Recovery of ammonia nitrogen from industrial wastewater treatment as struvite slow releasing fertilizer

摘要

Struvite,magnesium ammonium phosphate hexahydrated(MAP)(Mg NH4 PO4.6H2O)is a white inorganic crystalline mineral that can be used as a slow releasing fertilizer.The present study evaluated the feasibility of using bittern as a by-product of salt manufacture,as a low-cost source of magnesium ions,to recover the ammonia from industrial wastewater.A lab-scale study was performed to investigate the efficiency of(MAP)precipitation using bittern at different pH_s from 7-11 at two different molar ratios of Mg:NH4:PO4(1:1:1)and(1.6:0.6:1)on synthetic struvite in distilled water.The optimum pH,settling time and solid/liquid ratio have been studied.Application of liquid bittern to industrial wastewater treatment for ammonia removal was confirmed by XRD-spectra difractograms of precipitate collected after bittern addition with final pH=9.6 was compared to synthetic standard struvite.