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Ammonium Phosphate (ammonium + phosphate)
Selected AbstractsPost-treatment of anaerobically treated medium-age landfill leachateENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 1 2010Ebru Akkaya Abstract This study focused on the removal of COD and NH4+ from medium-age leachate. Experiments were performed in a laboratory-scale upflow anaerobic sludge blanket (UASB), a membrane bioreactor (MBR), and using magnesium ammonium phosphate (MAP) precipitation. MBR and MAP were used for the post-treatment steps for anaerobically treated leachate to increase the removal of organics and ammonium. The UASB reactor removed nearly all biodegradable organics and supplied constant effluent COD for all concentration ranges of influent leachate. Ammonium removal efficiency in the UASB reactor was relatively low and the average value was ,7.9%. Integration of MBR to the effluent of UASB reactor increased the average COD removal efficiency from 51.8 to 65.6% and maximum removal efficiency increased to 74.3%. MAP precipitation was applied as a final step to decrease the ammonium concentration in the effluent of UASB+MBR reactors. The effect of pH and the molar ratio of MAP constituents on the removal of ammonium were evaluated. At optimal conditions (pH: 9.0 and Mg/NH4/PO4: 1/1.2/1.2), 96.6% of ammonium was removed and MAP provided additional COD and turbidity treatment. Consequently, the combined system of MBR and MAP precipitation could be used as an appropriate post treatment option for the anaerobically treated medium-age landfill leachate. © 2009 American Institute of Chemical Engineers Environ Prog, 2010 [source] Remote extinguishing of large fires with powder aerosolsFIRE AND MATERIALS, Issue 5 2006Article first published online: 9 JAN 200, Mikhail Krasnyansky Abstract A new method for distant extinguishing of fire spreading in an extended closed volume such as a mine working, storehouse, subway tunnel, electric cable channels, etc. is proposed. A novel extinguishing agent based on a stable mixture of superfine ammonium phosphate [NH4H2PO4] and modified fumed silica [SiO2,CH3] is supplied to the fire by a powerful ventilator. The properties of the extinguishing agent (average particle size, airborne residence time, distance of transfer by the air stream) have been studied in an experimental chamber (100 m3). A test extinguishing of a large-scale fire has been performed in an experimental tunnel 180 m in length. Extinguishing agent consumption, dynamics of temperature change over the tunnel length and composition of fire gases were recorded in this test. The influence of foam concentration, addition of nitrogen and halons to aerosol, were also studied. Copyright © 2006 John Wiley & Sons, Ltd. [source] Annual changes of the incidence and clinical characteristics of magnesium ammonium phosphate urinary stonesINTERNATIONAL JOURNAL OF UROLOGY, Issue 1 2003TAKAHIDE OGATA Abstract Background: Magnesium ammonium phosphate (MAP) urinary stones account for the majority of staghorn stones and frequently cause a non-functioning kidney. In the present study, we examined the annual changes of the number and clinical characteristics of MAP stones. Methods: The annual incidence of MAP stones was investigated in 2619 patients with urinary stones in whom composition of the stone was analysed at Chiba University Hospital between 1964 and 1999. In addition, the annual number of patients with MAP stones was examined at Funabashi Clinic. In a total of 644 patients with MAP stones, age and sex of the patients, location and size of the MAP stones, urinary cultures and etiological factors were analysed. Results: The number of MAP stones in the lower urinary tract was relatively constant. In contrast, MAP stones in the upper urinary tract had dramatically decreased since 1989, resulting in an increase in the rate of MAP stones in the lower urinary tract. Age distribution of the MAP stone patients ranged from 10 years to >,80 years, with the majority aged 30,60 years. The proportion of larger MAP stones in the upper urinary tract increased. There was no significant difference in prevalence of urine cultures. Among etiological factors for MAP stones, difficulty on urination tended to be common in recent years. Conclusion: The number of MAP stones, especially in upper urinary tract, has been decreasing during the last decade. At present, treatment of urinary tract obstruction seems important for the management of MAP stones in lower urinary tract. [source] Impact of citrate therapy on the circadian rhythm of urinary magnesium ammonium phosphate saturation in normal individualsINTERNATIONAL JOURNAL OF UROLOGY, Issue 8 2000Yoshihide Ogawa Abstract Background: Alkaline citrate has been used widely in the prevention of stone formation. However, the