Laboratory Study on Leachate Treatment by Electrocoagulation Using Fly Ash and Bottom Ash as Supporting Electrolytes

摘要

In this study, the treatment of stabilized landfill leachate by electrocoagulation (EC) batch experiments was carried out. Commercially pure aluminum electrodes were used for conducting EC. A 67% chemical oxygen demand (COD) removal was observed when electrocoagulation was performed on landfill leachate for an electrolysis time of 30 min with a current density of 666.66 A/m~2. EC was compared with the classical chemical coagulation (CC) process via COD removal. The comparison results with 333.33 A/m~2 current densities indicated that the EC process has higher treatment performance than CC process with an alum dosage of 1.4 g/200 mL. Experiments were carried out to improve the COD removal and heavy metal removal by adding fly ash F, fly ash C, and bottom ash as supporting electrolyte. Fly ash F showed a higher COD and heavy metal removal efficiencies of 74.3 and 91.6% respectively, when compared with bottom ash and fly ash C. The results of the study reveal that electrocoagulation can be used for treatment of stabilized landfill leachate, and fly ash F, fly ash C, and bottom ash slurry can be used as a supporting electrolyte during electrocoagulation. The addition of fly ash and bottom ashes to EC increased more than 10% of the system efficiency and indicates that these waste products can be used as supporting electrolytes in EC process.