Treatment of a sanitary landfill leachate using combined solar photo-Fenton and biological immobilized biomass reactor at a pilot scale

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• 作者：Ví ; tor J.P. Vilar^a ; ^{vilar@fe.up.pt} ; Elisangela M.R. Rocha^b ; Francisco S. Mota^b ; Amé ; lia Fonseca^c ; Isabel Saraiva^c ; Rui A.R. Boaventura^a
• 关键词：Sanitary landfill Leachate ; Solar-driven photo-Fenton ; Anoxic and aerobic biological treatment ; Pilot plant
• 刊名：Water Research
• 出版年：2011
• 出版时间：April 2011
• 年：2011
• 卷：45
• 期：8
• 页码：2647-2658
• 全文大小：613 K

文摘

A solar photo-Fenton process combined with a biological nitrification and denitrification system is proposed for the decontamination of a landfill leachate in a pilot plant using photocatalytic (4.16 m² of Compound Parabolic Collectors – CPCs) and biological systems (immobilized biomass reactor). The optimum iron concentration for the photo-Fenton reaction of the leachate is 60 mg Fe²⁺ L⁻¹. The organic carbon degradation follows a first-order reaction kinetics (k = 0.020 L kJ_UV⁻¹, r₀ = 12.5 mg kJ_UV⁻¹) with a H₂O₂ consumption rate of 3.0 mmol H₂O₂ kJ_UV⁻¹. Complete removal of ammonium, nitrates and nitrites of the photo-pre-treated leachate was achieved by biological denitrification and nitrification, after previous neutralization/sedimentation of iron sludge (40 mL of iron sludge per liter of photo-treated leachate after 3 h of sedimentation). The optimum C/N ratio obtained for the denitrification reaction was 2.8 mg CH₃OH per mg N–NO₃⁻, consuming 7.9 g/8.2 mL of commercial methanol per liter of leachate. The maximum nitrification rate obtained was 68 mg N–NH₄⁺ per day, consuming 33 mmol (1.3 g) of NaOH per liter during nitrification and 27.5 mmol of H₂SO₄ per liter during denitrification. The optimal phototreatment energy estimated to reach a biodegradable effluent, considering Zahn–Wellens, respirometry and biological oxidation tests, at pilot plant scale, is 29.2 kJ_UV L⁻¹ (3.3 h of photo-Fenton at a constant solar UV power of 30 W m⁻²), consuming 90 mM of H₂O₂ when used in excess, which means almost 57 % mineralization of the leachate, 57 % reduction of polyphenols concentration and 86 % reduction of aromatic content.