• 한국물환경학회지
• /
• 제33권4호
• /
• pp.387-393
• /
• 2017

A chemical batch tests were conducted to evaluate if microwave heating enhances phosphorous release from waste activated sludge (WAS) at pH 2.5, 5, 7, 9 and 11. Polyphosphate-accumulating organisms have a unique physiological feature, which releases intracellular polyphosphate granules when they are exposed under high temperature environments. Microwave irradiation was found to encourage large amount of phosphorus release from WAS, depending on pH and temperature conditions. Most of phosphorus was released below $59^{\circ}C$ within 30 min. A marked increase in phosphorus release was observed under alkaline or acidic conditions. However, based on control tests for phosphorus release under different pH conditions without microwave heating, the largest amount of phosphorus released by microwave irradiation was found at pH 7, followed by 5, 9, 11. On the other hand, crystallization was conducted to obtain magnesium ammonium phosphate (MAP) from phosphate released by microwave heating at pH 7. X-ray diffraction analysis confirmed that the recovered crystalline materials were MAP. MAP is an environmentally friendly fertilizer, which slowly releases ammonia and phosphorus in response to the demand of plant root. Thus, the recovered MAP as a phosphate fertilizer is fully expected to play a important role in the reduction of agricultural non-point pollution.

• 상하수도학회지
• /
• 제30권2호
• /
• pp.123-130
• /
• 2016

Phosphorus (P) removal by aluminum sulfate solution was investigated with varying pH and initial P concentrations. P removal was the highest at around pH 6. The pH range where P removal occurred was slightly wider at higher initial P concentrations. Compared to theoretical calculations, it was confirmed that $AlPO_4$ precipitation was the main reason for P removal at low pH. At high pH, where there should be no $AlPO_4$ precipitates, the P removal by adsorption of amorphous $Al(OH)_3$ precipitates was experimentally observed. The P removal by adding amorphous $Al(OH)_3$ precipitates prepared before the adsorption experiments, however, was lower than that by injecting aluminum sulfate solution because the prepared precipitates became larger, leading to less specific surface area available for adsorption. Ions other than sulfate had little influence on P removal.

• 생명과학회지
• /
• 제15권4호
• /
• pp.584-589
• /
• 2005

담체인 황토볼와 Chromobacterium WS 2-14을 이용하여 F-STEP공정(혐기${\rightarrow}$ 호기${\rightarrow}$ 무산소)에서 실제폐수에 존재하는 인산을 효율적으로 제거하기 위해 최적 황토볼 크기 및 소성 온도, 폐수의 초기 pH,폐수의 초기 인산염 농도, 운전온도, 그리고 통기를 검토했다. 최적 조건은 다음과 같다. 황토볼 크기 및 소성 온도, $2\~4mm,\;960^{\circ}C$; 실페수의 초기pH, 6.0; 실페수의 초기 인산 농도, 5.0mg/1. 운전온도, $30^{\circ}C$; 그리고 통기, 5.0L/min등이 얻어졌다. 그리고 최적 운전조건을 이용해서 pilot test을 65일 동안 진행했다. 인산 평균 제거율은 $92.0\%$였고. 또한 최종 유출수에서 COD와 BOD의 평균 제거율은 각각 77.1와 $74.2\%$였으며, SS의 경우는 평균 제거율이, $86.4\%$였다. 이상의 결과로부터 황토볼을 담체로 이용한 Biofilter System은 실제폐수에 존재하는 인산 제거 가능성을 암시했다.

• 한국물환경학회지
• /
• 제21권1호
• /
• pp.59-65
• /
• 2005

A phosphate recovery system from artificial wastewater was developed using a completely mixed phosphorus crystallization reactor, in which powdered converter slag was used as a seeding crystal. In preliminary test, the optimal pH range for meta-stable hydroxyapatite crystallization for high phosphorus concentration was observed to be 6.0 to 7.0, which was different from the conventionally known pH range (8.0~9.5) for effective crystallization in relatively low phosphorus concentration less than 5 mg/L. The average phosphorus removal efficiency in a lab-scaled completely mixed crystallization system for artificial wastewater with about 100 mg/L of average $PO_4-P$ concentration was shown to be 60.9% for 40 days of lapsed time. XRD analysis exhibited that crystalline of hydroxyapatite formed on the surface of seed crystal, which was also observed in SEM analysis. In EDS mapping analysis, composition mole ratio (=Ca/P) of the crystalline was found to be 1.78, indicating the crystalline on the surface of seed crystal is likely to be hydroxyapatite. Particle size distribution analysis showed that average size of seed crystal increased from $28{\mu}m$ up to $50{\mu}m$, suggesting that phosphorus recycling from wastewater with high phosphorus concentration can be successfully obtained by using the phosphorus crystallization recovery system.

