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

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 pHs 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.