Study On Ammonium Wastewater Treatment By The Pyrogenation And Recycle Of Magnesium-ammonium-phosphate

The traditional struvite precipitation need MgC12 and Na2HPO4 and PH regulator such as NaOH that is forbidden the calcium phosphate deposition,It result in the expensive cost of struvite precipitation.So It is important to find a cheap way to deal with the treatment of high concentration of ammonia nitrogen wastewater.In this paper, based on ammonium can elimination from MAP to magnesium phosphates and ammonium incorporation into the magnesium phosphates. It is confirmed that magnesium hydrogen phosphate (MgHPO4) is favorably obtained from the ammonium elimination from MAP at temperatures greater than 353 K, although magnesium phosphate (Mg3(PO4)?2) and magnesium pyrophosphate (Mg2P2O7) have been suggested as possible candidates. Based on the dissolution–precipitation mechanism for the removal of aqueous ammonium with magnesium phosphates, three magnesium phosphates were employed for the removal of aqueous ammonium.(1)MHP precipitation is effective in treatment of high concentration of ammonia nitrogen wastewater. Under the most favorible condition, the removal rate of ammonia nitrogen can comes to 90% above.(2)The present results show that MAP can be employed as an advanced material for the removal/recovery of ammonium,although it is generally accepted that an excess of MAP obtained from the wastewater treatment can be only used as a slow-acting fertilizer.The result show that the removal rate of ammonia nitrogen is still about 90% after 3 cycles.It is unnecessary to add magnesium salt and phosphate salt in this method,and also resolve the treatment of MAP,so it is feasibility and have a good economic benefit.