• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.121-132
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• 2000

This study is to investigate the performance of a new BNR process using predenitrification scheme focusing on nitrogen removal and the possibility of adapting a computer simulation scheme in BNR process development. By using a pre-denitrification basin, higher $COD/NO_3-N$ ratio could be sustained in this BNR process. The results of the investigation showed a SDNR value of 9.04mg/gMv/hr. In the anoxic tank, the average value of SPRR of 6.25mgP/gMv/hr was observed to be very sensitive to SCOD load of influents. By calibrating internal parameters (stoichiometric and kinetic parameters) of the simulation model, the results of simulation for various BNR processes gave good agreement with observed data. The major adjustment was given with three parameters, maximum specific growth rate of heterotrophic biomass, short chain fatty acid (SCFA) limit, and phosphorous release rate. With the series of simulations on varying operational conditions, the simulation by computer program can be a useful tool for process selection, and design and operation of municipal wastewater treatment plant.

• 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 Korean Society of Environmental Engineers
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• v.32 no.8
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• pp.761-766
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• 2010

This study was aimed to propose La(III)-zeolite composite which can effectively and simultaneously remove ammonia and phosphate in confined water bodies such as lakes and ponds. The optimum ratio of La(III):zeolite for the simultaneous removal of ammonia and phosphate was 0.0048 La(III) g:1 zeolite g. The drying temperature of La(III)-zeolite composite severely affected phosphate adsorption showing optimum condition at room temperature. It was revealed that the optimum dosage of La(III)-zeolite composite was 4.052 g/L at adsorption time of 90 min. The presence of alkalinity in aqueous solution brought positive effect on phosphate adsorption. Detachment of La(III) from La(III)-zeolite composite, which was dried at room temperature, was not observed in aquous solution. It indicates that La(III)-zeolite composite could effectively block phosphate released from sediment.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.414-414
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• 2019

농업으로부터의 비점오염은 지표수와 지하수 모두의 수질에 영향을 미친다. 특히, 비료, 퇴비, 농약 등의 인공적 질소가 살포된 토양은 강우시 화학 침출로 인한 수질오염이 발생되고 있다. 강우시 강우유출수와 함께 지표 수역으로 흘러들어오는 영양물질(질소, 인)은 저수지로 유입되어 침수시 작물이 죽게 되어 저수지의 부영양화 등의 수질 오염문제를 야기시킨다. 국내에서는 홍수조절용지에서의 영농활동의 전면 금지하고 있는 실정이지만, 불법적으로 경작활동이 진행되고 있다. 따라서, 본 연구에서는 다목적댐 홍수조절지 내 경작지 토양 및 양분 특성 평가를 수행하였다. 홍수조절지 내 경작지 토양 특성 및 양분 조사를 위하여 경작이 집중적으로 이루어지고 있는 대청호 지역을 모니터링 지점으로 선정하였다. 모니터링은 경작지 내 토양 시료 및 주변 토양을 채취하여 분석을 수행하였다. 채취한 토양은 토양표준분석법(농촌진흥청, 2012) 및 농업토양분석방법(국립산림과학원, 2014) 기준을 바탕으로 물리 화학적 분석을 수행하였다. 모니터링은 2018년 5월부터 수행되었으며 현재까지 월 1회씩 모니터링을 진행하고 있다. 연구 결과, 밭 경작지 토양은 논에 비해 실트질 함량이 절반으로 침투성이 높은 토양으로 분석되었으며, 영양염류의 침투를 통한 이동 가능(기저유출)이 높게 나타나는 것으로 조사되었다. 이는 중간유출 및 기저유출 저감방안 도입이 필요한 것으로 평가되었다. 작물별 토양 양분분석 결과 고추, 마늘, 담배 경작지에서 화학비료사용량이 타 작물에 비해 높은 것을 분석되었으며, 경작지에 화학비료 및 퇴비의 과다 사용으로 염류농도가 증가할 경우 전기전도도가 높아지며 토양의 삼투압을 증가시켜 물의 흡수와 각종 양분 흡수를 방해하는 것으로 평가되었다. 인의 존재 형태별 비교시 대부분의 경작지에서 높은 값을 보였으며, 특히 경작지 토양의 Residual-P의 농도가 원지반 보다 2~5배 정도 높게 나타났다. 이러한 원인은 퇴비의 사용으로 인한 Residual-P의 누적으로 평가되며, 환경변화에 따라 수층으로 인의 용출이 쉽게 발생하므로 향후 수질에 미치는 영향이 더 클 것으로 사료된다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.3
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• pp.188-197
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• 1999

