no.3
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• pp.169-173
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• 2006

This study used loess from the source region of Asian dust (a desert area in China) to analyze the effects of Asian dust on fruiting and fruit quality in Korean fruit trees. Asian dust and loess from the source region were highly alkaline compared to average Korean field soil. Organic material contents of Asian dust were about three times as high as that of the average field soil. Loess was dusted onto the stigma of apple, pear, and peach trees. fruiting, seed number, fruit quality and pollen tube elongation were investigated. Pollination and fertilization were not influenced while pollen tube elongation was slightly influenced. Consequently, fruiting, seed number and fruit quality were not affected by the dusting treatment.