Electrokinetic Removal of Heavy Metal in the Municipal Solid Waste Incineration Fly ash

Because of the high content of heavy metal in the fly ash from the burning system of the solid waste, the heavy metal can leach into the environment under natural conditions. Some technology must be adopted to improve the environmental pollution. Electrokinetic removal is a new kind of technology and it is paid high attention in many countries. This work shows the laboratory results of electrodialytic removal experiments about the fly ash from municipal solid waste in Chongqing. Two main mechanism of electrokinetic removal of heavy metal front the fly ash can be concluded: 1. heavy metal extracted from the fly ash; 2. the migration and enrichment of the metal ions. The electrolyte solution pH, electric current, electrical conductivity, voltage gradient were discussed to prove the removal effect in this experiment. The pH value changed smoothly in the cathode compartment, while it changed abruptly in the first 6 hours, but it changed smoothly in the rest lime. The electrical current increased in the first 50 hours, then gradually decreased in the rest time. The resistance in the removal process would become bigger while the electric current will decrease. The electrical conductivity in the anode compartment increased while the electrical conductivity decreased in the cathode compartment. The electrical conductivity in anode and cathode electrolyte solution is highly related to the concentration of mobile ions. The metal hydroxide precipitation was the most serious Actor that influenced the removal rate. From the experimental data, it can be seen that the content of Pb, Zn, Cd, As reduced to a certain level after the experiment, but a large proportion of heavy metal was not eliminated Some enhanced measures should be taken during the experiment.