• 한국물환경학회지
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• 제25권5호
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• pp.742-749
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• 2009

To examine the characteristics of the nutrient release from the sediments in two reservoirs, Lake Paldang and Lake Cheungpyeung, we analyzed physical and chemical properties of the sediments and calculated the nutrient release rates from the sediments. The particle properties of sediments in Lake Paldang changed from silt to sand after summer rainy season, especially in the water area of the Kyeungan River where the water depth was shallow and the width of river was narrow. The sediments in Lake Cheungpyeung had higher contents of silt and clay than in Lake Paldang, and the particle size was not much different before and after rainfall. The release rates of nutrients in two lakes varied with the kind of nutrients and the season. The release rates of DTN and ${NH_4}^+-N$ in Lake Paldang were faster in spring than autumn. But the Lake Cheungpyeung showed similar values of release rates before and after summer rainy season. ${NO_3}^--N$ and phosphorous were not released from sediments or were absorbed into sediments all the time in two lakes. Compared with other lakes, the sediments of two lakes consisted of bigger particles and had a lower organic matters content than other lake-type reservoirs. Due to the short hydraulic retention time and no stratification throughout the year in Lake Paldang and Lake Cheungpyeung, the release rates of nutrients from sediment in these reservoirs were lower than other lakes and this seems to be a typical characteristic of river-type reservoirs.

• 한국환경과학회지
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• 제11권12호
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• pp.1333-1337
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• 2002

A significant fraction of nutrients, such as nitrogen and phosphorus released from sediment are utilized by primary production in the shallow water of coast and lake. The purpose of this study is to introduce the mechanism of nutrients release from sediment and to introduce the methods of the measurement of nutrient released from sediment. One approach is to calculate nutrients released from sediment by a concentration gradient between sediment pore waters and overlying water based on the Fick's law. The other approaches of measurement are the undisturbed sediment core experiments and measurement of nutrient released from sediment by the in situ chamber equipment.

• 한국토양비료학회지
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• 제48권1호
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• pp.1-7
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• 2015

Global population is expected to reach nine billion in 2050 and the total demand for food is expected to increase approximately by 60 percent by 2050 as compared to 2005. Therefore, it is important to increase crop production in order to meet the global demand for food. Slow release fertilizers have been developed and designed in order to improve the efficiency of fertilizers. Mineral-based slow release fertilizers are useful because the minerals have a crystalline structure and are environmentally friendly in a soil. This review focuses on slow release fertilizers based on montmorillonite, zeolite, and layered double hydroxide phases as a host for nutrients, especially N. Urea was successfully stabilized in the interlayer space of montmorillonite by the formation of urea-Mg or Ca complex, $[(Urea)_6Mg\;or\;Ca]^{2+}$ protecting its rapid degradation in soils. Naturally occurring zeolites occluded with ammonium nitrate and potassium nitrate by molten salt treatment could be used as slow release fertilizer because the occlusion process increased the capacity of zeolites to store nutrients in addition to exchangeable cations. Additionally, surface-modified zeolites could also be used as slow release fertilizer because the modified surface showed high affinity for anionic nutrients such as nitrate and phosphate. Moreover, there were attempts to develop and use synthetic layered double hydroxide as a carrier of nitrate because it has positively charged layers which electrostatically bond nitrate anions. Kaolin was also tested by combining with a polymer or through the mechanical-chemical process for slow release of nutrients.

• 한국환경과학회지
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• 제30권3호
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• pp.195-206
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• 2021

Contaminated marine sediment is a secondary pollution source in the coastal areas, which can result in increased nutrients concentrations in the overlying water. We analyzed the nutrients release characteristics into overlying water from sediments and the interaction among benthic circulation of nitrogen, phosphorus, iron, and sulfur were investigated in a preset sediment/water column. Profiles of pH, ORP, sulfur, iron, nitrogen, phosphorus pools were determined in the sediment and three different layers of overlying water. Variety types of sulfur in the sediments plays a significant role on nutrients transfer into overlying water. Dissimilatory nitrate reduction and various sulfur species interaction are predominantly embodied by the enhancing effects of sulfide on nitrogen reduction. Contaminant sediment take on high organic matter, which is decomposed by bacteria, as a result promote bacterial sulfate reduction and generate sulfide in the sediment. The sulfur and iron interactions had also influence on phosphorus cycling and released from sediment into overlying water may ensue over the dissolution of ferric iron intercede by iron-reducing bacteria. The nutrients release rate was calculated followed by release rate equation. The results showed that the sediments released large-scale quantity of ammonium nitrogen and phosphate, which are main inner source of overlying water pollution. A mechanical migration of key nutrients such as ammonia and inorganic phosphate was depicted numerically with Fick's diffusion law, which showed a fair agreement to most of the experimental data.

