• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.194-200
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• 2000

The amount of swine wastewater reaches about $197,000m^3$ per day at live-stock houses in the whole country. A half of the swine wastewater resources are too small to be restricted legally. This untreated wastewater causes the eutrophication in the water bodies. In case of swine wastewater treatment, the solid-liquid separation must be performed because feces(solid phase) and urine(liquid phase) have large differences in nitrogen and phosphorus concentration. It is necessary to assess exactly the concentration of the pollutants in swine wastewater for planning the wastewater treatment facilities. A full-scale operation was carried out in K city and the plant is consists of conventional plant, the supplementary flocculation basin of chemical treatment process and $anaerobic{\cdot}aerobic$ basin for nitrogen removal. The improved full-scale swine wastewater treatment plant removed the $1,500{\sim}3,000mg/l$ of total-nitrogen(T-N) to 120mg/l of T-N and $131{\sim}156mg/l$ of total-phosphorus(T-P) to $0.15{\sim}1.00mg/l$ of T-N. Accordingly, as a results of operational improvement, the removal efficiencies of T-N and T-P were over $92{\sim}96%$, 99%, respectively. The continuous supply of organic carbon sources and the state of pH played important roles for the harmonious metabolism in anaerobic basin and the pH value of anaerobic basin maintained at about 9.0 for the period of the study.

• Korean Journal of Environmental Agriculture
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• v.13 no.3
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• pp.279-287
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• 1994

To develop mixed pesticides of herbicide and topdressing fertilizer for paddy rice, twelve mixtures were formulated with combination of urea coated with different level of acrylic acid wax(AAW) and four herbicides, which were thiobencarb, pretilachlor, mefenacet + bensulfuron-methyl and mefenacet + bensulfuron-methyl + dymron, and effects of the mixtures for weed control, phytotoxicity and rice tillering were investigated in the laboratory and the field experiments. Release rates of active ingredient of herbicides in the distilled water were over 90% during 24 hours same as that of the reference herbicides. The release rates of nitrogen showed different patterns according to coated level of granular urea with acrylic acid wax. Optimum release rate of nitrogen as $NH_4-N$ was obtained by 5.5% AAW coating on urea for thiobencarb or pretilachlor mixture, and by 4.0% AAW coating on urea for mefenacet + bensulfuron-methyl or mefenacet + bensulfuron-methyl + dymron mixture. The pesticide active ingredients of the mixtures were stable, which showed $3.7{\sim}8.0%$ of degradation rate after 90 days of storage under $50^{\circ}C$. Effects on weed control of mixtures were acceptable for both annual and perennial weeds, while ACRI-M9213 mixture showed considerable phytotoxicity at double dose of standard. When treated the mixed pesticides to paddy rice, rice growth status including culm length, ear length, panicle number and polished rice yield exhibited no significant differences compared with the conventional treatment.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.93-100
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• 2011

Maintenance of adequate soil water potential during the period of crop growth is necessary to support optimum plant growth and yields. A better understanding of soil water movement within and below the rooting zone can facilitate optimal irrigation scheduling aimed at minimizing the adverse effects of water stress on crop growth and development and the leaching of water below the root zone which can have adverse environmental effects. The objective of this study was to evaluate the feasibility of using a portable irrigation controller with an Watermark sensor for the cultivation of drip-irrigated vegetable crops in a greenhouse. The control capability of the irrigation controller for a soil water potential of -20 kPa was evaluated under summer conditions by cultivating 45-day-old tomato plants grown in three differently textured soils (sandy loam, loam, and loamy sands). Water contents through each soil profile were continuously monitored using three Sentek probes, each consisting of three capacitance sensors at 10, 20, and 30 cm depths. Even though a repeatable cycling of soil water potential occurred for the potential treatment, the lower limit of the Watermark (about 0 kPa) obtained in this study presented a limitation of using the Watermark sensor for optimal irrigation of tomato plants where -20 kPa was used as a point for triggering irrigations. This problem might be related to the slow response time and inadequate soil-sensor interface of the Watermark sensor as compared to a porous and ceramic cup-based tensiometer with a sensitive pressure transducer. In addition, the irrigation time of 50 to 60 min at each of the irrigation operation gave a rapid drop of the potential to zero, resulting in over irrigation of tomatoes. There were differences in water content among the three different soil types under the variable rate irrigation, showing a range of water contents of 16 to 24%, 17 to 28%, and 24 to 32% for loamy sand, sandy loam, and loam soils, respectively. The greatest rate increase in water content was observed in the top of 10 cm depth of sandy loam soil within almost 60 min from the start of irrigation.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.3
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• pp.189-197
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• 2012