risk of struvite stone during the alkalinizing therapy has not been adequately studied in terms of magnesium ammonium phosphate saturation. Methods: The circadian rhythm of the urinary saturation of magnesium ammonium phosphate was estimated by using the differential Gibbs' free energy values of magnesium ammonium phosphate before and during 5 days of treatment with sodium,potassium citrate (1 g t.i.d., 1 g q.i.d. or 3 g t.i.d.) in five healthy male volunteers. Results: The magnesium ammonium phosphate saturation varied during the day, peaking far below the solubility product between 08.00 and 10.30 h and between 13.00 and 18.00 h. The mean peak levels were increased by each treatment regimen in comparison with the control day. The mean increase on day 1 was significant between 10.30 and 23.00 h with the 3 g t.i.d. regimen, but the mean saturation still remained below the solubility product throughout the day. Conclusions: The urinary magnesium ammonium phosphate saturation appeared hard to exceed the solubility product with a high dose of alkaline citrate. [source] Strategies to optimize phosphate removal from industrial anaerobic effluents by magnesium ammonium phosphate (MAP) productionJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2009Marta Carballa Abstract BACKGROUND: Owing to more stringent phosphate discharge requirements and the increasing prices of fertilizers, beneficial recovery and reuse of phosphate from industrial anaerobic effluents is becoming an important issue. Phosphate recovery by struvite or magnesium ammonium phosphate (MAP) permits its recycling in the fertilizer industry because struvite is a valuable slow release fertilizer. Two different approaches to MAP crystallization depending on initial levels of phosphate in the wastewaters were tested and compared. RESULTS: For low-phosphate-containing anaerobic effluents (<30 mg PO43, -P L,1), a novel approach using ureolytic induced MAP formation with MgO addition appeared to be suitable. The residual phosphate concentrations in the effluent ranged from 5 to 7 mg PO43, -P L,1 and the separated matter contained residual amounts of Mg(OH)2. High-phosphate-containing anaerobic effluents (100 to 120 mg PO43, -P L,1) were treated efficiently using air stripping combined with MgCl2 and NaOH reagents, yielding residual phosphate levels of 8 to 15 mg PO43, -P L,1 and spherical pure MAP crystals of 0.5 to 2 mm. CONCLUSION: Results show that depending on the initial phosphate concentrations in the wastewaters and the ammonium and magnesium levels, the strategy selected for struvite crystallization is a determinative factor in achieving a cost effective technology. Copyright © 2008 Society of Chemical Industry [source] Complex disorder in ,-NH4Fe2(PO4)2: deciphering from a five-dimensional formalismACTA CRYSTALLOGRAPHICA SECTION B, Issue 4 2007Olivier Pérez A new mixed-valent iron ammonium phosphate, ,-NH4Fe2(PO4)2, has been synthesized. The diffuse scattering observed on the diffraction patterns implies complex disorder phenomena and prevents a direct structure resolution. The latter can be solved by generating an artificially ordered orthorhombic structure, using a five-dimensional approach and performing partial integration of the diffuse streaks. In the artificially ordered structure, hexagonal tunnels, delimited by FeO6 octahedra, perpendicular to the directions [011] and [01] can then be seen; they are filled either by [FeP2O10], zigzag ribbons or by NH cations. It is shown that the disordering originates from the shifting of adjacent (100) tunnel slices of the structure with respect to each other along [011], allowing the formation of either new commensurate (superstructure) or incommensurate modulations, or even complete disorder along a. The close relationships with the ordered monoclinic form ,-NH4Fe2(PO4)2 are also explained by this description. [source] Crystallization and preliminary crystallographic analysis of the central domain of Drosophila Dribble, a protein that is essential for ribosome biogenesisACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 5 2010Tat-Cheung Cheng Dribble (DBE) is a Drosophila protein that is essential for ribosome biogenesis. Bioinformatics analysis revealed a folded central domain of DBE which is flanked by structural disorder in the N- and C-terminal regions. The protein fragment spanning amino-acid residues 16,197 (DBE16,197) was produced for structural determination. In this report, the crystallization and preliminary X-ray diffraction data analysis of the DBE16,197 protein domain are described. Crystals of DBE16,197 were grown by the sitting-drop vapour-diffusion method at 289,K using ammonium phosphate as a precipitant. The crystals belonged to space group P212121. Data were collected that extended to beyond 2,Ĺ resolution. [source] | |||||||||||||