• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.197-204
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• 2007

The reciprocal effects towards the enhanced biological phosphorus removal were performed for anaerobic, aerobic and anoxic phases. The batch experiments showed that the p-absorption in the anoxic phase was 50% lower than aerobic phase. The correlation coefficient between p-back-solution and p-absorption was found to be $R^2=0.557$ however, the coefficient b(b = 8.4049) was relatively higher than the other researchers results. The increase and/or acceptance of the $K^+-,\;Mg^{2+}-$ and $NH_4-N$-concentration was proportional to those of the $PO_4-P$-concentration in the batch test. The relationship between $K^+-,\;Mg^{2+}$ and $PO_4-P$ was determined. The average value of this relation-ship agreed with 0.2 mol $K^+Ion$ / mol $PO_4-P$ ion and 0.21 mol $Mg^{2+}Ion$ / moi $PO_4-P$ ion in the anaerobic phase. The absorbed ratio of $K^+$ to $Mg^{2+}$ over $PO_4-P$ was found to be 1 : 5.

• The Korean Journal of Physiology
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• v.12 no.1_2
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• pp.35-40
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• 1978

To evaluate orthostatic brain hypoxia from the passive tilt, anesthetized dogs were tilted from supine to $90^{\circ}C$ upright and $90^{\circ}C$ head down position. Blood pH, $Pco_2$ and $Po_2$ changes during tilt were measured on 8 dogs. Respiratory rate was decreased in upright position and increased in head down position comparing to that in rte horizontal position. pH in arterial blood was increased in upright position and decreased in venous blood comparing to that in the horizontal position. No significant changes were found in the head down position. $Pco_2$ of arterial and venous blood was decreased both in upright and head down. position A significant decrease was found in the head down position. $Po_2$ in arterial blood was increased both in the upright and head down position. However, it was decreased in the venous blood. The cause of increased $Po_2$ in arterial blood seemed to do due to hyperventilation and the cause of decreased $Po_2$ in venous blood was thought to be due to increased $O_2$ consumption of animals during the tilt.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.4
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• pp.309-316
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• 2010

The performance of grass filter strips (GFS) in reducing $PO_4$-P concentrations and soil loss from the forage cropland was tested in an experiment on the 10% slope in Grassland and Forages Division, National Institute of Animal Science, Rural Development Administration (RDA) from October 2007 to September 2009. Forage cropland with rye-corn double cropping system receiving inorganic fertilizer or livestock manure (LM) were compared in a natural condition. The plots were hydrologically isolated in a randomized block layout of 3 treatments $\times$ 2 factors $\times$ 3 replicates. Main plots consisted of the length of GFS, such as $25\;m^2$ ($5{\times}5\;m$), $50m^2$ ($5{\times}10\;m$), $75m^2$ ($5{\times}15\;m$). Sub plots consisted of the type of LM, such as chemical fertilizer (CF), cattle manure (CM) and swine manure (SM). Concentrations of $PO_4$-P in surface runoff water were reduced as the length of GFS increased. Especially, GFS with 10 m and 15 m reduced $PO_4$-P concentrations significantly compared to that with 0 m (p<0.05). However, there was not significant different between $PO_4$-P concentrations of GFS with 10m and that of GFS with 15 m. Moreover, Soil loss in surface runoff water were reduced as the length of GFS increased. GFS with 15 m reduced soil loss significantly compared to that with 5 m and 10 m (p<0.05). The results from this study suggest GFS improve the removal and trapping $PO_4$-P and soil loss from forage cropland.

