BOTTOM ASH FROM THE MUNICIPAL SOLID WASTE INCINERATION PLANTS IN HAMBURG

摘要

Nowadays, waste composition is tending to vary and becoming an important factor which determines the further process and end-pipe treatment. Different composition of waste determines different waste management processes, while different processes lead to different consequences to environment, economy and society. The first waste incineration plant in Germany was built in 1894/95 in Hamburg. This so-called "waste incineration works" took up operation in Bullerdeich, Hamburg on 1 January 1896, disposing of the waste of the city's 300,000 inhabitants. Therefore, the foundations had been laid for a new method of waste treatment which proved to be viable not only from health and environmental aspects but also economically. The massive air pollutant emissions and the resulting environmental burden were not an issue at that time. After the age of industrialization, further development of the technology from the view of environmental performance led to the municipal solid waste incinerator (MSWI) of the modern age which is equipped with fully automated plant operation developed firing technology, powerful flue gas cleaning systems and continuous bottom ash removal. This kind of incineration process is commonly used to treat municipal solid waste (MSW) in Germany. There are 4 MSWI plants in Hamburg region. In addition, approx. 800.000 tonnes of MSW were thermally treated in these plants. MSW combustion produces some residues such as bottom ash and top/fly ash which need to be treated and recovered or disposed. The most important residue of MSW incineration in quantitative terms is represented by the bottom ashes, which are about 20-35% in mass of the incinerated waste in Hamburg, according to its content of inerts. In this study, the amount and characterization of the MSW was determined, as well as the precious metal substances of the MSWI bottom ash was analysed. Finally, the recovery potential of valuable metals from MSWI bottom ash was indicated.