• Biomolecules & Therapeutics
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• 제6권4호
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• pp.371-377
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• 1998

The aim of the present study was to investigate the effect of Palmiwon on the type 1-prediabetic models induced by streptozotocin (STZ) in RINm5F cells and HIT-T15 cells. Palmiwon increased the cell proliferation and insulin release when pre- and post-treated for the STZ-exposed pancreatic beta cells. The cell proliferation and insulin release of these beta cells were measured by $^3$H-thymidine uptake and RIA, respectively. We also analyzed nutrients such as sugars, fatty acid and amino acids and minerals containing in Palmiwon using by gas chromatography, amino acid analyzer and AA spectrometer, respectively. Palmiwon seems to have protective and recovery properties on the prediabetic model in cellular level, which were ascribe to various nutrients and minerals containing in Palmiwon. From these results, it could be suggested that Palmiwon may be available as preventive and therapeutic prescription of type 1 diabetes mellitus.

• 한국물환경학회지
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• 제31권6호
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• pp.644-652
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• 2015

In this study the releasing of nutrients from sediments of Nak-dong River were investigated. We perfomed lab-scale simulation experiments using field sediment and ware. Nutrients, orgarni matter, particle size of the sediments and nutrients of released water were analyzed. Analyzed results of the sediments, mainly composed of mS(muddy Sand) sedimentary facies and IL were 2.46~6.83%, T-N were 1.189~2.492 mg/kg, and T-P were 333~726 mg/kg in the study area. Analyzed results of the nutrients of released water, pH and TOC were each 7.8~9.2% and 31.7~40.8% decreased after 20 days. T-N increased steadily, and NH₃-N increased steadily then decreased, at this time NO₃-N increase. Also NH₃-N increased steadily, then decreased at this time. Furthermore release of phosphorus were mostly decreased.

• Journal of Pharmaceutical Investigation
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• 제38권3호
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• pp.177-182
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• 2008

The purposes of this study were to prepare dual-layered coated compact pellets containing three nutrients Glucose, Chromium picolinate, Vitamin C) for rumen bypass. The core compact pellets were prepared by an extrusionspheronization method and then double layered coated with pH independent EC (ethyl cellulose) and pH-dependent polymers ($Eudragit^{(R)}$ E100) using a fluid-bed spray coater. Depending on the coating levels of EC and $Eudragit^{(R)}$ E100, release profiles were variable in simulated rumen (pH 6.8) and abomasums (pH 2.0) fluid using USP apparatus I (basket method). When compact pellets were coated with EC (about 10% level in inner layer) and then $Eudragit^{(R)}$ E100 (20% level in outer layer) in a dual-layered manner, rumen-bypass delivery resisting rumen fluid followed by release in abomasums fluid could possible. The friability was also satisfactory based on chewing behavior of ruminants. The dual-layered coated compact pellets showed smooth surface and distinct inner/outer layers using scanning electron microscopy (SEM). The current rumen bypass delivery system can be also applicable to deliver other nutrients in ruminants.