Geochemical composition of fracture filling minerals and groundwater was investigated to characterize geochemical characteristics of groundwater system at the KURT site. Minerals such as calcite, illite, laumontite, chlorite, epidote, montmorillonite, and kaolinite, as well as I/S mixed layer minerals were detected in the minerals extracted from the fracture surfaces of the core samples. The groundwater from the DB-1, YS-1 and YS-4 boreholes showed alkaline conditions with pH of higher than 8. The electrical conductivity (EC) values of the groundwater samples were around $200{\mu}S/cm$, except for the YS-1 borehole. Dissolved oxygen was almost zero in the DB-1 borehole indicating highly reduced conditions. The Cl- concentration was estimated around 5 mg/L and showed homogeneous distribution along depths at the KURT site. It might indicate the mixing between shallow groundwater and deep groundwater. The shallow groundwater from boreholes showed $Ca-HCO_3$ type, whereas deep groundwater below 300 m from the surface indicated $Na-HCO_3$ type. The isotopic values observed in the groundwater ranged from -10.4 to -8.2‰ for ${\delta}^{18}O$ and from -71.3 to -55.0‰for ${\delta}D$. In addition, the isotope-depleted water contained higher fluoride concentration. The oxygen and hydrogen isotopic values of deep groundwater were more depleted compared to the shallow groundwater. The results from age dating analysis using $^{14}C$ indicated relatively younger (2000~6000yr old) groundwater compared to other european granitic groundwaters such as Stripa (Sweden).

• Journal of Environmental Science International
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• v.16 no.4
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• pp.523-532
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• 2007

This study utilized the 1/25,000 topographic map of the upper area from the Geum-ho watermark located at the middle of Geum-ho river from the National Geographic Information Institute. For the analysis, first, the influence of the size of critical area to the hydro topographic factors was examined changing grid size to $10m{\times}10m,\;30m{\times}30m\;and\;50m{\times}50m$, and the critical area for the formation of a river to $0.01km^2{\sim}0.50km^2$. It is known from the examination result of watershed morphology according to the grid size that the smaller grid size, the better resolution and accuracy. And it is found, from the analysis result of the degree of the river according to the minimum critical area for each grid size, that the grid size does not affect on the degree of the river, and the number of rivers with 2nd and higher degree does not show remarkable difference while there is big difference in the number of 1st degree rivers. From the results above, it is thought that the critical area of $0.15km^2{\sim}0.20km^2$ is appropriate for formation of a river being irrelevant to the grid size in extraction of hydro topographic parameters that are used in the runoff analysis model using topographic maps. Therefore, the GIUH model applied analysis results by use of the river level difference law proposed in this study for the explanation on the outflow response-changing characters according to the decision of a critical value of a minimum level difference river, showed that, since an ogival occurrence time and an ogival flow volume are very significant in a flood occurrence in case of not undertow facilities, the researcher could obtain a good result for the forecast of river outflow when considering a convenient application of the model and an easy acquisition of data, so it's judged that this model is proper as an algorism for the decision of a critical value of a river basin.

• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.333-339
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• 2017

This research was aimed to establish rapid analysis technique for the determination of nitrate ($NO_3{^-}$) concentration in the leaves of paprika, which has key role for the stable vegetative and reproductive growth. Leaf petiole and blade sap of two paprika cultivars ('Raon red' and 'Raon yellow') were used for the determination of $NO_3{^-}$ concentration, separately using rapid detection kit (RQ-flex) and spectroscopy quantification methods. In addition, two paprika cultivars namely, 'Nicole' and 'TP2001' were used to determine the status of $NO_3{^-}$ concentration in leaf of each fruiting group. $NO_3{^-}$ concentration in leaf blade sap and the content in leaf showed significant correlation ($R^2=0.8628$), analysed by RQ-flex and spectroscopy methods, respectively. Furthermore, leaf petiole sap and the content in leaf also showed significant correlation ($R^2=0.6734$) but the relationship was poor compared to leaf blade sap and the leaf content. $NO_3{^-}$ concentration in petiole sap decreased in all the cultivars from early to late fruiting group. The higher concentration in the lower leaves and the continuous decrease towards the upper leaves in the both years were found through the analysis of $NO_3{^-}$ concentration in different leaf position. In addition, daily short-term fluctuation of $NO_3{^-}$ in petiole sap could be rapidly monitored. These results showed that long-term or short-term monitoring by test strip-based rapid analysis technique might be useful tool for the diagnosis of nutritional status for the stable of nutritional management in paprika.

• Korean Journal of Ecology and Environment
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• v.47 no.1
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• pp.53-61
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• 2014

The origin of particulate organic matter (POM) and food web structure were investigated in Shingu reservoir based on stable isotope analysis from pre-monsoon (July) to post-monsoon (September) 2007. According to the depth in Shingu reservoir, the $^{13}C$ and $^{15}N$ values of POM for pre-monsoon period were nonsignificant distinction, while it was significant variation after rainfall period. The ${\delta}^{13}C$ values of POM in premonsoon period ranged from -25.1‰ to -26.1‰ in whole water column, but the ${\delta}^{13}C$ values of POM in post-monsoon period showed relatively wide range between -23.2‰ and -27.5‰. The apparently lighter values (average -27.5‰) in near bottom water (7 m water depth) demonstrate that POM in high turbid water in post-monsoon period may be derived from the outside terrestrial plants (allochthonous) through heavy rainfall during the summer monsoon period. After rainfall period, $^{13}C$ and $^{15}N$ values of D. brachyurum showed -23.3‰ and 12.2‰, respectively, while B. longirostris showed -27.1% and 8.7%, respectively. It suggested that D. brachyurum mainly feed on POM in autochthonous organic matter pool, but B. longirostris mainly consumed POM in allochthonous organic matter pool after rainfall period. Carbon and nitrogen stable isotope ratios were markedly different among secondary consumers. The carp (C. carpio) and catfish (S. asotus) were in the higher trophic level and crucian carp (C. auratus) and mudfish (M. mizolepis) were in the lower trophic level. $^{13}C$ and $^{15}N$ values of Z. platypus didn't significantly changed between before and after rainfall period. But P. parva and C. auratus apparently changed the $^{13}C$ and $^{15}N$ values after rainfall period. It is suggested that P. parva and C. auratus seem to feed allochthonous food source while Z. platypus depend on autochthonous food source.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.227-234
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• 2017

