Photo-Electro-Fenton Treatment Of Landfill Leachate Based On 2-Ethylanthraquinone Modified Gas Diffusion Electrode

Landfill leachate that accompany with sanitary landfills is a kind of secondary pollution. The properties of landfill leachate exhibit great complex and heavily pollution that may cause terrible risk to human and environment. 。The existence technologies can’t reconcile the demand of cost and treatment efficiency. The primary aim of this thesis was to provide a high treatment efficiency and economical way to remove biorefractory organics from landfill leachate by photo-electro-Fenton (PEF) process. H2O2 was efficiently and continuously produced by a novel 2-ethylanthraquinone modified gas diffusion electrode (MGDE). The in-situ generated H2O2 then reacted with the ferrous ion that was external added to produce a very powerful oxidant· OH. The problem could be solved well by PEF process.PEF process was effective in degradation of raw landfill leachate. COD removal efficiency could reach to 13.6～63.6% with its initial COD of 10000 mg·L-1. TOC removal efficiency could reach to 2.7～51.9% with its initial TOC of 2534 mg·L-1. After PEF treatment, most of the aromatic compounds were decomposed into aliphatic compound or other low-molecular weight substances. Nevertheless, the color and the suspended solids interferes the UV and the existence of the Fe2+ confined the treatment efficiency by PEF, which could be improved by pretreated by some physical method.The PEF process was employed to treat landfill leachate pretreated by membrane bioreactor. Under certain reaction conditions, the COD and NH3-N removal efficiencies were 98.9% and 97.1%, respectively, after 5 h of PEF treatment. The effluent can meet the discharge criteria (GB 16889-2008).The energy consumption for degraded 1 g COD in landfill leachate only cost 0.049 kW-h/m3.The main existence substance were the dissolved organic matters, which hardly degraded by biological treatment, can be removed efficiency by PEF process. The effective H2O2 rate in photo-Fenton was lack of 39%, which could help further decrease the energy consumption. The synergic effect of UV light and Fe2+ could greatly promote the Fenton reaction with higher oxidation effect.