• Journal of the Korea Organic Resources Recycling Association
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• v.23 no.3
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• pp.60-67
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• 2015

Objective of this study was to investigate adsorption characteristics of $PO_4-P$ to biochar produced from oak tree in respective to reduce eutrophication from runoff water in the cropland. For adsorption experiment, input amount of biochar was varied from 4 to 20 g/L with 30 mg/L $PO_4-P$ solution. Adsorption amounts and removal rates of $PO_4-P$ was increased at 3 times in 4~14 g/L, and increased at 28.6% in 4~16 g/L, respectively. The maximum adsorption amount ($q_m$) and binding strength constant(b) were calculated as 0.10 mg/g and 0.06 L/mg, respectively. The sorption of $PO_4-P$ to biochar was fitted well by Langmuir model because it was observed that dimensionless constant($R_L$) was 0.37. It was indicated that biochar is favorably adsorbed $PO_4-P$ because this value lie within 0 < $R_L$ < 1. Therefore, biochar produced from oak tree could be used as adsorbent for reduce eutrophication from runoff water in the cropland.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.775-782
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• 2009

PP-g-AA-Am nonwoven fabric, which possess anionic exchangeable function, was prepared by chemical modification of carboxyl (-COOH) group of PP-g-AA nonwoven fabric to amine ($-NH_2$) group using diethylene triamine (DETA). Its adsorption characteristics for anionic nutrients including isotherm, kinetics and co-anions were studied by batch adsorption experiments. Adsorption equilibriums of $PO_4$-P on PP-g-AA-Am fabric were well described by the Langmuir isotherm model, and their adsorption energies were ranged 10.3 kJ/mol indicating an ion-exchange process as primary adsorption mechanism. The adsorption selectivity of PP-g-AA-Am nonwoven fabric for anions under competition with each other was in following order: $SO_4\;^{2-}$>$PO_4\;^{3-}$>$NO_3\;^-$>$NO_2\;^-$. Also, all results obtained from this study indicate that the $PO_4$-P removal capacity of PP-g-AA-Am nonwoven fabric was extremely superior to that of PA308 anion-exchange resin.

• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.181-187
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• 1995

This study was conducted to investigate the effect of NH$_4$H$_2$PO$_4$ on pH of the nutrient solution using municipal tap water during hydroponic culture of crisp lettuce (Lactuca sativa var. capitata) seedlings. The composition of starter solution was different from that of supplementary solution. The pH in the nutrient solution was suddenly declined and recovered as the supplementary solution was supplied. The pH of nutrient solution was increased with high temperature and, on the contrary, the EC of nutrient solution was decreased. It shows that plant absorbed nutrients more than water in given solution when the temperature and light was high. After supplying supplementary solution in 1st and End experiment, pH was slowly increased to 7 in NH$_4$H$_2$PO$_4$ 0.25me/$\ell$, but maintained 6.4-6.5 in NH$_4$H$_2$PO$_4$ 3me/$\ell$ and 6me/$\ell$. In 3rd experiment, pH was slowly increased from 6.7 to 7.4 in NH$_4$H$_2$PO$_4$ 0.25me/$\ell$, but decreased from 6-6.5 to 5-5.5 in NH$_4$H$_2$PO$_4$ 3me/$\ell$ and 6me/$\ell$. So it is suggested that the concentration between 0.25 me/$\ell$ and 3 me/$\ell$ by concentration base or the amount of NH$_4$H$_2$PO$_4$ between 1me/6 $\ell$ and 7me/6 $\ell$ by total quantity in solution is appropriate for stabilizing pH in the nutrient solution. Also this experiment suggests that hand operated measurements must be cautious due to the change of pH and EC within a 24-hour cycle.

• Review of KIISC
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• v.28 no.3
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• pp.18-25
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• 2018

최근 블록체인 기술을 응용한 가상화폐에 대한 관심이 높아지면서 자본금이 많지 않은 사람들도 블록체인 네트워크에 참여하기 시작했다. 가장 유명한 가상화폐인 비트코인이 채택한 PoW 방식은 고성능 하드웨어의 과열된 열풍을 불어왔고 PoS 방식은 기존 지분이 많은 참여자들이 많이 존재하여 소수의 자본금을 가진 신규 참여자들이 네트워크에 새로 참여하기 어려운 환경이다. 따라서 본 논문에서는 기존 블록체인 증명방식인 PoW, PoS 방식보다 네트워크 참여를 위한 자본금이 적고 신규로 참여하더라도 리스크가 적은 PoP(Proof-of-Probability) 방식을 소개한다. PoP 방식은 블록을 생성할 시 실제 암호화된 해쉬와 수많은 가짜 해쉬를 각 노드들이 정렬하여 진짜 해쉬를 복호화하여 찾은 노드가 블록을 생성하는 방식이다. 또한 1개의 해쉬를 복호화하여 검증받을 때 1분의 대기시간을 두어 과열된 컴퓨팅파워 경쟁을 제한한다. 지분(Stake)이 많을수록 블록을 생성할 확률은 높아지지만 이는 PoS 방식처럼 절대적이지 않다. 이 방식을 이용한다면 지분을 많이 가진 유효성 검증자(Validators)에 의한 집중화를 피하며 블록체인 네트워크에 참여하려는 진입장벽도 낮출 수 있을 것 이다.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.664-672
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• 2010

