Pretreatment of landfill leachate by magnesium ammonium phosphate precipitation process
磷酸铵镁沉淀法预处理垃圾渗滤液

Landfill leachate was pretreated by magnesium ammonium phosphate(MAP) precipitation process.Some factors,such as the type of precipitants,pH,molar ratio and reaction time which affect the removal of ammonia,were discussed.When the concentration of NH3-N in the landfill leachate is 2 677.34 mg/L,the optimum treatment conditions are as follows: MgSO4·7H2O and Na2HPO4·12H2O used as precipitants,pH:9.5,n(Mg)∶ n(P)∶ n(N)∶ 1.3∶ 1.15∶ 1.0,reaction time:20 min.The removal rate of NH3-N is 97.05%,the concentrations of NH3-N and PO3-4-P in the effulent are 75.86 mg/L and 8.35 mg/L,respectively.The most sediment are confirmed as MAP by scanning microscopy(SEM) and energy dispersive X-ray spectroscopy(EDS).