• Korean Journal of Environmental Agriculture
• /
• v.39 no.2
• /
• pp.95-105
• /
• 2020

BACKGROUND: In this study, in order to verify the effects of supplemented organic amendment fertilizers recommended by the soil testing on cabbages, we used various amounts of organic amendment fertilizers. The amount of organic amendment fertilizers was decided by calculating each ratio of inorganic nitrogen, phosphorus, and potassium based on the recommended fertilizer composition. METHODS AND RESULTS: The cabbages subjected to treatments 1 and 2 showed similar or greater leaf colors (SPAD values), head heights, head widths, head weight, soil organic matter content, nitrate-nitrogen level, and conductivity after harvest, when compared with cabbages treated with chemical fertilizers. The phosphorus and potassium fixation in the soil were higher in the plot where cabbages were treated with chemical fertilizers, and the nutrient use efficiency was greater in the plots with organic amendments and mineral addition. CONCLUSION: The treatments 1 and 2 that were supplemented with 180-200% of nitrogen, 100-130% of phosphorus, and 185-250% of potassium in comparison to chemical fertilizers, applied by the inorganic ratios of nitrogen, phosphorus, and potassium can be used as organic amendment fertilizers for cabbages.

• 한국해양학회지
• /
• v.25 no.3
• /
• pp.145-150
• /
• 1990

An analysis of collected data on components of dissolved organic phosphorus (DOP) and DOP is made to search for important components of DOP pool and their implications in phosphorus (P) cycling. The significance of dissolved nucleic acids (D-NA) apparently tends to increase with increasing trophic status of oceanic waters. Interestingly the sum of all 5-nucleotide and D-NA seems to dominate the DOP pool. Thus, materialization of D-NA could be a significant pathway of P cycling in surface oceanic waters and it might be of great importance in lakes where P limits primary production. Processes related to death of Microbes are responsible for D-NA and DOP production in surface waters, and incomplete digestion of preys by grazers seems to be an important mechanism in D-NA production.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.29 no.1
• /
• pp.5-17
• /
• 2021

This study is a literature review on the recovering phosphorus from Incinerated Sewage Sludge Ash(ISSA), which has relatively high content of phosphorus. Experimental conditions and influencing factors related to the recovery of P and removal of heavy metals by wet and thermochemical methods were discussed. For the practical application of the recovery of P from ISSA, an integrated process linked to incineration facilities is required in terms of economy from the perspective of the entire system including disposal of wastewater and residues generated during the recovery process, and minimizing added chemicals and energy consumption.

• Clean Technology
• /
• v.23 no.4
• /
• pp.378-387
• /
• 2017

To obtain epoxy resin with permanently attached flame-retardant groups, phosphorus compound containing di-hydroxyl group [10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phospha phenanthrene-10-oxide, DOPO-HQ] and silicone compound containing di-hydroxyl group (polydimethylsiloxane, hydroxyl terminated, PDMS) were reacted with uncured epoxy prepolymer (diglycidyl ether of bisphenol A, DGEBA) and then cured using 4,4-diaminodiphenylmethane (DDM) as a crosslinking agent. The properties of the resulting epoxy materials were characterized using Fourier transform infrared (FTIR) spectrometer, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI) test/vertical burning test (UL 94-V test), tensile properties test and impact test. This study examined the effect of phosphorus/silicone compound contents on the thermal/mechanical properties and flame retardancy of cured epoxy resins containing phosphorus and silicone compounds. It was found that the thermal/mechanical properties of epoxy resins containing phosphorus and silicone components were higher than those of simple epoxy resin. The flame-retardancy (LOI: 29.9 ~ 31.8% and UL 94-V: V-0) of all samples containing phosphorus compound and phosphrous compound/silicone compound was found to be passed the flame-retardant requirements (LOI: > 30%, UL 94-V: V-0) of LOI and vertical burning tests. However, the flame-retardancy (LOI: 21.4% and UL 94-V: no rating) of simple epoxy resin was found to be failed the flame-retardant requirements.

• Applied Biological Chemistry
• /
• v.34 no.2
• /
• pp.117-124
• /
• 1991

Soybean plants inoculated with Bradyrhizobium japonicum MN 110 were supplied with nutrient solutions containing 1.0, 0.25 and 0.5.nM-P to characterize the effect of externaI-P supply on the phosphorus status of nodules and on the P-uptake system of isolated bacteroids from nodules. After 48 days of growth, whole plant dry mass in the 0.25 and 0.05 mM-P treatments decreased significantly. The Pi concentrations in nodules were 4.1, 2.5 and 2.0 mM for 1.0, 0.25 and 0.05 mM-P treatments, respectively. The external-P supply did not significantly affect the distribution of phosphorus among inorganic phosphate(Pi), soluble organic-phosphorus(SOP) and insoluble organic-phosphorus(TOP) fractions in nodules. The Pi concentrations in young leaves of 0.25 and 0.05 mM-P plants were 33% and 20% , respectively, of those in young leaves of 1.0 mM-P plants and Pi concentrations in old leaves were only 16% and 7%, respectively, of those in old leaves of 1.0 mM-P plants. Phosphorus deficiency decreased the percentage of total leaf phosphorus in the Pi fraction and increased the percentage of total leaf phosphorus in the IOP fraction. The bacteroid number ranged from 0.87 to $1.30{\times}10^{11}$ Per GFW nodule regardless of external-P supply to the host Plants and Plant age, The P-uptake rates were the same (15-16 pmoles /min./$10^8$ bacteroids) for the bacteroids isolated from nodules of 1.0 mM-P and 0.05 mM-P plants. These results indicate that Pi concentrations in nodules of phosphorus-deficient plants are sufficient for proliferation of bacteroids and that the P-uptake system of bacteroids is in a repressed state even when host plant growth is severely restricted by phosphorus-deficiency stress.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.6
• /
• pp.1159-1163
• /
• 2005

