A study on the application of Fenton process followed by coagulation for treatment of landfill leachate

In this study, leachate from Quang Hanh landfill (Quang Ninh) was treated by a combination of Fenton and coagulation processes. The experiment was conducted with various Fenton (i.e., pH, H2O2/Fe(II) ratio and dosage, and reaction time) and coagulation (i.e., dosage, aeration time, and flocculant concentration) conditions to determine the best condition for treatment of the leachate. Regarding Fenton process, under the best condition, the COD removal efficiency of around 80 % with an inlet concentration of 624 +/- 80 mg/L, meeting QCVN 25:2009/BTNMT (Column B2) while 75 % of color, 25 % of ammonia, and 12 % of TSS were removed, creating favorable conditions for the next stage of treatment by coagulation. In terms of coagulation, CaO and polyaluminum chloride (PAC) were sequentially used for treating the leachate after Fenton process. After treatment with CaO (6 g/L, 180 min), PAC (1,500 mg/L), and A101 (2 mg/L), the removal efficiencies achieved 85 %, 99 %, 99-99.5 %, and 88 % for COD, color, ammonia, and TSS, respectively, and the effluent can meet the treatment requirement by the discharge standards.