In order to estimate the uranium flux from seawater to sediments, we took pore water samples and deployed benthic chambers on seafloor of Chonsu Bay, Korea. The uranium flux across the sediment-water interface was estimated from the pore water to be 0.112-0.566 mg/$m^2yr$, corresponding to a removal flux of $4.3-21.5{\times}10^7$ gU/yr for the entire Yellow Sea. Nutrient fluxes from sediment to bottom water were estimated to be 135.6 mmol/$m^2yr$ for ammonia, 228.2 mmol/$m^2yr$ for nitrate, 36.8 mmol/$m^2yr$ for phosphate and 23.9 mmol/$m^2yr$ for silicate. The redox boundary, based on the distribution of pore water nitrate and solid phase manganese, was located at 3-5 cm below the sediment surface. Phosphate flux obtained by benthic chambers was 28.S mmol/$m^2yr$. On the other hand, estimates of uranium and silicate fluxes were orders of magnitude greater than those based on pore water profiles. Flux estimates on the basis of pore water concentration is believed to have greater reliability than those obtained from benthic chamber data.

• Korean Journal of Environmental Agriculture
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• v.20 no.1
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• pp.15-19
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• 2001

This study was carried out to investigate the effect of application time and amount of rice bran on rice yield, weed occurrence, and chemical change in water as applied at the level of 1.8 Mg/ha (1.8RB) and 3.5 Mg/ha (3.5RB) through field and pot experiment. $Nitrate(NO_3\;^-)$ in the surface water and the percolated water through pot were high in application of 3.5RB, and similar in application of 1.8RB as compared to chemical fertilization. Electric conductivity in surface water were higher by application of rice bran until 25 days after rice bran application. $NH_4-N$ in soil were lower in application of rice bran, and $NO_3-N$ in soil were higher in 3.5RB at tillering stage and panicle formation stage of rice. Rice bran application(3.5RB) showed 68% of weed occurrence as compared to that of chemical fertilization. Rice yield were increased by heavy application of rice bran; 4.41 Mg/ha in 1.8RB and 4.87 Mg/ha in 3.5RB, and top dressing of nitrogen at panicle formation stage caused to increased rice yield by $14{\sim}15%$. Rice yield was also increased by early application of rice bran.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.2 s.29
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• pp.103-110
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• 2007

This study estirmted the appropriate pollutant load reduction from point sources in Jinhae Bay, Korea, using an eco system model. The results of COD values in the inner part of the bay obtained through the simulation by ecosystem model were greater than 3.0mg/L, and exceeded the limits of Korean Coastal Water Quality Grade III. Engineering countermeasures to reduce the $70\sim90%$ of all land based pollution load or organic and inorganic material loads from point sources by more than 50% were required to keep the COD levels below 2 mg/L. The reduction loads is 5,632kg/day of COD, 481kg/day of DIP and 7,991 kg/day of DIN in case of the reduction of both the organic and nutrients. The estimated environmental currying capacity of that case is 13,112kg/day of COD, 206kg/day of DIP and 3,425kg/day of DIN to keep the COD levels below 2mg/L.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.6
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• pp.403-408
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• 2006