• Asian-Australasian Journal of Animal Sciences
• /
• 제12권2호
• /
• pp.197-202
• /
• 1999

Three barrows weighing 45.0 kg, fitted with simple T-cannulas in both the duodenum and terminal ileum, were assigned to diets in a $3{\times}3$ Latin Square design experiment to determine the effect of two calcium levels (0.8% vs 0.4%) on phytase activity and nutrient balance in growing pigs. The control diet contained 0.8% calcium, with no added inorganic phosphorus (0.45% total phosphorus) and no added phytase. The two additional experimental diets contained microbial phytase (750 phytase units/kg) and supplied either 0.8% or 0.4% calcium. With added microbial phytase, ileal and total tract digestibility of rotal phosphorus were improved by 20.9 and 13.8 percentage units, respectively (p=0.01). The apparent duodenal and ileal digestibility of phytate phosphorus were increased by 51.8 and 49.7 percentage units (p=0.01). Lowering dietary calcium in the presence of microbial phytase increased the digestibility of phytate phosphorus by an additional 10.9 (p=0.001) and 5.7 percentage units for duodenal and ileal digestibility, respectively. Supplementation with microbial phytase significantly reduced fecal excretion of nitrogen and phosphorus and increased the percentage of these nutrients retained by the pig. Lowering dietary calcium further increased the percentage of dietary phosphorus retained. Overall, reducing dietary calcium appeared to increase the effectiveness of added microbial phytase in degrading phytate phosphorus. As a result, care should be taken to avoid high levels of dietary calcium when supplementing swine diets with microbial phytase.

• 상하수도학회지
• /
• 제26권3호
• /
• pp.431-442
• /
• 2012

The purpose of this study, is to separate magnetic separation devices using permanent magnets by using magnetization characteristics remaining in treated water after adsorption and synthesizing phosphorus adsorbent capable of magnetic separation for efficient removal of phosphorus. The synthesis of the adsorbent which set Zirconium(Zr) having high friendly features for phosphorus as an element, and by synthesizing Iron Oxide($Fe_3O_4$, another name of $Fe_3O_4$ is magnetite) being able to grant magnetism to Zirconium Sulfate($Zr(SO_4)_2$), zirconium magnetic adsorbent(ZM) were manufactured. In order to consider the phosphorus adsorption characteristics of adsorbent ZM, batch adsorption experiment was performed, and based on the results, pH effect, adsorption isotherm, adsorption kinetics, and magnetic separation have been explore. As the experiment result, adsorbent ZM showed a tendency that the adsorption number was decreased rapidly at pH 13; however, it was showed a high amount of phosphorus removal in other range and it showed the highest amount of phosphorus removal in pH 6 of neutral range. In addtion, the Langmuir adsorption isotherm model is matched well, and D-R adsorption isotherm model is ranged 14.43kJ/mol indicating ion exchange mechanism. The result shown adsorption kinetics match well to the Pseudo-second-order kinetic model. The adsorbent ZM's capablility of regenerating NaOH and $H_2SO_4$, was high selectivity on the phosphorus without impacts on the other anions. The results of applying the treated water after adsorption of phosphorus to the magnetic separation device by using permanent magnets, shows that capture of the adsorbent by the magnetization filter was perfect. And they show the possibility of utilization on the phosphorus removal in water.

