Optimizing municipal solid waste combustion through organic and elemental carbon as indicators

The temperature, redox conditions, and residence times of the solid waste on the grate and of the raw gas in the secondary combustion zone determine the mineralization processes of organics in municipal solid waste incinerators. An improved knowledge of the influence of these factors on the incineration process might help to optimize incinerators with regard to mineralization efficiency of organics. This paper presents a method for investigating the influence of process parameters on mineralization of organics to CO2 by using the elemental carbon (EC) and organic carbon (OC) concentrations in the solid residues as indicators. The results obtained by experiments in full-scale incinerators show that the EC concentration in these residues is a good indicator of oxygen supply, whereas the OC/EC ratio is a good indicator of temperature in and above the furnace bed. Very effective burnout of the bottom ash up to 0.95 g of TOC (EC + OC) per kilogram of dry matter (DM) and of the electrostatic precipitator (ESP) ash up to 0.24 g of TOC per kilogram of DM was achieved in a full-scale incinerator.