Recovery of nitrogen from saponification wastewater by struvite precipitation.

In general, saponification wastewater produced from the separation process of rare-earth elements contains high ammonium concentration. In this study, a series of experiments were conducted to investigate the parameters to enhance the struvite precipitation potential for ammonium removal from the wastewater having an ammonium concentration of 4,100 mg/L. Experimental results showed that increasing the dose and grain size of pre-formed struvite, which was added as the seeding material in struvite reaction, could increase ammonium removal. The removal efficiency increased 7.6% when the dose of pre-formed struvite with crystal grain size range of 0.098-0.150 mm increased from 0 g/L to 60 g/L. Additionally, struvite precipitation was tested with the intermittent addition of magnesium and phosphate to utilize the struvite crystals formed during the reaction process as the seeding material for the subsequent reaction. The results revealed that intermittently adding magnesium 7 times effectively enhanced ammonium removal by around 8%, which was equivalent to that of using pre-formed struvite as the seeding material. Furthermore, the chemical composition of the struvite recovered with intermittent addition of magnesium was characterized, showing the struvite could be used as fertilizer. An economic evaluation indicated that intermittent addition of magnesium 7 times can save 13.4% cost for recovering per kg NH(4)(+) compared to that of bulk addition.

[1]  R. Ramadori,et al.  Nitrogen recovery from a stabilized municipal landfill leachate. , 2010, Bioresource technology.

[2]  Haiming Huang,et al.  Complex treatment of the ammonium nitrogen wastewater from rare-earth separation plant , 2009 .

[3]  B. Yan,et al.  Recycle use of magnesium ammonium phosphate to remove ammonium nitrogen from rare-earth wastewater. , 2009, Water science and technology : a journal of the International Association on Water Pollution Research.

[4]  G. E. Diwani,et al.  Recovery of ammonia nitrogen from industrial wastewater treatment as struvite slow releasing fertilizer , 2007 .

[5]  M. Kim,et al.  Enhancing struvite precipitation potential for ammonia nitrogen removal in municipal landfill leachate. , 2007, Journal of hazardous materials.

[6]  T. Imai,et al.  Resource recovery from excess sludge by subcritical water combined with magnesium ammonium phosphate process. , 2006, Water science and technology : a journal of the International Association on Water Pollution Research.

[7]  I. Kabdaşlı,et al.  Nitrogen recovery by urea hydrolysis and struvite precipitation from anthropogenic urine. , 2006, Water science and technology : a journal of the International Association on Water Pollution Research.

[8]  T.A. Kurniawan,et al.  Physico-chemical treatments for removal of recalcitrant contaminants from landfill leachate. , 2006, Journal of hazardous materials.

[9]  Nathan O Nelson,et al.  Struvite precipitation in anaerobic swine lagoon liquid: effect of pH and Mg:P ratio and determination of rate constant. , 2003, Bioresource technology.

[10]  Qingjian Zhao,et al.  Recovery of ammonium-nitrogen from landfill leachate as a multi-nutrient fertilizer , 2003 .

[11]  S. Parsons,et al.  Struvite formation, control and recovery. , 2002, Water research.

[12]  M. Cetin,et al.  Assessment of magnesium ammonium phosphate precipitation for the treatment of leather tanning industry wastewaters. , 2002, Water science and technology : a journal of the International Association on Water Pollution Research.

[13]  P Pearce,et al.  Potential phosphorus recovery by struvite formation. , 2002, Water research.

[14]  J. Lester,et al.  Conditions influencing the precipitation of magnesium ammonium phosphate. , 2001, Water research.

[15]  Y. Matsumiya,et al.  Phosphorus Removal from Sidestreams by Crystallisation of Magnesium‐Ammonium‐Phosphate Using Seawater , 2000 .

[16]  Petros G. Koutsoukos,et al.  Spontaneous precipitation of struvite from aqueous solutions , 2000 .

[17]  Olcay Tünay,et al.  Ammonia removal from young landfill leachate by magnesium ammonium phosphate precipitation and air stripping , 2000 .

[18]  T. Young,et al.  Kinetics Effects on Preferential Struvite Accumulation in Wastewater , 1999 .

[19]  Chung-Min Liao,et al.  Nitrogen and phosphorus removal for swine wastewater using intermittent aeration batch reactor followed by ammonium crystallization process , 1995 .