• 한국토양비료학회지
• /
• 제16권1호
• /
• pp.64-71
• /
• 1983

강산성(强酸性) 토양(土壤)인(pH 3.5) 특리산성답(特異酸性畓)에서 석회(石灰)와 인산(燐酸)의 시용(施用)이 토양(土壤)의 변화(変化) 및 수량증대(收量増大)에 미치는 효과(効果)를 구명(究明)하기 위(為)해 시험(試験)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 석회중화량(石灰中和量) + 인산(燐酸) 20/10a구(区)에서 무처리구(無處理区)에 비(比)해 수량구성요소(收量構成要素)를 증대(増大)시켜 60%의 증수효과(増收効果)가 있었다. 2. 수량증대(收量増大)에 미친 효과(効果)는 석회(石灰)는 36%, 인산(燐酸)은 15%로써 석회(石灰)의 시용효과(施用効果)가 컸다. 3. pH와 Eh에 있어서는 석회시용량(石灰施用量)이 많을 수록 pH는 높아졌고 반대(反対)로 Eh는 낮아졌으며 석회(石灰)와 인산(燐酸) 시용(施用)은 토양환원(土壤還元)을 촉진(促進)하였다. 4. 근(根)의 신장(伸長)은 무석회구(無石灰区) 논 표토(表土) (0~5cm)에 62%의 뿌리가 존재하였으나 석회(石灰)와 인산(燐酸)을 많이 시용(施用)할수록 하위(下位)(5~10cm)까지 뻗어갔다(60%). 5. 토양(土壤) pH변화(変化)는 최고분얼기(最高分蘖期)에 최고(最高)에 이르며 그 후 점차 감소하여 원(原) pH값에 접근하였으나 석회 소요량은 약(約) 반(半)이였다. 6. 토양중(土壤中) 규산(珪酸), 인산(燐酸)과 수량(收量)은 유의성(有意性)있는 정(正)의 상관(相関)으로 나타났고 pH를 높여줌으로 토양중(土壤中) 규산(珪酸)과 인산(燐酸)의 함량(含量)을 높여줄 수 있다. 7. 석회(石灰)와 인산(燐酸) 증시(増施)는 질소흡수(窒素吸水)를 증가(増加)시키고 식물체중(植物体中) 인산(燐酸)의 흡수(吸水)가 많을수록 수량(收量)은 증가(増加)한다.

• 한국환경과학회지
• /
• 제4권3호
• /
• pp.187-196
• /
• 1995

Phosphorus and nitrogen loadings from the main tributaries into the Nakdong River were estimated by measuring phosphorus and nitrogen concentration in the main tributaries, Nakdong River(Kangjung), Kumho River, Heichun, Hwang River, Nam River, Milyang River, and Yangsanchun from May 1994 to October. Total Phosphorus concenuation of Kumho River was vary high, average 1.0 mgP/1. The other rivers were the range 0.05 ~0.15 mgP/1. Total nitrogen concentration of Kumho River was vary high, average 6.27 mgN/1. The other rivers were the range 1.5~3.0 mgN/l. The phosphorus loading from Kumho River, Nakdong River(Kangjung), Nam River, Milyang River, Hwang River, Yangsanchun, and Heichun were calculated to be 1, 108, 603, 198, 57, 34, 23, and 21 tP/yr, respectively. Therefore, the loading from Kumho River accounted for 45 "yo of total loading, 2, 042 tP/yr, The nitrogen loading from Nakdong River (Kangjung), Kumho River, Nam River, Milyang River, Hwang River, Heichun, and Yangsanchun were calculated to be 12, 636, 7, 411, 2, 611, 1, 523, 779, 608, and 391 tN/yr, respectively. Therefore, the loading from Nakdong River(Kangiung) and Kumho River accounted for 50 % and 30% of total loading, 25, 959 tN/yr, respectively.vely.

• 한국농공학회논문집
• /
• 제52권5호
• /
• pp.47-52
• /
• 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.

• 한국분말재료학회지
• /
• 제27권1호
• /
• pp.31-36
• /
• 2020

Phosphorus is an element that plays many important roles in powder metallurgy as an alloy element. The purpose of this study is to investigate the influence of phosphorus addition on the microstructures and mechanical properties of sintered low-alloy steel. The sintered low-alloy steels Fe-0.6%C-3.89%Ni-1.95%Cu-1.40%Mo-xP (x=0, 0.05, 0.10, 0.15, 0.20%) were manufactured by compacting at 700 MPa, sintering in H₂-N₂ at 1260 ℃, rapid cooling, and low-temperature tempering in Ar at 160 ℃. The microstructure, pore, density, hardness, and transverse rupture strength (TRS) of the sintered low-alloy steels were evaluated. The hardness increased as the phosphorus content increased, whereas the density and TRS showed maximum values when the content of P was 0.05%. Based on microstructure observation, the phase of the microstructure changed from bainite to martensite as the content of phosphorus is increased. Hence, the most appropriate addition of phosphorus in this study was 0.05%.