• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.1
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• pp.35-40
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• 2010

Corn stover, hemp woody core and tobacco stalk were treated by dilute ammonium hydroxide soaking for improving the enzymatic saccharification of cellulose and xylan to monosaccharides by commercial cellulase mixtures. As more lignin removal by dilute ammonium hydroxide impregnation led to more enzymatic saccaharification of cellulose and xylan to monosaccharides (corn stover vs tobacco stalk). There was no relationship between xylan removal by dilute ammonium hydroxide impregnation and enzymatic saccharification of polysaccharides in pretreated samples. Except corn stover, lower temperature and longer treatment ($50^{\circ}C$-6 day) was less lignin removal than higher temperature and shorter treatment ($90^{\circ}C$ 16 h). Corn stover showed the highest enzymatic saccharification of cellulose and xylan but tobacco stalk showed the lowest.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.2
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• pp.110-123
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• 2021

We investigated geochemical constituents of pore-water and sediment, rates of organic carbon (C_org) oxidation and sulfate reduction (SR), and benthic nutrient flux (BNF) to elucidate characteristic of C_org oxidation and its control in the coastal area near Lake Shihwa. The study sites were selected in the vicinity of Soraepogu (E0), Songdo tidalflat (E1) and Oido dock (E3) and in front of floodgate Shihwa tidal plant (E5). The C_org contents in the sediments and concentrations of ammonium and phosphate in pore water exhibited the highest value at EO, and gradually decreased toward the outer sea (E1, E3, E5). Rates of anaerobic C_org oxidation (260.6 mmol C m^-2 d^-1) and SR (91.4 mmol S m^-2 d^-1) at E0 were 4-9 and 6-54 times higher than at the site of outer sea (E1, E3, E5). Rates of SR at E3 and E5 accounted for 11-23% of anaerobic C_org oxidation, whereas it comprised 47-70% of anaerobic C_org oxidation at E0 and E1. Rates of C_org oxidation and SR showed a highly positive correlation with the concentration of dissolved organic carbon (r² = 0.795 and 0.777, respectively). The BNF at E0, E1, and E3 accounted for 120-510% and 26-178%, respectively, of the N and P required for primary production in the water column. Overall results suggest that the C_org oxidation in the sediment controlled by concentration of dissolved organic carbon in the pore water and the excessive C_org oxidation stimulates the benthic nutrient flux, which may cause a phytoplankton bloom in the water column.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.3
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• pp.243-248
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• 1996

To find out the oxidation process of potential acid sulfate soil(PASS) along with time. the PASS were treated with lime and ammonia water to adjust soil pH in laboratory column condition. pH range of PASS showed 6.5 to 7.5. however, complete oxidized PASS by $H_2O_2$ showed 2.1 to 2.5. After pilling the PASS under the natural condition. oxidation occured slowly from surface of the pilled soil. The oxidation of PASS proceeded slowly when the soil was in submerged condition. but quickly in dried condition. The content of sulfide-sulfur in PASS sharply decreased after exposing to the air and the decreasing rate was greater in dried than in submerged condition. The content of sulfate-sulfur continuously decreased in submerged condition. but increased in dried condition. Contents of $Fe^{+{+}}$ and $Al^{+{+}}$ in PASS were generally increased with time and the increasing rate was greater in submerged than in dried condition. Liming to PASS was slowly acting to pH change and ammonia water caused fast pH change within a short period of time. The contents of sulfate-sulfur and exchangeable aluminum in drainage water decreased with time and the contents of sulfide-sulfur and ferrous iron were increased.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.3
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• pp.206-213
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• 2014

Nutrients such as phosphorus and nitrogen have been widely known as important source of algal appearance in eutrophic water. In order to prevent lake eutrophication, it is required to remove these nutrients not only presented in the lake water, but also released from the sediment. In order to solve this problem this study, the trivalent lanthanum ions and ammonia Nitrogen ($NH_4{^+}-N$) for the adsorption capacity of a zeolite support as it combines the lake water has dissolved in the nutrient removal, as well as deposits in the eluted in the continuously adsorbing the complex to develop and study was to inhibit the growth of algae. In experimental results, lanthanum complexes when the adsorption characteristics were evaluated $PO_4{^{3-}}-P$ and the $NH_4{^+}-N$ removal was confirmed that has an excellent ability, when it applied lake water the time of Chl-a and the turbidity decreased. In this study, these results suggest that the lanthanum complexes produced inhibitory effects on algae in the lake water is determined to excellent. Further, when applied to a complex of lanthanum in lake water to a standard 48 hours Acute Toxicity Method of toxicity were measured, and the results for the toxic effect was not observed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3285-3294
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• 2012

