| With the development of economy, the land, which can be used for MSW landfill, is less and less in Easten China developed area. So MSW incineration is a better way to smooth the conflict in that area. But it's the newer thing for China to use incineration treatment MSW, there is more hard work to do on using the technology. At the present time, in China there are not matured sorting and collection systems. A large amount of industrial and some hazardous wastes are mixed together with municipal solid wastes, thus the contents of heavy metals in solid wastes are rather high. Hence, it is more difficult to dispoal solid wastes safely by incineration. In some areas people have not understood that incineration is a complicated process, and ignore the hazard of fly ash, incineration residue and garbage pool leachate water in incineration plants. Therefore, it is urgently necessary to study the distribution rule and treatment technology of heavy metals in incineration system.The thesis studies heavy metal distribution detailing by systematic point of view with the operation of incineration based on the case of Shanghai and Beijing. And study the harzardous wastes like fly ash stabilization, then provided a way to treatment the harzard waste. At first, through experiments study, optimal methods of both heavy metals' digesting and leaching areidentified; then by simulation expirents, the contents of heavy metals in leachate in garbage pool are mensurate, thus the distribution percentage in garbage is determined; to follow, considering the operating performance of incinerator and exhaust disposal system, we analysied the contents of heavy metals in residue and fly ash, and find out the distribution rule of heavy metals in incinerator and exhaust disposal system. Finally, aftering determining the distribution of heavy metals in incineration system, we focused on the study on the measures and influencing factors of the stabilization of fly ashand and provided the optimal pollution control technologies of heavy metals after incineration.Through the study, a series of valuable results are gained: 1) standard methods of digesting fly ash and incineration sludge are under-provided so far. we studied the methods. We got the results that it is better that using the HCl/HNO3/HF/HClO4 to digest the fly ash and sludge to detect lots of heavy metal except As and Hg, using the HNO3/H2O2/HCl to digest the fly ash to detect As and Hg, using the HF/AR/H2O2 to digest the residue to detect As and Hg. 2)SPLP experiment is more suiTable to study the heavy metal leaching from fly ash and sludge, and under the condition of landfilling little fly ash with large quantity MSW TCLP experiment is better. 3) a high percentage of heavy metal distribute in garbage pool. As the study results, near 30% of the total of Pb distributes in garbage pool, and for Cr the quantity is close to 10%. The main reason is that through the garbage powder gos into the leachate pool, it will influence the effection of leachate treatment. 4) In incinerator a large quantity of Cr, Zn, Mn, Cu and As distributes in residue, Cd and Pb have the same quantity distrbition percentage in fly ash and residue, almost all Hg distrbutes in fly ash. The higher the temperature in incinerator, the more heavy metal distrbutes in fly ash. 5) The residue's leaching experiments show it can be used for some construction materials for the leaching out heavy metal is according with the GB, but for fly ash Hg, Cd and Zn is higher than GB. So fly ash should be specially stabilized for safe disposal. 7) When using the cement to treat the fly ash, the experiments show, although it has enough mechanical intensity, but in SPLP experiment the intensity will drop down. And some heavy metals will leach out and exceed the GB, but using the chelate material will meet these two demands.In the thesis some creative ideas were provided: It's the first time to study the heavy metal distribution in MSW incineration plant from the garbage inlet to the residue outlet, and it is helpful for heavy me...
|
PDF Full Text Request