• Analytical Science and Technology
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• v.24 no.5
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• pp.378-386
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• 2011

The goal of this study is to understand the influence of temperature on phosphorus release rate from soil into water. As the temperature increases, $PO_4$-P reaches equilibrium more quickly and the equilibrium concentration increases, and thus the $PO_4$-P concentration increases, and pH decreases. The $PO_4$-P concentration affects pH. $PO_4$-P released from turbidity is not adsorbed onto the turbidity. $PO_4$-P was independent on the turbidity and yet $PO_4$-P was steadily increasing. However, $PO_4$-P was dependent upon the turbidity concentration as the turbidity releases $PO_4$-P. The total phosphorous (T-P) and turbidity were directly linked because T-P changed with the turbidity. T-P includes the $PO_4$-P content of water and the phosphorus content of the turbidity. As the temperature decreases, density of water increases, and the precipitation of turbidity decreases, resulting in an increases in T-P concentration. As the temperature increases, the T-P concentration decreases, but the PO4-P release rate from turbidity increases. At the same time, even at different temperatures, the T-P concentrations of the samples were about the same. When the lake gets deepened, the water temperature decreases, hence, the phosphorus release rate from soil into water was decreased. This mechanism is of great interest because phosphorus is released from soil sediment into the lake water.

• Journal of Environmental Science International
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• v.30 no.3
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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.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.994-1001
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• 2001

An easier way of understanding the BNR system was proposed from the study on substrate, nutrient removal tendency, microbial community and its metabolic function by applying the municipal settled sewage. During the anaerobic period, the phosphorus release rate per VFACOD we varied depending on the phosphorus content in the sludge. When the phosphorus content in the sludge was $6\%$ VSS, according to influent VFACOD, the phosphorus release rate and PHA production were $0.35 gPO_4P/gVFACOD$ and 1.0 gPHA/gVFACOD, respectively. The $NO_3N$ requirement for the phosphorus uptake as an electron acceptor was about $0.5 gNO_3N/gPO_4P_{uptake}$ based on the proposed equation with PHA, biomass, production, and the concentration of phosphorus release/uptake. Bacterial-community analysis of the sludge, as determined by FISH and 16SrDNA characterization FISH, revealed that the beta-subclass proteobacteria were the most abundant group ($27.9\%$ of the proteobacteria-specific probe EUB338), and it was likely that representative of the beta-subclass played key roles in activated sludge. The next dominant group found was the gamma-protebacteria ($15.4\%$ of probe EUB338). 16S rDNA clone library analysis showed that the members of${\beta}$- and ${\gamma}$-proteobacteria were also the most abundant groups, and $21.5\%$ (PN2 and PN4) and $15.4\%$ (PN1 and PN5) of total clones were the genera of denitrifying bacteria and PAO, respectively. Prediction of the microbial community composition was made with phosphorus content (Pv, $\%$ P/VSS) in wasted sludge and profiles of COD, PHA, $PO_4P,\;and\;NO_3N$ in an anaerobic-anoxic SBR unit. Generally, the predicted microbial composition based upon metabolic function, i.e., as measured by stoichiometry, is fairly similar to that measure by the unculturable dependent method. In this study, a proposal was made on he microbial community composition that was more easily approached to analyze the reactor behavior.

• Journal of Environmental Science International
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• v.3 no.4
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• pp.427-437
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• 1994

Batch experiments were performed to evaluate the effect of sludge acclimation and contact load on the behavior of phosphorus and organic substrates under anaerobic conditions. Four different sludges were acclimated in the sequencing batch reactors operated by intermittent aeration. All the experiments performed in a bench scale have shown the following results: 1. The unreleaseable phosphorus contents for four different sludges are the range of 16 mg P/g SS to 24 mg P/g SS, depending on the sludge acclimation conditions. 2. All the specific substrate uptake rates(SSUR) are expressed in the first order equation for releaseable phosphorus contents. The reaction rate coefficient k, has the values of 4.0, 8.9, and 13.8 mg COD/mg P/hr, depending on the contact load and slut식e species. 3. As reaction proceeds, the ratios of $\delta$P to -$\delta$COD at high contact load are almost constant in the range of 0.10 to 0.14, but at low contact load, they increase from 0.08 to 0.27.

• Journal of the Korean GEO-environmental Society
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• v.2 no.4
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• pp.29-38
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• 2001

In this study, the fractional composition and the releasing of nutrients and metals from sediments of Boryung reservoir were investigated. Based on present study, the forms of sediment phosphorus of the four sites in reservoir were classified as adsorbed phosphorus, non apatite inorganic phosphorus(NAI-P), apatite phosphorus and residual phosphorus. Residual phosphorus showed the highest fration, NAI-P second, apatite phosphorus third and absorbed phosphorus fourth. The sedimentation rate of T-P and T-N in aerobic condition were $0.31mg/m^2{\cdot}day$ and $29mg/m^2{\cdot}day$. The sedimentation rate of T-P and T-N in anaerobic condition were $0.12mg/m^2{\cdot}day$ and $13.6mg/m^2{\cdot}day$. The releasing rate of T-P and T-N in anaerobic condition were $0.23mg/m^2{\cdot}day$ and $10.5mg/m^2{\cdot}day$.

