The Removal of High NH3-N Concentration in Wastewater by Chemical Precipitation
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.
Zhong Cao, Lixian Sun, Xueqiang Cao, Yinghe He
W. H. Song et al., "The Removal of High NH3-N Concentration in Wastewater by Chemical Precipitation", Advanced Materials Research, Vols. 233-235, pp. 733-736, 2011