scholarly journals Ammonium Recovery from Biocatalytic Calcification Reactor Effluent by Struvite Precipitation

2017 ◽  
Vol 19 (2) ◽  
pp. 251-256 ◽  
Keyword(s):  
Ph Value ◽  
Ammonium Phosphate ◽  
Chemical Precipitation ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Magnesium Ammonium Phosphate ◽  
Magnesium Ammonium ◽  
S Period ◽  
Slow Mixing ◽  
Biological Methods

Chemical precipitation is a suitable method for the recovery and removal of ammonium in water and a fertilizer known as MAP (magnesium ammonium phosphate; MgNH4PO4.6H2O; struvite) is obtained. Additionally, the advantage of this method is that environmental conditions do not have any effect compared to biological methods. In this study, the recovery of ammonium (Cmean=348 mg NH4 +/L ± 38.1; n=25) occurred after the hydrolysis of urea in the biocatalytic calcification reactor (BCR) effluent and it precipitated as struvite. The effects of operating parameters, such as different phosphate and magnesium sources, Mg2+:NH4+:PO43- molar ratio, pH value, mixing speed-time, and fertilizer effect, were examined. The precipitates were characterized by X-ray diffraction and scanning electron micrograph. The optimum molar ratio of Mg2+:NH4+:PO43− was determined as 1.25:1:1. Studies using different pH ranges (7–10) and this molar ratio showed that the ammonium recovery of approximately 96% was reached at a pH value of 9.36. It was seen that the rapid mixing (200 rpm) of 30-s period and the slow mixing (30 rpm) of 2-min period were sufficient for MAP precipitation. Struvite that was obtained after precipitation was used as a fertilizer and it was observed to have a positive effect on plant growth.

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.

The Removal of High NH3-N Concentration in Wastewater by Chemical Precipitation

2011 ◽  
Vol 233-235 ◽  
pp. 733-736
Author(s):  
Wei Hua Song ◽  
Jun Yin ◽  
Jian Hui Wang
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Ammonium Phosphate ◽  
Chemical Precipitation ◽  
Ammonia Nitrogen ◽  
Precipitation Method ◽  
Magnesium Ammonium Phosphate ◽  
Ph Values ◽  
N Concentration ◽  
Magnesium Ammonium

A lab-scale study was conducted to precipitate the ammonia from high NH3-N concentration wastewater in the form of magnesium ammonium phosphate(MAP) by applying such chemicals such as MgCl2·6H2O and KH2PO4.The influences of pH value, reactive time and removal rate of ammonia nitrogen were tested.The results shows that the feasible pH values of crystallization and precipitation were between 8 and 10. The structure of struvite crystallization was destroyed under high pH value condition that resulted in ammonia nitrogen dissociating from MAP, which reduced the removal rate of ammonia nitrogen. Results also demonstrated that ammonia nitrogen was effectively reduced from initia1981mg/L to final 5 mg/L, which removal efficiency reached 99% with crystallization and precipitation method when the optimal pH, precipitation time mole ratio of Mg2+, NH4+, PO43- were 8.0, 20 min and 1.4∶1∶1.4 respectively.

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.

Assessment of magnesium ammonium phosphate precipitation for the treatment of leather tanning industry wastewaters

2002 ◽  
Vol 46 (4-5) ◽  
pp. 231-239 ◽  
Author(s):  
I. Kabdaşli ◽  
O. Tünay ◽  
M.Ş. Çetin ◽  
T. Ölmez
Keyword(s):  
Biological Treatment ◽  
Ammonium Phosphate ◽  
Chemical Precipitation ◽  
Optimum Conditions ◽  
Magnesium Ammonium Phosphate ◽  
Ammonium Removal ◽  
Leather Tanning ◽  
Magnesium Ammonium ◽  
Recent Method ◽  
Study Application

Magnesium ammonium phosphate (MAP) precipitation has a potential for ammonium removal from industrial wastewaters. Application basis of this recent method of treatment has not been fully determined. In this study application of MAP precipitation to leather tanning wastewaters has been experimentally evaluated. Five alternative places of MAP precipitation in leather tanning wastewater treatment scheme tested were; instead of plain settling, after plain settling, after polyelectrolyte added plain settling, within the chemical precipitation and after biological treatment. Among these alternatives MAP application instead of plain settling and within the chemical precipitation were found to be most favourable and efficient by reducing the nitrogen load to the level of nutrient requirement in the biological stage. pH 9.0-9.5 and stoichiometric magnesium and phosphate doses were determined to be optimum conditions for MAP precipitation.

