Study On Treatment Process Of Leachate Based On Pd-catalyzed And Coagulation By Two Reactor

Landfill leachate is one kind of wastewater, very difficult to be treated. It will neverachieve the national emission standards when only biochemical process is used forleachate treatment, and advanced treatment should be added following the biochemicaltreatment process. This paper, based on review of domestic and overseas leachatetreatment processes, chose Pd-catalyzed oxidation and coagulating sedimentation foradvanced treatment of landfill leachate after biochemical treatment processes, which willprovide a new path of leachate treatment.We build static cell catalytic reactor of two electrodes and two vessel to exploreprocess parameters of the Pd-catalyzed oxidation and coagulation sedimentation processstage. Through experimental Study of the Pd-catalyzed oxidation and coagulationsedimentation, that is used to treat biological effluent, we determine optimal reactionconditions of Pd-catalyzed oxidation and coagulation precipitation. The results show:(1)The optimal reaction conditions of Pd-catalyzed oxidation: reaction time t=4h, thedosage of Pd catalysts W1=1.5g/L, the dosage of FeSO4W2=0.5g/L, reaction pH=6～7,electrolysis current I=0.3A. Under the optimal reaction conditions, the removalefficiency of COD is57.72%. The most significant factorsinfluenced COD removalefficiency were ranked as: pH> electrolysis current I> the dosage of Pd catalysts> thedosage of FeSO4. These four factors have a very significant impact on COD removalefficiency. The regression equation among these factors and COD removal efficiency:COD removal efficiency=6.39p H7.25W18.44W242.83I0.62The regression effiction of the equation is remarkable. Substituting the optimalreaction conditions into the regression equation, theoretical COD removal efficiency wascalculated as64.85%, and the experimental results of COD removal efficiency is57.72%,with a certain bias.(2) PAC obtained by coagulating sedimentation experiments is suitable for biologicaltreatment of leachate water. Considering the processing time, the economic costs and otherfactors, we identify the optimal conditions for the PAC coagulation: time of coagulationt=2～3h, pH=6～8and dosage of PAC is0.5～1.0g/L. (3) For small-scale landfill leachate treatment, this paper proposes a "preprocessing+biochemistry (MBR)+Pd-catalyzed+coagulation" process combinations. Pd-catalyzedand the coagulation as depth treatment fully integrate the advantages of the prior art. Thisprocess based on advanced oxidation, ensure the efficiency and enhance the treatmenteffect according to the characteristics of pollutants using air stripping and precipitationmethods. We estimate operating costs of the depth treatment. Its operating cost is18.79yuan/ton, and will be economic viability.