A field test on mud flat remediation was carried out in order to observe the effects of the treatments such as microbial dose and an oxygen releasing compound like $CaO_2$. The size of each treatment site was $100m^2$ and the dosage was 3.6 kg per site. The 6 week monitoring showed that pH on two sites was below 7 and ORP increased from .178~-188 mV to .121~-142 mV. In Ignition loss and COD there were no significant changes. Meanwhile nitrogen and phosphorus concentrations changed: ammonia concentration decreased both on control and treatment sites. Nitrate nitrogen decreased more on combined treatment site than on single microbial treatment (11.3% vs. 7.3%) probably because the extra oxygen supplied by $CaO_2$ formed more oxic environment so that the facilitated nitrification might produce more nitrate but the nitrate would be much rapidly released into the water layer out of the sediment. That also explains the total nitrogen reduction(6.1%). Similarly, T-P and $PO_4-P$ reduced by 29% and 31.8%, respectively on combined treatment sites, resulting from the phosphorus release effect though the initial concentrations of the two factors were considerably high.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.2
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• pp.105-109
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• 2001

Poorly drained coarse textured paddy soils has harmful substances(e.g. $Fe^{2+}$, $H_2S$, organic acid etc.) due to reduction condition, and lower soil temperature during early stage of rice crop. The roots of the rice plant usually were distributed in the surface layer, and prone to lodged. To solve the problems, the study was carried out in the typical poorly drained, sandy loam textured paddy soils during 1997-1998. Coated urea and urea fertilizers were applied on the surface and whole layer mixed respectively. Yield of the surface fertilization of coated urea had increasing tendency but not significant. Advantages of this experiment was saving of about 30% of nitrogen fertilizer and top dressing labour, which would reduce possibility of water pollution.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.565-571
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• 2010

One of the disadvantages of flooding treatment for desalting from soils is that salts move to deep soils after flooding and at the end reaccumulate at the soil surface through capillary movements. This study was carried out to remove salts from soils in plastic film houses by a modified flooding method, drainage after flooding. The method successfully removed salts at the soil surface and salts did not move to the deep soil. Drained water containing N, P and K could be reused as fertilizer. By applying small amount of MgO, turbidity of water flooded decreased in 30 min by 95%. Struvite should be formed since the flooded water contain ammonia and phosphorous and their concentrations were decreased. This could be utilized as fertilizer which provides a slow-release source of phosphorus, magnesium and nitrogen that features low inherent water solubility.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.547-555
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• 2000

The surface water in the upstream and midstream of Nakdong river, which is being used as tap water and industrial water supply in Daegu city and Kyungpook province, was analyzed in its water quality. In addition, the sediments of which was analyzed in terms of heavy metal and organic substance contents. All the sampling was done in the drought season for 2 days of June 22-23 and carried out in 10 sampling sites. The sites cover the whole Kyungpook provincial region, starting from Yangsam Bridge in Chyeong Ryang Provincial Park as the upper end, to the Ko Ryung Bridge as the lower end sampling site of Nakdong river that flows through Kyungpook province. The 22 items including $NH^{+}_{4}$, $NO^{-}_{2}$ and COD were analyzed for surface water and 11 items including organic constituents(trichloroethylene, etc) and heavy metals were analyzed for sediments. The sediments samples were analyzed by elution testing method and acid dissolution method and then the results were compared with each other. All heavy metals in samples were determined by Inductively Coupled Plasma-Atomic Emission Spectroscopy(ICP-AES) and other constituents were analyzed by standard testing methods of the Korean Ministry of Environment.

• Journal of Applied Biological Chemistry
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• v.65 no.1
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• pp.1-6
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• 2022

Urea is one of the most common nitrogen fertilizer, but nitrogen use efficiency by crop is low because of rapid hydrolysis of urea and loss of nitrogen in environments. Therefore, it is important to control the nitrogen release from nitrogen fertilizers. In this study, pyroligneous acid (PA) was used as a mean to inhibit urease in soil and prevent excessive nitrogen release from urea. Active ingredient in PA (AI) inhibited ammonification of urea in soil by reducing extracted ammonium nitrogen at 79.7% compared to the soil without PA. In order to evaluate the effect of PA on fertilization efficiency of urea, Chinese cabbage (Brassica campestris var. Pekinensis) was cultivated in soil treated with urea and PA both in pot and field. For PA treatment, half amount of urea was used compared to the amount of urea conventionally applied to Chinese cabbage. The PA treatment with half amount of urea resulted in similar Chinese cabbage biomass to the conventional urea application. Nitrogen concentration in Chinese cabbage was less in PA treatment indicating that Chinse cabbage effectively used nitrogen. Consequently, fertilization of urea with PA will reduce amount of fertilizer and frequency of application.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.669-675
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• 2006

Intermittent aerobic digestion experiments using a sequencing batch reactor (SBR) were carried out in this study. Aeration ratio was found to be an important operation factor for the reduction of solids and nitrogen. As the sludge digested, organic nitrogen was released from the solids and oxidized to nitrate nitrogen. Biological denitrification was also significant and the denitrification rate was limited by aeration ratio. Under the condition of 0.25-0.75 of aeration ratio, acclimation of ammonia nitrogen was not observed and pH were preserved near neutral in the intermittent aerobic digestion. As the aeration ratio increased, solids reduction was increased whereas dissolved nitrogen removal was decreased. Based on the experiments, 17-2% of VSS reduction and over 80% of dissolved nitrogen removal were practicable by intermittent aerobic digestion using a SBR when the MSRT were designed 8-32 days and aeration ratio was operated about 0.25-0.75.