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An electrocoagulation-flotation bioreactor is used to research the removal effect on COD, NH3-N, SS et.al. by the laborarory simulation and theoretical analysis. Through the orthogonal test, the best technological condition on the treatment of leachate by electrocoagulation-flotation is confirmed. Comparing and analyzing the technical condition and the treatment result which use electrocoagulation-flotation technology as full-treatment and pre-treatment for the leachate; then, the basis is provided to evaluate the role of electrocoagulation-flotation technology in high concentration of organic wastewater treatment.The technical condition of leachate treatment by using one-step electrocoagulation-flotation technology and the composite electrocoagulation-flotation-SBR technology are discussed. The result is indicated below.①When the one-step electrocoagulation-flotation technology is used to treat leachate, if only consider the typical indicators of COD, the best removal condition is that the velocity of water rising at 10 L/h, influence of COD concentration being 10000 mg/L, electric current being 7.5A. The COD of leachate can be reduced to 953mg/L in this condition.②Consider the indicators of COD, NH3-N, SS, the best technical condition of removal is that the velocity of water rising at 10 L/h, influence of COD concentration being 8000 mg/L, electric current being 7.5A. Under this condition, the COD, NH3-N, SS of leachate can be reduced to 986mg/L, 197 mg/L, 398 mg/L, and the removal rate reached 87.68%, 85.93%, 80.98%.③Through the single factor experiment, the effect on pre-treating the leachate by electrocoagulation-flotation is researched. The result shows that when using one-step electrocoagulation-flotation technology to pre-treat leachate, the suitable condition is the Velocity of water going up to 12 L/h, PH being 8, electric current being 6.5A. Under this condition, the BOD5/COD of leachate can be increased from 0.093 to 0.25 of which is propitious to biochemical treatment continuously. By using SBR to treat the leachate after treated by the electrocoagulation-flotation, COD can be reduced from 10000mg/L to 703mg/L.④To the removal of COD, for the high concentration leachate with COD 10000mg/L, both one-step electrocoagulation-flotation technology and composite electrocoagulation-flotation-SBR technology are satisfied for the three grade discharge standard（GB16889-1997）, the latter one is a little better. For the low concentration leachate with COD 2000mg/L, one-step electrocoagulation-flotation technology is satisfied for the three grade discharge standard（GB16889-1997）, however, compositeelectrocoagulation-flotation-SBR technology is satisfied for the one grade discharge standard（GB16889-1997）. For the circulating cost, composite electrocoagulation-flotation-SBR technology is lower, especially, the cost of treating high concentration leachate is lower than that of low concentration. Thus, the composite electrocoagulation-flotation-SBR technology can be choosed as the pre-treatment for the high concentration leachate and as full-treatment for the low concentration.
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