Evaluation and thermodynamic calculation of ureolytic magnesium ammonium phosphate precipitation from UASB effluent at pilot scale

2012 ◽  
Vol 65 (11) ◽  
pp. 1954-1962 ◽  
Author(s):  
E. Desmidt ◽  
K. Ghyselbrecht ◽  
A. Monballiu ◽  
W. Verstraete ◽  
B. D. Meesschaert
Keyword(s):  
Removal Efficiency ◽  
Pilot Plant ◽  
Saturation Index ◽  
Ammonium Phosphate ◽  
Phosphate Removal ◽  
Operational Cost ◽  
Magnesium Ammonium Phosphate ◽  
Magnesium Ammonium ◽  
Ph Increase ◽  
High Phosphate

The removal of phosphate as magnesium ammonium phosphate (MAP, struvite) has gained a lot of attention. A novel approach using ureolytic MAP crystallization (pH increase by means of bacterial ureases) has been tested on the anaerobic effluent of a potato processing company in a pilot plant and compared with NuReSys® technology (pH increase by means of NaOH). The pilot plant showed a high phosphate removal efficiency of 83 ± 7%, resulting in a final effluent concentration of 13 ± 7 mg · L−1 PO4-P. Calculating the evolution of the saturation index (SI) as a function of the remaining concentrations of Mg2+, PO4-P and NH4+ during precipitation in a batch reactor, resulted in a good estimation of the effluent PO4-P concentration of the pilot plant, operating under continuous mode. X-ray diffraction (XRD) analyses confirmed the presence of struvite in the small single crystals observed during experiments. The operational cost for the ureolytic MAP crystallization treating high phosphate concentrations (e.g. 100 mg · L−1 PO4-P) was calculated as 3.9 € kg−1 Premoved. This work shows that the ureolytic MAP crystallization, in combination with an autotrophic nitrogen removal process, is competitive with the NuReSys® technology in terms of operational cost and removal efficiency but further research is necessary to obtain larger crystals.

Optimization of Crystallization of Magnesium Ammonium Phosphate: Initial Phosphate Concentration, PH and Reactants Molar Ratio

2013 ◽  
Vol 295-298 ◽  
pp. 1289-1292 ◽  
Author(s):  
Kai Huang ◽  
Li Ping Qiu ◽  
Jin Feng Meng ◽  
Dong Wang
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Ammonium Phosphate ◽  
Xrd Analysis ◽  
Phosphate Concentration ◽  
Phosphate Removal ◽  
Molar Ratio ◽  
Septic Tank ◽  
Magnesium Ammonium Phosphate ◽  
Magnesium Ammonium

By- products are widespread in the crystallization of magnesium ammonia phosphate (MAP) as the differences in reactive conditions which effects the forms and habits of crystals. The study focused on the supernatant from septic tank in order to achieve in-situ treatment. Based on the effluent, the optimization research of initial phosphate concentration and pH was investigated by using single factor analysis. The crystal products with different reaction condition were also characteristiced through the XRD analysis. The experimental results showed that the optimum reactants molar ratio of n(NH4+):n(Mg2+):n(PO43-) were 90:25:1, 4:1.6:1 and 3:1.4:1 when pH value was 9.5 with initial phosphate concentration 8mg/L, 50mg/L and 100mg/L, respectively. It was also observed that the phosphate removal rate increased with increasing the initial phosphate concentration or pH value. As the aging time increased, the removal rate was in parabolic curve with 30 minute at the highest point. The XRD analysis revealed that the best MAP crystal could be produced with initial phosphate concentration 50mg/L and pH 9.0.

Recycle use of magnesium ammonium phosphate to remove ammonium nitrogen from rare-earth wastewater

2009 ◽  
Vol 59 (6) ◽  
pp. 1093-1099 ◽  
Author(s):  
H. M. Huang ◽  
X. M. Xiao ◽  
B. Yan
Keyword(s):  
Rare Earth ◽  
Removal Efficiency ◽  
Ph Value ◽  
Ammonium Phosphate ◽  
Treated Wastewater ◽  
Molar Ratio ◽  
Optimum Conditions ◽  
Magnesium Ammonium Phosphate ◽  
N Removal ◽  
Magnesium Ammonium

This paper presents a recycle MAP process (magnesium ammonium phosphate) to remove NH4-N from a typical rare-earth wastewater. The optimum conditions for the MAP precipitation and recycle use of the MAP with a newly-designed process were investigated in laboratory. The results showed that the pH value and dosages of P (phosphate) and Mg reagents have a significant influence on NH4-N removal, with a maximum removal efficiency of 99.4% at the conditions of pH = 9 and Mg:N:P molar ratio =1.2:1:1.2. In the process of recycle use of the MAP, adding some HCl to dissolve MAP decomposition residues could effectively enhance NH4-N removal. The NH4-N removal efficiency reached 99.6% by adding an HCl amount of H+:OH− molar ratio = 0.8 into the reused MAP decomposition residues, whereas the NH4-N removal efficiency without addition of HCl was only 96.4%. Moreover, the residual PO4-P from the end of reaction was recovered and the optimum recovery efficiency was achieved at a Mg:P molar ratio = 6 and pH = 10. Under these optimum conditions, the residual NH4-N and PO4-P concentrations in the treated wastewater, through 6 times of the recycling, were less than 15 mg/L and 1 mg/L, respectively. On the basis of this, an economic evaluation of the recycling MAP was made, and this recycle process could save 48.6% cost used in the chemicals for treating per cubic meter of the rare-earth wastewater, compared to the conventional MAP process.

scholarly journals A Giant Ureteral Stone without Underlying Anatomic or Metabolic Abnormalities: A Case Report

2013 ◽  
Vol 2013 ◽  
pp. 1-3 ◽  
Author(s):  
Selcuk Sarikaya ◽  
Berkan Resorlu ◽  
Ekrem Ozyuvali ◽  
Omer Faruk Bozkurt ◽  
Ural Oguz ◽  
...  
Keyword(s):  
Ureteral Stone ◽  
Ammonium Phosphate ◽  
Intravenous Urography ◽  
Metabolic Abnormalities ◽  
Magnesium Ammonium Phosphate ◽  
Distal Ureter ◽  
Double J Stent ◽  
Magnesium Ammonium ◽  
Left Flank Pain ◽  
Plain Abdominal Film

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.

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