This study was performed to evaluate the feasibility of industrial by-products such as converter slag, olivine, red mud and fly ash as a seed crystal of struvite crystallization for the removal of highly concentrated $NH_4-N$ and $PO_4-P$. In the kinetic experiments, more than 90% of $NH_4-N$ and $PO_4-P$ was eliminated by struvite crystallization within 30 minutes of reaction time. The pH range in meta-stable region of struvite crystallization was found to be pH 7.0~9.0 under the Mg:N:P=1:1:1 equi-molar condition with 100 mg/L of $NH_4-N$. Total removal efficiencies of $NH_4-N$ and $PO_4-P$ by both struvite precipitation and crystallization were increased with the increase of pH. Removal efficiencies of $NH_4-N$ and $PO_4-P$ were significantly enhanced by struvite crystallization using industrial by-products as a seed crystal compared with those by struvite precipitation without seed crystal. Red mud, converter slag, olivine and fly ash enhanced the removal efficiencies of $NH_4-N$ by 40.9%, 37.7%, 28.4% and 16.4%, respectively. Removal efficiencies of $PO_4-P$ for converter slag, red mud, fly ash, olivine were increased by 3.7 times, 2.6 times, 72.4% and 68.0%, respectively. Converter slag and red mud showed higher feasibility as a seed crystal than others for the removal of highly concentrated $NH_4-N$ and $PO_4-P$. In particular, converter slag might have a high capacity of phosphorus removal.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.5
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• pp.47-52
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• 2010

The purpose of this study is to investigate characteristics of total phosphorus (TP) and phosphate phosphorous ($PO_4$-P) concentrations in ponded water and redox potential (Eh) in paddy soil during the growing season. The TP and $PO_4$-P concentrations showed twice peak values after basal dressing and tillering fertilization. The ratio of $PO_4$-P to TP showed low values (0.07~0.18), indicating that most of phosphorus is particlulate. The $PO_4$-P concentrations significantly decreased with dissolved oxygen (DO) concentrations. The Eh showed high values (179~636 mV) under non-ponded aerobic condition, but low values (74~112 mV) under ponded anaerobic condition The TP and $PO_4$-P concentrations in ponded water increased shortly after tillering fertilization even if phosphorus was not applied. This may be due to the release of dissolved phosphorus from the bottom sediment and its associated algal and water flea blooms under anaerobic condition. Therefore, proper water management should be needed shortly after tillering fertilization.

• Journal of the Korean Electrochemical Society
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• v.16 no.3
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• pp.123-128
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• 2013

Organic carbons such as methanol, ethanol, iso-propanol, methoxy ethanol, glucose are added(1, 2, 3%) in the 2000 ppm $NH_3$ and $H_3PO_4$. As vol.%. cyclic voltammetry measurement of the capacity with the addition of organic carbon, the results of $NH_3$ + 3 vol.% Methanol Addition, $H_3PO_4$ + 2 vol.% iso-propanol addition of the increase in capacity was observed. Applying to the CDI Module cell with an addiction of organic carbon is confirm that remove $NH_4$-N and $PO_4$-P in sewage. Namely, the removal efficiency of $NH_3$ was increase of 16.4% during adsorption, 30.4% during desorption and the removal efficiency of $H_3PO_4$ was increase of 63% during adsorption, 54.7% during desorption. Therefore, the result of this research is confirm that effect of the N, P removal and considered that reduction of the operating costs without removing the organic matter in the influent wastewater.