Fluvio-marine paddy soils in Korea consist of high silt content and have the hardpan located below 20~30 cm from surface soil. This properties cause poor rice rhizosphere conditions such as low permeability and porosity, high bulk density and hardness. The aims of this study was to investigate the effect of popped rice hulls compost(PRHC) on soil fertility changes in the Fluvio-marine plain paddy soils. Total nitrogen content and nitrogen mineralization rate of PRHC were 1.17 and 33.5, respectively, and its C/N ratio was 35.4. Application of PRHC increased the content of organic matter and exchangeable potassium and improved the bulk density and porosity. The content of $NH_4-N$ in soil was high in the PRHC plot until maximum tillering stage. An uptake amount of fertilized nitrogen was greater in standard fertilization plot at early growth stage, however, it was greater more in PRHC plots at the ripening period than in standard fertilization plot. Among the PRHC treated plots, uptake amount was the greatest in 50% PRHC plot during the all growth period. Nitrogen efficiencies were higher in PRHC plot during the all growth period. Rice yields in all PRHC plots were lower than in standard fertilization, however, the yield of 40% PRHC plot was similar with that of standard.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.2
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• pp.130-141
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• 2020

The purpose of this study was to determine which fermented liquid fertilizer and application method yields the greatest amount of growth in red pepper (Capsicum annuum L.) and tomato (Lycopersicon esculentum MILL.) plants. Additionally, we investigated which extraction methods produce the most effective fertilizer with the highest levels of mineral nutrients. The liquid fertilizers used in this study were made from fish, bone and fish meal, red pepper leaves, and oil cake, and were extracted using fermentation or water and boiled water. In tomato plants, foliar-application of fermented fertilizer is known to promote more growth than application by drenching, regardless of the number of treatments (once or twice). In our studies, however, drenching with fertilizer promoted growth more effectively than foliar-application in red pepper plants. Studies in both tomato and red pepper have shown that the number of treatments does not significantly alter growth. Liquid fertilizers produced by a fermentation-extraction method promoted greater levels of growth in tomato compared to red pepper, and growth was greater when fertilizers were applied 20 (rather than 40) days post-sowing. Red pepper and tomato shoot fresh weight were affected more by fermented fertilizers than plant height 20 days post-sowing. In red pepper, we observed increased shoot fresh weight when using fermented liquid fertilizers with concentrations of 0.1% or greater. Tomato shoot fresh weight increased similarly in response to fermented fertilizer treatments at the same concentration levels, except those derived from fish. Fermented fish liquid fertilizer was only effective in increasing tomato shoot fresh weight in concentrations exceeding 1%. Red pepper and tomato shoot fresh weight also increased more than plant height in our studies using fermentation liquid fertilizers at 40 days after sowing. Red pepper fresh weight increased with application of bone + fish meal, red pepper leaf, and oil cake fertilizers at concentrations of 0.1%, but not with fish liquid fertilizer in concentrations under 0.5%. Shoot fresh weight in tomato increased with all liquid fertilizers. Growth in red pepper and tomato may be influenced by different kinds of fertilizers due to combinations of macro- and micro-nutrients, or specific macro-nutrients such as nitrogen, phosphoric acid, and potassium. The mineral nutrients found in fish, bone and fish meal, red pepper leaves, and oil cake were not easily extracted by fermentation; thus, liquid fertilizers made using water and boiled water methods more effectively promoted growth in red pepper and tomato due to the larger amounts of macronutrients eluted.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.135-139
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• 1999

A new effective and economic method was developed, removing interferences such as chlorophyll and lipid from leaves with small amounts of reagents and solvents in order to analyse PAHs(Polycyclic Aromatic Hydrocarbons). The extract from a soxhlet containing $4{\sim}5g$ of leaves and 100ml of dichlormethane and refluxed for 20 hrs was concentrated and eluted with 60ml of a hexane:dichloromethane (1:1) mixture through a column of 9mm wide inner diameter and 130mm long, packed from the bottom with 2.5g of $Al_2O_3$, 1.5g of $SiO_2$and 2g of anhydrous $Na_2SO_4$. The eluent was concentrated and loaded on a GPC column of 20mm wide inner diameter and 280mm long, packed with 12g of Bio-beads. The column was washed with 37ml of the hexane:dichloromethane(1:1) mixture. Another 43ml of the mixture was eluted as a PAH fraction and collected. This eluent was concentrated under gentle nitrogen to $50{\mu}l$ and analysed using GC-MS. The recoveries, obtained by comparing with the amounts of the internal standards of deuterated PAHs were $43.3{\sim}107.5%$(RSD $2.2{\sim}9.5%$).