Crystallization phenomena of magnesium ammonium phosphate (MAP) in a fluidized-bed-type crystallizer

2002 ◽  
Vol 237-239 ◽  
pp. 2183-2187 ◽  
Author(s):  
Izumi Hirasawa ◽  
Shogo Kaneko ◽  
Yuuji Kanai ◽  
Shingo Hosoya ◽  
Kumiko Okuyama ◽  
...  
2008 ◽  
Vol 58 (6) ◽  
pp. 1321-1327 ◽  
Author(s):  
M. S. Rahaman ◽  
D. S. Mavinic ◽  
N. Ellis

This paper is an attempt to model the UBC (University of British Columbia) MAP (Magnesium Ammonium Phosphate) fluidized bed crystallizer. A mathematical model is developed based on the assumption of perfect size classification of struvitre crystals in the reactor and considering the movement of liquid phase as a plug flow pattern. The model predicts variation of species concentration of struvite along the crystal bed height. The species concentrations at two extreme ends (inlet and outlet) are then used to evaluate the reactor performance. The model predictions provide a reasonable good fit with the experimental results for both PO4—P and NH4—N removals. Another important aspect of this model is its capability of predicting the crystals size and the bed voidage at different height of the reactor. Those predictions also match fairly well with the experimental observations. Therefore, this model can be used as a tool for performance evaluation of the reactor and can also be extended to optimize the struvite crystallization process in the UBC MAP reactor.


2013 ◽  
Vol 2013 ◽  
pp. 1-3 ◽  
Author(s):  
Selcuk Sarikaya ◽  
Berkan Resorlu ◽  
Ekrem Ozyuvali ◽  
Omer Faruk Bozkurt ◽  
Ural Oguz ◽  
...  

A 28-year old man presented with left flank pain and dysuria. Plain abdominal film and computed tomography showed a left giant ureteral stone measuring 11.5 cm causing ureteral obstruction and other stones 2.5 cm in size in the lower pole of ipsilateral kidney and 7 mm in size in distal part of right ureter. A left ureterolithotomy was performed and then a double J stent was inserted into the ureter. The patient was discharged from the hospital 4 days postoperatively with no complications. Stone analysis was consistent with magnesium ammonium phosphate and calcium oxalate. Underlying anatomic or metabolic abnormalities were not detected. One month after surgery, right ureteral stone passed spontaneously, left renal stone moved to distal ureter, and it was removed by ureterolithotomy. Control intravenous urography and cystography demonstrated unobstructed bilateral ureter and the absence of vesicoureteral reflux.


1991 ◽  
Vol 37 (12) ◽  
pp. 978-983 ◽  
Author(s):  
Berlin Nelson ◽  
James Struble ◽  
Gregory McCarthy

A strain of Bacillus pumilus, isolated from the soilborne sclerotia of a fungus, produced crystals of the mineral struvite (magnesium ammonium phosphate hexahydrate) on Difco nutrient agar and a yeast extract agar containing magnesium sulphate and potassium phosphate. Crystals were macroscopically observed after 6–20 days of bacterial growth and reached a maximum size of 3 × 0.5 mm. Crystals were identified by X-ray powder diffractometry. These findings support the hypothesis that bacteria are involved in the biogenic formation of struvite in nature. Key words: struvite, magnesium ammonium phosphate hexahydrate, Bacillus pumilus, biomineral.


2003 ◽  
Vol 10 (1) ◽  
pp. 1-5 ◽  
Author(s):  
TAKAHIDE OGATA ◽  
KOICHIRO AKAKURA ◽  
KEN-ICHI MIZOGUCHI ◽  
KAZUO MIKAMI ◽  
KUNIYOSHI NOZUMI ◽  
...  

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