• Fire Science and Engineering
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• v.29 no.6
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• pp.13-19
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• 2015

This study was performed to test the combustive properties of Pinus rigida specimens treated with phosphorus (P) and nitrogen (N) additives. Each Pinus rigida specimen was painted three times with 15 wt% P-N additive solutions at room temperature. After drying the treated specimens, the combustion properties were examined using a cone calorimeter (ISO 5660-1). The time to ignition (TTI) for the treated specimens was 90 to 148 s except for the specimen treated with PP/$4NH_4^+$, and the time to flameout (TF) was 556 to 633 s, which was longer than that of virgin plate. While the The specimens treated with P-N additives showed 12.5 to 43.4% higher mean heat release rate ($HRR_{mean}$) and 11.8 to 43.1% higher total heat release (THR) than virgin plate. The effective heat of combustion (EHC) was by 2.9 to 17.5% lower than that of virgin plate. It can thus be concluded that the combustion-retardation properties were partially improved compared to those of virgin plate.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1205-1212
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• 2000

The effect of temperature on the sources of organic acids and sludge when phosphorus was biologically released was evaluated in this study. The sludge used in this study was obtained from sequencing batch reactor processing the swine wastewater. Temperature is one of the most important parameters influencing the phosphorus release. As a result, the rate of phosphorus released was increased as the temperatures were increased from 5 to $30^{\circ}C$ regardless of the sources of organic acids used. Under anaerobic conditions, as acetate, propionate, glucose, and domestic wastewater were used as the sources of organic acids, the corresponding activation energy($E_a$) values were 49.83, 55.82, 54.61, and 45.44 KJ/mol, respectively. Temperature coefficient($\theta$) values were 1.0676, 1.0826, 1.0748, and 1.0698, respectively. Therefore, the rate of phosphorus released was increased as temperature was increased, whereas, the effect, of the sources of organic acids and temperature on the activation energy and temperature coefficient values were minimal. When the sludge previously adapted to acetate as external organic source was used, the activation energy and temperature coefficient values were 44.94 KJ/mol and 1.0570 respectively. The effect of temperature was minimal. These values obtained from the sludge previously adapted to acetate were smaller than those from the sludge not previously adapted to the same organic acid. This suggest that the sludge previously adapted to acetate was less dependent on temperature than that not adapted to the acetate.

• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.409-415
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• 2017

This study aims to evaluate the effect of capping materials on blocking pollutant elution from contaminated sediment to water body. Experiments were carried out under conditions in which the elution rate was intensified artificially using compost with high concentration of organic compound and nutrient salts instead of sediments. Activated carbon (AC), modified activated carbon (MAC), P. putida immobilized activated carbon (PBAC) and effective microorganisms immobilized activated carbon (EBAC) were used as capping materials. Zeolite (ZT) and two kinds of commercially available microorganisms immobilized zeolite products (ZC, ZN) were used for comparison experiment. The elution rate of organic compound, nitrogen and phosphorus were compared with that of control experiment. The experiments were conducted for 56 days. Concentrations of chemical oxygen demand, total nitrogen, and total phosphorus were measured to use the comparison of release rate of organic compound, nitrogen and phosphorus. From the experimental results, AC based materials showed better performance to block the elution of organic compound and nitrogen than ZT based materials. Although ZT based materials were more effective than AC and PBAC to block phosphorus, MAC and EBAC showed the best performance of phosphorus elution blocking among the all candidate materials. In conclusion, EBAC is considered as the most effective capping materials, because organic compound, nitrogen and phosphorus will be degraded continuously by EM in the long term.

• Elastomers and Composites
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• v.39 no.2
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• pp.105-120
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• 2004

The flame retarded NBR foams were prepared with metal hydroxides and various phosphorus/nitrogen-contain ing flame retardants. The dependency of the phosphorus content on thermal properties, flame retardancy, smoke density, and foaming properties were investigated in the foams. Foaming properties and morphology of the flame retarded NBR foams with P/N flame retardants( ${\le}10 phr$) were similar to those of the foams without P/N ones but containing metal hydroxides The flame retardancy of the foams was improved with increasing the phosphorus content and char formation under combustion atmosphere. The cone-calorimeter test and LOI index were also coincided with the TGA analysis quite well. The heat release rate (HRR), total heat release (THR), and effective heat of combustion (EHC) were decreased, whereas the carbon monoxide yield was increased with increase of the phosphorus content of P/N flame retardant. The smoke density values were closely related with CO yield values obtained by the cone-calorimeter test due to the high and hard char formation.

• Journal of Korean Society on Water Environment
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• v.20 no.1
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• pp.42-47
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• 2004

This study was accomplished to develope an advanced wastewater treatment process using high MLSS in anoxic tank aimed to improve nutrient removal and to reduce wasting sludge. It was operated with 4 Modes with varing solid concentration and internal recycle ratios. Mode I, II, III was operated 1.0~1.5% MLSS concentration at anoxic tank with 50% sludge recycle rate, however, each internal recycle rate were 100%, 200%, 300% and Mode IV was operated 1.5~2.0% MLSS concentration at anoxic tank with 50% sludge recycle rate and 100% internal recycle rate. The COD removal efficiency didn't show any big difference from Mode I to IV. The average COD removal rate was over than 90%. The T-N removal rate was 73%, the highest rate in all mode. The 36% of SCOD is used for the denitrification and phosphorus release in the anoxic tank. Specific denitrification rate was 3.5mg $NO_3{^-}-N/g$ Mv/hr and denitrification time was 0.7hr. As MLSS concentration is higher in anoxic tank as denitrification time would be shorter. The T-P removal rate was average 70%. The phosphorus release accomplished from the anoxic tank because the anaerobic condition was prevalent in the anoxic due to the prompt completion of denitrification. Sludge production was 0.28 kgVSS/kg $BOD_{removed}$ under the 1.5% MLSS and 17 day SRT. It is prominent result which has 40% sludge reduce comparing with traditional activate sludge system.