Study on the landfill leachate pretreatment based on coagulation and MAP precipitation

Landfill leachate was pretreated with different coagulants and precipitation reagents in this paper. The experimental results demonstrated that COD_cr was effectively removed from initial 12250mg/L down to final 9730.05mg/L, NH₃-N from 340.85mg/L to 35mg/L, SS from 845 mg/L to 106.55 mg/L when PAC was dosed into the leachate firstly with the optimal leachate pH value for the coagulation about 8, the mixing intensity was controlled at 150r/min, mixing time 20min, coagulation time 45min, then analytical grade chemicals of MgCl₂·6H₂O and Na₂HPO₄ were used and the ratio of Mg₂⁺: NH₄⁺: PO₄^3- was controlled at 1.0: 1.5: 1.5.