The production of hydrogen by Chlamydomonas reinhardtii UTEX 90, a marine green alga, was performed under dark fermentation. The effects of initial nitrogen and phosphorus concentration on the cell growth and the production of hydrogen and organic substances were investigated. In the growth stage, the maximum dry cell weight (DCW) was 3 g/l when the initial ammonium concentration was 15 mM. In the dark fermentation, the maximum hydrogen production was $3.5\;{\mu}mol/\;mg$ DCW when the initial nitrogen concentration was 7.5 mM. The nitrogen concentration had a greater effect on organic compound and hydrogen production than the phosphorus concentration during the dark fermentation. An investigation of the duration of dark fermentation showed that, at least until three days, dark fermentation should be prolonged for maximum hydrogen production.

• Journal of environmental and Sanitary engineering
• /
• v.17 no.4
• /
• pp.10-18
• /
• 2002

The changes of conventional clarification processe and an increase in treatment cost are required to meet increasingly stringent regulations related to the treated water quality. Although many enhanced coagulations have introduced to improve organic matter removal, the results to remove color, nitrogen and phosphorus as well as organic material have not been very efficient yet. In this context as new flocculation using calcium hydroxide and magnesum sulfate was carried out. The removal of waste matters such as SS, organic matter, COD, nitrogen and phosphorus contained in stock wastewater was carried out by using the combination of calcium hydroxide and magnesium sulfate. The flocculation was investigated as a function of coagulant dose, pH, mixing time, settling time and coagulant addition modes such as the sequential addition of the two coagulants and the simultaneous addition of them. The flocculation by the combination of calcium hydroxide and magnesium sulfate was compared with that by aluminum sulfate. The mechanism of flocculation was investigated as well. About 60% of COD in stock watewater was removed by flocculation with combination of calcium hydroxide and magnesium sulfate.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.4
• /
• pp.861-866
• /
• 2007

This study was conducted to investigate an aeration tank with RBC process attached Bacillus sp. known as a suitable microorganism for the removing of organic carbon, nitrogen and phosphorus. An aeration tank was based on tapered aeration because Bacillus sp. was well grown in this like environment conditions. The biofilm process with Bacillus sp. as an advanced treatment process could be a best technology for the prominent removal of organic carbon, nitrogen and phosphorus if the mechanism in the process is verified. The operation conditions of DO in the tapered aeration tank were maintained as $1.2{\sim}1.5mg/L$ in aeration tank1, as $0.3{\sim}0.5mg/L$ in aeration tank 2 and less than 0.2 mg/L in aeration tank 3, respectively. Lab-scale experiments were conducted, at room temperature, internal recycle rate was from 200% to 50% and returned sludge rate was from 100% to 50%. As a result, concentration of organic carbons, nitrogen and phosphorus in Period 1 (the time of Bacillus sp. adapted to environment) were decreased gradually. Ultimately, each removal rate in this biological experiment were TCODCr 94%, BOD 87%, T-N 85%, T-P 89% in Period 2. Hence, this process showed an excellent performance of the removal of organic carbon, nitrogen and phosphorus and this is an effective system fur treating of wastewater.

• Environmental Engineering Research
• /
• v.10 no.5
• /
• pp.257-263
• /
• 2005

A batch and a continuous type experiments were conducted to test the conditions for simultaneous phosphorus release and uptake, and denitrification, taking place in one process. The bacteria able to denitrify as well as to remove phosphorus were evaluated for the application to biological nutrient removal(BNR) process. In the batch-type experiment, simultaneous reactions of phosphorus release and uptake, and also denitrification were observed under anoxic condition with high organic and nitrate loading. However the rate and the degree of P release were lower than that occurred under anaerobic condition. BNR processes composed of anaerobic-anoxic-oxic(AXO), anoxic-anaerobic-oxic(XAO) and anoxic-oxic(XO) were operated in continuous condition. The anoxic reactors in each process received nitrate loading. In the AXO process, P release in anaerobic reactor and the luxury uptake in oxic reactor proceeded actively regardless to nitrate loading. However in XAO and XO processes, P release and luxury uptake occurred only with the nitrate loading less than $0.07\;kg{NO_3}^--N$/kgMLSS-d. With higher nitrate load, P release increased and the luxury uptake decreased. Therefore, it appeared that the application of denitrifying phosphorus-removing bacteria (DPB) to BNR process must first resolve the problem with decrease of luxury uptake of phosphorus in oxic reactor.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.30 no.1
• /
• pp.33-39
• /
• 2022

Batch experiments were conducted to find out the effects of various types of magnesium compounds on phosphorus recovery by magnesium ammonium phosphate (MAP) crystallization. The phosphorus recovery from the centrate of anaerobic digested sludge was performed using magnesium chloride, magnesium hydroxide and magnesium oxide under different pH (7.5, 8.0 and 8.5) and Mg/P molar ratio (1.0, 1.5, 2.0, 2.5) conditions. The phosphorus recovery rate increased with increasing pH and Mg/P molar ratio in all magnesium compounds. At pH 7.5, magnesium oxide showed the highest phosphorus recovery rate, followed by magnesium hydroxide and magnesium chloride. However, at pH 8.5, more than 90% of phosphorus recovery rate was obtained in all Mg/p molar ratios. Thus, it is expected that magnesium hydroxide and magnesium oxide are able to replace magnesium chloride as a magnesium source in terms of phosphorus recovery efficiency and cost.