Ammonium removal from wastewater via struvite pyrolysate recycling with Mg(OH)2 addition

2013 ◽  
Vol 68 (12) ◽  
pp. 2661-2667 ◽  
Author(s):  
Rongtai Yu ◽  
Subin Cheng ◽  
Hongqiang Ren ◽  
Yanru Wang ◽  
Lili Ding ◽  
...  
Keyword(s):  
Heating Temperature ◽  
Ammonium Phosphate ◽  
Heating Time ◽  
Phosphate Concentration ◽  
Molar Ratio ◽  
Optimum Conditions ◽  
Magnesium Ammonium Phosphate ◽  
Ammonium Removal ◽  
Ammonia Release ◽  
Magnesium Ammonium

Magnesium ammonium phosphate (MAP) pyrolysate recycling technology was investigated with Mg(OH)2-mediated pyrolysis. The results revealed that the removal ratio of ammonium was stable at about 75%, and could be increased to 79% after additional acidolysis. The phosphate concentration in the supernate was low at 2 mg/L. The optimum conditions for ammonia release were a 1:1 molar ratio of Mg(OH)2:NH4+, a heating temperature of 110 °C and a heating time of 3 h. With continual additions of Mg(OH)2 to release ammonia, magnesium phosphate (Mg3(PO4)2) was suggested as a possible derivative. However, with Mg(OH)2-mediated pyrolysis, the growth and nucleation of MAP was inhibited during MAP pyrolysate recycling.

Characterization of Nano-Biphasic Calcium Phosphates Synthesized under Microwave Curing

2008 ◽  
Vol 3 ◽  
pp. 67-87 ◽  
Author(s):  
Wafa I. Abdel-Fattah ◽  
Fikry M. Reicha ◽  
Tarek A. Elkhooly
Keyword(s):  
Ph Value ◽  
Calcium Phosphates ◽  
Chemical Precipitation ◽  
Calcium Deficiency ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Curing ◽  
Tcp Phase ◽  
Diffraction Patterns

Two biphasic BCP ceramic samples were synthesized by chemical precipitation and microwave curing of calcium deficient hydroxyapatite CDHA under the same pH value and temperature but varied in their initial Ca/P molar ratio. Precipitates were characterization after thermogravimetric analysis, fourier transform infrared spectroscopy, X-ray diffraction, atomic absorption spectroscopy and TEM. Hydroxyapatite (HA) contents were measured for the two biphasic calcium phosphate (BCP) ceramics by sintering the calcium-deficient apatites (CDHA). The results reveal two condensation mechanisms of HPO42- affecting the Ca/P molar ratio after calcination. The X-ray diffraction patterns of BCP powders show the in situ formation of -TCP in the BCP powder. The amount of -TCP phase increases as the initial Ca/P molar ratio decreases due to more calcium deficiency in CDHA structure. The influence of HPO42- incorporation on increasing -TCP phase content after calcination is evaluated. TEM micrographs proved the effect of microwave curing during the preparation process on reducing of particle size to nanoscale range and the destruction of CDHA to finer HA and -TCP particles upon calcination.

scholarly journals Analysis Of Temperature Effect on Struvite Scales Controlling in A Vertical Reactor

2021 ◽  
Vol 328 ◽  
pp. 01016
Author(s):  
Sutiyono Sutiyono ◽  
Luluk Edahwati ◽  
Atika Nandini ◽  
W D Lestari ◽  
Wiliandi Saputro ◽  
...  
Keyword(s):  
Temperature Effect ◽  
Crystallization Process ◽  
Ph Value ◽  
Ammonium Phosphate ◽  
Industrial Applications ◽  
Maintenance Cost ◽  
Heating Process ◽  
Magnesium Ammonium Phosphate ◽  
Air Inlet ◽  
Magnesium Ammonium

Scale is forming and controlling in industrial applications causes the clogs or decreasing in volume flows in the pipes, so increasing maintenance cost can occur as a consequence. Struvite discovered as Magnesium Ammonium Phosphate Hexahydrate (MgNH4PO4.6H2O) and referred as a scale due to the heating process of fluid through pipes. The aim of this research was investigated the temperature effect on process of scales forming and controlling. The process was used a vertical bulkhead reactor. The process starts from mixing the equimolar solutions of MgCl2, NH4OH, H3PO4 with 1: 1: 1 of ratio concentration. Then, crystallization process was carried out with the condition at the variation of temperature (20-40°C), variation of pH value (pH 8-10) and variation of air inlet rate (0.25; 0.50; 0.75; 1.0; 1.25 L/min) while the feed rate was 25 ml/min. The process continues until the condition becomes steady state. The scale controlling process was determined by the presence of struvite deposits. The deposits were analyzed by using the XRF method to determine composition content. The optimal conditions were obtained at a temperature of 30°C, pH 9, and air rate of 1.25L/min.