This study aimed to investigate the nutrient solution developed by based on nutrient-water absorption rate of strawberry 'Maehyang' by comparing growth and yield for 8 months with 5 kinds of nutrient solution with different ion composition. Strawberry plants were planted at elevated bed and supplied with five kinds of nutrient solutions (RDA), Yamazaki, PBG, University of Seoul (UOS) and NewUOS from one month onwards. Five types of nutrient solution were supplied to the strawberry plants associated with EC $1.0dS{\cdot}m^{-1}$, pH 6.0, $150{\sim}300mL{\cdot}plant^{-1}$ per day. At 60 days after planting, leaf width and leaf petiole of the strawberry plants showed significant differences among nutrient solution types and photosynthesis was higher in RDA and NewUOS nutrient solution and lower in PBG nutrient solution. The EC of the drainage on vegetative growth stage was $0.7{\sim}0.8dS{\cdot}m^{-1}$, which is lower than the supplied EC level, and to $1.0-1.2dS{\cdot}m^{-1}$, afterwards. The pH of the drainage was higher in Yamzaki solution as 6.2~6.8, while the pH of the UOS nutrient solution was lower in 5.1~5.2. Nitrate content was most absorbed in vegetative growth stage and after flower clusters development. The potassium uptake was highest at the NewUOS followed by UOS and Yamazaki nutrient solution. At six months after -planting fresh weight and dry weight of shoot and root were higher in UOS and NewUOS nutrient solution than other nutrient solutions, and the dry matter ratio was lower at 43.5% in Yamazaki nutrient solution and 30.6% in NewUOS nutrient solution than other solutions. Length, width, weight, and sugar content of the strawberries harvested from December to February were unaffected by treatment, but yield was higher in NewUOS nutrient solution due to increasing fruit number and average weight. From March to May, number of fruit was higher in Yamazaki nutrient solution. In conclusion, there was no difference in the growth of 'Maehyang' when 5 nutrient solutions were grown under hydroponics. But in order to improve the marketability, the NewUOS nutrient solution is appropriate to use from planting to February and it is suitable to use Yamazaki nutrient solution after March when temperature is high and the amount of fruit set per inflorescence.

• Economic and Environmental Geology
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• v.36 no.1
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• pp.39-48
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• 2003

The removal of chromate from aqueous solution using finely ground pyrite and biotite was investigated by batch experiments and the kinetics and the mechanism of chromate reduction were discussed. The chromate reduction by pyrite was about hundred times faster than that by biotite and was also faster at pH 3 than at pH 4. When pyrite was used, more than 90% of initial chromate was reduced within four hours at pH 4 and within 40 min. at pH 3. However, more than 400 hours was taken for the reduction of 90% of initial chromate by biotite. The results indicate that the rate of chromate reduction was strongly depending on the amount of Fe(II) in the minerals and on the dissolution rate of Fe(II) from the minerals. The reduction of chromate at pH 4 resulted in the precipitation of (Cr, Fe)(OH))$_3$$_{ (s)}$, which is believed to have limited the concentrations of dissolved Cr(III) and Fe(III) to less than expected values. When biotite was used, amounts of decreased Fe(II) and reduced Cr(Ⅵ) did not show stoichiometric relationship, which implying there was not only chromate reduction by ferrous ions in the acidic solution but also heterogeneous reduction of ferric ions by the structural ferrous iron in biotite. However, the results from a series of the experiments using Pyrite showed that concentrations of the decreased Fe(II) and the reduced Cr(Ⅵ) were close to the stoichiometric ratio of 3:1. It was because the oxidation of pyrite rapidly created ferrous ions even in oxygenated solutions and the chromate reduction by the ferrous ions was significantly faster than ferrous ion oxygenation.

• Journal of Animal Environmental Science
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• v.13 no.1
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• pp.13-20
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• 2007

Sawdust biofiltration is an emerging bio-technology for control of ammonia emissions including compost odors from composting of biological wastes. Although sawdust is widely used as a medium for bulking agent in composting system and for microbial attachment in biofiltration systems, the performance of agitated bed composting and sawdust biofiltration are not well established. A pilot-scale composting of hog manure amended with sawdust and sawdust biofiltration systems for practical operation were investigated using aerated and agitated rectangular reactor with compost turner and sawdust biofilter operated under controlled conditions, each with a working capacity of approximately $40m^3\;and\;4.5m^3$ respectively. These were used to investigate the effect of compost temperature, seed germination rate and the C/N ratio of the compost on ammonia emissions, compost maturity and sawdust biofiltration performance. Temperature profiles showed that the material in three runs had been reached to temperature of 55 to $65^{\circ}C$ and above. The ammonia concentration in the exhaust gas of the sawdust biofilter media was below the maximum average value as 45 ppm. Seed germination rate levels of final compost was maintained from 70 to 93% and EC values of the finished compost varied between 2.8 and 4.8 ds/m, providing adequate conditions for plant growth.