• 한국환경농학회지
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• 제30권2호
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• pp.144-152
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• 2011

본 연구는 주암호 홍수조절용지내에 서식하는 침수식물체들의 영양염류 용출이 주암호 수질에 미치는 영향을 조사하고자 침수상태의 수질, 토양 및 식물체를 자연상태 그대로 column으로 옮겨와 침수기간별 영양염류의 제거속도 및 용출속도를 조사하였고, 이들 결과를 토대로 각 홍수조절용지에서 침수식물체별 영양염류 용출량을 산출하였다. COD 제거속도 상수(K, $day^{-1}$)는 이삭사초의 경우 침수 0~4 day, 5~19 day 및 20~33 day 구간에서 0.07~0.18, -0.23~-0.17 및 -0.28~0.03 $day^{-1}$이었고, 물억새의 경우 침수 0~6 day, 7~19 day 및 20~33 day 구간에서 0.14~0.22, -0.19~-0.04 및 -0.05 $day^{-1}$이었다. T-N 제거속도 상수(K, $day^{-1}$)는 이삭사초의 경우 침수 0~4(8) day 및 5(9)~33 day 구간에서 0.02 및 -0.13~-0.10 $day^{-1}$이었고, 물억새의 경우 침수 0~2(4) day, 3(5)~19 day 및 20~33 day 구간에서 0.01~0.04, -0.03 및 -0.18~-0.17 $day^{-1}$이었다. T-P 제거속도 상수(K, $day^{-1}$)는 이삭사초의 경우 침수 0~4 day 및 5~33 day 구간에서 0.05~0.06 및 -0.14~-0.09 $day^{-1}$이었고, 물억새의 경우 침수 0~4 day 및 5~33 day 구간에서 0.05~0.06 및 -0.15~-0.12 $day^{-1}$이었다. 이상의 결과에서 침수초기에는 침수식물체가 생육하면서 영양염류를 분해 이용하여 수질을 정화하였으나, 침수식물체에 따라 다소 차이가 있었지만 침수 4~10일후부터 침수식물체가 미생물에 의해 서서히 분해되면서 영양염류가 수질내로 용출되는 경향이었다. 홍수조절용지에서 침수식물체별 영양염류용출량은 이삭사초가 물억새에 비해 약간 많았다. 특히 site 1에서 COD, T-N 및 T-P 용출량은 이삭사초의 경우 각각 6,719, 2,397 및 466 kg/month/area이었고, 물억새의 경우 각각 53.1, 14.8 및 3.30 kg/month/area이었다.

• 한국환경과학회지
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• 제13권7호
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• pp.675-680
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• 2004

This study was conducted to remove organics and nutrients using 2 stage intermittent aeration reactor. First reactor, using suspended microbial growth in intermittent aeration instead of anaerobic reactor in the typical BNR process, used minimum carbon source to release P, and it was possible to reduce ammonia loading going to second reactor. In the second reactor, using moving media intermittent aeration, it was effective to reduce nitrate in non-aeration time by attached microorganisms having long retention time. In aeration time, nitrification and P uptake were taken place simultaneously. From the experiment, two major results were as follows. First, the removal of organics was more than 90%, and optimum aeration/non-aeration time ratio for organic removal was corresponded with aeration/non-aeration time ratio for nitrogen removal. Second, in the first reactor, optimum aeration/non-aeration time ratio was 15/75 (min.) because it was necessary to maintain 75 min. of non-aeration time to suppress of impediment of return nitrate and to lead release of phosphate. In the second reactor, optimum aeration/non-aeration time ratio was 45/90 (min.).

• 한국폐기물자원순환학회지
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• 제35권8호
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• pp.701-708
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• 2018

Chemical batch tests were conducted to investigate the amount of nutrients that were released from the wasted activated sludge during microwave heating. For this study, three types of activated sludge were obtained from $A_2/O$, MLE and oxidation ditch (OD) processes. Polyphosphate-accumulating organisms in the activated sludge have a unique trait: they releases phosphate from the cell when they are exposed to high temperatures. The sludge obtained from the $A_2/O$ process released the largest amount of phosphate, followed by those from the MLE and OD processes. The release of phosphate increased with increasing polyphosphate content in the sludge under strongly alkaline or acidic conditions. Furthermore, ammonia and heavy metals were released with phosphorous. The largest amount of ammonia was observed from the sludge obtained from the MLE process. The release of heavy metals strongly depends on the pH conditions. Therefore, the chemical analysis results strongly suggest that both phosphorus and ammonia react with $Mg^{2+}$ or $Ca^{2+}$ to form metal complexes such as magnesium ammonium phosphate or hydroxyapatite under alkaline conditions.