Pretreatment of High Strength Ammonia Removal from Rare-Earth Wastewater by Magnesium Ammonium Phosphate (MAP) Precipitation

2012 ◽  
Vol 496 ◽  
pp. 42-45 ◽  
Author(s):  
Hao Wang ◽  
Guan Wen Cheng ◽  
Xiao Wei Song ◽  
Zai Han Xu ◽  
Jin Jie Meng ◽  
...  
Keyword(s):  
Rare Earth ◽  
Reaction Time ◽  
Removal Rate ◽  
Ammonium Phosphate ◽  
High Strength ◽  
Ammonia Nitrogen ◽  
Ammonia Removal ◽  
Molar Ratio ◽  
Magnesium Ammonium Phosphate ◽  
Magnesium Ammonium

Ammonia is one of the most important contaminants affecting the quality of water environment. Magnesium ammonium phosphate (MgNH4PO4·6H2O), which is a slow releasing fertilizer, is one possible way to remove high strength ammonia from the wastewater. The wastewater is collected from the effluent of extraction of rare earth elements factory, the study investigate the influence of pH, magnesium and phosphate dosing molar ratio and reaction time for ammonia removal rate. The results show that: when the pH = 9.2, n (Mg): n (N): n (P) = 2.2:1:2, reaction time t = 20min, ammonia concentration of the wastewater from 4420mg / L down to 1440mg / L , ammonia nitrogen removal rate can reach 67%, the remaining TP = 0.9mg / L; higher Ca2 + concentration will affect the MAP precipitation for removing ammonia, but it help to reduce total phosphorus concentrations of effluent; it is not the longer reaction time the better removal rate, because the MAP-formation will destroy with longer reaction time.

Struvite precipitation potential for nutrient recovery from anaerobically treated wastes

2001 ◽  
Vol 43 (11) ◽  
pp. 259-266 ◽  
Author(s):  
A. Miles ◽  
T. G. Ellis
Keyword(s):  
Batch Reactor ◽  
Ammonium Phosphate ◽  
Ammonia Concentration ◽  
Pilot Scale ◽  
Ammonia Removal ◽  
Molar Ratio ◽  
Magnesium Ammonium Phosphate ◽  
Wide Range ◽  
Magnesium Ammonium ◽  
Struvite Precipitation

Geochemical equilibrium speciation modeling was used to determine optimum conditions for precipitation of magnesium ammonium phosphate, or struvite, for the recovery of nutrients from anaerobically digested wastes. Despite a wide range of pH values with the potential to precipitate struvite, the optimum pH was determined to be 9.0. Bench experiments conducted on effluent from an anaerobic sequencing batch reactor (ASBR) treating swine wastes achieved a maximum of 88% ammonia removal at a pH of 9.5 with added magnesium and phosphate to achieve an ammonium: magnesium: phosphate molar ratio of 1:1.25:1. Struvite precipitation was performed on a continuous basis in a pilot-scale ASBR treating swine wastes. Through the addition of supplemental magnesium and phosphate, the ammonia concentration was reduced from 1500 mg/L as nitrogen to less than 10 mg/L. The supematant from the struvite precipitation clarifier was recycled to the feed of the ASBR without adverse impact, simulating on-farm effluent reuse as flush water.

Pilot Study on Removal and Recovery of Nitrogen and Phosphorus in Human Urine by Crystallization of Magnesium Ammonium Phosphate

2010 ◽  
Vol 113-116 ◽  
pp. 2310-2313
Author(s):  
Qiang Liu ◽  
Yu Lan Tang ◽  
Jing Xiang Fu ◽  
Yu Hua Zhao ◽  
Zhi Wang
Keyword(s):  
Reaction Time ◽  
Human Urine ◽  
Ammonium Phosphate ◽  
Molar Ratio ◽  
Nitrogen And Phosphorus ◽  
Experimental Conditions ◽  
Magnesium Ammonium Phosphate ◽  
Magnesium Ammonium ◽  
Initial Ph ◽  
Removal And Recovery

Laboratory-scale tests for removal and recovery of nitrogen and phosphorus in human urine were conducted by magnesium ammonium phosphate precipitation (MAP) method. Proper Na2HPO4•12H2O as a phosphorus source and MgCl2•6H2O as a magnesium source were added to adjust the ratio of Mg2+, NH4+and PO43-. The effects of initial pH, (Mg2+): n (NH4+), n (PO43-) : n (NH4+), temperature, reaction time and stirring speed on removal and recovery of nitrogen and phosphorus in urine were studied by MAP method. Results showed that the optimum experimental conditions were at room temperature, pH, the molar ratio of Mg2+：PO43-：NH4+, reaction time and stirring speed were set 10, 1.2:1:0.9, 30min and 100r/min.

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