treatment of mature landfill leachate by chemical precipitation and fenton advanced oxidation process

background: mature landfill leachate is a complicated mixture which is resistant to biological treatment processes. the treatment of mature landfill leachate by struvite precipitation and fenton oxidation was the main objective of the current research. methods: struvite with the phosphate/ammonia/magnesium molar ratio of 1/1/1.05 was considered during all experiments. five initial phs of 3, 4, 5, 6, and 7, four different h2o2/fe mass ratios of 50, 100, 200, and 400, and reaction times of 20, 40, 80, 120, and 160 minutes were examined for the fenton oxidation process. results: a leachate sample with average chemical oxygen demand (cod), bod5, and nh4 concentrations of 7350, 2220, and 2280 mg l-1, respectively, and a bod5/cod ratio of 0.3 was introduced to the chemical precipitation unit. an nh4 removal efficiency of 87% was obtained at ph 8.5 for struvite precipitation. under optimum conditions of fenton oxidation, including ph 3, an h2o2/fe2+ mass ratio of 200, and a reaction time of 160 min, more than 95% cod and bod5 removal was observed. conclusion: struvite precipitation and fenton oxidation are reliable and efficient alternatives for mature landfill treatment.